Category Archives: US

Vultee XA-41

USA flag United States of America (1944)
Prototype Ground Attack Aircraft – 1 Built

XA-41 in flight

The Vultee XA-41 was a single-engine aircraft that began life as a dive bomber. Months later, its role was changed to a low-level attack aircraft. The XA-41 performed admirably in flight tests, but the United States Army Air Corps (USAAC) eventually decided that the fighter aircraft then in service were already performing well enough in the attack role. Despite its job being erased, the XA-41 continued development as a testbed, showing off the powerful XR-4360 engine it mounted and how much it could carry. The aircraft itself would have been deadly had it been produced in large numbers, as it boasted four 37mm cannons. As the war went on, the XA-41 was still being tested. Throughout the trials, the aircraft had extremely good performance, even being able to outturn a P-51, but its speed wasn’t quite enough for its role. At one point, it was given to the Navy for testing and eventually it would wind up at Pratt & Whitney (PR). At PR, it served as a testbed through the war and was eventually scrapped in 1950.

History

Cutaway Concept for the XA-41

The XA-41 began as part of a United States Army Air Corps (USAAC) requirement in October 1941 for a new single-seat attack aircraft. The Douglas A-20 Havoc (and soon to be produced North American A-36 Apache) was performing well at the time, but the USAAC wanted something new. The aircraft requested had to be able to reach at least 300mph (482.8kph) at sea level, have a service ceiling of at least 30,000ft (9,144m), and a range of 1,200 miles (1,932km). For the attack role, the aircraft was to have either 37mm, 20mm, or 50. cal guns mounted in the wings. Given this imposing armament, it is likely the aircraft would have attacked soft targets or even been used for tank-busting.

The USAAC commissioned Vultee Aircraft Corporation, Kaiser Fleetwings, and Curtiss to design a new aircraft for the role. Kaiser Fleetwings developed the XA-39, which would have mounted the R-2800-27 engine. Their aircraft didn’t progress beyond the mockup stage. Curtiss reused their naval XTBC-1 prototype for their part, renaming it the XA-40. This also didn’t go beyond the mockup stage. Vultee’s answer was the V-90, a ground attack aircraft mounting the fairly new and powerful R-4360 engine. Interestingly, the XA-41 started off as a dive bomber, despite it being commissioned as an attack aircraft. It isn’t often stated, but the Army had been interested in dive bombers since 1940, going as far as purchasing several Navy designs. The Army bought several SB2D-1 Helldivers in December of 1940 and renamed them the A-25 Shrike. They also had a troubled history with one of Vultee’s own aircraft, the A-35 Vengeance, which they tried numerous times, but to no avail. The XA-41 was most likely a chance for the Army to have a successful dive bomber or attack aircraft. The Army was satisfied with Vultee’s V-90 design and awarded a contract for two prototypes on November 10, 1942. Shortly after a mockup inspection, the Army interestingly switched the role from a dive bomber to a dedicated attack aircraft. The switch was rather abrupt and caused a delay in the development.

XA-41 Prototype

On April 30th, a new contract was signed which included a static mockup. Vultee continued construction on the project until the prototype was halfway completed, at which point the Army decided that the most current aircraft, the Republic P-47 Thunderbolt and North American P-51 Mustang, were already quite capable in the attack role. But this wouldn’t be the end of the XA-41. Maj.Gen Oliver P. Echols, Chief of the Material Division, opted not to cancel the program and instead complete it in order to show the true potential of a new attack aircraft with the new R-4360 engine. This decision went through on November 20th, with the prototype ¾ the way through completion. The 2nd prototype was cut at this point and only one would be built (Serial No. 43-35124/5).

On February 11th, 1944, the XA-41 flew for the first time from Vultee Field, California, with test pilot Frank Davis at the controls, and landed at March Field, California. Several flights after this were conducted at the nearby army base. The aircraft was flown by both Vultee and Army pilots, and both agreed it handled well. There were some problems here and there, which Vultee quickly fixed with some additions to the airframe. On June 25, the Army accepted the XA-41. On July 16th, on its 60th flight, the aircraft was ferried to Eglin Field, Florida. Testing proved the XA-41 was an exceptional aircraft, with many great features. The craft had an excellent turn rate, being able to outturn the P-51. For its size, it carried an impressive arsenal of weapons. But the Army wanted an attack aircraft that could also defend itself if the need would arise, and the 350mph (563.2 km/h) of the XA-41 wasn’t that impressive compared to other aircraft in service. The United States Navy became interested in the XA-41 at some point and the prototype was given to them for testing at Patuxent River, Maryland. The Navy wanted to see if the aircraft could be flown from aircraft carriers. After the Navy briefly tested it, the XA-41 was given to Pratt & Whitney (PR) on August 22, 1944. It was obvious at this point that the XA-41 would never see combat, but would remain in the US as a testbed aircraft. Serving with PR, it was used as a flying testbed for their R-4360 engine, as well as having a supercharger mounted. As testing continued, the aircraft was purchased by PR on October 9 and re-registered as NX6037N. There are few documents that reference the XA-41 post-war. The only thing mentioned is that the sole XA-41 was finally scrapped in 1950, having served for many years at PR.

Design

The XA-41 was a conventional single-engine aircraft. It had a slight gull wing and a tail sitter configuration. The landing gear in the wings would retract inboard and was placed widely to allow better landing performance. During development, the tail wheel had doors installed to completely cover it in-flight. The cockpit was placed far forward and raised to allow the pilot to see over the engine, giving him better visibility when attacking ground targets. The ventral tail had an extension that spanned most of the length of the aircraft. This was added during development. A spinner was also added at some point. The XA-41 mounted the PR XR-4360 Wasp Major engine, which was the main reason the Army and PR were so interested in the project.

For armament, the XA-41 had four M2 Browning .50 cal machine-guns mounted in the wings. For the attack role, it was meant to mount four more 37mm cannons (sources don’t mention what particular kind of gun) in the wings. All armament in the wings was placed outside of the propeller’s range. For bombing, the XA-41 had a bomb bay that could carry four 500Ibs bombs, a torpedo, additional fuel, or two 1,600Ibs weapons. In total, it had up to 6,500Ibs of ordnance. Documents mention that up to 1,100Ibs of additional bombs could be mounted to the wings. The aforementioned competing XA-39 only sported the four Brownings, two 37mms, as well as a predicted carrying capacity of six 500Ibs bombs.

Variants

  • XA-41 – [The sole prototype built, used as a testbed for the XR-4360 engine.]

Operators

  • United States of America – The United States Army Air Corps would have operated it had it entered production. After serving as a testbed for the Army, the Navy and Pratt & Whitney also did tests with the aircraft.

XA-41 Specifications

Wingspan 54 ft / 16.4 m
Length 48 ft 7 in / 14.8 m
Height 14 ft 5 in / 4.4 m
Wing Area 540 ft² / 164.5 m²
Engine 1x 3,000 hp ( 2240 kW ) XR-4360-9
Propeller 1x 4-bladed Hamilton Standard propeller
Weights
Empty 13,400 lb / 6078.1 kg
Gross 18,800 lb / 8527.5 kg
Maximum 23,359 lb / 10595.4 kg
Climb Rate
Rate of Climb at Sea Level 2,326 ft / 708.9m per minute
Maximum Speed 353 mph / 568 kmh at 15,000 ft / 4572 m
Cruising Speed 270 mph / 434.5 kmh
Range 800 mi / 1287.4 km
Maximum Service Ceiling 27,000 ft / 8229.6 m
Crew 1 pilot
Armament
  • 4 Browning M2 machine guns (400rpg)
  • 4 37mm cannons (30rpg)
  • Up to 6,500 Ibs of weapons

Gallery

llustrations by Haryo Panji https://www.deviantart.com/haryopanji

Vultee-XA-41 Original Prototype Colors
Vultee XA-41 with possible service markings (artist interpretation)
XA-41 at Patuxent River
XA-41 on the runway
XA-41 in a slight climb
XA-41 parked on the ramp

Sources

 

Douglas XTB2D-1 Skypirate

usa flag USA (1945)
Prototype Torpedo Bomber – 2 Built

XTB2D-1 on the Runway
First prototype of the Skypirate on the runway.

The Douglas XTB2D-1 “Skypirate” was a large, single-engine torpedo bomber built for use on the Midway class carriers during World War 2. At the time, it was the largest aircraft to be used aboard a carrier, dwarfing even two-engine designs. Unfortunately for the Skypirate, engine troubles, little support from the US Navy (USN), and numerous setbacks with the construction of Midway-class carriers nearly doomed it from the start. By the time it was airworthy, it was trying to fill an obsolete role which other aircraft, such as the TBF/TBM Avenger, already filled adequately. Work continued after the war, with several attempts to revive the program but it proved to be too costly and the Skypirate program was finally cancelled in 1947, with the two prototypes being scrapped in 1948.

History

With engagements such as the Battle of the Coral Sea and the hunt for the Bismarck, the effectiveness of torpedo bombers, such as the TBF/TBM Avenger and Fairey Swordfish, was clear. With the announcement of the large Midway-class carriers, the possibility of a new torpedo-bomber/scout bomber came about. In February 1942, a competition was put forward by the Navy for this role. The Douglas Aircraft Company, based in Southern California, proposed the Skypirate. The single-engine Skypirate was picked from eight different designs, most of which were two-engined. The Bureau of Aeronautics (BuAer) wasn’t expecting a single engine design to be submitted, assuming the specified massive carrying capacity would require a two-engine design. The program was being headed by Ed Heinemann as lead designer and Bob Donovan as the chief engineer, who would be on the project until the end.

XTB2D-1 Frontal View
An impressive look at the massive Skypirate from the front.

In November of 1942, Douglas was given permission to begin production of two prototypes and a mockup of the XTB2D-1 (then called the Devastator II, before being changed to Skypirate). Delays in the development of the Midway class would continue to hamper the Skypirate throughout its life. The finished product was a formidable aircraft, capable of carrying four torpedoes from land or two torpedoes from a carrier, the former being four times the carrying capacity of the TBM Avenger. In March and May of 1943, the mockup was inspected and an order for 23 production aircraft was put in. This was enough for a single squadron to operate from a Midway carrier. Problems began about this time, with the delivery of engines and propellers being delayed. By 1944, the Skypirate was still not airborne and it was obvious it wouldn’t be operational anytime soon. With earlier torpedo bombers performing adequately, a lack of support from the Navy, most of the Japanese fleet in shambles and continued delays with the Midway class (which would eventually sail after the war), the 23 production planes were cancelled. On February 18th, 1945, the first Skypirate was rolled out of the production facility, being completed on March 13th and finally going airborne on May 8th. Neither of the prototypes had any defensive armaments, but they were tested with torpedoes and drop tanks. Although no production was to ever start, the Skypirates would continue flying until the end of the war. During one such flight in June of 1945, a Skypirate was damaged mid-flight, but the craft was brought down safely. Engine problems were a frequent issue with the Skypirate and propeller problems would ground it in August of 1945, not flying again until after the war.

Skypirate Landing
Perhaps the most well known photo of the aircraft, the Skypirate prepares to land.

Postwar, the aircraft industry changed with the introduction of jet aircraft, thus eliminating the need for many prototypes being developed during the war. The Skypirate was no exception. With the torpedo bomber role now fading, the Douglas firm looked at other options to revive their Skypirate. Some ideas included using the Skypirate for an electronic warfare role or even as an anti-submarine aircraft (a role overtaken by another piston engine aircraft, the Grumman AF Guardian), but none of these propositions ever managed to become reality. As the Cold War was just beginning, the Skypirate program ended in 1947 and the 2 prototypes were scrapped in 1948.

Design

The Skypirate is most likely the largest single-engine aircraft to ever be designed for carrier operations. In comparison, the twin-engined B-25 Mitchell medium bomber measured around the same in length and width.

In flight
The 2nd prototype in flight, notice how the tail is shorter in comparison to the first prototype.

The initial Skypirate design had an internal bomb bay, which the prototypes dropped in favor of four external Mark 51 Mod 7 bomb hardpoints. These hardpoints could carry a range of weapons including 500Ib-2000Ib bombs, torpedoes, depth charges, mines or even incendiary bombs. The use of up to 4 Mk.13 Torpedoes (from land) were planned had it entered production. The Skypirate could alternatively carry up to 8,400Ibs of bombs. For offensive armament, the Skypirate had 4 M2 Browning machine guns in the wings. For defense, it had a Firestone model 250CH-3 remote turret behind the cockpit which carried 2 M2 Brownings and a turret in the back of the lower fuselage which carried a single M2 Browning. The lower turret was remotely fired through electronic control and powered hydraulically. Drawings indicate that Mark 2 Gun Containers could be added for extra forward firepower but none were ever attached during testing. 300 gallon drop tanks were also fitted during testing and could have been used had the craft been operational.

The Mockup
The sole mockup made alongside the 2 prototypes.

Along with such an impressive weapons payload, the Skypirate was full of advancements which would have improved its performance. To get such a large aircraft off the ground, the Skypirate was powered by a single Pratt & Whitney XR-4360-8, the largest radial engine ever built up to that time. The engine had a unique exhaust style that combined the exhausts in alternating rows to lower the effects of backpressure. Being a carrier-based aircraft, the Skypirate had folding wings as well as a catapult hook. The inclusion of a tricycle landing gear was also interesting, as it helped with bomb loading and carrier space. Most single engine aircraft of the time preferred using a tailwheel. The Skypirate had large flaps that extended the length of wingspan. The outer flaps served as ailerons while the midsection flaps were used as dive flaps. The dive flaps could also be lowered to help the aircraft cruise or assist in turning to help ease the stress off the aircraft when fully loaded. To assist with bombing or flight in general, a Type 3 Sperry vacuum-controlled, hydraulic autopilot was also to be added. A de-icing system was also added that pumped hot air over the wings and tail section.

The planned modifications of the prototypes are interesting to note. The 2nd prototype (Bu.36934) differed from the first, having a shorter tail of 8.6 ft, compared to the regular 10.5 ft tail of the original design. This was done most likely to conserve valuable space when inside a carrier. Along with these differences, plans to fit a jet engine in the fuselage of the 2nd prototype were made, but nothing ever came to fruition. The first prototype (Bu.36933) had a larger tail and was planned to be converted for the scout bomber role. These plans included adding cameras onboard. As with the jet engine designs, these also never came to be.

Variants

  • XTB2D-1 Bu.36933 – Prototype version, lacked any armament
  • XTB2D-1 Bu.36934 – The 2nd prototype. The tail was shortened to 8.6 ft. Also lacked any armament.
  • TB2D-1 – Proposed production version, 23 were ordered and planned production was to be 100 built every month. These versions were to be fitted with four .50 caliber machine guns in the wings, two in a Firestone power turret and one remotely controlled in the ventral hull. Eventually, the production versions were cancelled in favor of higher priority projects.

Operators

  • United States of America – Slated to be used aboard the Navy’s Midway-class carriers, with the end of the war and other setbacks, the XTB2D-1 was never used operationally.
XTB2D-1 Rollout
The design team poses with the first Skypirate on rollout day.

TB2D-1 Specifications

Wingspan 70 ft / 21.3 m
Length 46 ft / 14 m
Height 22 ft 6 in / 6.9 m
Wing Area 605 ft² / 184.4 m²
Engine 1x 3,000 hp ( 2240 kW ) XR-4360-8
Propeller 1x 8 bladed Hamilton Standard contra-rotating propeller
Fuel Capacity 501 US gal / 1896 L
Oil Capacity 28 US gal / 106 L
Empty Weight 18,405 lbs / 8350 kg
Gross Weight 28,545 lbs / 12950 kg
Maximum Weight 34,760 lbs / 15765 kg
Rate of Climb at Sea Level 1,390 ft / 425 m per minute
Time to 10,000 ft / 3048 m 8.2 minutes (Normal) 10.2 minutes (Military)
Time to 20,000 ft / 6096 m 22.3 minutes (Normal) 26.5 minutes (Military)
Maximum Speed 340 mph / 550 km/h at 15,600 ft / 4755 m
Cruising Speed 168 mph / 270 km/h

312 mph / 500 km/h (with torpedoes)

Range 1,250 mi / 2010 km (Torpedoes)

2,880 mi / 4635 km (Maximum)

Maximum Service Ceiling 24,500 ft / 7470 m
Crew 1 pilot

2 gunners

Armament 4 Browning M2 machine guns mounted in the wings (1600rds)

2 Browning M2 machine guns mounted in turret (1200 rds, incl remote 50.)

1 remote Browning M2 machine guns mounted in ventral hull

4 x Mk 13 Torpedoes (from land)

2 x Mk 13 Torpedoes (from carrier)

2 x 2,100 lbs Bombs

Total of 8,400 lbs payload capacity

2 x Mark 2 Gun Containers

Gallery

llustrations by Haryo Panji https://www.deviantart.com/haryopanji

Douglas XTB2D Skypirate Side View
Douglas TB2D Skypirate Side View – With the Defensive Gun Pod

 

XTB2D End
The last known photos of the Skypirates before being scrapped.
XTB2D Loaded
One of the prototypes with mounted Mk-13 torpedoes.
XTB2D Backside
A back view of one of the prototypes
XTB2D-1 on the Runway
First prototype of the Skypirate on the runway.
XTB2D-1 Frontal View
An impressive look at the massive Skypirate from the front.
Skypirate Landing
Perhaps the most well known photo of the aircraft, the Skypirate prepares to land.
In flight
The 2nd prototype in flight, notice how the tail is shorter in comparison to the first prototype.
The Mockup
The sole mockup made alongside the 2 prototypes.
XTB2D-1 Rollout
The design team poses with the first Skypirate on rollout day.

Sources

 

Plane side view

Consolidated Vultee XP-81

USA flag United States of America (1944)
Prototype Escort Fighter – 2 Built

The first XP-81 powered by the TG-100 engines (Convair)

The Consolidated Vultee XP-81 was a prototype mixed power fighter developed in late 1943 by the Consolidated Vultee Aircraft Corporation in order to meet an Army Air Force requirement calling for a high altitude escort fighter. Plagued by slow development and engine problems, the XP-81 would never see active service and development would be terminated in 1947. Despite this, the XP-81 still holds a distinct place in history as America’s first turboprop engine plane to fly and the world’s first plane to fly with a turboprop engine and a jet engine together.

History

With the formal introduction of the Boeing B-29 Superfortress on May 8th of 1943, it would be clear that a high altitude escort fighter would soon be needed to accompany the Superfortress on its bombing missions over the Pacific. In the summer of 1943, this need was realized and the United States Army Air Force (USAAF) issued a list of design requirements that consists of the following:

  1. 1,250 mile (2,012 km) operating radius
  2. Fuel for 20 minutes of combat plus reserve fuel supply for landing
  3. Cruising speed of 250 mph (402 km/h) at 25,000 ft (7,620 m)
  4. Maximum speed over 500 mph (804 km/h)
  5. Combat ceiling of 37,500 ft (11,430 m)
  6. Climb rate of 2500 fpm (feet per minute) / 762 mpm (meters per minute) while at 27000 ft (8230 m)
  7. Two engines*
  8. 12 ° angle of vision over the nose

* – The USAAF recommended that the designers use a two engine setup consisting of a propeller engine for long range flights while complemented by a jet engine for high speed combat situations.

Promotional illustration of the XP-81 showing a diagram of the XP-81. (Consolidated Vultee)

Interested in this proposal, the Consolidated Vultee Aircraft Corporation, later known as Convair, began work on an aircraft which would meet the specifications, appointing Charles R. Irving, who was a chief engineer of the Vultee Field Division and Frank W. Davis, the assistant engineer, who was also the chief test pilot, as the leaders of the design team. The project was known as the “Model 102” within Consolidated Vultee. In the early stages of development, the designers faced a dilemma of engine selection. The Pratt & Whitney R-2800 Double Wasp radial engine was considered, as was the General Electric TG-100 turboprop engine. After some evaluating and testing however, the TG-100 was selected as it was deemed to have superior performance for combat and cruising situations. As for the jet engine in the rear, a relatively straightforward choice to mount a General Electric J33-GE-5 (also known as I-40) jet engine was made. After a couple of months of development, Consolidated Vultee submitted a preliminary design proposal to the United States Army Air Force in September of 1943. Relatively interested in this design, the plane was given the greenlight for further development and received the designation “XP-81” by the Air Material Command.  

Detailed work on the XP-81 began in January 5th of 1944 and on January 18th, Consolidated Vultee was given the contract (no. W33-038-ac-1887) by the USAAF worth about $4.6 million to construct two flying XP-81 prototypes and one airframe for ground testing under the USAAF project name “MX-480”. Another contract followed on June 20th of 1944 worth $3,744,000 for the two flying examples, the airframe and the testing data. The contract was later modified to include 13 YP-81 under the project name “MX-796”. The construction of the first XP-81 prototype would begin on January 20th at the formerly independent Vultee aircraft factory in Downey, California but problems soon surfaced. Some time in April, the Air Material Command was notified that there would be a delay in the delivery of the TG-100 due to a couple of technical difficulties. As such, construction of the first prototype was delayed as the designers sought out an alternative engine to replace the TG-100 in June.

Consolidated Vultee flight test crew poses with the first XP-81 prototype. (XP-81)

The Packard V-1650-3 (some sources state V-1650-7), which was the American copy of the British Rolls-Royce Merlin engine, was selected to fill in the gap and the USAAF promptly provided Consolidated Vultee with such an engine taken from a North American P-51D Mustang. Within a week of receiving the engine, Consolidated Vultee engineers were able to install it after making considerable structural modifications to the first prototype’s airframe. A radiator similar to that of the Lockheed P-38J’s “beard” radiator would also be mounted on the XP-81, under the propeller spinner. Unfortunately for the designers however, the change of powerplant would add 950 lb (431 kg) to the plane while taking away 960 hp at takeoff and 1720 hp at top speed. With the relatively slow development, the first XP-81 prototype would finally be completed in January of 1945 bearing the serial number of “44-91000”.

Although the aforementioned issues with weight gain and horsepower loss were present, the Packard engine powered XP-81 was still deemed safe for flight tests, and as such, the first XP-81 prototype was prepared for test flights at Muroc Dry Lake in California and finally took to the skies on February 7th of 1945 with Frank W. Davis in the cockpit. Amazingly enough, 46 test flights were made with the Packard engine and it accumulated a total of 47.75 flight hours. In the testing phase it was noted that with the Packard engine installed, the XP-81 had poor directional stability at low speeds and the occasional splatter of oil on the windscreen by the propellers. Plans to replace the Packard engine were brought up on May 18th of 1945 when the TG-100 turboprop was finally available. The conversion was completed and the first prototype was returned back to Muroc for more tests on June 11th. Due to the new engine installation, extensive ground work had to be accomplished before flight tests were to continue. Throughout June 23rd to December 20th of 1945, numerous ground tests were conducted and a few problems surfaced. For one, the TG-100 was difficult to start and once it did, the pilot would have difficulty controlling the propeller. As this was an early turboprop engine,

reliability was low and the turbine wheels had to be replaced constantly, sometimes only after half an hour of use. The 10 inch (25 cm) oil cooler for the TG-100 was also deemed a problem, and it was thus increased to a 12 inch (30 cm) system instead. Perhaps the biggest problem however, was the throttle lag the XP-81 suffered. Frank W. Davis describes the problem by stating “The pilot had about a 10 second lag when he wanted to go and about 2 seconds lag when he wanted to stop, with both thrust and drag being powerful and non-adjustable when they did occur.” (Consolidated Vultee XP-81, by Steve Ginter). The ground personnel concluded in these ground tests that the current Aeroproduct A542 propeller and drive shafts were incompatible with the TG-100, and that new propellers should be developed. An emergency engine feathering system was also recommended.

The first flight of the XP-81 with the TG-100 engine occured on December 21st of 1945. This was the 47th test flight the first XP-81 underwent. Performance was rather satisfactory, and the flight concluded after a mere 5 minutes. Excessive oil consumption was noted however. Test flights with the TG-100 proved disappointing as the turboprop did not perform as it was advertised, delivering less horsepower than was expected. Out of the estimated 2,300 hp the TG-100 was suppose to achieve, only 1,400 hp was achieved. The I-40 engine was no help either, as it developed nearly 250 lb (113 kg) less thrust than advertised as well. The estimated performance of 478 mph (769 kmh) at sea level was not achieved with only a mere 400 mph (643 kmh) achieved. Due to these factors, the performance achieved was similar to that of the Packard engine installation. Despite these problems, the XP-81 still did well in some aspects. The relatively decent handling and decent climb rate was complemented, as was the light controls. The second prototype (serial no. 44-91001) was produced some time before November of 1946, and was ready for flights by February of 1947. It featured a longer ventral fin than that of the XP-81 and had a four blade Hamilton Hydromatic propeller replacing the Aeroproducts propeller used on the first prototype. Unfortunately, it is unknown what date the second prototype made its maiden flight, but it is speculated that it first flew some time in February of 1947.

In total, 116 flights were made by both of the XP-81 prototypes, 22 of which were done by the second XP-81 prototype. More tests were planned, as on January 14th of 1947, Consolidated Vultee called for the following areas to be studied and tested:

  1. Firearms testing of the Browning AN/M2 and the Hispano T31. Bombs and rockets tests will also be included.
  2. Anti-icing equipment efficiency.
  3. Control characteristics and lateral stability.
  4. Cabin pressurization experiments.
  5. Power plant operations.
The first XP-81 prototype taxiing on the Muroc airstip in preparation of a flight on January 22nd of 1946 (SDAM)

However due to the previously mentioned issues of the XP-81 underperforming, the USAAF gradually lost interest in the XP-81 program. Consolidated Vultee was well aware of this, and they had been trying since December of 1946 to improve their design. A proposal was made in December 31st to the Air Material Command to fix the underperforming prototypes. This proposal suggested that an improved TG-110 (the ones that would have been used on the YP-81) should replace the TG-100 and a J33-19 jet engine should replace the J33-GE-5. The Air Material Command however was not impressed by the proposal due to the amount of redesigning and time needed and in early 1947, their engineering department ceased work on the TG-100 turboprop engine. Things would look even more grim for the XP-81 when on January 27th of 1947, the contract for the 13 YP-81 pre-

The first XP-81 prototype flies over the Mojave Desert. (Convair)

production fighters were cancelled. Finally on May 9th, the XP-81 program reached its end when the government decided to cancel the contract on its development. The two prototypes were then taken in by the USAAF on June 24th and 25th. Finalization of the cancellation was conducted on June 23rd of 1948 after the USAAF was reorganized into the United States Air Force (USAF) when Consolidated Vultee was reimbursed with $4,578,231 for their work on the program.

Though development stopped for the XP-81 program, the two prototype’s story did not end there. At the time when the USAAF took in the prototypes, the engine and propeller development branches of the Air Material Command was in the middle of developing more advanced propeller control techniques and a suitable machine was needed to perform tests on as wind tunnels and models were not available. The USAAF promptly provided the two XP-81s which were redesignated as “ZXF-81” for this new role. The two planes were then stored in Edwards AFB (previously known as Muroc AAF) for future use. Unfortunately, they were never used and on April 29th of 1949, all useful parts and gadgets were stripped from the two planes by order of the USAF. The two empty airframes were then dragged onto the photography & bombing range of the Edwards AFB.

Despite the XP-81s now sitting in the desert, Consolidated Vultee was still not willing to yield completely. The company tried proposing reviving the XP-81 program using different power plants and repurposing the role. The proposal called for the use of the British Armstrong-Siddeley Double Mamba turboprop producing 4,000 hp and a Rolls-Royce R.B 41 jet engine producing 6,250 lbf (2,835 kgf) of thrust replacing the original engines. The idea behind this was to create a ground attack aircraft which could be exported to other countries. However, this idea was understandably met with skepticism by the Air Force, but an investigation to see the feasibility of this proposal was made. On September 14th of 1950, a report was finalized stating that at least ⅔ of the airframe would need to be modified in order to mount the new engines.  New drop tanks, rocket rails, hardpoints and various other parts would also need to be redesigned. Another investigation was done on this proposal by comparing the hypothetical performance to the all-turboprop Douglas A2D Skyshark, a ground attacker aircraft in service with the USAF. It was determined that the Skyshark would outperform the XP-81 with British engines in all aspects, so there was no point in developing an inferior aircraft. Another factor that was noted was the excessive amount of maintenance, training and logistics needed to service the ground attacker. With all these factors in mind, the proposal was discarded by the USAF and Consolidated Vultee finally gave up on the XP-81.

Frank Davis sits in the cockpit of the XP-81. (Convair)

The two XP-81 airframes would remain in the desert exposed to the elements for decades until August of 1994 when Air Force Flight Test Center Museum curator Doug Nelson retrieved them. They were in derelict condition, with the second XP-81 prototype being more damaged than the first. As of 2018, the two airframes remain in the National Museum of the United States Air Force in Dayton, Ohio awaiting future restoration. Although never seeing service, the XP-81 still holds a distinct spot in history as America’s first turboprop engine powered plane to fly and the world’s first plane to fly with a turboprop engine and a jet engine together.

The first XP-81 prototype at the Edwards AFB shortly before recovery. (AFFTCHO)

Design

Airframe:
The XP-81’s semi-monocoque fuselage was constructed using age hardened 24-SRT aluminum alloy, followed by the exterior surfaces being flush riveted. The entire fuselage is made from metal. The wing design was a NACA laminar flow type, made from aluminum-alloy. The design allowed for a stressed-skin wing which was flush riveted as well, with the rivet heads being milled. Due to the relatively heavy materials used in the wings, the surface was relatively smooth thus allowing for good aerodynamics. The majority of the heavy plating was mounted in the frontal 34.5% of the wings, and thus allowed a decent mount for aerial weapons and permitted ordinance to be mounted. There were spoilers present on each wing which automatically operated in accordance to the ailerons. Another interesting feature was a thermal anti-ice system derived from the hot hair emitted from the TG-100 turboprop and the exhaust. Within the fuselage two fuel tanks were installed directly behind the cockpit, making for a total 811 gallons (3670 L) of fuel. The fuselage also housed the XP-81’s tricycle landing gear which was electrically operated. The main gear was fitted with disc brakes, also doubling as a parking brake.

The first XP-81 prototype’s Packard engine installation being finalized at the Vultee plant. (Convair)

The canopy on the cockpit was based off of the British bubble design, which allowed for a relatively clean 360° view. This type of canopy was used on many planes in service with the United States and Britain. The canopy would be controlled by the pilot via a hand crank on the left hand side of the cockpit. For fatal combat situations, an emergency canopy jettison system was provided allowing for the pilot to bail out quickly. The pilot’s seat was an ordinary World War II styled seat, but this was eventually replaced with an ejection seat modelled after the one used on the Convair XP-54. As the XP-81 was a long range fighter, an automatic piloting system was also installed. The cockpit would also be pressurized using the air from the TG-100 engine. For pilot comfort, a temperature system was installed allowing for optimal temperatures in all climate and altitudes.

For communication, the XP-81 was fitted with a VHF (Very High Frequency) SCR 522-A radio set. The cockpit also had room for a BC-1206 beacon receiver and an SCR 695 identification friendly-or-foe system, but these were never installed. The pilot would operate the SCR 522-A radio from the right side of the cockpit, where the radio controls were based.

It is also interesting to note that the second YP-81 prototype had a longer ventral fin than the first prototype.

Powerplant:

The Packard-powered XP-81 prototype idle on the Muroc airstrip. (Convair)

The XP-81’s design called for a General Electric TG-100 (also known as XTG-31-GE-1) turboprop and General Electric/Allison J33-GE-5 (I-40) jet engine as its power plants. The first prototype had a four blade Aeroproducts A542 brand propeller driving the TG-100 while the second prototype had a Hamilton Standard Hydromatic 4260 propeller instead. The TG-100 had a capacity for 8 gallons (30 L) of oil while the I-40 had 3.5 gallons (13 L). In terms of fuel, 811 gallons (3,670 L) was available in the XP-81’s two standard fuel tanks in the fuselage, but could go up to 1,511 gallons (5,720 L) with the installation of drop tanks.

The TG-100 Turbo Prop Engine

Armament:
The standard armament envisioned for the production P-81 would consist of either six 12.7x99mm Browning AN/M2 machine guns with 400 rounds each or six 20x110mm Hispano T31 cannons with 200 rounds each. The loadout of these guns would be in groups of three in each wing. For ordinance, a single hard point was mounted under each wing, allowing the plane to carry two bombs size ranging from 100 lb (45 kg) to 1,600 lb (725 kg), allowing for a maximum of 3,200 lb (1,451 kg). Chemical tanks, drop tanks, depth charges could also be equipped. Alternatively, 14 High velocity Aircraft Rockets (HVAR) could be carried.

Variants

  • XP-81 – Prototype fighter variant powered by a TG-100 turboprop and I-40 jet engine. Two examples were produced and extensively tested up until the cancellation of the project. Both prototypes were redesignated as “ZXF-81” in 1948 and stored in Edwards AFB. They would be stripped of useful parts and towed to the photography/bombing range near Edwards AFB and left there in derelict condition until August of 1994 when they were retrieved by Doug Nelson. The two airframes still survive to this day and are currently awaiting restoration at the National Museum of the United States Air Force in Dayton, Ohio.
  • YP-81 – Planned batch of 13 pre-production fighter variant powered by a lighter but more powerful TG-110 turboprop engine and an uprated General Electric J33-GE-5 turbojet engine. These planes would have been armed with either the Browning AN/M2 machine guns or the Hispano T-31 cannons. It would have differed from the XP-81 by having the wings moved back 10 inches (2.54 cm). No YP-81s were produced.
  • ZXF-81 – Post development termination designation for the two XP-81 prototypes. This designation signified that the prototypes were now flying test beds. However, no use of the prototypes after its termination was noted.
  • XP-81 (British Engines) – Unofficial variant proposed by Consolidated Vultee some time in 1949/1950 calling for the revival of the XP-81 project using British Armstrong-Siddeley Double Mamba turboprop producing 4,000 hp and a Rolls-Royce R.B 41 jet engine producing 6,250 lb (2,835 kg) of thrust replacing original engines. This new variant would be used as a ground attacker that would be solely used for export. This proposal never saw any development and was thus discarded.

Operators

  • United States of America – The XP-81 was intended to be used by the USAAF, but development carried over to the USAF. The project was eventually cancelled.
Consolidated Vultee Aircraft Corporation XP-81
(Taken from “Consolidated Vultee XP-81 by Steve Ginter”)
Wingspan 50 ft 6 in / 15.39 m
Length 44 ft 8 in / 13.61 m
Height 13 ft 10 in / 4.21 m
Wing Area 425 ft² / 39.48 m²
Wing Loading 45.9 ft² /  4.26 m²
Tire Loading 80 in² / 516.12 cm²
Wings Sweep Back
Wing Dihedral
Root Cord 13-1
Engines 1x General Electric XTG-31-GE-1 (TG-100) turboprop
1x General Electric / Allison J33-GE-5 (I-40) jet
Oil Capacity TG-100: 8 gallons / 30 L
I-40: 3.5 gallons / 13 L
Empty Weight 12,755 lb / 3,887 kg
Normal Weight 19,500 lb / 8,845 kg
(Maximum internal fuel with reduced armaments)
Maximum Combat Weight 24,650 lb / 11,181 kg
Fuel Capacity 811 gallons / 3,070 L – Internal Fuel Tanks
1511 gallons / 5,720 L – Internal Fuel Tanks + Drop Tanks
350 gallons / 1,325 L – Individual Drop Tank
Center of Gravity Max Forward – 17%
Max Aft – 27%
Rate of Climb 0 to 5,000 ft / 0 to 1,524 m – 5,200 fpm / 39.31 mps
Time of Climb 30,000 ft / 9,144 m in 9.6 minutes
Speed 299 mph / 481 kmh at Sea Level
253 mph / 407 kmh at 15,000 ft / 4,572 m
224 mph / 360 kmh at 30,000 ft / 9,144 m
Maximum Speed 546 mph / 877 kmh
Diving tests were never finalized due to propeller and engine problems. Flight #90 on September 4th of 1946 achieved the highest speed as mentioned above.
Range Conditions under maximum combat weight

Ferry Range – 2,393 mi / 3,851 km
Speed at 247 mph / 397 kmh – 2,002 mi / 3,222 km
Speed at 274 mph / 441 kmh – 1,622 mi / 2,610 km

Service Ceiling 47,000 ft / 14,000 m
Crew 1x Pilot
Radio Equipment SCR 522-A VHF Radio
Armament 6x 12.7x99mm Browning AN/M2 (400 rpg, 2,400 total)
or
6x 20x119mm Hispano T31 (200 rpg, 1,200 total)
Never Fitted on Prototypes, Intended Armament
Gunsight 1x K-14 Gyro Gunsight
Ordinance 2x hardpoints capable of carrying 3,200 lb / 1,452 kg of either bombs, depth charges, chemical tanks or drop tanks
or
14x 5 inch / 12.7 cm High Velocity Aircraft Rockets (HVAR)

Gallery

Plane side view
Sideart of the XP-81 by Escodrion

 

XP-81 parked on a ramp.
Side view of the XP-81 on the ground.
Rear view of the XP-81 on the ground. Note the position of the exhaust pipe relative to the two fuselage mounted air intakes.
XP-81 in flight.
Instrument panel of the XP-81. (USAF)
Controls of the XP-81. (USAF)
The second XP-81 prototype at the Edwards AFB shortly before recovery. (AFFTCHO)
The second XP-81 prototype at the Edwards AFB shortly before recovery. The helicopter shadow visible is possibly an H-21 ‘Flying Banana’ (AFFTCHO)
The second XP-81 prototype preparing to be transported. (AFFTCHO)
The second XP-81 prototype preparing to be transported. (AFFTCHO)

Sources:
Ginter, S. (2006). Consolidated Vultee XP-81. Simi Valley: Steve Ginter.Jenkins, D. R., & Landis, T. R. (2008). Experimental and Prototype: U.S. Air Force Jet Fighters. North Branch: Specialty Press.Wegg, J. (1990). General Dynamics Aircraft: And their Predecessors. London: Putnam Aeronautical Books.Baugher, J. (1991). Convair XP-81. National Museum of the US Air Force (n.d.). Convair XP-81. Images: Side Profile Views by Escodrion – https://escodrion.deviantart.com

 

Beechcraft XA-38 Grizzly

usa flag USA (1944)
Prototype Attack Plane – 2 Built

Colorized photos by Michael J.

The Beechcraft XA-38 Grizzly was an experimental attack aircraft stemming from a USAAF requirement for a two seated attack bomber. Two prototypes were constructed between 1944 and 1945, and saw extensive testing within the US. The Grizzly showed promising performance, but was ultimately cancelled due to the engines intended for use was given priority to the Boeing B-29 Superfortress and the inevitable victory of the Allies.

History

Bottom view of Beechcraft XA-38 (S/N 43-14407) in flight. (U.S. Air Force photo)

In 1942, the United States Army Air Force (USAAF) issued a requirement for a two seater attack bomber. Beechcraft was quick to respond, and proposed their design to the USAAF. The USAAF was very interested in the design, and ordered two prototypes to be constructed in December of the same year after granting the contract to Beechcraft. In anticipation of the two prototypes, the USAAF assigned serial numbers to them, being “43-14406” and “43-14407”.

 

Beechcraft specifically designed the Model 28 to be able to destroy gun emplacements, ships, armored vehicles and bunkers while keeping great maneuverability and able to remain airborne after being damaged. All of this would be done by the addition of a powerful 75mm T15E1. The task of developing the Grizzly was given to a team led by Bill Cassidy with Jess Vint and Alex Odevseff in charge of designing the armaments, Bill Irig in charge of the control surfaces, Gus Ericson in charge of the design of wings, Mervin Meyers in charge of hydraulics, Ralph Harmon in charge of the landing gear structure and Noel Naidenoff in charge of the engine compartment. The Grizzly is common thought to be a modified Model 18 design, but this is untrue. The Grizzly did take inspirations from the Model 18, though.

Beechcraft XA-38 during ground vibration tests. Tests were set-up to determine natural frequencies excited during engine operation. (U.S. Air Force photo)

The first Grizzly (43-14406) was delivered to the Army Air Force and flown on May 7th of 1944 by test pilot Vern L. Carstens. The first test flight went relatively well except for an unplanned touch-and-go during landing. This was due to Carsten’s inexperience with landing such a large plane. The first prototype had no armaments installed, but had a wooden mockup of the 75mm T15E1 cannon. In the next few test flights, the Grizzly proved itself to be very aerodynamically stable, and made a good impression with the designers. A memorable flight test includes a performance comparison between the Grizzly and a recently manufactured North American P-51B. The Grizzly and P-51B were put in a mock pursuit, and the P-51B was reported to have been unable to keep up. Afterwards on July 7th of 1945, the first Grizzly was transferred to Wright Field to be used by the USAAF. It then participated in 38 test flights from between October 13 and October 24 of 1944 flown by Captain Jack W. Williams. Williams affectionately noted that the Grizzly was a great aircraft and “very maneuverable” for an aircraft of its size. It is also interesting to note that the turrets on the first Grizzly were dummies.

Front view of Beechcraft XA-38 (S/N 43-14407) in flight. (U.S. Air Force photo)

The second Grizzly (43-14407) had its maiden flight on September 22nd of 1945, once again piloted by Carstens. The second prototype was intended for armament testing, so it had all weapons fitted. The 75mm T15E1 prototype cannon was already successfully tested the year before on July 1st. The second Grizzly flew a total of 38 hours afterwards in tests at Eglin Field in Florida.

As successful as the Grizzly was, it would never reach mass production status because of two reasons. The first reason was that the R-3350 engines were in short supply, as the Boeing B-29 Superfortress had top priority for the engines. Second, the war situation was already in America’s favor, thus cancelling out the need for such an aircraft. As a result, both of the Grizzlies were retired from active service. One was scrapped while the other one was transferred to the Davis-Monthan Airfield in Arizona, meeting an unknown fate.

Design

The XA-38 Grizzly was an all metal, two seat, twin engined semi-monocoque plane with cantilever wings, conventional landing gears, oleo-pneumatic shock absorbers and hydraulic brakes. It was powered by two Wright R-3350-43 Duplex Cyclone engines, the same engine that powered the Boeing B-29 Superfortress. The propellers measured at 4.32m (170in) each in diameter.

The plane used flush riveting and butted skin joints to give the plane its pristine, shiny look. The foil used to construct the wings were derived from the NACA 23000 series which was good for high and low speeds. The engine hub was made from stainless steel and aluminum alloy. The oil coolers were placed in the wings. Four fuel tanks were installed in the wings with a capacity of 2,422 litres (640 US Gallons). Two self-sealing fuel tanks were also placed behind the cockpit which can carry 681 litres (185 US Gallons) if needed to. There were pumps and connectors installed onto the tanks, which would stop fuel flow if the tanks took damage.

Beechcraft XA-38 (S/N 43-14407, the second and last XA-38 built). (U.S. Air Force photo)

As for armaments, the XA-38’s 75mm T15E1 was the defining feature. Could carry 20 rounds fed by a Type T-13 feeding system. There would be a Type N-6 reflector sight to help the pilot aim. The cannon would fire every 1.2 seconds if the pilot pressed the trigger button. Two .50cal (12.7mm) M2 Browning machine guns were installed under the cannon with 500 rounds each. The entire nose section of the XA-38 could be unhinged, where mechanics can easily access the guns for maintenance.

The Grizzly had two turrets, one located on the top of the fuselage and one on the bottom. The turrets were manufactured by General Electric and had two M2 Brownings each with 500 rounds. These two turrets were controlled by a single gunner seated in the rear fuselage. He would aim the guns with a periscope to control the turrets. Interestingly enough, the turrets can also be fixed to fire forward to accompany the T15E1. Ordinance wise, the XA-38 was designed to carry a wide range of things. It could have carried bombs, napalm, torpedoes, fuel tanks, smoke tanks and depth charges.

Operators

  • United States of America – The USAAF was the sole operator of the XA-38. The USAAF extensively tested the XA-38, and concluded it was a success. However, the XA-38 never reached mass production status.

Beechcraft XA-38 Grizzly

Wingspan 64 ft 4 in / 20.52 m
Length 51 ft 9 in / 15.77 m
Height 15 ft 6 in / 4.72 m
Wing Area 626 ft² / 58.15 m²
Engine 2x Wright R-3350-43 Duplex Cyclone (2,300hp)
Fuel Capacity 640 US Gallons / 2,422 L

Additional Tanks: 185 US Gallons / 681 L

Maximum Takeoff Weight 35,265 lbs / 15,996 kg
Empty Weight 22,480lbs / 10,197 kg
Wing Loading 56.3 lb/ft² / 275.1 kg/m²
Power Loading 7.67 lb/hp / 3.48 kg/hp
Climb Rate 2,600 ft/min / 792 m/min
Maximum Speed 330 mph / 531 km/h at Sea Level

348 mph / 560 km/h – at 5,000 ft / 1,525 m

370 mph / 595 km/h – at 17,000ft / 5,180m

Cruising Speed (75% Throttle)

289 mph / 465 km/h – at Sea Level

350 mph / 563 km/h – at 16,000 ft / 4,875 m

Range 1,625 mi / 2,615 km – at 225 mph / 362km/h

745 mi / 1,200 km – at 289 mph / 465 km/h

Service Ceiling 29,000 ft / 8,840 m
Crew 1x Pilot

1x Gunner/Observer

Forward Firing Armaments 1x 75mm T15E1 (20 rounds)

2x 12.7mm M2 Browning (500 rpg)

Defensive Armaments 2x 12.7mm M2 Browning (Upper Turret) (500 rpg)

2x 12.7mm M2 Browning (Belly Turret) (500 rpg)

Ordinance Planned Options:

  • Bombs
  • Fuel tanks
  • Napalm
  • Torpedoes
  • Depth Charges
  • Smoke Tanks

Gallery

Grizzly Prototype 314407 – armed with two 500 lb bombs

Sources

Beechcraft XA-38. (2008). National Museum of the US Air ForcePearce, W. (2013). Beech Aircraft Company XA-38 Grizzly. Old Machine Press.Pelletier, Alain J. (2005). Beech aircraft and their predecessors. Putnam, Images:  Side Profile Views by Ed Jackson – Artbyedo.comColorized Images by Michael J.

Douglas XB-19

usa flag USA (1941)
Prototype Heavy Bomber – 1 Built

The XB-19 parked on the ground.

The XB-19 was a heavy bomber designed in 1935 to fulfill a request made by the United States Army Air Corps (USAAC) to develop an experimental heavy bomber with extreme range. Although slow in its development and obsolete by the time it was produced, it served as a test vehicle to evaluate plane and engine performances. The sole XB-19 was converted to a cargo transport plane and was eventually scrapped in 1949. The XB-19 was the largest plane operated by the USAAC and USAAF until the Convair B-36 came into service.

History

The roots of the XB-19 can be traced to 1935 on February 5th when the United States Army Air Corps (USAAC) commenced “Project D”. The purpose of Project D was to experiment with the maximum distances achievable with bombers. The USAAC contacted and discussed the project with Douglas Aircraft Company and Sikorsky. Douglas representatives agreed to the terms of the design and plans were made during a conference on June 5th, 1935. The initial plan was to begin the basic design on July 31st of 1935, detailed designs on January 31st of 1936, and have the plane physically produced by March 31st, 1938. The plan however was soon found out to be too ambitious, with the designers underestimating the work required. The designers would be plagued with a lack of proper funding and the sheer enormity of the task. The project would finally be completed in May of 1941, nearly four years after the original deadline.

Douglas XB-19 under construction. (U.S. Air Force photo)

Douglas Aircraft Company received a contract to the project in October of 1935 which required Douglas to create a general and detailed design of the plane, create a mockup of the plane and test the wing centre section, undercarriage, and engine nacelles of the plane. Douglas accepted the contract on October 18th. Later that year, the USAAC would evaluate the mockups provided by Douglas and Sikorsky. Douglas’s design was ultimately chosen, and was given the task of further developing the plane.

The XB-19 under construction at the Douglas Aircraft Factory located in Santa Monica, California. 1940.

The plane would be known as the “XBLR-2” (Experimental Bomber Long Range 2) in its early stages of development. The progress of developing the bomber proved to be tedious and slow. Lack of funding would severely hinder work on the plane. During that time the USAAC made a change to the requirements, the plane was suppose to be powered by four Allison XV-3420-1 engines producing 1,600 horsepower each, but was ordered to be replaced by four Wright R-3350 engines producing 2,000 horsepower each instead. This would also hinder work as the plane had to be slightly redesigned. As time went on, Douglas had to loan a Douglas OA-4A from the USAAC to test an experimental tricycle landing gear configuration intended for the XBLR-2. The tests proved to be a success. Later, the XBLR-2 would be redesignated as “XB-19” (Experimental Bomber 19). Douglas eventually managed to scrape together enough funds to produce a prototype, and the production was authorized on March 8th of 1938.

XB-19_38-471_at_Mines_Airfield_Colorized copy
The XB-19 parked at Mines Airfield. (Colorized by Michael J.)
Washing XB-19 at March Field 1941. (Colorized by Michael J.)

During its development, the Douglas company had many problems with the XB-19. They were forced to allocate more funds than initially expected, and needed design staff to work on other aircraft which had a more promising production future. They claimed the XB-19’s design was obsolete due to the production delays it suffered over the past three years and the fact that the plane’s weight was far heavier than expected. The Douglas company officially made a recommendation to cancel the XB-19 project on August 30th, 1938. This recommendation was denied by the USAAC. Interestingly enough, two years later, the USAAC would suggest that the slow development of the XB-19 already rendered the project obsolete when they removed the plane from the top secret classified list. The XB-19 would finally be completed in May of 1941.

The XB-19 parked on the ground next to a P-40 Kittyhawk.

Shortly after completion, the XB-19 was used in taxiing tests on May 6th, 1941. The flight test was scheduled to be on May 17th, but was postponed three times due to critical mechanical errors. The landing gear break was found to have defects, its engines had backfiring issues, and the propeller pitch control system had to be worked on. On June 27th however, the XB-19 would finally have its maiden flight. In the maiden flight, seven crewmembers were on board with Major Stanley M. Ulmstead in charge. The flight lasted 55 minutes from Clover Field in Santa Monica to March Field. The flight went by smoothly without any problems and was successful. Shortly afterwards, Donald Douglas would receive a congratulatory telegram from President Roosevelt. The USAAC unofficially accepted the XB-19 in October of 1941.

Eager observers watch the XB-19 preparing for its maiden flight. Clover Field, 1941.

After the Japanese attack on Pearl Harbour on December 7th of 1941, the United States was on high alert. The XB-19’s turrets were armed and a new layer of olive camouflage paint was applied, replacing its bare metal USAAC livery. It would make 4 more tests flights in California before being transferred to Wright Field on January 23rd, 1942 as another safety measure. By then, the XB-19 had over 70 hours of flight time.

The XB-19 was finally accepted officially by the USAAF in June of 1942 after minor modifications were made to the plane’s brake system. The contract cost to the United States government was $1,400,064. The Douglas Aircraft Company also spent $4,000,000 in personal company funds. The XB-19 was extensively tested by the USAAF for eighteen months to see the engine performances and different altitudes and the maneuverability of the aircraft.  The results of these tests would later go on to influence the design of the Boeing B-29 Superfortress and the Convair B-36. The XB-19 performed well in all aspects and was generally free of problems. The only problem noted however was the inefficient engine cooling process. Due to this, the cooling gills on the plane had to be open the whole time in longer flights, thus reducing the effective speed of the XB-19.

The XB-19 in flight over Santa Monica with an AT-6 following it.

After the XB-19 was thoroughly tested and experimented with, the USAAF no longer had a need for it. It was brought to the Wright Field and modified to be a cargo transport aircraft. It was refitted with Allison V-3420-11 engines and had its armaments removed. The new aircraft would be designated “XB-19A”. For the next two and a half years, the XB-19A would fly to numerous airfields within Ohio. It was documented to have been stationed at Wright Field, Patterson Field, Lockbourne Air Base, and Clinton Country Air Base. The XB-19A would make its last flight on August 17th, 1946, where it flew to the Davis-Monthan airfield in Arizona from Wright Field to be stored. It stayed in storage for three years before finally being scrapped in 1949, thus ending the legacy of the XB-19.

XB-19_in_flight_1942_Colorized copy
The XB-19 in flight some time in 1942. (Colorized by Michael J.)

To this day, only two wheels of the XB-19’s landing gear survives. One can be seen in the Hill Aerospace Museum in Oregon, and the other can be seen in the National Museum of the United States Air Force in Ohio.

The wheel of the XB-19 with a car and person for comparison.

Design

The XB-19 is described as a colossal, all metal low wing monoplane installed with a conventional tricycle landing gear. The two main wheels of the landing gears measured at 2.44 m (8 ft) in diameter, which was impressive for the time. The original design specifications ordered wanted the engines to be four Allison XV-3420-1, but was swapped for four Wright R-3350-5 engines instead with a three blade metal propeller with a 5.18 m (17 ft) diameter. The engines would be switched once again to Allison V-3420-11 after the plane was repurposed as a cargo transport aircraft. The plane could carry an impressive amount of fuel, at 38,178 L (10,350 US Gallons) in its auxiliary fuel tanks, with an optional 3,210 L (824 US Gallons) that could be stored in the bomb bay.

A shot of the underside of the XB-19 with the gear down.

The XB-19 carried 8,480 kg (18,700 lbs) of ordinance usually, but could be overloaded to 16,828 kg (37,100 lbs) if fuel was reduced significantly. As for armaments, the initial prototype was unarmed. Later though, two 37mm Oldsmobile T9 autocannons, five 12.7mm M2 Brownings and six M1919 Brownings were fitted to the plane. One T9 was fitted to the nose while the other was fitted to the upper front turret, each accompanied by a single M1919 machine gun. There would be one M1919 on each side of the bombardier’s position, and a M1919 on each side of the stabilizer. A single M2 Browning was fitted in the tail of the XB-19, two M2 Brownings on each side of the galley compartment, one in the bottom turret, and one in the upper powered turret.

In the crew compartment, there was eight seats and six bunks. The compartment could accommodate two flight engineers, and six relief crew members. The normal combat crew consisted of sixteen people. (Refer to Specifications Table).

The cockpit of the XB-19.

Variants

  • XB-19 – The original model and design. Initially developed as a long range heavy bomber for the USAAC, but was outdated by the time it entered service. It served as a “flying laboratory”, testing engine performances and plane handling. It was converted to the XB-19A after the USAAF no longer had use for it.
  • XB-19A – The XB-19A was a converted XB-19 using improved Allison V-3420-11 engines. It was used as a cargo transport aircraft after the air force was done experimenting with it. All armaments were removed. It was scrapped in 1949.

Operators

  • United States of America – The XB-19 and XB-19A was operated by the USAAC and USAAF throughout its service life.

 

Douglas XB-19

Wingspan 212 ft / 64.62 m
Length 132 ft & 4 in / 40.34 m
Height 42 ft / 12.8 m
Wing Area 4,285 ft² / 398.091m²
Wing Loading 32.6 lb/sq ft / 159.5 kg/sq m
Power Loading 17.5 lb/hp / 7.9 kg/hp
Engine 4x Wright R-3350-5 Duplex Cyclone (2,000 hp)
Fuel Capacity 10,350 US Gallons / 38,178 L – in auxiliary fuel tanks + 824 US Gallons / 3,120 L – in bombay (Optional)
Maximum Weight 140,000 lbs / 63,503 kg
Empty Weight 86,000 lbs / 39,009 kg
Climb Rate 650 ft/min / 198 m/min
Speeds Cruising: 135 mph / 217 km/h – Sea Level

Operational: 186 mph / 299 km/h – @ 15,700 ft / 4,785 m

Maximum Speed: 224 mph / 360 km/h – @ 15,700 ft / 4,785 m

Normal Range 5,200 mi / 8,369 km
Maximum Range 7,710 mi / 12,408 km
Service Ceiling 23,000 ft / 7,010 m
Crew 2x Pilots

1x Commander

1x Navigator

1x Engineer

1x Radio Operator

1x Bombardier

2x Flight Mechanics

1x Turret Operator

8x Gunners

6x Relief Crew

(24 Crew – 16 Active, 2 Emergency Stations, 6 Relief Crew)

Defensive Armament 2x 37mm Oldsmobile T9 Autocannon

5x 12.7mm M2 Browning

6x 7.62mm M1919 Browning

Normal Ordinance 18,700 lbs / 8,480 kg
Maximum Ordinance 37,100 lbs / 16,828 kg *

* – with reduced fuel load

 

Douglas XB-19A

Wingspan 212 ft  / 64.62 m
Length 132 ft 4 in / 40.34 m
Height 42 ft / 12.8 m
Wing Area 4,285 ft² / 398.091m²
Wing Loading 32.71 lb/sq ft / 159.8 kg/sq m
Power Loading 13.51 lb/hp / 6.1 kg/hp
Engine 4x Allison V-3420-11 (2,600 hp)
Loaded Weight 140,230 lbs / 63,607 kg
Empty Weight 92,400 lbs / 41,912 kg
Maximum Speed 265 mph / 426 km/h
Cruising Speed 185 mph / 298 km/h
Normal Range 4,200 mi / 6,759 km
Service Ceiling 39,000 ft / 11,885 m

Gallery

A spectacular shot of the XB-19 flying low. 1942.
XB-19A on the ground with Allison V-3420-11 engines.
Crewmen washing the XB-19 at March Field, some time in 1941.
The crew of the XB-19 operating in the cockpit.
XB-19A on the ground with Allison V-3420-11 engines.
XB-19 Before Scrapped
A photo of the XB-19 post-war before it was scrapped.

 

Sources

Bunker, Howard G. Development, Test and Acceptance of Douglas XB-19 Airplane, AAF No. 38-471. 1942, pp. 18–25, Development, Test and Acceptance of Douglas XB-19 Airplane, AAF No. 38-471., Francillon, René J. McDonnell Douglas aircraft since 1920. Putnam, 1988., Images:  Side Profile Views by Ed Jackson – Artbyedo.com, Colorized Images by Michael of PE

 

Vought F4U Corsair

sweden flag USA (1942)
Naval Fighter Plane – 12,571 Built

black-and-white-f4u

The F4U Corsair is another most famous fighter and fighter-bomber of WWII, although it saw action mostly against the Japanese in the Theatre of the Pacific, therefore being primarily used by the US Navy and the Marines. This airplane in particular was specifically designed for aircraft carriers, being a naval aircraft in essence, although initial doubts over its performance on-board an aircraft carriers made it to serve initially as a land-based asset. It saw also action during the Korea War as a ground attack and Close Air Support (CAS) aircraft, and with the French in the Indochina, Algeria, and Suez Canal crisis. It also saw some service in the Atlantic during WWII, mainly with the British Fleet Air Arm, where reportedly provided air cover to the airplanes attacking the battleship Tirpitz, and served in the Indian and Pacific Oceans. The Corsair contributed to change the balance over the skies of the Pacific by shooting down many Mitsubishi A6M Zeros, although not as much as the Grumman F6F Hellcat.

The Corsair is single-seat and single engine fighter/fighter-bomber for day and night-time, featuring a characteristic inverted gull wing (Similar to that of the Junkers Ju-87 Stuka and the Loire-Nieuport 40) and a very long propeller-blade. The development of the Corsair began following a request by the US Navy for twin and single-engine fighters in 1938, with the single-engine required to obtain the maximum speed possible and a stalling speed of no more than 110 km/h (70 mph), and a long range. Interestingly, the initial requirements comprised the aircraft to carry anti-aircraft bombs to be dropped on enemy formations. That same year, Vought – the builder company – was awarded a contract to start with the development of the Corsair.

The Corsair was a pretty advanced aircraft for the times, and this characteristic meant that its development would find several problems that required solution, which in turn, were quite remarkable. Even so, the Corsair required improvements while in service, which does not deny the fact that it was one of the greatest and unique airplanes of the war, let alone a good complement to other aircraft carrier-based fighters and among the best naval fighters in the war.

One of the main features during development was the incorporation of the largest engine available, the Pratt & Whitney R-2800 V-18 Double Wasp of 2250 hp, requiring the installation of a wide three-blade Hamilton propeller. This installation had two visible effects on the design: First, the characteristic shape of the airframe, where the bow is basically the area where the big and long engine is located, almost displacing the cockpit further aft. Second, it yielded speeds of up to 652 km/h (405 mph), making it the first single-engine American design to reach such speed. But the first problems emerged, especially in regards to diving speed that, although achievable, meant considerable damage to control surfaces and access panels, as well as problems with the engine. Spin recovery standards also needed to be revisited.

The wing itself, along with the longitudinal shape, were both a challenge when designing the frame. In regards to the inverted gull wing, it was purposed to make the width and the landing gear as short as possible, benefiting also the minimization of drag, as the anhedral of the center section gave an optimal meeting angle between the wing and the fuselage. Yet the weight of the wing alone neutralized those effects. But it also had the problems when recovering from developed spins, as the shape of the wing interfered with the elevator. It also had problems with the starboard strip, that used drop without warning, requiring the installation of small stall strips on the leading edges. The port wing also had the potential of stalling and dropping in failed landings, which was further dangerous if throttle was abruptly increased in such cases. The inverted gull wing was also a product of solving the problem of the landing gear, as they needed to be tall enough to keep the propeller away from the ground (the same problem the Saab J-21 had). It simply shortened the length of the legs, while the landing gear was able to retract and rote 90° into an enclosed wheel well, maintaining the streamline of the wings.

The Corsair, however, was benefited during its development thanks to the experiences of other air forces when the war sparked in Europe. As a result, the set of 2 X 7.62mm synchronized engine cowling-mount machine guns, and the 2 X 12.7mm wing machine guns was deemed unsuitable, prompting the armament scheme to be modified. Three 12.7mm machine guns were fitted on each wing, increasing the firepower of the Corsair.

redbull-f4u-corsair-and-b25-mitchell
A Corsair and Mitchell bomber, fly together at an airshow.

As it was abovementioned, other problems prevented the Corsair to serve as a carrier-based fighter until 1944, mainly those related to the type of landing required in that type of vessel. Not only the wing-related problems when performing this manoeuvre, but also the location of the cockpit plus the long bow made landings particularly dangerous for new pilots. Furthermore, during landing approaches manoeuvres, the oil from the hydraulic cowl flaps had the tendency to spatter onto the windscreen, compromising visibility, and the oleo struts had bad rebound when landing, making the entire aircraft to bounce upon landing. The top cowl flap down was sealed, while a valve was fitted to the landing gear legs in order to solve the issues, solution that were, on the other hand, implemented by the British firstly. It had its first flight in 1940, entering in service in December 1942 intended as a naval fighter, but these problems delayed its utilization as carrier-borne fighter and the US Navy initially preferring the F6F Hellcat, but it also meant that the Marines would use the Corsair as their main air assets, and it was with this branch that the Corsair began to carve its reputation. It entered in service in the late 1942, where the Marines began to make use of it at the Battle of Guadalcanal and the Solomon Islands, where its first debut was rather disappointing. But once the Marines learned how to maximize the advantages of the Corsair, they began to contest the air supremacy the Japanese had. It also saw extensive action as a fighter-bomber/attacker in the Marshall Islands, Palaus, Iwo Jima and Okinawa.

It was the British the ones that solved the operational problems of the Corsair for naval use, as they began to operate with the Corsair in 1944, on-board the HMS Victorious. Those Corsairs saw action as carrier-borne aircraft by supressing Flaks and providing escorts to aircraft performing raids against the Kriegsmarine battleship DKM Tirpitz in three raid operations: Operation Tungsten, Operation Mascot and Operation Goodwood. Later on the British Corsairs were deployed in the Indian Ocean and the Pacific, attacking Japanese targets on April 1944.

The Corsair saw action in post-WWII conflicts such as the Korean War, the Indochina War, among others. Many served with other air forces as surplus or donated aircraft, where it served more than 30 years after WWII was over, when it scored its last air victories and gave an honourable closure to an era past gone. 10 F2G ‘Super’ Corsair series also served as civilian racers after the war.  A total of 12571 Corsairs were built, being in service with the US Navy, the Marines and other air forces from 1942 to 1979, attesting the good quality of the aircraft and its endurance, being produced until 1953. A total of 15,386 Mustangs were built.

Design

The Corsair is a low inverted gull wing fighter, with a single tail and a single engine: Pratt & Whitney R-2800 V-18 Double Wasp of 2250 hp, with a wide propeller fitted as to maximize the power yield. As a result of the size of the engine, the bow or nose of the Corsair is particularly long, which made the cockpit to be located further aft. The relocation and reconfiguration of the armament – which was placed at the wings – and the resulting relocation of the fuel tank in front of the cockpit contributed to its location in the airframe, which in turn had to be elongated.

The wings with their characteristic shape were the result of the need for shortening the legs of the landing gear and for accommodating also a folding wing, while being located also well ahead the pilots’ cockpit, making the Corsair to have a cross shape. This wing design also resulted in the Corsair having remarkable aerodynamics over similar airplanes of its type. The shape of the wing was also beneficial in the sense that the meeting angle between the wing as the fuselage reduced drag and saved the utilization of wing root fairings, although the bent wing tended to neutralize such benefits given its weight. On a similar way to the Saab J 21, the supercharger air intakes, alongside the oil coolers, were placed at the wings, this case on the anhedraled center section of the wings. The combination of the propeller diameter, the engine and the wing’s shape and length – alongside the resulting aerodynamics – made the Corsair the fastest naval aircraft the US had at its disposal. The flaps were changed to a NACA slotted type while the ailerons were increased in span.

The fuselage, mainly the large panels, were made of aluminium and attached to the frames by spot welding, which eliminated the use of rivets. The top and the bottom areas of the outer wings were made out of fabric, as well as the ailerons, the elevators – which were also made of plywood – and the rudder. At the rear an IFF (Identification Friend or Foe) transponder device was installed.

The landing gear consisted typically of two ‘legs’ at the wings and a rear small wheel, with the carrier-based version having also a tail hook for the arresting cable. All of the set was retractable, only that the ‘legs’ at the wings rotated 90° and then swivelled backwards, a trait that common among many US fighters. Noteworthy to remark that the landing gear was hydraulically operated, alongside the cooling flaps, the wing flaps, the wing folding and locking, the arresting gear, the gun charging, and the dive breaks.

The aft cockpit had some interesting features and modifications resulting from the assessed hazards while landing on an aircraft carrier. As this problem was the result of the nose and the location of the same cockpit, a rectangular plexiglass panel was fitted in the lower center section, so to allow the pilot to see below and perform carrier landings with more safety. In addition, armour plates were applied to the canopy area, with the windscreen being a 38mm bullet-proof installed internally and the behind the curved windscreen. To aid the pilot’s rear view, half-elliptical planform transparent panels were placed at each side of the structure right behind the cockpit, yet the view provided was rather limited.

The aft section of the Corsair is also full of noticeable characteristics, with a projecting fuselage tip where the vertical stabilizer is placed, which is large. The horizontal stabilizer is, in turn, placed ‘aft’ of the tail.

The Corsair’s armament was originally a set of two 7.62mm machine guns at the frontal section of the nose, and two 12.7mm machine guns, one at each wing. But as the abovementioned reports from the war in Europe obliged the armament to be modified, the final disposition was of 6 X 12,7mm machineguns at the wings, three on each side.

Death has bent wings.

F4U Climb

The Corsair was the most effective fighter the US Navy and the USMC had from the moment it was introduced and entered combat in the Solomon Islands in 1943. It was appraised by the pilots due to its performance and its capacity to remove the threat posed by the Mitsubishis A6M Zeros, as well as to break Japanese bombing raids. It was also capable of outfling and outfighting any land-based aircraft. It was capable of performing interception, bombing, ground-attack and fighter missions. The Corsair was a fighter that was also an ace-maker, with Kenneth Walsh (21 kills), Gregory “Pappy” Boyington (28 kills) and Joe Foss (26 kills). It was under Boyington lead that his squadron, the “Black Sheep” were the most effective squadron, scoring 97 kills and 103 damaged airplanes on the ground. Noteworthy to remark, the Corsair was also appraised by Admiral Nimitz giving its performance.

As the Corsair was cleared for carrier use, it began to operate on-board USS Essex and USS Bunker Hill. The Corsair also performed dive bombing missions in the Marshal Islands as it dropped more than 90718 kg (200000 lbs) of bombs against Japanese installations. It also took part in combats at China Sea, Okinawa, Iwo Jima, Formosa and the Philippines. It also took part on the Saigon and Tokyo Raids, which were diversionary attacks prior to Okinawa. It was also during Okinawa where they had to operate as fleet air defence against the Kamikaze attacks in the earlier stages of the battle, performing CAS with bombs, rockets and Napalm once the threat was neutralized. They reportedly achieved remarkable feats, like keep flying after ramming an enemy. The Corsairs scored 2140 Japanese airplanes with only 189 Corsairs lost, along with 14 warships and 33 merchants sunk (Saigon raid). These scores earned the Corsair Nimitz’s appraisal and a US government citation, and the builder granted an “E” after the War.

The Corsair was among the few WWII-era aircraft to serve right into the earlier days of the Cold War, as it took part in low altitude attack fighter-bombing and CAS missions in Korea, as well as heckling the enemy in night missions. It also attacked enemy installations It dropped bombs, Napalms, rockets and cannons the same way as in WWII, being both aircraft and pilots both veterans of that conflict, and operating from WWII aircraft carriers (USS Essex and USS Bon Homme Richard). As tough as it was, it was able to cary alarge payload and remain more time in the combat zone for CAS missions, and even the Corsair even managed to kill a North Korean Mig-15. The Corsair also had a high rate of availability and hard resistance against enemy fire.

One last dogfight over the jungle

F4U in flight

When the 1969 ‘Soccer War’ sparked between Honduras and El Salvador, both nations were having among their air forces inventories some WWII-era fighters, namely F4U/FG-1 and P-51D/TF—51 fighters. These airplanes were to perform the last dogfight between WWII-era (or piston-propelled engine) airplanes, like two medieval knights clad in armour, ready to joust for a last opportunity as to write the last chapter of an era. The morning of the 17th of July, 1969, the encounter was bound to take place. As Honduran Captain Fernando Soto was leading a group of three F4U-5 to strafing missions at the border, one of the Corsairs was attacked by two Salvadorian P-51, with Capt. Soto shooting it down. But there was to be a second encounter between the veteran aircraft, as late on the same day, during a bombing mission alongside another F4U-5, they encountered Salvadorian FG-1. The result was that both FG-1 were shot down, making of Capt. Soto the only “Ace” of the War.

P-51 of the Salvadorian Air Force, piloted by US mercenaries, patrolled the Salvadorian skies and border, looking also for the Honduras Corsairs, with no avail.

Variants

  • F4U-1 (Corsair Mk I)/FG-1 – This was the first production series of the Corsair, being characterized by a ‘bird cage’ canopy and a low seating position, featuring also the definitive abovementioned modifications for the series-production models, including the 6 X 12,7mm machine guns’ configuration. An additional pair of auxiliary fuel tanks were installed in each wing edge A two-seat trainer was built but was not accepted by the US Navy. The Corsairs in service with the Marine Corps did not had folding wing capacity neither they were fitted with an arrester hook but a pneumatic tail wheel, as they were land-based, receiving the designation FG-1 and being built by the Goodyear. Those with the British Fleet Air Arm were denominated Corsair Mk I.
  • F4U-1A (Corsair Mk II) – A post-war denomination introduced to differentiate the mid-to-late production batch. This version – which would be the second production version – would have a new type of canopy, similar to a Malcolm hood type – like that of the Spitfire – and with only two frames. It had a simplified windscreen, which improved visibility overall along with the canopy being taller. That the pilot’s seat was raised 180mm (7 in), in combination with a lengthened tailwheel strut, meant that visibility was also improved, solving the problems posed by the long nose. This is the version that, along canopy modifications, also introduced wing and undercarriage oleo struts modifications, becoming in the US Navy carrier-based version. This version also received a new power plant, the R-2800-8W water-injection engine, and the capacity to carry a center-section fuel drop tank. Goodyear also built a variant of this version, land-based and without folding wing capacities. Those in service with the British had their wings modified – shortened by 2cms/8 in – for use in their carriers, denominated FG-1A.
  • F3A-1 (Corsair Mk III) – Denomination for those built by the Brewster, which none of them reached front-line units as the building both production and quality control were poor, noticeable after having speed restrictions and broken wings (due to poor quality wing fittings).
  • F4U-1B – Unofficial post-war denomination to identify Corsairs modified for Fleet Air Arm use.
  • F4U-1C – Ground attack and fighter version, with the 6 X 12,7mm guns replaced by a set of 4 X 20mm AN/M2 (Hispano-Suiza) cannons thus providing considerable firepower for ground attack missions. Based on the F-4U-1. This version had a remarkable performance in the Battle of Okinawa, as it was introduced in 1945.
  • F4U-1D/FG-1D/F3A-1D (Corsair Mk IV and Mk III) – Ground attack and fighter version, developed and built in parallel to the F4U-1C. It had the new engine fitted in the F4U-1A, yielding speeds of up to 684 km/h (417 mph). It also carried an increased payload of rockets and a twin-rack plumbing for an additional belly drop fuel tank, which increased firepower but also drag. The range was also increased, meaning it could perform long missions. A single piece – Malcolm hood type – canopy was adopted firstly as a standard for this version, then for the following Corsairs. Goodyear and Brewster also produced this version, under denominations FG-1D and F3A-1D, respectively.
  • F4U-1P – Photo-reconnaissance version.
  • XF4U-2 – Nigh-time fighter version fitted with two auxiliary fuel tanks.
  • F4U-2 – Experimental carrier-based night-time fighter. Armed with 5 X 12,7mm guns, with the starboard gun being replaced by an Airborne Intercept radome containing a radar. 32 were modified by Naval Aircraft Factory, ant two more were modified in the front-line. It saw action in the Solomon Islands and in Tarawa.
  • XF4U-3 – Experimental version used to test different engines that never entered into combat. Goodyear also produced some units of this version, denominated FG-3. A single XF4U-3B was produced with some modification, intended to be issued to the British Fleet Air Arm.
  • XF4U-4 – Version with new engine and cowling.
  • F4U-4 – A naval fighter/fighter bomber version, being the last one taking part in WWII, as it was introduced by late 1944. It was powered by a 2100 hp dual-stage-supercharged V18 cylinder engine, with its power boosted to 2450 hp when the cylinders were injected with a water/alcohol mixture. An air scoop was fitted under the nose, while the wing fuel tanks were removed. The propeller was also changed from a three blade to a four blade type. The new engine, the mixture and the new propeller blades allowed the F4U-4 to reach speeds of up to 721 km/h (448 mph) and a better climbing rate (4500 ft/min / 1180 m/min). A flat bulletproof windscreen was also installed, avoiding optical distortions. Versions with wingtip tanks and a six-blade contra-rotating propeller were proposed but ultimately rejected by the US Navy.
  • F4U-4B – Corsair that were set to be delivered for the British Fleet Air Arm, but were confiscated by the US.
  • F4U-4C – A version with an alternate weapons set of 4 X 20mm AN/M2 (Hispano-Suiza) cannon. 300 delivered.
  • F4U-4E/F4U-4N – Night fighters with the starboard wing radar radome. The F4U-4E was equipped with an APS-4 search radar, and the F4U-4N was equipped with an APS-6 search radar. These Corsairs would have an armament of 4 X 20mm AN/M2 (Hispano-Suiza) cannons. These Corsairs served in the Korean War.
  • F4U-4K – Experimental drone version
  • F4U-4P – A photo-reconnaissance version.
  • XF4U-5 – Version with new engine cowling.
  • F4U-5 – A modified version of the F4U-4, introduced in 1945 and aimed at increasing the Corsair’s performance and introduce many of the suggestions issued by the pilots. It was powered with a Pratt & Whitney R-2800-32(E) engine with a two-stage supercharger of 2850 hp. Automatic blower controls, cowl flaps, intercooler doors and oil cooler for the engine were fitted. Spring tabs for the elevators and rudder, a modernized cockpit, a retractable tailwheel, heated cannon bays and pitot head were also fitted. The cowling was lowered two degrees, and the wings were all-metal. 223 units delivered.
  • F4U-5N – A radar equipped version. 214 units delivered.
  • F4U-5NL – A winterized version equipped with rubber de-icing boots on the leading edge of both wings and tail. 72 units delivered and 29 units modified from F4U-5N.
  • F4U-5P – A long range photo-reconnaissance version. 30 units delivered.
  • F4U-6/AU-1 – A re-designated AU-1 (which in turn, was based on a modified F4U-6), which was the ground-attack version in use by the Marine Corps. The AU-1 had extra armour protecting both pilot and fuel tank, as well as extra racks, and the oil coolers relocated inboard to reduce changes of ground fire damage. The supercharger was redesigned for low-altitude operations. Capable of carrying up to 3720kg (8,200lbs) of bombs and of reaching speeds of 383 Km/h (238mph) or 479 Km/h (298mph) when armed with bombs or rockets and with one or two fuel tanks. At empty payload this version could reach speeds of 626 Km/h (389mph). produced in 1952 and retired in 1957, seeing action in the Korea War.
  • F4U-7 – Version based on the AU-1 for service with the French Navy.
  • FG-1E – Goodyear-made Corsairs FG-1 with radar equipment.
  • FG-1K – Goodyear-made Corsairs FG-1 used as drones.
  • FG-3 – A turbosupercharger version from modified FG-1D airframes.
  • FG-4 – Goodyear-made Corsairs F4U-4 that were never delivered.
  • Super Corsairs (F2G-1 / F2G-2) – Versions developed after the war, powered by a Pratt & Whitney R-4360 Was major with 4-row 28-cylinder radial engine and a teardrop/bubble canopy. The F2G-1 had a manual folding wing and a 4,3m (14ft) propellers, the F2G-2 had hydraulic operated folding wings, 4m (13ft) propellers and carrier arresting hooks. Development problems delayed and finally ended further developments, with the F2G-2 becoming racing planes.

Operators

  • f4u-4-vmf-124-13-kenneth-a-walsh-okinawa-06-45_03
    U.S. Navy F4U-4 – VMF 124 No 13 – June 1945
  • United States of America – The Corsair was primarily used by the US Navy and the United States Marine Corps in most of the campaigns of the Pacific War. It started its service at Solomon Island in 1943 as fighter in the hands of the USMC, where three famous Pacific War American Aces marked their scores with Corsairs. It also took part of dive bombing operations in the Marshal Islands, seeing also action in the China Sea, Okinawa, Iwo Jima, Formosa, the Philippines and also in the Tokyo and Saigon Raids. In Okinawa, it became the main defence against Kamikaze attacks. The Korean War brought the Corsairs back given its capacity to carry large and heavy amounts of payload/ordnance, performing ground-attack and CAS missions, used by the USMC. Many were also sold as surplus aircraft, serving in the air forces of Argentina, El Salvador and Honduras.
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    Royal Navy F4U-1 (F.Mk.1) 1855 NAS FAA – Oct 1943
  • United Kingdom – 2,012 Corsairs were issued to the British Royal Navy Fleet Air Arm in 1943, where the wings were clipped 8 inches in order to increase storage in the lower carrier decks, being the British Corsairs the first ones to be used in on an aircraft carrier. The Corsair also took part as escort fighter and anti-air defences in three operations – Operation Tungsten, Operation Mascot and Operation Goodwood – against German battleship DKM Tirpitz. In 1944, British Corsairs took part in operations at the Indian and the Pacific Ocean, remarkably used in Java as bombers. It was during Corsair service with the British, that enhancements for carrier operation were made.
  • French Navy F4U-7 - 14F Aeronavale No.133704 - Circa 1956
    French Navy F4U-7 – 14F Aeronavale No.133704 – Circa 1956
  • France – France and its naval air branch or Aéronavale operated with 69 AU-1 and 94 F4U-7s from 1954 to 1964. It was introduced to replace the Supermarine Seafires, Grumman Hellcats, Curtiss Helldivers and SBD Dauntless that equipped the naval air service. They operated from 4 carriers – Arromanches, Dixmude, La Fayette and Bois Belleau – that were part of the French Navy. 4 squadrons – the 14F, 12F, 15F and 10F – were operating with the Corsair, alongside two training squadrons – 10S and 57S. French Corsairs intervened firstly in Indochina, as they were handed by the US (AU-1 Korean War veterans) and where they were well received by French troops and pilots. In Indochina 6 Corsairs lost and 2 pilots dead.
  • The Corsairs also operated in Africa, namely in Algeria, Suez and Tunisia. In Algeria, they provided fire support, bombing, reconnaissance and protection of airborne troops. There were some considerable losses due to accidents and AA fire took place. In Suez, they took part in operations from carriers Arromanches and La Fayette, attacking the Cairo-Almanza airfield with only one loss against 12 planes damaged and 1 damaged of the Egyptians. The last action the French Corsairs saw was in Tunisia, where they provided support to besieged troops at a French airbase after Tunisian independence, attacking also Tunisian troops and vehicles. 3 Corsairs were lost due to the AA. The French reportedly used the Corsairs to experiment with anti-tank missiles, but they were never used. As new carriers and new air naval assets were introduced, the Aéronavale withdrew its Corsairs.
  • f4u-1a-rnzaf-22sqn-49944-1944_03
    Royal New Zealand AF F4U-1A – 22 Sqn 49944 – July 1944
  • New Zealand – The New Zealand air force shifted from the P-40 to the Corsair in 1944, receiving in total 424 airframes as a lend-lease, with 13 squadrons operating it. The RNZAF operated with F4U-1A, F4U-1D and FG-1D, concentrating on attacking the bypassed islands with ground support, escort and air patrols. Only 17 Corsairs were lost, as the Japanese air superiority was, by the time the Corsairs were received, almost neutralized. A squadron equipped with Corsairs served an occupation duty for two years once the Pacific War was over.
  • Argentina – Argentine acquired the day-time and night-time fighter versions of the Corsairs (26 F4U-5/5N/5NL) in 1957, being incorporated to the Argentinian aircraft carrier ARA Independencia. As the abovementioned versions were fitted with Radar, Argentina became the first nation in the region to operate aircraft with radars. They intervened during the 1958 border incidents with Chile, and in the period of 1959-1960, the Corsairs were used as submarine chasers – equipped with depth charges – following the detection of unidentified submarines. They also took part during the political revolt of 1963, being 1964 their last year of operational service during another set of border incidents with Chile. They were withdrawn from service in 1968.
  • Honduras – The Honduras Air Force operated the Corsair from 1956 to 1979, with 19 units. The Honduran Corsairs also took part in the 1969 ‘Soccer War’, where a single Corsair scored three victories against two Salvadorian Corsairs and one Mustang, piloted by Capt. Fernando Soto. These were the only air-to-air victories of the war. The Honduras Corsairs also performed strafing missions at the border. The Corsair that scored those victories is now a war memorial.
  • fg-1d-el-salvador-fas-201-67087-1958_03
    El Salvador Air Force FG-1D – 67087 – Circa 1958
  • El Salvador – The Salvadorian Air Force operated the Corsair from 1957 to 1976, with 25 F4U-/FG-1D. They took part in combats during the 1969 ‘Soccer War’, where took some losses in the hands of the Honduras Air Force operating similar F4U-4 and F4U-5 fighters.
  • Germany – Germany captured only one British Corsair that was forced to land in Norway due to technical issues while taking part in Operation Mascot.
  • Japan – Japan also captured two Corsairs after emergency landings, with one possible tested in flight.

 

F4U-4 Specifications 

Wingspan  12,49 m / 41 ft 0 in
Length  10,27 m / 33 ft 8 in
Height  4,5 m / 14 ft 9 in
Wing Area  29,17 m² / 314 ft²
Engine  1 Pratt & Whitney R-2800-18W 18 cylinder radial engine of 2,250 hp
Propeller Diameter  4,06 m/ 13 ft 4 in
Maximum Take-Off Weight  6149 Kg / 13,556 lb
Empty Weight  4174 kg / 9,202 lb
Loaded Weight  5626 kg / 12,405 lb
Maximum Speed  718 km/h / 446 mph
Range  2511 Km / 1,560 miles
Maximum Service Ceiling  12650 m /41,500 ft
Climb Rate  3050m in 5,1 minutes (22.1 m/s; 4,360 ft/min)
Crew  1 (pilot)
Armament
  • 6 X 12,7mm (0.50 caliber) M2Browning machine guns or 4 X 20mm AN/M2 cannons.
  • Up to 1000 kg (4000 lbs) of bombs.
  • 8 X 127 mm high velocity aircraft rockets.

Gallery

f4u-4-vmf-124-13-kenneth-a-walsh-okinawa-06-45_03
U.S. Navy F4U-4 – VMF 124 No 13 – June 1945
U.S. Navy F4U-1 VMF 123 no. 15 ‘Daphne C’ – July 1943
f4u-1a-vf-17-jolly-rogers-17640-bighog-11-43_03
U.S. Navy F4U-1A – VF-17 17640 ‘Big Hog’ – Nov 1943
U.S. Navy F4U-1D - VMF-451 20141 - Apr 1945
U.S. Navy F4U-1D – VMF-451 20141 – Apr 1945
Royal Canadian Navy FG-1D - 1841 Sqn BuNo 76236 - Aug 1945
Royal Canadian Navy FG-1D – 1841 Sqn BuNo 76236 – Aug 1945
f4u-1a-rnzaf-22sqn-49944-1944_03
Royal New Zealand AF F4U-1A – 22 Sqn 49944 – July 1944
Royal New Zealand AF F4U-1 - No. 21 Sq NZ5315 BuNo 49909 - Jun 1944
Royal New Zealand AF F4U-1 – No. 21 Sq NZ5315 BuNo 49909 – Jun 1944
f4u-1f-mk-1-1855-nas-faa-5f-jt150-10-43_03
Royal Navy F4U-1 (F.Mk.1) 1855 NAS FAA – Oct 1943
French Navy F4U-7 - 14F Aeronavale No.133704 - Circa 1956
French Navy F4U-7 – 14F Aeronavale No.133704 – Circa 1956
fg-1d-el-salvador-fas-201-67087-1958_03
El Salvador Air Force FG-1D – 67087 – Circa 1958

 

 

Sources

Aviation Publications (1977). Pilots Manual for F4U Corsair., Berger, R (Ed.). Aviones [Flugzeuge, Vicenç Prat, trans.]. Colonia, Alemania: Naumann & Göbel Verlagsgessellschaft mbH., Chant, C (2001). Aviones de la Segunda Guerra Mundial [Aircraft of World War II, Fabian Remo Tamayo & Fernando Tamayo, trans.]. Madrid, Spain: Editorial LIBSAD’Angina, J. (2014). Vought F4U Corsair. Oxford, UK: Osprey Publishing., Gunston, B. (1995). Guía Ilustrada de los Cazas y Aviones de Ataque Aliados de la Segunda Guerra Mundial (II). [An Illustrated Guide to Allied Fighters of World War II, Gearco, trans.]. Barcelona, Spain: Ediciones Folio (Original work published in 1981)., Gustin, E. (n.d.). Chance Vought F4U Corsair. F4UCorsair.com.HISTARMAR (n.d.). Chance-Vought F4U-5 Corsair. Fundación HISTARMAR.Lyford, C., & Tillman, B. (2014). Corsairs vs. Mustangs: The last dogfight. The Flight Journal, 16-24.Marsaly, F., & Bocognano, J. (2002). Les Corsairs de la Royale. Aérostories.org.Rochotte, L. (1999). Les Corsair Français. Net-Marine.Sherman, S. (2012). Vought F4U Corsair. Acepilots.com.The National WWII Museum (n.d.). Airplanes in the Us Freedom Pavilion: The Boeing Center.UTDallas (n.d.). Chance Vought/LTV History.Vought.org. (n.d.). F4U Corsair – WWII Record. Vought.org.Werbaneth, J. P. (2009). His Majesty’s Corsairs. Avalanche Press.Vought F4U Corsair. (2016, September 11). In Wikipedia, The Free Encyclopedia. Images: Black and White F4U by Brian Struble / CC BY 2.0,   F4U in FlightF4U Climb by Airwolfhound / CC BY-SA 2.0, Royal Navy F4U by Tony Hisgett / CC BY 2.0,  Redbull F4U Corsair and B25J Mitchell by Ronnie Macdonald / CC BY 2.0,   Side Profile Views by Ed Jackson – Artbyedo.com, Additional Side Profile Views by Brendan Matsuyama

P-51 Mustang

US Flag U.S.A. (1940)
Fighter Plane – 15,000 Built

Mustang Front View

The P-51 Mustang is one of the most famous fighters of WWII and of all time thanks to its exceptional performance characteristics, strong airframe and the role this fighter plane played in the European Theatre against the German Luftwaffe. Contributing to its defeat and aiding the Allies in gaining full control of the skies. It was also a long-enduring aircraft, with the last ones retired in 1984. It was by far the best day and night-time fighter of the Allies’ arsenal, with the Lockheed P-38 being its closest in-service rival.

The Origins of the Mustang

The Mustang was a single-seat and single engine fighter/fighter-bomber for day and night-time, with low wings. Its development began after a 1940 request by the Royal Air Force (RAF) for further license-built Curtiss P-40 Fighters to the North American Aviation. The British realized that bombing missions over German occupied territories were risky, suffering heavy casualties at the hands of the highly skilled Luftwaffe pilots and their fighters. The company made a move that would have a ripple effect throughout history, as it proposed to develop a new fighter instead of issuing the RAF an old model that was in short supply. The P-40 chain of production was already overloaded, with the P-40 component manufacturers reportedly turning down requests.

Tuskeegee P-51C
Tuskeegee P-51C

As a result, in 1940 the development of the Mustang began, which was by itself a feat as it took only four months. Its first flight took place in October 1940. The plane was a very advanced aircraft for its time, as it had an entirely metallic airframe, while slightly bigger than the Luftwaffe’s Messerschmitt Bf-109. The P-51 featured laminar wings and a radiator located in the rear. It developed speeds of 615 km/h thanks to its Allison V-1710 engine, found in the early P-51 Mk I and P-51A Mk II. By 1942 it had joined the ranks of the RAF, with nearly 620 units issued, executing reconnaissance missions during the first landings the Allies attempted at the French port of Dieppe in August 1942, as well as ground-attack missions following poor high-altitude performance. The V-1710 tended to underperform at altitudes above 4500 meters.

Improvements

Beautiful Doll P-51D
Beautiful Doll P-51D

As time went by, the Mustang would receive improvements that would enhance its already stellar performance. By late 1942 North American improved the propeller, the radiator and the aircraft’s aerodynamics. The developments in the engine design gave the Mustang increased horsepower and climbing ability, thus making the aircraft an exceptional air asset. The initial 12 cylinder Allison V-1710 engine was replaced with a Packard V-1650, which itself was based on the legendary Rolls Royce Merlin. As a result speed and range both were increased, with the top speed nudging up to 703 km/h and the range increasing up to 3703 km in the P-51B and C models. Furthermore, the upgrades were the key behind the Mustang’s celebrated reputation alongside its 6 12.7mm Browning machine guns. The Mustang reportedly shot down nearly 5000 enemy airplanes in air combat sorties, and destroyed nearly 4000 ground targets. Further improvements followed in the P-51D which had its airframe slightly shortened in the rear while received a revolutionary new bubble-shaped canopy. Additionally it had greater oil capacity and provisions for carrying rockets under the wings.

During the Sicily campaign the Mustang devastated the Luftwaffe and the Regia Aeronautica (Italian Air Force.) It also served as a notable escort fighter on bombing missions deep into Germany, wiping out the Luftwaffe’s defending fighters from the skies. It also had a very limited participation in the Pacific during WWII, seeing more action during the Korea War with the US Air Force, the Republic of Korea Air Force, the Royal Australian Air Force, and the South African Air Force, until all of the aforementioned replaced the Mustang with newer platforms. During the Korean conflict Mustangs were used for ground-attack and reconnaissance missions sustaining heavy losses due to ground fire. It was then in service with reserve units until 1956, except for three F-51Ds. The nomenclature for US fighters was changed from P for ‘Pursuit’ for F for ‘Fighter’ after WWII. These F-51s were used as chase planes for the Lockheed YAH-56 Cheyenne attack helicopter project and other experimental purposes until the late 60s.

Service

The Mustang also saw extensive use in combat with other air forces. The Netherlands used them during the Indonesian War of Independence. Israel deployed the Mustang during its War of Independence and the Suez Canal Crisis also known as Operation Kadesh. The Philippines used the Mustangs for counter-insurgency purposes during the Huk campaign against communist guerrillas. Indonesia and many South American countries used the P51 in many similar campaigns against guerrilla fighters. Sweden used the Mustangs on reconnaissance versions for Operation Falun, a reconnaissance of soviet Baltic coast military installations in 1946-47; El Salvador’s Air force also made use of this model during the 1969 Soccer War against Honduras, being the last combat use between piston engine fighters (with Honduras using the Vought Chance F4U-5); and the Dominican Republic, were they took part in Operation Power Pack, an US intervention during the brief 1965 Dominican Republic Civil War. This was the last air force in withdrawing the Mustang from active duty in 1984.

The Mustang also had a civilian life after WWII and other conflicts it served. Many are now privately owned with some now in museums and on static display. Others are still airworthy and maintained by hobbyists and historical societies. Some have even been modified for racing.  A total of 15.386 Mustangs were built.

Design

The Mustang is a low-wing fighter, with a single tail and a single engine: 1 Allison V-1710 V-12 developing 1,325 hp used in the P-51 Mk.I and P-51A Mk.II or 1 Packard V-1650 V-12 of 1,315 hp in the P-51D and onwards. Its wings featured a laminar flow airfoils that generated very low drag at high speed, also providing outstanding aerodynamic characteristics. The radiator is a remarkable feature of the Mustang, in both its shape and performance as it takes advantage of the ‘Meredith effect’ which creates a slight jet thrust from the heated air flowing outward providing more propulsion to the engine and increasing the speed of the aircraft. A 2 stage supercharger gave the Mustang power enough to outperform its German counterparts. This designs also had incidence with the length of the aircraft, which allowing the fitting of a bigger inner fuel oil tank that increased its maximum range and speed. The fuselage shares the same features as the Lansen, which was lofted mathematically using conic sections. This resulted in a smooth fuselage with low drag surfaces. The Mustang had another unique feature: its fuselage was divided into 5 sections – forward, center, rear fuselage, and two wing halves which made assembly during production very efficient.

The aircraft material was covered in aluminum overall, which made the Mustang a lightweight aircraft for its day. Combined with its aerodynamic characteristics, it was an aircraft easy to fly with good performance in-flight and during combat.

The first versions of the Mustang (P-51 to P-51C) had conventional canopy setup with the door opening and closing upwards and downwards to the side albeit possessing poor rearward visibility. The P-51D and the following versions introduced the bubble-shaped canopy that is widely known which gave the pilot a full 360° view. This design slid on rails that moved backwards, making easy entry and exit. This would influence the design of future fighters and light bombers canopies alongside its bullet-proof windscreen.

Earlier versions were armed with 4 X 12.7mm / .50 caliber AN/M2 Browning machine guns. As North American decided to upgrade the firepower, the P-51D through H versions received 6 Browning guns.

A Reliable “Little Friend” 

Mustang Bomber Escort
Mustang Bomber Escort

The Mustang would go on to win the skies and the hearts of the bombers crews, as it provided good escort to the very risky and dangerous long-range bombings deep into German territory. Needless to say, it also won the respect and fear of its adversaries. The crew of the bombers dubbed the Mustangs as “little friends” for the invaluable protection they afforded to the bombers during the deep raid missions over German-controlled skies.

The P-51 Mustang came about initially by request from the RAF to be provided with a fighter capable enough to match the German Messerschmitt, but it had the P-40 in mind. North American, the manufacturing company, proposed instead a new airplane. When it came in service with the RAF, it became the first fighter capable of penetrating deep into the German skies from England. As a result, the US decided to operate it over the skies of Italy and Sicily. Evaluating the performance and range, the P-51 was then used as bomber escort plane, being capable of reaching even Poland and Czech Republic. When executing this particular task, it became an important air asset for the Allies to control the skies of Europe. But it was not mere realization about such need what brought the P-51 into the scene. In fact, there were two factors that pushed the Allies into adopting the Mustang as escort airplane: First, the initially reluctant allies were able to assess the potential the Mustang had once the D type was introduced with all of its improvements. Second, two disastrous raids over the German city of Schweinfurt, where the bombers suffered heavy casualties at 59 destroyed, morale was low. The resulting evaluation showcased the need for bombers to be provided with escort fighters to carry out strategic bombing operations with minimal losses.

The Mustang also executed the similar escort missions in the Pacific theatre alongside the Boeing B-29 Superfortress bombers over Japan. Once the island of Iwo Jima was taken by the Marines, the Americans had a base from which both bombers and escort fighters could strike mainland Japan.

Variants

  • NA.73X – The only prototype of the Mustang, which was ready only four months after contracts were signed
  • A-36 Apache / A-36 Invader – Dive-bomber and ground attack. The ‘Apache’ and ‘Invader’ were the original nicknames for the airframe, before Mustang was adopted. Fitted with the same Allison engine of the earlier versions. It was also equipped with dive brakes and two hardpoints allowing 2 X 500 lb (227 kg) bombs on each wing, as well as two fuel drop tanks of 75 gallons. It was armed with six guns .50 cal Browning machine guns, 2 of those guns were placed at the nose. It could have a secondary role as low-altitude fighter, being as a P-51A. 500 produced.
  • P-51 – Mustang Mk IA taken over by the USAAC. 57 units.
  • F-6A – Reconnaissance version fitted with cameras. Number unknown.
  • P-51A – Fighter version. Was a good low-altitude fighter. It also had two hardpoints allowing bombs or drop fuel tanks. It served also in the China,Burma, and India theatre as fighter and escort. 310 delivered.
  • P-51B – Fighter version. This model featured a better engine in the form of the Packard V-1650-3, based on the Rolls-Royce Merlin. This version was capable of performing as high-altitude fighter. However it had problems of poor rear visibility and guns jamming when intense G maneuvers were performed.   All in all, this version began to turn the tide against the Luftwaffe and Germany’s infrastructure. 1,988 delivered.
  • P-51C – Fighter version. Built in Dallas, Texas. It had the same engine of the P-51B, but also the same visibility and gun jamming problems. 1750 delivered.
  • TP-51C – A field modification intended at creating a dual-control variant, for VIP transport and training. 5 built.
  • P-51D – Fighter version that received a suite of improvements that would make the Mustang a powerful fighter, becoming a milestone for fighter development and the Allies’ air superiority in Europe. Amongst the improvements, there was the bubble canopy, shortened fuselage, greater on-board fuel capacity, and a modified wing allowing 3 Browning .50 cal machine guns on each. Provisions for rockets were also complemented by a K-14 gun sight that used an analog computer, which improved accuracy. 7966 delivered.
  • XP-51F – Lightweight version. 3 built.
  • XP-51G – Lightweight version, with a 5-bladed propeller. 2 delivered.
  • P-51H – A lightweight version, powered by a Rolls-Royce Merlin 1650-9, decreased fuel capacity, and a distinctive tall tail.  555 delivered.
  • XP-51J – A lightweight version powered with an Allison engine. 2 built.
  • P-51K – A P-51D having a different propeller (A Hamilton Standard 11’12’’ 4-blade. 1337 delivered.
  • P-51L – Cancelled version.
  • P-51M Cancelled version
  • Mustang Mk I – The very first operational version of the Mustang, entering in service with the RAF in October 1941. Having the same engine as the models P-51 and P-51A, as well as the same armament but bombs and rockets. 620 delivered.
  • Mustang Mk IA  A second version for the RAF, being the version with the most powerful armament as it had 4 X 20 mm Hispano guns at the wings, being the machineguns of the nose removed. 150 delivered and 57 deviated for US use.
  • Mustang Mk II – A third version for the RAF, based on the P-51A. Equipped with an Allison V-1710-81 engine with an improved supercharger that enhanced mid-altitude performance, making of the Mk II the fastest fighter for such altitude. It was equipped also with a fixed belly scoop, drop tanks but only 4 X 12,7mm machine guns
  • Mustang Mk III – A fourth version for the RAF that also received the same improvements than the P-51B in regards of the power plant, yet having the same 4 X 12,7mm machine guns of previous models. It was widely used to chase and take down the German V-1 flying bombs. 852 delivered under Lend Lease programme.
  • Mustang Mk IV and IVA – Fifth and sixth versions for the RAF, receiving the upgraded canopy and other upgrades similar to those of the P-51D (including the 6 12,7mm guns and the K-14 gun sight). These versions were based on the P-51D and P-51K, respectively. 284 Mk IV and 594 Mk IVA were delivered.
  • Rolls Royce Mustang Mk X – An experimental version developed by the Great Britain powered with a Rolls-Royce Merlin engine, taking as a basis the airframes of Mustangs Mk I, for medium and high altitudes. Despite success, the 500 planned series production was cancelled. 5 airframes modified.
  • Commonwealth CA-17 Mustang Mk 20 – The Royal Australian Air Force (RAAF) was in need of new fighters and high-altitude interceptors. An agreement between the RAAF and North American resulted in the Australian Commonwealth Aircraft Corporation (CAC) allowed to build the P-51D version under license. Powered by the Merlin engine. 100 unassembled P-51D were issued, with only 80 being fully completed by CAC (CA-17 Mk 20).
  • Commonwealth CA-18 Mustang Mk 21, Mk 22 and Mk 23 – These versions were licensed built versions by CAC. The Mk 21 was powered by a Merlin V-1650-7, the Mk23 was powered with Rolls Royce Merlin engines. The Mk22 was modified to be a reconnaissance version similar to the F-6D. 120 CA-18 were built.
  • Mustang Cavaliers (or Mustang II F-51/Mustang III-Piper PA-48 Enforcer) – Surplus P-51Ds that were modified, with all the military equipment initially removed, and a second seat added. Some received increased fuel capacity with wing tip tanks, upgraded avionics and a tall tail. Some F-51 were repaired and upgraded by Cavalier, being delivered to the Dominican Air Force (36), to the Salvadorian Air Force (9), to the Indonesian Air Force (6), and two to the US Army serving as chase planes for the Cheyenne AH-54 attack helicopter program. Attempts to keep the P-51 in service by adding a turboprop (Rolls Royce Dart) were made, resulting in the Mustang III, but they came to no avail. The project was sold to Piper, which developed the Piper PA-48 Enforcer, finding the same fate. Only two PA-48 Enforcers exist as museum pieces.
  • P-82/F-82 Twin Mustang  Designed as a long-range, high-altitude bomber escort, with a high maximum range (3600 km/2300 miles) and very high ceiling 12192m (40,000 ft), being able to escort the B-29 bombers over Japan. It had two elongated P-51 fuselages (hence its name) that gave the aforementioned characteristics, having two pilots as crew, with one later on operating a radar. The power plants were the same of the P-51D, reaching speeds of 750 km/h (500 mph). Its firepower was the same 12,7mm machineguns, placed at the central wing, 25 air-to-ground rockets or up to 4000 lbs of bombs. It saw action in the early Cold War protecting US mainland against soviet bombers, and during the earlier stages of the Korean War, as night-fighters and ground attackers.

Operators

  • United States of America – The US Air Corps/Air Force became the second and the main operator of the P-51. As the US needed a capable bomber escort, the P-51 became the choice for this purpose with the P-38 and P-47 for the initial stages of the bombing operations. The Mustang became the mostly used escort fighter in Europe by the US. When the Mustang was used in advanced formations to the bombers, fighting the German fighters before they were able to strike the bombers, it achieved air superiority. After the Luftwaffe was nearly wiped out, it performed ground-attack mission. It was on this sort of missions that the Mustang was able to destroy the German-introduced Messerschmitt 262. The top ace using Mustangs shot down 26 enemy airplanes. It had a secondary participation in the Pacific theatre. It lasts service with the USAF was during the Korean War, when it was re-denominated as F-51, until it came to be replaced with F-86 Sabres.
  • United Kingdom – The nation whose request gave birth to the Mustang P-51, being the very first operator in January 1942. 620 were Mustangs Mk I, 93 were Mk IA, 50 were Mustangs Mk II, 308, 944 were Mustangs Mk III, 208 were Mk IV, and 600 were MK VIA. The RAF used the P-51 initially as close cooperation, ground-attack and reconnaissance, due to earlier models poor performance at high altitude. Mostly returned to the US or scrapped, remained in service with the RAF until 1947.
  • Australia – Became an operator of the P-51 in 1944, although operated the Mustangs under RAF badge. It received its first P-51 in Italy, in 1944. Received 80 and 120 later on as CA-17 and CA-18, respectively. It was deployed in the Pacific, as part of the occupation force in Japan and in the Korean War. The Citizens Air Force (CAF)reserve units used the P-51s until 1960.
  • Netherlands (East Indies Air Force) – The Netherlands used the P-51 on its East Indies Air Force, receiving 40 P-51D, using them during the Indonesian War of Independence. After the war, it handed some Mustangs to the nascent Indonesian Air Force.
  • New Zealand – Ordered 370 P-51 but received only 30 P-51D when the war came to an end. The delivered Mustangs were stored in their packing cases until 1951, when they were assembled and assigned to 4 squadrons of the Territorial Air Force. Remained in service until 1955 following corrosion problems in the undercarriage and coolant system. Some P-51s were flown as loaned airplanes with the RAF, and even some flew with the USAAC.
  • Sweden – The Flygvapnet operated initially 4 P-51s (2 P-51B and 2 P-51D) that were diverted to Sweden during operations. 50 additional P-51D were purchased, later on 111 being acquired, forming two wings. 12 were modified for photo reconnaissance, being designated as S 26 and taking part in Operation Falun, Sweden’s operation in mapping the new Soviet military installations in the Baltic countries in 1946-47. Replaced by the S 29C Tunnan in the early 50’s, selling some 25 P-51 to Israel and some Latin American countries.
  • Switzerland – The Schweizer Luftwaffe operated 100 P-51 that were diverted to Switzerland during operations, purchasing additional 130 P-51. They were in service until 1958
  • Israel – Around 4 P-51 were obtained by Israel in 1948 by buying surplus scrapped airframes, assembling and disassembling them again, packing and smuggling them to Israel in crates labelled as irrigation equipment, using them during the Israeli Independence War. They also were used as reprisal-attack aircraft, protection of an Israeli Navy Ship that ran aground, latter destroying it, and reconnaissance operations. Received 25 further P-51 from Sweden in 1951. They took part in the Operation Kadesh during the Suez Crisis, and even disrupted communications of Egypt during a parachute drop at Mitla Pass. In service until 1957.
  • Italy – Italy operated 173 P-51s after the war, with fighter, training, experimental and acrobatic purposes. Had to fly with some restrictions due to some factors affecting flight.
  • South Africa – 95 Mustangs were used in the Korean War, suffering heavy casualties yet performing well. The models used were Mk IV, Mk IVA, and P-51D. In service until 1952-53 when replaced with F-86 Sabres.
  • Canada – The Royal Canadian Air Force (RCAF) had five squadrons equipped with Mustangs during the war (Mk I, Mk III and Mk IVA). After the war, it received 150. Most were retired in 1956, with some remaining on special purposes service until the early 60s.
  • France – France began to operate with Mustangs by 1944, operating some of the F-6 series on reconnaissance missions in Germany in 1945. Remained in service until the earlier 50s, as they were replaced with jet fighters.
  • Poland – It operated Mustangs Mk I as the Polish Air Force in Britain, under RAF command. Then it operated Mk III until 1944, replacing the Mk III with Mk IV and IVAs in 1945. After the war, 80 Mk III and 20 Mk IV and Mk IVAs were returned to the RAF, and then to the US.
  • Japan – Only one unit that was damaged by gunfire and forced to do a belly landing in 1945 was used by Japan for testing purposes.
  • South Korea – 10 P-51D were supplied to the Republic of Korea Air Force following the beginning of the war, being the backbone of the ROKAF until they were replaced by F-86 Sabres. They also served as the black Eagles acrobatic team until 1954.
  • Taiwan – Some P-51 were used by the Nationalist forces against the Japanese, and then against the communists. In 1949 and following the Nationalist withdrawal to Taiwan, some P-51 were flown to the island, becoming part of the Taiwanese Air Force.
  • Germany – Some captured P-51s were used by the Luftwaffe, with some P-51B, P-51C and P-51D operating with the Germans for testing purposes.
  • Costa Rica – Four P-51D were operated from 1955 to 1964.
  • Cuba – 3 P-51D were smuggled into the country to serve with the rebel forces, but never gained operational status, becoming instead pieces of museum.
  • Dominican Republic – It was the second largest air force and the largest Latin American air force to operate the P-51, having 44 in its arsenal in 1948, and in service until 1984.
  • Guatemala – 30 Mustangs P-51D were in service with this country from 1954 to the first half of the 70s.
  • Haiti – 4 were operated by this country from 1951 to 1971, selling them for spare parts to the Dominican Air Force.
  • El Salvador – 6 Cavaliers (5 Mustang II and 1 dual control Cavalier TF-51) were purchased in 1968-69, in service until 1974. They saw combat action during the 1969 Soccer War against Honduras, with one being lost by a F4U.
  • China – 39 P-51s were captured from the Nationalists.
  • Indonesia – Some P-51D were acquired following the Netherlands withdrawal from the country, used against the Commonwealth (RAF, RAAF and RNZAF) during the Indonesian crisis in the early 60’s. Six Cavalier II were shipped to Indonesia in 1972-73, remaining in service until 1976.
  • Nicaragua – 26 P-51D were purchased from Sweden by this nation, receiving a further 30 P-51D US surplus along with two TF-51. In service until 1964.
  • Philippines – 103 P-51D were acquired after the war, becoming the backbone of the Philippine Air force and Air Corps, having action during the Huk campaign, fighting communist insurgents. It served also in the Blue Diamonds demonstration squadron and serving as COIN until the early 80’s, when 56 F-86 relegated them from first-line fighter missions in the late 50s.
  • Uruguay – 25 P-51D Mustangs were in service from 1950 to 1960, with some being sold to Bolivia.
  • Bolivia – 7 Cavalier F-51D and 2 TF-51 were issued to Bolivia under Peace Condor program. 23 P-51 were also sold to Bolivia. All remained in service from 1958 to 1978.
  • Somalia – 8 P-51D served in this nation after the war.
  • Soviet Union – 10 Mustang Mk I from the RAF were received, relegated for training missions after tests supposedly rendered them as underperforming to soviet fighters.

 

Mustang Specifications

Wingspan 11.28 m / 37 ft 0 in
Length 9.84 m / 32 ft 3 in
Height 4.18 m / 13 ft 8.5 in
Wing Area 21.83 m² / 235 ft²
Engine 1 Allison V-1710 V-12 – 1,150 hp (P-51 Mk I & P-51A Mk II

1 Packard V-1650 V-12 of 1,315 hp (P-51D version and following)

Propeller Diameter 3.40 m / 11 ft 2 in
Maximum Take-Off Weight 5,493 Kg / 12,109 lb
Empty Weight 3,103 kg / 6,840 lb
Loaded Weight 5,262 kg / 11,600 lb
Maximum Speed 703 km/h / 437 mph
Range 3703 Km / 2,300 miles
Maximum Service Ceiling 12770 m /42,000 ft
Climb Rate 6,095m in 7 minutes and 18 seconds (16.3 m/s ; 40,000 ft/min)
Crew 1 (pilot)
Armament
  • 6 X .50 caliber (12.7mm) AN/M2 Browning Machine Guns
  • 2 hardpoints that could allow 453 lb (907 kg) of payload. 2 x 100 lb (45 kg) bombs; 2 x 250 lb (113 kg) or 2 x 500 lb (226 kg) bombs. 6 or 10 x 5.0 in (127mm) T64 H.V.A.R rockets
  • 2 X 75 gallon (284 Liter) fuel oil drop tanks

Gallery

P-51D-25-NA "Swamp Fox"
P-51D-25-NA “Swamp Fox”
P-15D-5-NA "Tika IV"
P-15D-5-NA “Tika IV”
P-51D Mustang - 464153 Side Profile View
P-51D Mustang – 464153
P-51D-5-NA 8AF 44-13691
P-51D-5-NA 8AF 44-13691
P-51D-25-NA "The Enchantress"
P-51D-25-NA “The Enchantress”
P-51D "Nooky Booky IV"
P-51D “Nooky Booky IV”
P-51D "Old Crow" Side Profile View
P-51D “Old Crow”
Royal Australian Air Force – 3 Sq H677
P-51D-25-NA 21FS Republic of China Air Force
P-51D-25-NA 21FS Republic of China Air Force
Captured P-51D with German Markings
Captured P-51D with German Markings
XF-82 Twin Mustang
The dual fuselage ‘twin’ Mustang
P-51D - Miss Kandy
P-51D – Miss Kandy

Sources

Berger, R (Ed.). Aviones [Flugzeuge, Vicenç Prat, trans.]. Colonia, Alemania: Naumann & Göbel Verlagsgessellschaft mbH., Chant, C (2001). Aviones de la Segunda Guerra Mundial [Aircraft of World War II, Fabian Remo Tamayo & Fernando Tamayo, trans.]. Madrid, Spain: Editorial LIBSA (Original work published in 2001).Donald. D. (2009). Aviones Militares, Guia Visual [Military Aircraft. Visual Guide, Seconsat, trans.]. Madrid, Spain: Editorial Libsa (Original work published in 2008).Eaker, I. C. (1945). Pilot Training Manual for the P-51 Mustang. (AAF Manual 51-127-5). Washington, USA: Headquarters Army Air Force., Editorial Sol90 (2014). P-51B. El Legendario potro salvaje con alas. Barcelona, Spain: Editorial Sol90., Haggerty, A. & Dr. Wood R.L. (2010). The P-51 Mustang: A Case Study in Defence Acquisition. Fort Belvoir, Virginia: Defense Acquisition University.Levine, J. (2016). IAF Inventory: North American P-51D Mustang. Jewish Virtual Library.Military History Now (2015). Double-Trouble – The Strange History of the P-82 Twin Mustang., Murray, W. & Millet, A. R (2005). La guerra que había que ganar [A War to be Won, Critica S.L, trans.]. Barcelona, Spain: Critica.MustangsMustangs (2016). The North American P-51 Mustang …the aircraft that changed the course of a war.Senor, D. & Singer, S. (2009). Start-up Nation: The Story of Israel’s Economic Miracle. New York, USA: Twelve.Stallion 51 (2012). Mustang Facts. Kissimmee, Florida.The Spyflight Website (2003). Swedish Cold War Reconnaissance.USAF Historical Division Research Studies Institute (1955). Development of the Long-Range Escort Fighter. US Air Force Historical Study N. 136 (EO12958). Maxwell, Alabama: Air University.White, D. M., Hoover, H. H., & Garris, H.W. (1943). Flying Qualities and Stalling Characteristics of North American XP-51 Airplane. (Memorandum Wartime Report AAF No. 41-38). Langley Field, Virginia: National Advisory Committee for Aeronautics., North American P-51 Mustang variants. (2016, July 13). In Wikipedia, The Free Encyclopedia.Rolls-Royce Mustang Mk.X. (2015, June 23). In Wikipedia, The Free Encyclopedia. Images: Tuskeegee P51 by Ken Mist / CC BY 2.0, Beautiful Doll P-51 by Jessica Spengler / CC BY 2.0, Mustang Front by Steve Gregory / CC BY-SA 2.0, Mustang Escort by Tony Hisgett / CC BY 2.0, P-51D Miss Kandy by Airwolfhound /  CC BY-SA 2.0Plane Profile Views by Ed Jackson, Additional Side Profile Views by Brendan Matsuyama and Bad-Rabbit-Design