Republic of China (1946)
Prototype Glider Aircraft – 1 Built
The XG-1 was a glider developed by the 3rd Air Force Aircraft Manufacturing Factory Republic of China in 1943 with the intended purpose of transporting paratroopers and supplies behind enemy lines. It holds a special place in aviation history, as it was the first glider in the world to be built with bamboo. It would never see service, as the war ended and the air force was demobilized. It would meet an unknown fate after 1947. With the lack of information and documents detailing it, the XG-1 remains one of the world’s most obscure gliders.
Ever since gliders were introduced to China in the early 20th century, they were never as popular as powered planes. In early-mid 1943, the Chongqing Aeronautic Research Institution received Allied gliders (such as the Waco CG-4A) and realized the practicality of glider based transport. The ROCAF (Republic of China Air Force) then decided to develop their own transport glider. Due to this need, the vice president of the Chongqing Aeronautic Research Institute, Wang Zhu (王助), began closely studying the development of gliders.
During the mid 1940s, the Chinese established paratrooper schools in Kunming with assistance from America. The paratroopers went through 9 months of training and were kept in reserve. The Chinese did not prioritize paratroopers but saw their potential near the end of the war.
In late 1943, the glider project was well under way. The glider would be named 研滑-1 meaning “Experimental Glider”. The Latinized designation would be “XG-1”. Wang Zhu designed the glider to be built with wood and high quality Sichuan bamboo, a first in glider development history. Everything except the landing gear, cockpit instruments, and control sticks were made with bamboo. The XG-1 was specially designed to be able to glide behind enemy lines, to drop and supply paratroopers. Due to unknown complications, the XG-1’s production was delayed until 1946, when a single example was produced by the 3rd AFAMF.* The XG-1 would have been able to carry 30 fully equipped paratroopers with two pilots.
After the XG-1 was produced, Wang Zhu immediately pressed the Air Force to begin trials. However, due to the end of the war and a massive reform in the Air Force, the XG-1’s test flight was denied. Very angry that all his work was for nothing, he resigned from his position as vice president of the Research Institute and went back to his former job at CNAC**. Interestingly enough though, the XG-1 was rumored to have been test flown in 1947. This was likely due to the need of a transport aircraft during the Chinese Civil War.
The XG-1 would meet an unknown fate after 1947, much like many other domestically designed prototype planes. There are theories as to what could have happened to the prototype:
Theory One: The XG-1 was scrapped sometime during the Civil War by the Nationalist for materials.
Theory Two: The XG-1 was buried or hidden to prevent capture by the Communists.
Theory Three: The XG-1 was destroyed during a test flight, or in a firefight.
However in the end, these are all theories with no evidence to prove it.
* – Air Force Aircraft Manufacturing Factory ** – China National Aviation Corporation
The XG-1 slightly resembled the Douglas DC-2, a relatively popular and common plane in service with the Chinese at the time in civilian airliners. As Wang Zhu used to work for CNAC, it could be assumed he used it as a base model during the development of the XG-1. The XG-1’s structure consisted mostly of bamboo and wood, but was painted over in metallic paint.
The landing gear and cockpit instruments were all American made, while everything else was domestically made. The landing gear was in a fixed position, meaning that it couldn’t be retracted. There were small windows installed on the side of the plane for the paratroopers to look out of. The glass that was installed was made domestically.
Republic of China – The XG-1 would have been used by the ROCAF to transport supplies and paratroopers.
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.
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 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 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.
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.
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.
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.
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.
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 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.
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).
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.
United States of America – The XB-19 and XB-19A was operated by the USAAC and USAAF throughout its service life.
212 ft / 64.62 m
132 ft & 4 in / 40.34 m
42 ft / 12.8 m
4,285 ft² / 398.091m²
32.6 lb/sq ft / 159.5 kg/sq m
17.5 lb/hp / 7.9 kg/hp
4x Wright R-3350-5 Duplex Cyclone (2,000 hp)
10,350 US Gallons / 38,178 L – in auxiliary fuel tanks + 824 US Gallons / 3,120 L – in bombay (Optional)
140,000 lbs / 63,503 kg
86,000 lbs / 39,009 kg
650 ft/min / 198 m/min
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
Republic of China (1943)
Prototype Transport Aircraft – 2 Built
The Zhongyun was an indigenous designed Chinese passenger/cargo transport plane, which would see limited service within the Republic of China Air Force. In terms of speed, the Zhongyun series was evaluated by factory test pilots and deemed superior to the Douglas DC-2 the Chinese had in service at the time. Unfortunately, like many prototype planes of that time, the ones that were produced would meet an unknown fate as World War II ended and the Chinese Civil War began. However, a replica of the Zhongyun 1 can be seen in the Beijing Aviation Museum.
During the early stages of the Second Sino-Japanese War, the Nationalist Chinese government lacked an effective means of transporting supplies to the frontlines due to Japanese aerial superiority and the rapid loss of ground. Due to this, the Ministry of Aviation issued an order to Chinese factories to design an effective cargo plane suitable for Chinese airfields. Another requirement was to be capable of transporting a reasonable amount of cargo while having decent performance. The Second Air Force Aircraft Manufacturing Factory (AFAMF) in Chongqing proposed a cargo plane made out of quality Szechuan wood, and was approved.
The design of the new cargo plane began in 1941 with 林同骅 (Lin Tong Hua) as the Head Designer, 顾光复 (Gu Guang Fu) as Vice Head Director, and about 20 people as assistant directors. The name assigned to this project was “C-0101” (later renamed Zhongyun). Due to the ongoing war, the factory wanted to complete the design as quick as possible, so they designed and manufactured at the same time. In the Autumn of 1942, the design was finalized, but the designers were faced with one big problem. They did not have a wind tunnel to use, making them oblivious as to whether or not the design was stable. All the performance estimations were calculated by hand and paper, which simply wasn’t safe enough due to possible defects the designers overlooked, or the designers calculated the performance wrong. Shortly after the design was completed, the project was temporarily halted for an unknown reason.
The project was revived in 1943, and the designers refined the C-0101 by reworking the ailerons and various other small things. Finally, in August of 1944, the C-0101 rolled out of the factory line, powered by two Wright R-975E-3 “Whirlwind” engines. The C-0101 stood by until the summer of 1944 when the Japanese launched Operation Ichi-Go, where it was evacuated along with the factory. The C-0101 was disassembled into smaller parts and loaded onto many trucks. It took a week for the convoy to reach the new factory in Chongqing. The convoy only travelled at night and hid during the day to avoid Japanese reconnaissance and fighter planes. When they finally arrived, the C-0101 was quickly reassembled.
In late October of 1944, the C-0101 would take off for the first time. It flew over the Chongqing Bashiyi airfield for 20 minutes before landing. The test flight was a success. Lin Tong Hua was thoroughly impressed with the performance, and opted to board the plane in its next test flight. The next test flight would be on November 18, 1944 from Bashiyi airfield to Chengdu. This time, the plane was piloted by 李新唐 (Li Xing Tang) with 彭成 (Peng Cheng), Lin Tong Hua and Gu Guang Fu as passengers. The test flight lasted around an hour without any problems. En route to Chengdu Airport, Li Xing Tang noted that the plane’s speed and handling was superior to the Douglas DC-2, the most popular cargo/passenger plane in China at the time. The C-0101’s landing was observed by members of the Institute of Aviation.
Shortly after landing in Chengdu, people wanted to see the C-0101 in action again, so a new pilot was assigned and 高作揖 (Gao Zuo Yi), a designer from the Institute of Aviation, boarded the plane with Lin Tong Hua again. The plane would then perform various flight tests before landing again. The plane performed exceptionally well and was met with positive feedback. In celebration of the successful testing, the C-0101 was renamed to “中运-1” (Zhongyun 1) meaning “China Transport 1”. However, with the abundant supply of American C-46 and C-47 transport planes, only one Zhongyun 1 model was built. The designers still worked on improving the design, however.
Sometime after the Zhongyun 1’s test flight, there was an idea to create a bomber variant of the Zhongyun 1. The bomber variant was still its very early design stages when the Japanese capitulated. The Chinese then cancelled all work on the Zhongyun bomber since there was no need for such a plane anymore. This was also due to the 2nd AFAMF already exceeding their budget.
In 1946, the Zhongyun 1 was given to the Republic of China Air Force to serve in a transport unit. The designers then began working on the Zhongyun 2. The Zhongyun 2’s construction was similar to the Zhongyun 1, with some minor improvements. For example, the Zhongyun 2’s landing gear was taken from a retired P-40B, the fluidity of the ailerons were improved, and the passenger cabin was made more comfy. The plane would once again be made out of a mix of wood and metal.
The Zhongyun 2 would be equipped with two Pratt & Whitney R-985 “Wasp Junior” engines, an improvement of the Zhongyun 1’s Wright R-975E-3 “Whirlwind” engines. On December 19th of 1948, the Zhongyun 2 took off successfully for the first time. It is worth noting, however, the pilot reported slight shakiness during flight. The observers told the designers that the Zhongyun 2 looked beautiful in flight. With that in mind, the designers worked hard to improve the Zhongyun 2’s design.
There was a plan to make a full metal version of the Zhongyun, named “Zhongyun 3”. The designer estimated that the Zhongyun 3 would reach 353km/h. Work was in progress until December 1st 1948, when the 2nd AFAMF evacuated to Taiwan and stopped all work on the Zhongyun 3.
In late 1949, the Nationalists lost the Chinese Civil War. This forced them to flee to Taiwan. During their evacuations, the Nationalists left behind the Zhongyun 2 in haste. As a result, the Zhongyun 2 was pressed into service by the Communists and performed a test flight by pilot 刘懊统 (Liu Au Tong). The flight path was intended to go from Nanchang airfield to Hanko. During the test flight, the Zhongyun 2 allegedly suffered from an engine malfunction mid way, and tried to return to Nanchang. The Zhongyun 2 would never make it back to Nanchang, and was assumed to have crashed.
The Zhongyun was a domestically designed plane made from wood and metal. The design resembles a tubular cylinder with a rounded, pointed nose. The Zhongyun series used components taken from scrapped planes, and used American instruments in the cockpit. Zhongyun 1 had three windows on each side of the passenger’s compartment, followed by a door near the tail. This would later change to four windows in the Zhongyun 2, with the last window after the door.
Zhongyun 1 – Initial design powered by two Wright R-975E-3 “Whirlwind” engines. Made from a combination of metal and wood. The sole prototype met an unknown fate, but a replica can be seen in the Beijing Aviation Museum.
Zhongyun 2 – Improved design of the Zhongyun. It was powered by two Pratt & Whitney R-985 “Wasp Junior” engines. The flaps, ailerons, passenger compartment and the tail wheel was all refined and improved. The landing gears were replaced by the P-40B’s landing gear. The Zhongyun 2 would meet an unknown fate during a test flight by Communist Chinese pilots.
Zhongyun 3– Planned variant that would be made completely out of metal. Work was underway before the design staff evacuated to Taiwan after Chongqing was liberated by the Communist Chinese, thus stopping all work on it.
Zhongyun Bomber– Shortly after testing the Zhongyun 1, the Chinese realized that this plane had great potential for being a light bomber. However, this never happened due to the Japanese capitulation and lack of funds.
Republic of China – The Republic of China Air Force was the primary operator of the Zhongyun series.
Communist Party of China – The Communist Party of China briefly operated the Zhongyun 2 before it supposedly crashed during a test flight.
51.1 ft / 15.58 m
39.2 ft / 11.95 m
8.7 ft / 2.67 m
2x Wright R-975E-3 “Whirlwind” (450 hp)
6660 lbs / 3021 kg
214 mph / 344 km/h
6940 lbs / 3148 kg
17500 ft / 5334 m
1054 miles / 1696 km
8x Passengers or Cargo
Gang, W., Ming, C. Y., & Wei, Z. (2011). 中国飞机全书. Bei jing: Hang kong gong ye chu ban she.,中國自行設計的第一種雙發運輸機—中運一號及中運二號. (n.d.). Retrieved September 30, 2017., Huang, X. (2012). 中華民國飛機百年尋根. Tai bei shi: Gao shou zhuan ye., Chen, Y., & Liu, W. (1991). Kang Ri zhan zheng shi qi Zhongguo kong jun fei ji. Taipei?: Zhongguo ji yi zhu ban she.
The Ikarus IK-2 was the first all metal, high wing monoplane fighter built designed and built in Yugoslavia, for the Royal Yugoslavian Air Force. The transition from biplane to monoplane gives this high-wing fighter a distinctive appearance, not unlike a gull in flight. The Ikarus’ powerful engine and impressive armament paved the way for Yugoslavia’s later advanced monoplane, the IK-3. Its performance in key areas gave it an advantage over the Hawker Fury. The IK-2 saw combat against Germany’s advances in the early 1940’s.
At the beginning of the 1930s, the Yugoslav Air Force was mainly equipped with the old (Czech) Avia BH-33 biplane fighters built by “Ikarus” under license. During the second half of the thirties and early forties the company “Ikarus” designed and later produced the first Yugoslav all-metal, high wing, monoplane fighter aircraft named IK-2. The IK-2 was constructed by a team led by engineers Ljubomir Ilić and Kosta Sivčevićem.
The first prototype was named IK-1L. The capital “I” is for Ilić “K” for Kosta, the “L” was for fighter, Ловац-Serb. (on some sources it was mark as IK-L1) The prototype was completed in 1934, and was ready for its first flight testing by April 1935. It had a Hispano-Suiza 860 hp engine, and it was planned be armed with a 20mm cannon, and two Darn type machine guns caliber 7.7mm.
The wing was braced with two struts on each side of the fuselage, the fixed and conventional landing gear was spatted and mounted off the wing struts. The half glazed cockpit was located behind the wing. The horizontal stabilizer on each side was braced from below with two rigid braces from the lower tailcone, and tied from above with two flying wires from the vertical stabilizer.
IK-1L had a difficult start, due to a disagreement between the manufacturer and military top brass, but also by individual pilots like Captain Leonid Bajdak who was a great supporter of biplane aircraft. Unfortunate for the constructors a decision was made, that Leonid Bajdak would be the first test pilot for the IK-1L to determine if the plane had the potential for further development and eventual production. The first test flight was conducted on 22 April 1935 at Zemun airfield near Belgrade. In these tests, which were scheduled for several days, a light fuel load was used and the plane was not equipped with any weapons.
The following day, Bajdak put the IK-1L into several aerobatic maneuvers, and at that time there were no major problems. But during the third test flight there was an accident in which Bajdak made several unplanned aerobatics and in one of them he failed to cope with the loss of power and was forced to bail out with a parachute, while the IK-1 crashed to the ground. Although he insisted the plane was unsuitable as a fighter plane, a detailed analysis of the incident revealed that the accident was a consequence of poor build quality. Despite the opposition of some pilots, including Bajka, Ikarus company decided to build a second prototype with more reinforced wings construction and with much better assembly.
Second prototype got the name IK-02 (or simply IK-2 depending on the source) and it took about ten months to be built and was completed in June 1936. The main difference from the IK-1L was that the IK-02 had wings covered with metal sheeting, leaving only the rear fuselage and tailplane fabric covered. Other changes were a radiator of reduced size and improved shape, and modified air intakes, making for a more streamlined fuselage. This prototype was armed with one 20mm cannon, and two machine guns mounted above the engine. Machine guns were initially Darn type caliber 7,7mm but were replaced with the new Browning 7,92mm.
After several tests flights, there were some minor changes, like the new improved cockpit layout. IK-02 also participated in several mock (16 to some sources) dogfights against Hawker Fury biplane which was already part of the Yugoslav Air Force. In this mock dogfights IK-2 showed complete superiority in all respects over the biplane.
The interesting fact during this tests flights, there was a fierce discussion between two pilots of the “old school” Captain Leonid Bajdak and the new test pilot 1st Lieutenant Janko Dobnikar, that resulted in a “fly duel”, IK-02 vs. the Hawker Fury. The conditions of the duel were:
Taking off and climbing up to 4000m above sea level, at Zumen Airfield,
Race on the route Belgrade-Novi Sad-Belgrade (some 140 km)
A mock dogfight above Belgrade.
The first two rounds were easy victory for the IK-02. The final round was a spectacular aerial battle over the Capital Belgrade. Despite his experience, Bajdak simply could not put his Fury in position behind the IK-02, while Dobnikar once was in position of the Fury, he kept on his nose until the end. Bajdak had to end the fight and acknowledge defeat.
Unfortunately the fate of this plane was similar to the first one. It was lost in an air accident during June of 1940 when flying in bad weather and hit by lighting. The pilot managed to save himself with the parachute, but the plane was lost.
Since additional testing and postponing the start of production took a lot of time, only a small batch of 12 aircraft were built until 1939 six were delivered in December 1938 and six more in February 1939 by the Ikarus. But while still in series production this plane was obsolete, and the planned later production was dropped, but nevertheless they saw some use in the April war German invasion of Yugoslavia 6th -18th April 1941.
Before the start of the German attack on the April 6th 1941, all available IK-2 fighters were located in the 2nd mixed Air Brigade, which consisted of the 4th Fighter Regiment and the 8th Bomber Regiment in total 20 Hurricanes, 8 IK-2s and 23 Blenheims were based in Bosanski Aleksandrovac, Bosnia. The primary mission of The 2nd mixed Air Brigade was to defend the territory of Croatia, Bosnia and Slovenia from possible enemy attacks and to provide fighter support for the 8th Bomber Regiment.
On the first day of the war, The 2nd MAB only carried out scouting missions in the direction of Austria and there were few encounters with enemy planes without losses on either side. During the following days, performing their primary task, the 4th Fighter Regiment tried to stop a German air attack on the airport of Rovina near Banja Luka, at which the 8th Bomber Regiment was based. Some eight Hurricanes and six IK-2sattacked a group of 27 German Me-109s. Although it seemed that they did not have any chance, thanks to the knowledge of the hilly terrain and the cloudy weather they managed to surprise the German fighters. In the battle that followed, three Yugoslav and two German fighter planes were shot down. For this air battle, we could say that the Yugoslav fighter emerged as winners, because the primary goal of airport security and safety of the 8th Bomber Regiment was achieved.
The same day, these bombers were sent on to carry out bombing runs on the enemy territory of Hungary. Of 13 planes that had left the airport without the support of the fighters only 4 survived.
On April 9th, the Germans launched new air attacks on the 8th Bomber Regiment Aerodrome. At first only one IK-2 intercepted German aircraft. The lone IK-2 managed to get out of the fight with no damage. Soon almost all available Yugoslav fighters joined the battle Six IK-2s and eight Hurricanes in total 14 Yugoslav vs. 27 German aircraft. The battle was somewhat chaotic, Yugoslav fighters attacked individually or in pairs, while the Germans attacked larger groups. The battle lasted around 10 minutes, as the Me-109s were running out of fuel, they left the battle. Yugoslav losses were two Hurricanes and one IK-2. German losses are unknown, but it is estimated they sustained one or two losses.
After the 9th of April, because of the bad weather, there were very few flights. In the days that followed the 4th Fighter Regiment shot down one more German plane, a Ju-88. As German ground forces approached the airport on April 14 all planes were destroyed by the ground crew.
At the end of the April War, the Germans allocated three IK-2s to the Independent State of Croatia “NDH”. In order to equip existing aircraft with spare parts and fuel, and thus extend their operative use, Croatian Air Forces with German approval tried to collect as many military materials from airports and factories located in Serbia.
IK-2s were stationed in the 6th Air Group in Sarajevo by the end of 1941. Participation of these planes in the war was limited. By the 1944 they were removed from operational use, because of the lack of any spare parts, their final fate remains unknown.
Kingdom of Yugoslavia (Kraljevina Jugoslavija) – Eight were used during the April War.
Independent State of Croatia NDH (Nezavisna država Hrvatska) – Used few planes supplied by the Germans, their service was limited.
37 ft 5 in / 11.4 m
25 ft 10 in / 7.8 m
12 ft 7 in / 3.84 m
190 ft² / 18 m²
One Hispano-Suiza liquid-cooled V-12 piston engine 860 hp (640 kW).
Maximum Takeoff Weight
4,094 lb / 1857 kg
3,311 lb / 1502 kg
16,000 ft / 5,000 m in 5’ 25’’ minutes
270 mph / 435 km/h
155 mph / 250 km/h
435 mi / 700 km
Maximum Service Ceiling
39,370ft / 12,000m
One 20mm cannon Hispano-Suiza HS.404 – fixed forward-firing cannon in an engine installation.
Two 7.92 mm Browning/FN machine guns with 250 rounds per gun.
Kratka istorija vazduhoplovstva u Srbiji, Čedomir Janić i Ognjan petrović, Beograd 2011.
Elitni vidovi jugoslovenske vojske u Aprilskom ratu. Dušan Babac.
Zrakoplovstvo nezavisne države Hrvatske 1941-1945, Vojislav V. Mikić, Target Beograd 2000,
Lovačka Avijacija 1914-1945. Zlatko Rendulić, TEOVID Beograd 2014,
Empire of Japan (1944) Rocket Powered Fighter Aircraft – 7 Built
The Suzuka 24* was an obscure rocket fighter plane developed from the Yokosuka MXY-7 “Ohka” suicide bomber. The Suzuka 24 was armed with two 20mm cannons and is speculated to have been powered by a Toko Ro.2 (KR-10) rocket. It was allegedly seen in action 3 times near the end of the Pacific War by B-29 bomber crews, but did not inflict damage and retreated shortly afterwards. A single example was found in Suzuka Airfield after the war, which led to the name “Suzuka 24”. The machine was further described in detail in a prisoner of war interrogation with two Japanese petty-officers.
Please note this article is done in collaboration with Eun Ae Sun’s (Mai_Waffentrager) Sensha blog. The article is still a work in progress as info is still being collected. The article will be updated as soon as more info is found and verified. Please also note that some of the information presented here is speculation, and will be corrected when verified sources are found.
* – The “Suzuka 24” was the American designation for the aircraft. The actual name is not yet known.
One of the most troubling machines for the Japanese during the war was the Boeing B-29 Superfortress. The B-29 could fly at high altitudes with little resistance due to the lack of performance of Japanese aircraft at such altitudes. The Japanese developed many aircraft in response to this threat such as the Ki-94-II, Ki-61-II, J8M/Ki-200 and probably the Suzuka. It is undeniable that the German technology exchange program helped the Japanese substantially in their rocket development.
It is unknown whether or not the Suzuka was developed by the Army or the Navy, but the original Ohka model was developed used exclusively by the Navy. The Army would have been a more likely designer and operator, however. The Suzuka was rumored to have been developed late 1944.
During the war, a few examples of the Suzuka were found by the US military on various airfields. The first such discovery was made by AC/AS intelligence when they photographed Suzuka Airfield and found a single example. Soon afterwards, XXI Bomber Command discovered 4 examples on photographs of an airfield in Kanoya. The photos are yet to be found.
In an interview conducted post-war of two Japanese petty officers confirmed the existence of the Suzuka. One of the interrogates described seeing the Suzuka at Yokosuka airfield in October of 1944. He described it as a “ground-launched, rocket-propelled, interceptor bomb”. The primary target seems to be Boeing B-29 Superfortresses.
One of the biggest misconceptions is that Suzuka is related to the Ohka 43B, which is incorrect. The Ohka 43B and Suzuka are two completely different machines.
The Suzuka 24’s design differed from the Ohka significantly. First, the Suzuka completely removed the warhead from the nose and replaced it with a fuel tank and two 20mm cannons were fitted. (There is debate as to whether the 20mm cannons were Ho-5 or Type 99)
The tail of the Suzuka also differed significantly from the Ohka. The tail was redesigned to accommodate the new fighter role. It featured a singular vertical stabilizer along with a horizontal stabilizer, as opposed to the Ohka’s twin vertical stabilizer. This design would have improved handling in flight. The wingspan of the Suzuka was increased by 0.5m on each side and was reinforced. This would help with maneuverability.
The engines for the Suzuka was one of the most important changes. The average Ohka Type
11 would be powered by three Navy Type 4 Mark 1 Model 20 rockets, each producing approximately 2.6 kN (590 lbf) of thrust. The Suzuka would be powered by a single Toko Ro.2 (KR-10) rocket (Japanese copy of the Walter HWK 509A rocket used in the J8M/Ki-200 interceptors) producing around 14.7 kN (3007 lbf) of thrust. The fuel capacity accommodated an estimated 7 minutes worth of fuel.
The Suzuka 24 would have been launched from a ramp, and is unknown whether or not it had landing gear.
Highlights of the Aircraft’s Service Record
There were a total of three different alleged combat encounters of the Suzuka 24 near the end of the war.
The first encounter occurred on April 3rd of 1945 during a B-29 raid on the Tachikawa Aircraft Factory. A B-29 crew reported seeing a “ball of fire” at their 5 o’clock closing in behind them.The B-29 pulled quick evasive turning maneuvers while lowering their altitude. The “ball of fire” quickly closed in on the lost distance, but suddenly turned back a few seconds later. One of the crew members reported that he saw a stream of fire following the object, and faded when the object turned. The blister gunner reported seeing a wing attached to the object, and what seemed to be a navigational light burning on the wing’s left tip.
The second encounter occurred during a raid near Tokyo Bay. A B-29 crew member reported seeing a “ball of fire” following it at approximately 4,000ft (1,220m) while the bomber was at approximately 7,000ft (2,130m). The B-29 began evasive maneuvers right away, gaining and losing 500ft (152m) quickly. It also changed its course by 35 degrees, and increased the airspeed from 205mph (330km/h) to 250mph (402km/h). The B-29 crew lost sight of the “ball of fire” three times as it was flying through the clouds but to their surprise, found it sitting on their tail when the B-29 came out of the clouds. The “ball of fire” followed the B-29 for approximately 5 miles (8km) across Tokyo bay before turning around.
The third encounter supposedly happened at night, a waist gunner of a B-29 at 8,000ft (2,440m) reported seeing what was thought at first to be light from an amber colored searchlight. The light gained altitude and followed the B-29. The pilots then climbed to 12,000ft (3,660m) and then came down to 10,000ft (3,050m) but the light followed. The radar operator then picked up an object trailing behind the B-29 at approximately 1 mile (1.6km) behind. Shortly afterwards, the tail gunner reported seeing a stream of fire emanating from the pursuing object. The fire appeared to be coming out in bursts, with each burst measuring approximately 24 inches (61cm) with a 6 inch (15cm) break between each burst from the gunner’s perspective. The fire kept emanating for about 7 minutes before ceasing for good. The B-29 continued through evasive maneuvers, but the object kept on following. The object was last seen about 30 miles beyond the coast line above the ocean.
Empire of Japan – The designer of the Suzuka 24 is unclear, but it’s speculated to be either the Imperial Army Air Service or the Imperial Naval Air Service. It was rumored to have seen action in the closing stages of the war.
Estimated 20 feet / 6.097m
Estimated 20 feet / 6.097m
Speculated to be 1x Toko Ro.2 (KR-10) rocket – 3,307 lbs / 1,500kg thrust
Estimated 10,000ft / 3,050km per minute
Maximum Glide Speed
Estimated 520mph / 840km/h
Maximum Service Ceiling
Estimated 32,000ft / 9,755m
2x 20mm Ho-5 or Type 99 cannons* (60 or 150 rpg)
*- It is unknown which of the two would have been used.
Republic of China (1942)
Prototype Fighter – 2 Built
The XP-1 can be considered one of the most obscure planes in World War 2. It is relatively unknown in the Western world, and the fact that it utilized a very unique design by a nation that was relatively inexperienced at designing and building planes. The XP-1 was a Chinese-designed plane that was first conceived in late 1940, and was finalized in 1944. The purpose of it would be to specifically counter the Japanese A6M Zero, and also try to regain aerial superiority in the Chinese skies. Two models were built, one of which would crash on its maiden flight, and the second model would meet an unknown fate.
The initial design of the XP-1 came from a man named Constantine L. Zakhartchenko. He was a Russian emigre in America who studied at MIT and received a master’s degree in aeronautics. In 1935, the Republic of China’s 1st AFAMF (Air Force Aircraft Manufacturing Factory) hired Zakhartchenko as a designer to work for them.
In the summer of 1940, the Republic of China Air Force faced the Mitsubishi A6M2 Zero for the first time, and it proved to be vastly superior over the Polikarpov I-16 and I-153 (which were supplied by the Soviet Union) the ROCAF currently had in service. This caused mass panic amongst the Chinese Air Force, and prompted the Chinese Air Force industry to make a plane that would be able to face the A6M2 on even (or better) terms. The project was officially approved in 1942 and Zakhartchenko was put in charge. The new project would start out designated as “D-2”, and later on be changed to “研驱-1” (meaning Experimental Machine) or “XP-1”. The XP stood for (Experimental Pursuit) as the Chinese was following the structure of the USAAF in an attempt to improve their own air force.
On January 9th of 1943, Zakhartchenko’s contract with the 1st AFAMF expired, but he voluntarily stayed until June (he would later return to the United States and join the McDonnell Douglas company). Due to this, the director of the 1st AFAMF Lei Zhao Hong (雷兆鸿) took over the responsibility of design. As the XP-1 was being finalized, there came the need to find a good engine to power it. Hong made a request to the Committee of Aviation for two fighter engines (although he did not specify which model), but was initially denied due to the lack of spare engines. However, the Committee of Aviation did commence a search for spare engines, and eventually found a single Wright SGR-1820 salvaged from a crashed USAAF C-47. The 1st AFAMF gladly took it in, but saw that the propeller would need to be replaced. An order was then placed to the 2nd AFAMF to produce a propeller. Once the propeller was fitted, the XP-1 prototype was almost ready. However, progress was hindered even further when the Japanese launched Operation Ichi-Go on April 14th of 1944, which forced the airfield to be relocated to Guiyang, in the Guizhou Province in Southwest China.
On January 18th 1945, the XP-1 would finally have its maiden flight. The pilot chosen for the flight was Tan Shou (谭寿), an experienced Chinese-American pilot who joined the Chinese Air Force in 1927. Before the test flight, observes noted that Tan Shou was in his most flashy flying gear, which included a leather jacket, a pair of aviator sunglasses, a leather flying cap, a polished pair of dress shoes and an American-made parachute. Usually when a prototype aircraft is about to have its maiden flight, there would be a massive celebration which would include a ribbon cutting ceremony and a tea party. As the Chinese wanted to keep the XP-1’s test flight a relative secret, only a small number of military officials were invited to observe. Tan Shou taxied the plane to the Southern end of the airstrip, and turned 180 degrees to face the North. Once the plane accelerated about 500m, it took off and was met by cheers and applause from the spectators. The plane climbed steadily until reaching 500m, where Tan Shou then began maneuver trials. He initially turned left of the airfield, which went fine. On the second turn, the plane experienced instability and went into a tail spin. This would ultimately end in with the plane crashing into a tree, then a house. The initial impact instantly killed Tan Shou, and completely destroyed the plane. Tan Shou was the only casualty of this incident.
Results and Aftermath
Shortly after the crash, the Lei Zhao Hong gave the blueprints to the Chongqing Aeronautics University and the Chengdu Aeronautics Research Facility to get their opinion on why the XP-1 failed. Chongqing University concluded that the design was not stable, and was thus the cause for the crash. Chengdu Aeronautics Research Facility did not give an answer. However, the local factory workers believed that the American engine they salvaged from the crashed C-47 was the reason why the plane crashed. As a result of the crash, the very obscure XP-2, still in the design stage, was cancelled.
There is debate as to why the XP-1 crashed amongst the history community. When Tan Shou turned left the first time after reaching 500m, the people spectating the plane were obstructed by trees, and thus could not get an accurate look at the incident leading up to the crash, meaning that eyewitnesses had little to contribute to the debate. The first theory speculates that once he reached 500m and turned successfully, he then tried to pull up but couldn’t due to the weight of the engine. He tried to pull up a second time, but to no avail. Tan Shou then tried to turn back to the airfield to land but the plane dove too fast, thus destroying both him and the plane. The second theory is that on the second turn, Tan Shou tried to pull up but the controls stiffened, thus not allowing Tan Shou to maneuver. Due to this, the XP-1 stalled and went into a flat spin and caused him to crash.
The crash of the XP-1 didn’t particularly affect the Chinese Air Force, as they were already receiving superior Lend-Lease planes from the USA (such as the P-51D, or the P-40) at the time which could fight the A6M Zero on equal terms.
Interestingly enough, the second XP-1 would be met with an unknown fate. There are some theories as to what possibly happened to it.(***) The first theory would be that during Operation Ichi-Go, the XP-1 was destroyed by Japanese bombing either in the factory or during transport. The second theory was that after the first XP-1 crashed, the second one was either scrapped or sent to either the Chongqing Aeronautics University or the Chengdu Aeronautics Research facility for evaluation, where it was eventually scrapped too. The third theory is the second XP-1 was hidden somewhere to prevent capture by the Communists during the Civil War. The fourth theory is that the Communists could have destroyed the XP-1 during the Civil War during a firefight.
(***) Please note that these are all theories and speculations, with no solid evidence to back it up.
The XP-1 took inspiration from many foreign aircrafts, but also had unique features to it as well. Its engine cowling resembled that of the P-43 or the P-47. Its canopy was designed after the P-40’s canopy. Also, the tail structure was strongly influenced by the CW-21. Its wings were designed in a gull style, similar to the Ju 87 or F4U (but not inspired by them). The landing gears however, were a unique design. It was also fitted with American cockpit instruments (altimeter, speed gauge, fuel gauge, etc.). It was however, not fitted with a radio which would have made it more difficult to communicate, and is one of the reasons why the circumstances around the XP-1’s crash is unclear – the ground observers didn’t know what Tan Shou was trying to do.
For armaments, there are no credible sources which mention what weapons the XP-1 would have received. However, the most popular and agreed upon armament would be four Hispano Suiza 404 cannons. This is unlikely as the XP-1’s design would not have allowed such armaments if space and weight was considered. The M2 Browning or M1919 would have been more likely candidates. Ultimately, it is unknown precisely what the armament would have been as both XP-1 prototypes were solely to test the aerodynamic properties of the design.
XP-1 – Original model powered by a Wright R-1820F-3 Cyclone. Two models were made in 1944, none of which were armed. One crashed during its maiden test flight, and the second one met an unknown fate.
XP-2 – Nearly nothing is known about this design other than the fact that it was to be powered by an Pratt & Whitney R-1690 Hornet engine and was partly based on the XP-1. The XP-2 remained a paper project only and was cancelled after the crash of the XP-1.
Republic of China – The ROCAF was the only operator of the XP-1.
Empire of Japan (1945) Prototype Special Attack Aircraft – 3 Built
The Ta-Gō was an attempt at creating an easily made and cheap kamikaze aircraft in anticipation of Operation Downfall and Operation Olympic. The plane would have been used by special “shinpū” (kamikaze) units to ram advancing Allied tanks, infantry and boats. Fortunately for the Allies, the Ta-Gō project was cancelled once the Empire of Japan capitulated.
The concept of the Ta-Gō came in late 1944, when Japan was beginning to lose the war. With the recent loss of Guam, Okinawa, Iwo Jima, and other islands, Japan’s military was becoming weaker and weaker. By 1945, Japanese factories and industries suffered from constant bombings by the USAAF. This led to the deprivation of much needed materials to produce planes and tanks. Because of this, much of the already existing aircrafts were designed to be built with wood. (Example: Ki-106 from Ki-84, D3Y from D3A). Even then, Japan’s industry could barely produce such planes due to the situation of the war.
Watching his country’s resources slowly depleting and the rapid advance of the Allies, IJA Captain Yoshiyuka Mizuyama wanted to make a difference. He wanted to design a simple, cheap and easily producible plane requiring minimum materials for designated kamikaze units. If the Ta-Gō was mass produced, it could easily fill already depleted kamikaze units, and would make kamikaze attacks more popular. Once Mizuyama finished designing the plane, he went to Tachikawa Hikōki Kabushiki Kaisha (Tachikawa Aircraft Company) and submitted his design. His design was however rejected because Tachikawa Hikōki simply could not afford to allocate resources for the Ta-Gō. It was also rejected due to the fact that Mizuyama’s design was not officially approved by the state.
Determined to initiate his project, Mizuyama looked around the city of Tachikawa until he discovered a small woodwork shop. He rented the shop and began constructing his first prototype with the help of his men. Around February of 1945, Tachikawa was firebombed by the USAAF. The workshop was completely destroyed along with the sole prototype. Still determined to initiate the project despite the major setback, Mizuyama approached Nippon Kokusai Kogyo K.K (Japanese International Aviation Industries Ltd) to continue his project. Luckily for him, Kokusai accepted his project. Since Kokousai accepted the project, they asked that Mizuyama redesign certain parts of the plane to so that it would require even less materials and manpower. The Kokusai design’s dimensions was significantly scaled down compared to Mizuyama’s original design and was simpler altogether.
Now satisfied that his work was accepted, he began building the new model of the Ta-Gō with help from Kokusai. The prototype was completed around the middle of June, and was test flown for the first time on June 25th, 1945 with an experienced pilot from Kokusai in the cockpit. The test pilot expressed obvious handling concerns and gave helpful tips to the designers. As a result, the Ta-Gō participated in more test flights and was modified on the drawing board. In the end, the blueprints for the production variant were finalized. Unfortunately for Mizuyama and Kokusai, the Empire of Japan surrendered to the Allies in August of 1945, and the Ta-Gō never entered production. Interestingly enough, the Allies discovered two variants for the Ta-Gō named “Gi-Gō” and “Tsu-Gō” after Kokusai surrendered all their documents. However, there is no known information on them today.
Tachikawa, funnily enough, took on the project too after the Kokusai prototype was completed and authorized by the Gunjushō (Ministry of Munitions) despite them rejecting the project earlier. Once the American Occupation forces arrived in Japan, they found the Tachikawa Ta-Gō incomplete. Once the Ta-Gō was accepted, it was given the designation Ki-128. It is not confirmed whether the designation was for the Kokusai or Tachikawa variant or both.
The Ta-Gō was a single seated kamikaze plane made mostly out of plywood, fabric, and wood lathes. The original Ta-Gō design used wood lathes for the fuselage and structure, and used plywood and fabric for the outer skin and control surfaces. The pilot’s compartment featured a simple acrylic glass. The landing gear was fixed, meaning they couldn’t be retracted. It featured a Hitachi Ha-13 Ko 9-cylinder radial engine that produced 450hp, with thin steel sheets as the engine cowling. The only armament it could carry was a 500kg bomb, which cannot be released. Other than these details, little is known about the original Ta-Gō as hardly any evidence exists.
The refined design for Kokusai made the Ta-Gō much smaller than its original size. Due to this, the plane could no longer house the Hitachi Ha-13 Ko, and was replaced by the Hitachi Ha-47 11 producing 110hp instead. Because of the severe engine power decrease, the 500kg bomb load had to be changed to 100kg. Another change from the original design was the cockpit was open topped. The only thing that covers the pilot is a simple acrylic glass pane that shields from the wind. As for the engine, it was protected by an angular wooden cowling. The engine was paired with a two-blade fixed pitch wooden propeller. The engine mount was made of metal, with the fuel tank placed on top of the engine, thus using a gravity feed system. In between the acrylic glass pane and the fuel tank, there was an oil cooler. As for cockpit instruments, only the very basic and important ones were kept. Such instruments used were a compass, speedometer, altimeter, and engine-related gauges such as fuel and oil. The fuselage was also boxier than the original design. This design feature was extremely simple to manufacture, but was very un-aerodynamic.
The fuselage and structure was made with wooden spars and plywood, much like the original Ta-Gō. The wings were rectangular shaped, and were hinged near the landing gear, which allowed the the wings to fold upwards. The reason why the wings could be folded was because the Ta-Gō was suppose to be hidden in caves and take up less space in the factory line. The rudder and elevator of the Ta-Gō were both rectangular shaped. As for the landing gear, it was made out of steel tubing and paired with rubber wheels. Each landing gear was supported by a metal strut.
Original Ta-Gō: The original Ta-Gō was powered by a Hitachi Ha-13 Ko (450hp) and could carry a 500kg bomb. It was almost completed before being destroyed in a bombing raid. Only one photo of the original prototype is known to have existed.
Revised Ta-Gō:The revised Ta-Gō design featured a smaller airframe to save the factories effort and materials. As a result of this modification, the engine had to be changed to a Hitachi Ha-47 11 (110hp) and the bomb load was reduced to 100kg. Two of these were made. One was completed by Kokusai, test flown and evaluated while the other one by Tachikawa was incomplete.
Gi-Gō: The Gi-Gō was a late war development of the Ta-Gō. There is no information known about it to this date. The project was commenced by Kokusai.
Tsu-Gō: Like the Gi-Gō, the Tsu-Gō was developed very late in the war. No information about it has been discovered to this date. The project was commenced by Kokusai.
Empire of Japan – The Ta-Gō would have been used by special kamikaze units in both the army and navy.
The Messerschmitt Me 209 (also known as the Bf 109R) was a racing plane designed by Willy Messerschmitt in 1938. The Me 209 would later establish a new world record which would not be beaten until 30 years later. Although commonly associated and confused with the Me 209 fighter plane designed in 1943, it holds no association at all other than the name. To this day, only the fuselage of Me 209V1 has survived and is now on display in a museum in Krakow.
Conceived in late 1937 by Willy Messerschmitt, the primary and sole focus of the Me 209 was speed. On August 1, 1938, the first test flight of the Me 209V1, piloted by Hermann Wooster, had lasted only 7 minutes due to engine and coolant problems.
Even though established practice dictated that if an aircraft had more than a dozen problems, it was to be abandoned, however Nazi officials were unwilling to give up on this promising aircraft due to the potential impact the aircraft could generate. Eventually, on April 26, 1939, piloted by Fritz Wendell, the Me 209 set the speed record it would hold for 30 years, though the He 100, the previous record holder, was suspected to have been able to break this record had it flown at a higher altitude but was prohibited from doing so by Nazi officials.
The designation Bf 109R was used for propaganda uses in order to cause confusion with the Luftwaffe’s primary fighter, the Bf 109, to maintain an image of invincibility which persisted until the Battle of Britain.
The Me 209 had a unique design, featuring a cockpit placed far back at the rear and a cross shaped tail section. A difference between the Me 109 and 209 was that it had a broad-track, inward-retracting undercarriage mounted in the wing section, instead of the fuselage. There was no tail wheel, instead using a spring loaded metal skid, which retracted into the lower part of the tail.
Because of the success of the racer, the Nazis attempted to arm it. The main factor that had inhibited adding weaponry was the fact that wings were almost entirely taken up the engine’s liquid cooling system, which was massive. The engine consumed 2 gallons (9 liters) of coolant water a minute. Holding 50 gallons (450 liters) of coolant, it had a flight time of approximately 35 minutes.
On August 1st of 1938, the Me 209V1 flew for the first time. Piloted by Hermann Wurster, the test flight lasted only 7 minutes. Unfortunately, Wurster found the plane very unsatisfactory. In a Messerschmitt AG document found post-war by the Allies, it was found that Wurster made several complaints about the Me 209.
The engine ran unevenly
The high temperature reached by the coolant fluid resulted in unsatisfactory cooling
Cockpit ventilation was inadequate, and engine gasses entered the cockpit, which necessitated the constant use of an oxygen mask
The landing gear could not be extended at speeds greater than 155 mph (250 km/h)
The main wheels tended to drop out of their wheel wells during high speed maneuvers
Fuel filler caps loosened at high speed
Undercarriage hydraulic oil escaped from its reservoir and sprayed on the windscreen
The takeoff run was excessive, and the takeoff characteristics dangerous
Visibility from the cockpit was limited
Marked instability noted during climbing maneuvers
The rudder was inadequate to control the plane’s yaw movement
When banking at full throttle, the plane rolled itself over
Stick forces were excessive and tiring
At speeds around 100 to 105 mph (160 to 170 km/h) the controls softened up
Landing characteristics were extremely dangerous
On touchdown, the plane swerved violently
It was impossible to employ the brakes during the landing run, as immediately when they were applied, the aircraft swerved from the runway
The only remaining Me 209V1’s fuselage, formerly part of Hermann Göring’s personal collection, currently lies in the Polish Aviation Museum in Kraków, Poland. Germany has offered to purchase the Me 209 but has been unable to do so.
Me 209V1: The first version of the Me 209, which used the Daimler-Benz DB 601A and had steam cooling.
Me 209V1 (mod. 1939): This was the variant that set the speed record of 755.138 km/h (~469.22 mph). It was fitted with the DB 601ARJ engine, a modification of the DB 601A, which brought the total horsepower up to 2,300, from 1,800. It suffered greatly from overheating when operating at full power.
Me 209V2: It crashed during a test flight and was completely destroyed, and was subsequently abandoned.
Me 209V3: Originally intended to break the speed record, it was made too late. Instead, it became a test bed for improvements.
Me 209V4: One built. It was to be armed with two 7.92 mm MG 17 machine guns in the cowling and 20 mm MG FF/M cannon firing through the propeller hub. It also would have had lengthened wings and vertical stabilizer, strengthened undercarriage, a stock DB 601N engine, and did not feature a surface evaporation cooling system. Tests showed that the modifications made the plane inferior to the Bf 109E series, and was therefore abandoned.
Nazi Germany (1942)
Light Transport and Trainer – 1,216 Built
The Siebel Si204 was a twin engined light transport and trainer aircraft built by Siebel for the Luftwaffe in World War II.
The story of the “Siebel” factory starts in the 1934, with the founding of “Hans Klemm – Flugzeugwerke Halle“ that was a branch of “Leichtflugzeugbau Klemmin Böblingen”. In December 1937 the name changed to “Siebel Flugzeugwerke“ when it was taken over by Friedrich Siebel.
Initially Siebel had a license to produce the Focke-Wulf Fw 44 “Stieglitz” and later during the war Heinkel He 46, Dornier Do 17 and the Junkers Ju-88. In addition to the production of licensed aircraft, in 1937, “Siebel” produced its own aircraft under the name Fh 104. It had its first test flight that same year, and some 46 planes where build during the period of 1938-42. The Fh 104 made a number of notewortly flights:
In March of 1939 flying a 39975 km tour of Africa,
Winning the “Littorio rally in Italy”,
And flying a 6200 km across 12 countries in 1938 (Europa Rundflug).
By the end of 1930, “Siebel” company was commissioned by the Luftwaffe to design a new type of all-metal twin-light light transport aircraft with a capacity of eight persons with two crew members. In 1940 the first prototype of the twin engine and larger and also heavier Si 204 appeared with originally a conventional stepped cockpit and a powerplant of two 360 hp (268 kW) Argus As 410 engines . The prototype made its first flight during the period of May to September 1940. Second prototype made it first test flight in early 1941. The third prototype was re-designed as a trainer aircraft for blind flying. Because of this, its first test flight was only possible at the end of 1941 or the beginning of 1942. The other 12 planes produced by “Siebel” were used for general flight evaluation. After this small production run Siebel stopped building this aircraft, and future planes would be built in France and Czechoslovakia.
Model A was build in relatively small number by the French “SNCAC” (Société Nationale de Constructions Aéronautiques du Nord) factory. It was designed as a transport and communication aircraft.
The next model D appeared in 1942, with a new glazed nose and cockpit with no separate flat windscreen for the pilot. Almost all German bomber aircraft during the war shared this design. The D model also had more powerful 600 hp As 411 engines. The D model was used for radio navigation and for training. This model was mostly used during the war.
The production of the D-3 version start in October 1944 by the “Aero” company. The D-3 had wooden wings and a tail-plane made of wood because due to material shortages. In France, production of this aircraft was stopped in August 1944 as a result of the Liberation.
“BMM” produced the aircraft until October 1944 and then changed to producing spare parts for the Si 204. The “Aero” was scheduled to cease production of the D-1 in March 1945 after building 486 aircraft and then switch to D-3 only. The E version was built in limited numbers and can be considered as an experimental series.
After the war, production of Si 204 continued in Czechoslovakia and France. Czechoslovakia produced some 179 Si 204D, developed into military trainer variants Aero C-3A, passenger variant C-103 and military transport variant D-44. France produced 240 transport NC.701 Martinets and a number of passenger NC.702 Martinets.
During the war the Luftwaffe put the plane to use for transport, communication while also seeing use as an advanced trainer and blind flying trainer.
It was generally regarded as a good plane, but with some drawbacks like the lack of any armament, which prevented many exercises for the combat training program and possible use as a combat aircraft, although for this role it is not designed.
Designers in Halle had developed few different military projects, like installing bomb racks, machine gun turrets and other necessary equipment, but none of these plans were ever realized. This problem was attempted to be solved with some modified Si 204D airplanes with three 13mm MG 131 machine guns, intended to be used as a night combat aircraft but this model was not used in combat and was built in limited numbers.
Despite these unsuccessful attempts, Germans tried to make a new bomber variant, in order to be used in anti guerrilla fighting with a built to this specification. Three Si-204E were sent to the military tests in Belarus. They were treated as special anti-guerrilla aircraft. The scope of the actions of the Belarusian partisans forced the Germans to throw against them not only regular troops, but armored vehicles and aircraft. The extent to which they were used in this role remains unknown.
Si 204 is reported to has the “honor”, of being the last German aircraft shot down on the Western Front. On May 8, 1945 an Si 204 was shot down by an American P-38 Lightning, three miles southeast of Rodach, Bavaria.
Because Siebel produced the Junkers Ju-88 under licence and the need for as many military aircraft as possible, Germans decided to increase the volume of production for this aircraft. This was done by moving the production to French “SNCAC” and Czechoslovakian “Aero”, and “ČKD-BMM” factories. The “SNCAC” produced some 168 aircraft and the “Aero” and “ČKD-BMM” produced 1033 aircraft, Siebel produced only the first 15 prototype Aircraft, before the production was stop in favor of Ju-88. In total some 1,216 aircraft of this type where build, during the war.
Si 204 – Prototype version with 15 plane build by Siebel (Number V1 to V15),
Si 204A – Model A was a transport and a communication aircraft, with crew of two and eight passengers.
A-0 – Passenger plane version,
A-1 – French built version.
Si 204B and C – Were paper projects
Si 204D – Model with a new glazed nose and cockpit and with two 600 hp As 411 engines. Model D was used for radio navigation and for flying training.
D-0 – Blind flying trainer,
D-1 – Czechoslovakian production version,
D-3 – This model had wooden wings and tailplanes, in order to save on metal.
204E – Experimental night fighter plane. This model had on its nose two 13mm MG 131 machine guns plus one more machine gun (same caliber) in a glazed cupola on the upper hull of the plane. This model was not used in combat and was build in limited number using rebuild Si 204D planes.
E-3 – Proposed version to be armed with bombs, and to be used in anty guerrilla fighting, possibly only few were build.
Flying carrier – Paper project that was originally intended to carry one DM-1 (Doctor Alexander Lippisch plane) on the back of a Siebel Si 204. Little is known about this project
Aero C-3 – Used for flying and crew training,
Aero C-103 – Used for Civilian transport,
Aero D-44 – Military transport version.
SNCAC NC.701 Martinet – Military transport version with SNECMA 12S-00 air-cooled V-12 engines,
SNCAC NC.702 Martinet – Improved Passenger transport version.
Germany – Most produced planes where used by the Luftwaffe as advanced schools training, transport, blind flying trainer (usage in this role was at best was sporadic) and communication. There were plans for arming this plane for night fighter and anti-partisan operatons, but it all left on paper only with few model build and not a single one was used in combat.
Czechoslovakia – Used German build planes and the new Aero C-3 version after the war.
France – Used some captured German planes and also the NC. 701 version which was build by France after the war.
Hungary – Operated some C-3 Aero version after the war.
Poland – Used six NC.701 version.
Soviet Union –They were captured in some numbers at the end of the war. At first, the captured Si-204 was mostly used by the military. The headquarters of many regiments and divisions stationed in Germany used the Siebel for official flights, but only for short period.
Sweden – Operated five NC.701 (1962-1970) for mapping photography.
Switzerland – Operated some Si.204 D planes.
Specifications (Si 204D)
70 ft / 21.33 m
39 ft 3 in / 12 m
14 ft / 4.25 m
495 ft² / 46 m²
2x Two Argus As 411 12 cylinder inverted piston engines (447kW/600 hp)
The Saab B 17 is the product of Sweden’s need to procure assets to defend its sovereignty and neutrality in the light of a gradually complicated international and regional context, to the point that it was prioritized over the equally capable and versatile Saab B 18. This aircraft was a milestone for the main company in the Swedish aerospace industry, as it was the very first airplane produced and delivered by this company following its acquisition and merge with ASJA, the aircraft branch of the Swedish Railroad Workshops company. It was also the application of the lessons and experience provided by the licensed-manufacturing of the Northrop 8-A1 bomber by AJSA/Saab. AJSA was already commissioned by the Defence Material Administration to develop and build a single-engine and light fighter-bomber, so Saab took over the design and development process in 1939 after both companies merged, evolving into the final light bomber, dive bomber and reconnaissance aircraft. Designated as the L 10 by ASJA, the design became the Saab 17, incorporating a good number of innovations and becoming a very versatile and adaptable airframe. Yet its time of service with the Flygvapnet was rather brief, as it was de-commissioned by the late 40’s. This was due to new and more powerful powerplant technologies such as jet propulsion. Instead, it served for a long period of time in Ethiopia until 1968.
The Saab B 17 is a light bomber/dive bomber and reconnaissance plane with two seats, a single engine and a single tail, whose design bears a close resemblance with the Mitsubishi Ki-30 “Ann”, the Mitsubishi Ki-15, the Vought OS2U, and the Curtiss SB2C Helldiver, especially with the elongated shape of the main airframe and equally elongated windscreen of the cabin (as well as the same cockpit), which occupies most of the superior area of the airframe and it is fully incorporated in the fuselage. The wing is a mid-wing (cantilever) of trapezoid shape with a remarkable characteristic: where the retractable landing gear, which was covered with streamlined fairings, was placed, the rear part of the wing was divided. From the fuselage to the place of the landing gears, it was straight; from the landing gears area to the wingtip, it was angled. The forward area of the wing was straight, and the wingtips were rounded. The wing, from a frontal perspective, was slightly angled upwards from the landing gear area to the wingtip. It was also a reinforced wing to allow it to deal with the high stress by dive bombing missions.
The Saab B 17 was powered by different powerplants during its career, as many versions had their own powerplants. The two prototypes (L 10) were powered by a licensed-built Bristol Mercury XII of 880hp by NOHAB (Nydqvist & Holm AB) and by a Pratt & Whitney R-1830 Twin Wasp of 1065hp each. The first production version (B 17A) was powered by the same Pratt & Whitney R-1830 (S1G3C) of 1050hp, while the B 17B (and also the B 17BL and B 17BS) was powered by a licensed-built Bristol Mercury XXIV of 980hp, with the B 17C powered by a Piaggio P.XIbis R.C.40D of 1040hp. Consequently, speed tended to vary from version to version as well. For instance, the B 17A could reach speeds of up to 435 Km/h (270 mph); the B 17B could reach speeds of up to 395 Km/h (245 mph), the B 17BL and B 17BS could reach speed of up to 330 Km/h (205 mph); and the B 17C could reach speed of up to 435 Km/h (270 mph). The landing gear was also varied from version to version, as it could have the classic set of two wheels at the wings and a small tailwheel, skies as replacement for the wheels, and even special twin floats permanently attached. This gave the B 17 considerable versatility, as it could take off and land in normal runways to snow-covered terrain, and also in water surfaces.
The armament had no modifications, comprising of two 8mm Ksp m/22F machineguns placed at the forward section of the wings and after the landing gear area, a single and moveable 8 mm Ksp m/22R machine gun firing backwards for the observer/navigator/radio operator, and a payload of up to a 500-kg (1,102 lb) bomb or 700-kg (1,500 lb) bomb. Interestingly, the dive bomber version had an under-fuselage trapeze to accommodate a 500 Kg bomb, along the wing weapons stations. And it had state-of the art avionics for bombers by the time, like the bomb-sight BT2 (also known as m/42) that increased precision, mostly the late versions. In addition, it had two radios, an FR-2 and FRP-2. The reconnaissance version had a camera placed at the bottom of the fuselage.
The initial roles of the airplane were reconnaissance and artillery spotting, roles that were, however, already filled by other air assets such as the Fieseler Storch and the Hawker Hart. As a result, the new airplane was required to be a light dive-bomber as well. Nevertheless, the final model retained all of the two missions through its variants, as well as receiving a level light-bomber and dive-bomber role. It would also be used for target towing later in its career. The Saab B 17, like the B 18, had an American ‘soul’ as well, thanks to the 40-50 American engineers that were part of ASJA and contributed with the design and construction of the airplane, hence the abovementioned similarity with the American airplanes. And it needed to receive some structural modifications, especially for the dive-bombing missions, such as the reinforcing of the wings and the landing gear folding system. This could be retracted backwards and used as an airbrake, taking advantage of the fairing.
Development of the B 17 began in 1937 when ASJA began works on its L 10; as Saab merged with ASJA that same year, it continued with the development of the given aircraft, which would be an all metal airframe – something that was a novelty as airplanes back then used to have wood and other materials part of the fuselage. Two prototypes were built, each one having a different powerplant and flying for the first time in May 1940. The test pilot, Claes Smith, assessed the design as a good one, despite the fact the cockpit wheel came loose and fell prior landing. During development, it was realized that some modifications were needed, like changing the carburetor air intake from the top of the engine cowling to the starboard side of the cowling. This was done to prevent the engine from stopping. A spin fin was also added. By the end of 1940, the first 8 B 17s were produced, entering in service with the Flygvapnet in 1942. Some issues delayed the production programme, however. Nonetheless, 324 airframes were produced between 1942 and 1944, with three main versions: the B 17A light bomber and later target towing aircraft, the B 18B – and its sub-variants B 17B I, B 17B II, B 17BL and B 17BS – light bomber and reconnaissance versions (this version was the one that received most of structural the modifications), and the B 17C bomber version.
The B 17 had one of the shortest service period with the Flygvapnet, as it was retired 7 years after it was introduced; yet it remained in service in Austria, Finland, and Ethiopia until 1968. In Sweden, they remained in service with civilian operators and in very small numbers until 1959, where they received new avionics.
5 airframes remain, one of them airworthy and still operating today in airshows. Two are museum pieces in Linköping and one in Helsingør, Denmark. Two airframes are reportedly located in Lithuania.
The design of the B 17 is similar to other aircraft used in WWII by other countries, meaning it has the typical ‘WWII style’. But instead of being the average WWII design, the B 17 has some remarkable and particular characteristics. The airplane is an all-metal airframe, with the bow having a cylinder shape thanks to the radial engine and the stern is topped off with the tail, and the overall airframe being elongated with a sort of conical shape. The airplane is also a semi-straight leading-edge wing airplane, but the wings also have a particular characteristic. In fact, the wings have a ‘divided’ shape, with the area of the landing gear being the dividing point. First, from the fuselage to the landing gear, the leading-edge is straight while the rear-edge is also straight, having two ‘dog-teeth’ that mark where the rear area of the fairings are located. Second, from the landing gears to the tip of the wings, the leading-edge of the wings are straight as well, but the rear-edges are angled, making this area of trapezoid shape. The tips are rounded. The wings also have a divided shape from a frontal perspective, with the landing gear being also the dividing area. From the fuselage to the landing gear area, the wing is straight. However, from the landing gear to the tip of the wings, it is angled upwards, similar to the Ju-87 Stuka or the Douglas SBD ‘Dauntless’, only that the angle is not as wide. The wing, furthermore, is installed in the middle of the fuselage (cantilever), also being reinforced. Such reinforcement can be seen through its thickness. The horizontal stabilizers are also of trapezoid shape, with the control surfaces per se having an inwards angle at the tip of the surface. The tail has a similar shape with the rudder occupying most of the surface and having also an inwards angle near the tip. Both horizontal and vertical stabilizers have an equally rounded shape.
The canopy is another remarkable characteristic of the B 17, as it is very elongated, occupying almost 40% of the superior area of the fuselage and making an impression that the B 17 has a crew of three, rather than the actual crew of 2: the pilot and the radio operator/navigator/observer. As a result, the cockpit had a lot of space, which allowed the second crewman to slide the seat back and forwards between the two different workstations. Beneath the forward area of the cockpit was where the bombs bay was located. A long antenna was placed above the canopy, right after the pilot’s seat, with a long cable connecting it with the tail. The landing gear was of classic configuration, with two (extended) wheels placed beneath the wings and a third wheel placed beneath the tail. The two forward wheels have a particular trait that gave the B 17 another distinctive characteristic either in land or when in flight: the forward landing gears were covered with an aerodynamic fairing as it folded backwards, into the wing. The purpose was to use such fairing as an airbrake, yet it was not entirely functional as the hydraulic system wasn’t powerful. The fairings were met by a ‘hood’ of sorts at the wing; when the landing gear folded, it gave the landing gears cover a cylinder shape, making the B 17 to have two cylindrical structures at the wings while in flight, making easy its recognition while in flight. The B 17 went through a series of modifications, especially the reconnaissance versions, as they received floats – with the purpose of operating from water – along with small endplates (placed right before the wing tips) and aerodynamic struts. The landing gear, in turn, could be replaced with skis instead of wheels, an ideal device for winter or Arctic operations.
The B 17 received three different type of powerplants. The first two prototypes were powered by a NOHAB-built Bristol Mercury XII and a Swedish-made Pratt & Whitney R-1830 Twin Wasp engines. The production versions had the following powerplants: a Swedish-made Pratt & Whitney R-1830 Twin Wasp (B 17A); a Swedish-made (by SFA) Bristol Mercury XXIV (B 17B and the different sub-variants); and the Piaggio P.XIbis R.C.40D (B 17C). All the engines were radial and air-cooled, with 9 or 14 cylinders. The propeller was a three-bladed Piaggio P.1001 variable pitch propeller. The engines yielded different speeds. The B 17A could reach speeds of up to 435 Km/h (270 mph), the B 17B could reach speed of up to 395 Km/h (205 mph), and the B 17C could reach also speeds of up to 435 Km/h (270 mph).
The B 17 had a standard armament with no variation from model to model, except for those with reconnaissance tasks. It consisted of two 8mm Ksp m/22F mounted at the wings and firing forwards, and one 8mm Ksp m/22R mounted at the stern of the cockpit, which was moveable and could fire backwards. A 500 Kg (1,102 lb) (B 17A) or a 700 kg (1,500 lb) (B 17B andC) could also be carried. Some units of the B 17A were modified to carry air-to-ground rockets. The reconnaissance versions were fitted with a camera type N2. An advanced bomb sight named the ‘m/42’ was introduced to enhance bombing efficiency, especially at dive-bombing, reducing the angle of bombing.
The B 17 was the very first plane produced by Saab, and incorporated many of the lessons and experiences acquired with the licensed-manufacturing of the Northrop 8-A1 bomber by ASJA and then Saab itself, being also the first then modern all-metal light bomber produced by Sweden during WWII. As the m/42 bomb-sight was developed and introduced for this aircraft, it was reportedly exported to the US.
An ‘all-terrain’ airplane
If there is something that makes the B 17 a remarkable design, it is the fact that modifications to its landing gear allows the plane to operate from any type of terrain… literally. The main landing gear configuration is that with wheels for normal operations in normal airstrips. But when winter comes, the wheels could be replaced with skis, allowing the airplane to operate even in harsh cold weather conditions with snow-covered airstrips. This might indicate that Sweden needed an all-time available air asset to defend its sovereignty and neutrality, or maybe that it absorbed the operational lessons the Swedish Volunteer squadron that took part during the Winter War, or the lessons provided by that same conflict. But the B 17 received another modification that allowed it to operate from the surface of any water body, as it could be fitted with two floats replacing the wheeled-landing gears, becoming the B 17BS. This variant was mainly used for water-borne aerial reconnaissance.
Close to War and the architect of an air force
Despite being a rather obscured airplane in history, the B 17 would have been one of the few neutral airplanes to take actual part in a conflict, besides those belonging to the Flygvapnet that took part during the Winter War. For instance, the Danish Brigade, a unit comprised of refugee Danish airmen supported and equipped by Sweden, would have been close to assist in the liberation of their country, if it weren’t for the fact that the Swedish government did not allow it to take off with the supplied B 17 units to Denmark. The B 17s were then offered to the Danish Air Force, but were rejected as the German surrender took place some days before the offering was made, being returned to the Flygvapnet.
But the adventures of the B 17 would not finish there, Ethiopian country was looking for assistance in building a more advanced air force of its own after WWII. Sweden became the main supporter of this small air force, supplying Saab Safir trainers and B 17 light bombers, as they later were being phased out in 1947. It also employed some former Flygvapnet personnel and under orders of Carl Gustav von Rosen, who also became the chief instructor of the rebuilt Imperial Ethiopian Air Force. It remained in service there until 1968.
L-10 – The prototype version of the B 17 under the denomination it had when ASJA was tasked with the design and development process. One unit was powered by a NOHAB-made Bristol Mercury XII 880hp engine and another was powered by a Pratt & Whitney R-1830 Twin Wasp engine.
B 17A – Bomber version powered by a Pratt & Whitney R-1830-S1C3G Twin Wasp engine of 1050 to 1200 hp. Some units were modified to carry air-to-ground rockets. The armament of this version became standard for the bombers and its other variants: 2x8mm machine guns placed on the wings and firing forwards, and an 8mm rear machine gun placed at the second crewman’s post, along a 500 kg (1,102 lb) bomb. 132 units delivered.
B 17B – Bomber version powered with a Swedish-built Bristol Mercury XXIV (Svenska Flygmotor Aktiebolaget SFA) engine, with the same armament configuration except for a 700 kg (1,500 lb) bomb. 55 units delivered.
B 17B I – Dive-bomber version fitted with a trapeze under the fuselage, carrying a 500 Kg (1,500 lb) bomb, and underwing hardpoints for bombs. It was equipped with the m/42 bombsight.
B 17B II – A light level bombing version fitted with an internal bomb bay and underwing hardpoints.
B 17BL – Reconnaissance version fitted with a wheeled landing gear and a camera in the fuselage, replacing the HE 5 Hansa and the Fokker C.VD/C.VE. 21 units delivered.
B 17BS – Reconnaissance floatplane version fitted with twin floats, aerodynamic struts, and endplates on the horizontal stabilizers. 38 units delivered.
B 17C – Another bomber version fitted with the Piaggio P.XIbis R.C.40D 1040hp engine, and carrying a 700 kg (1,500 lb) bomb. 77 units produced.
Sweden The Flygvapnet was the main operator of the B 17, with 132 units of the B 17A model, 55 units of the B 17B and its modified sub-variants, and 77 of the B 17C variant. The first model was fitted with an inner bomb bay with some airframes modified to carry air-to-ground rockets. The following version was used as bomber – equipped with the advanced m/42 bombsight and some with the trapeze and underwing hardpoints – up until 1945. Some airframes were modified for reconnaissance duties and subsequently equipped with cameras. These modified aricraft served until 1949. Some airframes received further modifications such as the twin floats and other structural modifications. The B 17C was used for bombing missions, having an internal bomb bay and hardpoints until 1948, when they were withdrawn due to problems with the engines. The B 17 operated in six squadrons from 1942 to 1949 as it follows: the B 17 bomber and dive-bomber versions operated in F4 Frösön, F6 Karlsborg, F7 Stenäs, and F12 Kalmar. The B 17BS sea-based planes operated with F2 Hägernäs, and the land-based reconnaissance planes operated in the F3 Malmslätt.Following the B 17 withdrawal from service with the Flygvapnet, the airplane was operated by civilian companies for various purposes, target towing included. Two B 17BS were purchased by the Osterman Aero and used to carry fish and shellfish from Bergen (Norway) to the Swedish capital. In addition, 19 B 17A were loaned to AVIA and Svensk Flygtjänsk AB and modified for target towing; 5 of them received ECM equipment in 1959. One B 17A remains airworthy in airshows, with 2 additional airframes used as museum displays.
Finland The Ilmavoimat (Finnish Air Force) received two B 17A for target towing tasks, which were lost in accidents.
Austria The Österreischische Luftstreitkräfte (Austrian Air Force) received a B 17A via Svensk Flygtjänsk AB in 1957. This was done to facilitate the deal as it was a privately-owned airplane, considering the restrictions the Swedish government sets on sales abroad on Swedish-made military equipment.
Denmark As this country was under German occupation, a Danish brigade was established in Sweden in 1943 with 15 pilots and equipped with 15 B 17C under loan, taking part in training and exercises with the Flygvapnet, being painted with Danish colors. They were not given permission to leave the Swedish territory despite being ready to enter action against the Germans; the 15 units were offered to Denmark, but this country never accepted them, with Germany surrendering some time after the offer was made. One remains as a display in a museum.
Ethiopia The Ethiopian Air Force received 46 B 17As between 1947-1953 as the airplanes were being phased out in Sweden, and mainly as Sweden agreed to support the establishment of the Ethiopian Air Force under the lead of Carl Gustav von Rosen and with some former Flygvapnet personnel. The Ethiopian B 17 remained in service until 1968.
44 ft 11 in / 13.7 m
32 ft 10 in / 10 m
14 ft 9 in / 4.5 m
307 ft² / 28.5 m²
1x Piaggio P.XIbis R.C.40D 9 cylinders air-cooled radial piston engine, with a 3-bladed Piaggio P.1001 variable propeller.