Category Archives: German Empire

The Red Baron's Fokker Dr.1 475/17 - March 1917

Fokker Dr.I

German Empire Flag German Empire (1917)
Fighter Plane – 320 Built

The Fokker Dr.I was a triplane built by Fokker-Flugzeugwerke during the First World War. The design, based off of Britain’s Sopwith Triplane, is well known thanks to the Red Baron, Manfred von Richthofen, for being the plane in which he scored his final kills.

A Borrowed Idea

In the early part of 1917 the Sopwith Triplane of the Allies began appearing on the battlefield, quickly trouncing German Albatros D.III fighters with its superior maneuverability and climbing ability. The Idfleig, the German bureau overseeing aircraft design immediately ordered development of a triplane, known as dreidecker (3 winged) in German.

Nearly all of the German aircraft manufacturers followed suit. Fokker set about to develop its own triplane by modifying an unfinished prototype biplane. This initial prototype, like Sopwith’s design, utilized a rotary engine and steel tube fuselage. However the initial prototype, the V.4 did not have external interwing bracing. The next prototype, the V.5 introduced bracing between the wings to minimize flexing on the upper wing. The prototypes were met with much excitement for their exceptional maneuverability and climb rate over anything else the Germans had previously produced. The Red Baron himself, Manfred von Richthofen was believed the Dr.I held much promise for the fortunes of German air power and demanded his superiors to commence production immediately, as well as promising his men that they would soon be able to “move like devils and climb like monkeys.”

Construction

Replica Dr.1 in a Black and White Striped Livery
Replica Dr.1 in a Black and White Striped Livery

The appearance of the Dr.1 is characterized by its three-wing design – therefore dubbed a ‘triplane.’ The design also featured small sustentation surface of an aerofoil shape mounted between the wheels of the landing gear. The tail was also completely mobile with unbalanced ailerons possessing more surface area than the ailerons of the upper wing. The wings had deep section hollow box-spars that provided lightweight strength to the wings. The lack of interplane struts on the initial prototype resulted in excessive wing vibration during flight, so interplane struts were added. The ribs were of plywood, as well as the leading-edges covers at the spar, with the leading-edges made of wire. The middle wings had some cut-outs to improve downward visibility of the pilot. The fuselage was constructed using welded steel-tubing bracing with diagonal wires to create the rigid box-shaped structure, being a fabric-covered with triangular plywood fillets, except the undercarriage and center-section, which were made of steel streamlined tubing.

The tail-plane had a triangular shape, being framed in steel tubing the same way as the balanced rudder and elevators. The wheels featured an elastic shock cord, while a steel-tipped tailskid was installed at the rear.

Evaluation

The first prototype Dr.1 flew in July of 1917. Production of the Dr.I commenced on August 11th of 1917. In preproduction the triplane carried the designation F.I. Two were made and issued to Richthofen and Leutenant Werner Voss. These two aces promptly used these planes on the battlefield, scoring kills within the first few days of flying in early September. Voss took to the skies on August 28th and by September 11th had scored 8 kills.

The result of this evaluation period led Voss and Richthofen to recommend the Dr.I for production as soon as possible, declaring it superior to the Sopwith Triplane. Orders were placed for 300 Dr.I’s.

On September 14th the commander of Jasta 11, OberLeutnant Kurt Wolff was shot down whilst flying Richthofen’s F.I by a new Sopwith Camel of Britain’s Naval 10 squadron. Voss, whilst flying on September 23rd, scored his 48th victory just before being shot down in an epic dogfight wherein he managed to damage all 7 of his opponent’s SE-5a’s in the skirmish.

The Fokker Dr.I in Use

Replica Dr.1 in Flight
Replica Dr.1 in Flight

The Dr.I, upon its arrival to the battlefield in October was well regarded for its climbing ability and light controls. The ailerons were not very effective, however the tailplane elevator and rudder controls were very yielding. Rapid turns to the right were very quick thanks to the directional instability afforded by the rotation of the rotary engine, a characteristic that was taken advantage of by pilots.

Although not a particularly fast plane, it balanced this shortcoming with great maneuverability thanks to its light weight, while also having good upward visibility. It also had a decent climb rate, characteristics that all seemingly made the Dr.I a formidable adversary to its Allied opponent, the Sopwith Camel. This made of the Dr.1 a good aircraft for dogfights, yet structural and construction problems in the wings would hamper the aircraft’s promising initial assessment.

The Dr.I was armed with twin 7.92 Spandau machine guns, which could fire simultaneously or independently in synchronization with the propeller.

The Dr.I, for all its improvements over previous German aircraft, had numerous  shortcomings. Among them was its tendency to ground looping upon landing. This occurs when the aircraft tilts on landing such that one wing makes contact with the ground. For this reason skids were attached to the wingtips of the lower wing on the production version. Also while the Dr.I had excellent climbing ability, its dive and level flight speed were less than desirable, leaving it vulnerable to faster Allied planes in many situations.

Wing Problems

Following the proper introduction of the production model Dr.I in October, by the end of the month two consecutive top wing failure accidents promptly caused all triplanes to be grounded. The wing structure of the Dr.I was thoroughly investigated and numerous problems were discovered, the first of which was weak attachment of wingtips, ailerons, and ribs. Further, the doping of the fabric and wood varnishing was found to be of poor and inconsistent quality, leading to water absorption and premature rot in crucial wing spars.

Fokker’s corrective action was to improve quality control on the production line, as well as modifying and repairing existing models. The problem was believed to have been solved, and the Dr.I continued to see use well into 1918, but later the wing failures returned.

Much later in 1929, research at NACA revealed that a triplane configuration like the Dr.I’s exerted as much as 2.5 times more lift coefficient on the upper wing. The extreme difference in this force no doubt contributed to many of the wing failures seen in the Dr.I over its operational lifespan. Examples such as this show the importance of research and competence in advanced aerodynamics during the design phase of an aircraft.

Legacy

As had been seen in September 1917, the Dr.I was inferior to the capabilities of the British Sopwith Camel by the time production had commenced. Despite this, German production went on for the initial 300 ordered.

Fokker D.VII would eventually replace the Dr.1 on the battlefield, with surviving dreideckers relegated to training and home defence units, re-powered with a Goebel Goe II 100 hp engine. By the time of the armistice was signed, the Dr.1 was tested by Allied pilots at fighter flying schools in Nivelles (Belgium) and Valenciennes (France), being deemed as an aircraft with impressive performance.

Variants

  • V.4 – The initial prototype
  • V.5 – First production prototype
  • V.6 – Enlarged prototype powered with a Mercedes D.II engine
  • V.7 – Prototype with Siemens-Halske Sh.III engine

Dr.1 Specifications

Top Wingspan 7.12 m / 23 ft 4 in
Mid Wingspan 6.23 m / 20 ft 5 in
Lower Wingspan 5.7 m / 18 ft 8 in
Length 5.77 m / 18 ft 11 in
Height 2.95 m / 9 ft 8 in
Wing Area 18.66 m² / 200.85 ft²
Engine 1  9-cylinder rotary Oberursel UR II engine (110 HP), or a LeRhône Type 9Ja (110 HP)
Maximum Take-Off Weight 586 Kg / 1,291 lb
Empty Weight 406 kg / 895 lb
Loaded Weight 586 kg / 1,291 lb
Climb Rate 5.7 m/s (1,122 ft/min) or 1000 meters in 2’45’’
Maximum Speed 185 km/h / 115 mph at sea level; 165 km/h / 102,5 mph at 4000 m
Range 300 Km / 186 miles
Maximum Service Ceiling 6100 m /20,000 ft
Crew 1 (pilot)
Armament 2 X 7.92 mm Spandau 08/15 with 500 rounds each

Gallery

The Red Baron's Fokker Dr.1 475/17 - March 1917
The Red Baron’s Fokker Dr.1 475/17 – March 1917
Fokker Dr.1 217/17 - March 1917
Fokker Dr.1 217/17 – March 1917
Fokker Dr.1 152/17 - March 1917
Fokker Dr.1 152/17 – March 1917
Replica Dr.1 in a Black and White Striped Livery
Replica Dr.1 in a Black and White Striped Livery
Replica Dr.1 Ready for Takeoff
Replica Dr.1 Ready for Takeoff
Closeup of Replica Dr.1's Cockpit
Closeup of Replica Dr.1’s Cockpit
Fokker Dr.1 9 Cylinder Rotary Engine
Fokker Dr.1 9 Cylinder Rotary Engine
Replica Dr.1 in Flight
Replica Dr.1 in Flight

Sources

Guttman, R. (2011). The Triplane Fighter Craze of 1917. HistoryNet., Berger, R (Ed.). Aviones [Flugzeuge, Vicenç Prat, trans.]. Colonia, Alemania: Naumann & Göbel Verlagsgessellschaft mbH., Donald. D. (2009). Aviones Militares, Guia Visual [Military Aircraft. Visual Guide, Seconsat, trans.]. Madrid, Spain: Editorial Libsa.Dwyer, L. (2013). Fokker Dr.I Triplane. The Aviation History Online Museum.Leivchentritt, L. (2013). Fokker Dr.I Specifications. Fokker Dr.I.com., Old Rhinebeck Aerodrome (2016). Fokker Dr.1 Triplane. Cole Palen’s Old Rhinebeck Aerodrome.The Aerodrome (2016). Fokker Dr.I. The Aerodrome.Fokker Dr.I. (2016, June 19). In Wikipedia, The Free Encyclopedia. [Images] Dr1 Black-White Livery by Neal Wellons / CC BY-NC-ND 2.0Dr1 Dark Red by Geoff Collins / CC BY-NC-ND 2.0, Dr1 Cockpit by Phil Norton / CC BY-NC-ND 2.0, Dr1 Flight by Ian / CC BY 2.0, Dr1 Engine by Erik Wessel-Berg / CC BY-NC-ND 2.0Plane Profile Views by Ed Jackson

Spandau LMG08/15 1918 - Side Profile View

Spandau LMG 08

German Empire Flag German Empire (1915)
Machine Gun – 23,000 built

The Spandau LMG 08 was the air cooled aircraft version of the German Army’s MG 08 machine gun. The infantry version of the MG 08, like the Vickers Machine Gun, was water cooled and based on the design of Hiram Maxim’s famed Maxim Gun.

Design

After the success of the MG 08 in infantry use, Spandau set about lightening the weapon and adding large slots to the water jacket for aircraft use.  The first letter in lMG 08 is actually a lowercase L which stands for luftgekühlt meaning air cooled. From the beginning the lMG was designed to fire in a fixed position from an aircraft.

Early Spandau LMG 08 Triple Mount
Early “Overlightened” LMG 08

Early designs had so many cooling slots that the weapon was considered “over-lightened” and the rigidity of the cooling jacket was considered “fragile.” Various slot patterns were experimented with until the final design of the LMG 08/15, a refined version of the weapon with many improvements as well as a lighter weight. The final weight for the refined lMG 08/15 came out to 26 lbs compared with 57 lbs for the original iteration of the MG 08. The various versions of the lMG were all designed to be interchangeable so aircraft could be easily upgraded to newer versions. Like the Vickers, the closed bolt design lent itself to easy synchronization with the propellers, with most German fighters appearing with twin LMGs by late 1916 with the introduction of the Albatros D.I and D.II.

The ammunition belt of the lMG 08 utilized the design of the Parabellum MG14 for its light weight, rather than that of the infantry version of the MG 08. After a cartridge was fired the belt was fed into a side chute on the side of the breech block. The chute would guide the empty belt into a storage compartment to prevent the empty belts from interfering with any aircraft mechanisms.  Empty cartridge cases however were expended out of a round hole on the receiver just under the barrel on all version of the MG 08. In most aircraft the empty cases were guided out of the aircraft.

Use of the Spandau lMG 08

The lMG 08 was used on almost all German fighter aircraft of the WWI period. After its introduction in 1915, synchronization technology was rapidly being developed. On the Fokker E.I the introduction of the synchronizer system with a single mounted lMG 08 led to a period of German air superiority over the Western Front known as the Fokker Scourge. Later aircraft almost universally used a twin synchronized setup, including Germany’s most famous ace, Baron von Richthofen ‘The Red Baron.’

Twin Synchronized lMG 08s on a replica Fokker DR.I
Twin Synchronized lMG 08s on a replica Fokker DR.I

There were various styles of cocking handles in use, seemingly dependent upon pilot preference. Safety interlocks were also introduced to ensure the safety of the ground crew who at times could be in the line of fire. Another modification seen in aircraft use was a countdown style rounds counter.

Spandau lMG 08 Gun Specifications

Weight 12 kg / 27 lb
Length 1.45 m / 4 ft 9 in
Barrel Length 720 mm / 28 in
Cartridge 7.92mm x 57
Action recoil with gas boost
Rate of Fire 400 to 500 rounds/min
Muzzle Velocity  860 m/s  /  2,821 ft/s
Effective Firing Range 2,000 m / 2,200 yd
Maximum Firing Range 3.500 m / 3,800 yd (indirect fire)
Feed System 250 round fabric belt

Gallery

Spandau LMG08/15 1918 - Side Profile View
Spandau lMG 08/15 – 1918

Sources

Fokker E.I. (2016, April 21). In Wikipedia, The Free Encyclopedia.Synchronization gear. (2016, May 15). In Wikipedia, The Free Encyclopedia.MG 08. (2016, March 22). In Wikipedia, The Free Encyclopedia.The Vintage Aviator (n.d.), The Spandau LMG 08/15, Images: Fokker DR.I Spandau Guns – 2013 by Julian Herzog / CC BY 4.0

Albatros D.III

German Empire Flag German Empire (1916)
Fighter Plane – 1,866 Built
The Albatros D.III was a bi-plane fighter manufactured by Albatros Flugzeugwerke Company in the Aldershof district of Berlin, Germany. The plane helped secure German air superiority and several top German aces flew the D.III, including Manfred von Richthofen – The Red Baron.  It was armed with 2 7.92mm LMG 08/16 machine guns which were an air cooled and synchronized version of Germany’s MG08.

Design of the D.III

Designed by Robert Thelen, the D.III was based off of the D.I and D.II that preceded it, utilizing the same basic fuselage.   This fuselage design was semi-monocoque, meaning that the skin of the aircraft, which was plywood, could bear some weight and add structural rigidity.

Albatros D.III - The Red BaronAfter seeing the success of the French Nieuport 11 and 17, the Idflieg which was the bureau overseeing German aviation development at the time requested that the new D.III adopt a sesquiplane layout similar to the Nieuports. A sesquiplane configuration consists of a modified biplane design with shorter and and narrower lower wings with the advantage being less drag at speed. As a result, the top wing was lengthened, and the lower wing’s chord was shortened, meaning the wing measured less from leading edge to trailing edge. The bracing, between the top and bottom wings was reconfigured to a “V” shape leading owing to the single spar used in the lower wings. Because of this the British coined their own nickname for the D.III: “The V-strutter.”

Water Cooled Mercedes Power

The D.III utilized a water-cooled Mercedes inline 6 cylinder 4 stroke engine appropriately designated as the D.IIIa. The water cooling and overhead camshaft yielded more horsepower than the radial engines that were more common, with the D.IIIa pumping out 170 hp. In the interest of weight savings the crankcase was aluminum, whilst the separate cylinders were steel and bolted onto the crankcase. Unlike previous designs each cylinder had a separate water jacket.

Flaws Emerge

Several problems were discovered during the D.III’s introduction. The first of which was the placement of the aerofoil shaped radiator above the cockpit. Although it was well placed to avoid battle damage, it tended to scald the pilot if there was a leak or puncture in the radiator for any reason. The design was changed to relocate the radiator right of the cockpit.

Albatros D.III - Wrecked at FlandersAnother issue had to do with several lower wing failures. Even The Red Baron himself, Manfred von Richthofen experienced this with a crack appearing on his new D.III and was forced to make an emergency landing.  Initially this puzzled engineers and was attributed to poor workmanship during manufacturing, but in reality the lower wing was experiencing excessive flexing under aerodynamic load. The eventual cause was determined to be the wing’s spar which was located too far aft. As a result of the changeover to the sesquiplane layout, only a single spar was used in the lower wing. Modifications were made to the design and existing aircraft to strengthen the wing. In spite of the modification pilots were advised to avoid steep or prolonged dive maneuvers.

Performance

The D.III was well regarded among pilots from its introduction despite having heavier controls. It offered improved stability, maneuverability, and climbing ability over the preceding D.II. Downward visibility was also much improved thanks to the narrower lower wing.

Bloody April

Albatros DIII - Climbing

The Albatros D.III was the most dominant fighter in the air during April 1917. The British forces attacking at Arras, France pushed for strong air support in the battle, but were their pilots were not nearly as well trained as the German pilots. To make matter worse, the British planes in use such as the Sopwith Pup, Nieuport 17, and Airco DH.2 were vastly inferior to the D series aircraft in use by the Germans. The British would go on to lose 275 aircraft. By contrast the Germans only lost 66 aircraft during the conflict.

Albatros D.III Specifications

Wingspan  9 m / 29 ft 6 in
Length  7.33 m / 24 ft 1 in
Height  2.9 m / 9 ft 6 in
Wing Area 23.6 m² / 254 ft²
Engine 1 water cooled inline Mercedes D.IIIa engine
Maximum Take-Off Weight 886 kg / 1,949 lb
Empty Weight 659 kg / 1,532 lb
Maximum Speed 175 km/h / 109 mph
Range 480 km / 300 mi
Maximum Service Ceiling 5,500 m / 18,000 ft
Crew 1 (pilot)
Armament 2 x 7.92 mm LMG 08/15 machine guns

Gallery

Sources

Albatros D.III. (2016, March 1). In Wikipedia, The Free Encyclopedia., Avistar.org (n.d.) Albatros D.III Images: Albatros D.III – Flying by DeciBit, Albatros D.III – Side View by Serge Desmet / CC BY-SA 1.0