Tuesday, September 8, 2015

Fokker D.VII

Easy flier: The Fokker D.VII was considered a fairly easy aircraft to fly – an important consideration, since, by the summer of 1918, pilots were being rushed to the front after a bare minimum of training.

Goering's Circus - Fokker D.VII Original Painting - Roger H. Middlebrook GAvA “We got into a dogfight with the new brand of Fokkers… we put up the best fight of our lives, but these Huns were just too good for us.” Lieutenant John M. Grider British pilot’s diary entry on first encountering the Fokker D.VII

By 1918, German pilots were desperate for a single-seat fighter to replace their outdated Albatroses and Fokker Dr.I triplanes. After evaluation trials held at Adlershof, Berlin, at the end of January, the Fokker D.VII was selected for mass production, and the first models arrived at the front the following April. Hard-pressed Jastas (fighter squadrons) greeted their new mounts with relief and enthusiasm. German pilot Rudolf Stark wrote: “The machines climb wonderfully and respond to the slightest movement of the controls.” Their impact on the fighting peaked during the summer of 1918, by which time some 40 Jastas were flying D.VIIs, many of them with BMW engines that gave substantially better performance than the original Mercedes power plants. Operating in skies crowded with Allied aircraft of all kinds, D.VII pilots achieved exceptional kill-rates. For example, one squadron, Jasta Boelcke, scored 46 confirmed victories in a month for the loss of only two of its own pilots. The BMW-powered D.VII was especially effective at high altitude – its pilots were among the first to be issued with experimental oxygen equipment, as well as parachutes. Flying high gave the D.VII the initial advantage in encounters with Allied fighters and also allowed it to hunt down the Allied reconnaissance aircraft, which depended on altitude for safety. About 1,500 D.VIIs were delivered before the end of the war in November 1918.
Fokker's chief designer, Reinhold Platz, had been working on a series of experimental planes, the V-series, since 1916. These planes were characterized by the use of cantilever wings, first developed during Fokker's government-mandated collaboration with Hugo Junkers. Junkers had originated the idea in 1915 with the first all-metal aircraft, the Junkers J 1, nicknamed Blechesel ("Sheet Metal Donkey" or "Tin Donkey"). The resulting wings were thick, with a rounded leading edge. This gave greater lift and more docile stalling behavior than conventional thin wings.

Late in 1917, Fokker built the experimental V 11 biplane, fitted with the standard Mercedes D.IIIa engine. In January 1918, Idflieg held a fighter competition at Adlershof. For the first time, frontline pilots would directly participate in the evaluation and selection of new fighters. Fokker submitted the V 11 along with several other prototypes. Manfred von Richthofen flew the V 11 and found it tricky, unpleasant, and directionally unstable in a dive. In response to these complaints, Reinhold Platz lengthened the rear fuselage by one structural bay, and added a triangular fixed vertical fin in front of the rudder. Upon flying the modified V 11, Richthofen praised it as the best aircraft of the competition. It offered excellent performance from the outdated Mercedes engine, yet it was safe and easy to fly. Richthofen's recommendation virtually decided the competition, but he was not alone in recommending it. Fokker immediately received a provisional order for 400 production aircraft, which were designated D.VII by Idflieg.

Fokker's factory was not up to the task of meeting all D.VII production orders. Idflieg therefore directed Albatros and AEG to build the D.VII under license, though AEG did not ultimately produce any aircraft. Because the Fokker factory did not use detailed plans as part of its production process, Fokker simply sent a completed D.VII airframe for Albatros to copy. Albatros paid Fokker a five percent royalty for every D.VII built under license. Albatros Flugzeugwerke and its subsidiary, Ostdeutsche Albatros Werke (OAW), built the D.VII at factories in Johannisthal (designated Fokker D.VII (Alb)) and Schneidemühl (Fokker D.VII (OAW)), respectively. Aircraft markings included the type designation and factory suffix, immediately before the individual serial number.

Some parts were not interchangeable between aircraft produced at different factories, even between Albatros and OAW. Additionally each manufacturer tended to differ in nose paint styles. OAW produced examples were delivered with distinctive mauve and green splotches on the cowling. All D.VIIs were produced with the lozenge camouflage covering except for early Fokker-produced D.VIIs, which had a streaked green fuselage. Factory camouflage finishes were often overpainted with colorful paint schemes or insignia for the Jasta, or the individual pilot.

Albatros soon surpassed Fokker in the quantity and workmanship quality of aircraft produced. With a massive production program, over 3,000 to 3,300 D.VII aircraft were delivered from all three plants, considerably more than the commonly quoted but incorrect production figure of 1,700.

In September 1918, eight D.VIIs were delivered to Bulgaria. Late in 1918, the Austro-Hungarian company MÁG (Magyar Általános Gépgyár - Hungarian General Machine Company) commenced licensed production of the D.VII with Austro-Daimler engines. Production continued after the end of the war, with as many as 50 aircraft completed.
Many sources erroneously state that the D.VII was equipped with the 160 hp Mercedes D.III engine. The Germans themselves used the generic D.III designation to describe later versions of that engine. In fact, the earliest production D.VIIs were equipped with 170-180 hp Mercedes D.IIIa. Production quickly switched to the intended standard engine, the higher-compression 134 kW (180 hp) Mercedes D.IIIaü. It appears that some early production D.VIIs delivered with the Mercedes D.IIIa were later re-engined with the D.IIIaü.

By the summer of 1918, a number of D.VIIs received the "overcompressed" 138 kW (185 hp) BMW IIIa, the first product of the BMW firm. The BMW IIIa followed the SOHC, straight-six configuration of the Mercedes D.III, but incorporated several improvements. Increased displacement, higher compression, and an altitude-adjusting carburetor produced a marked increase in speed and climb rate at high altitude. Because the BMW IIIa was overcompressed, using full throttle at altitudes below 2,000 m (6,700 ft) risked premature detonation in the cylinders and damage to the engine. At low altitudes, full throttle could produce up to 179 kW (240 hp) for a short time. Fokker-built aircraft with the new BMW engine were designated D.VII(F), the suffix "F" standing for Max Friz, the engine's designer. Some Albatros-built aircraft may also have received a separate designation.

BMW-engined aircraft entered service with Jasta 11 in late June 1918. Pilots clamored for the D.VII(F), of which about 750 were built. However, production of the BMW IIIa was very limited and the D.VII continued to be produced with the 134 kW (180 hp) Mercedes D.IIIaü until the end of the war.

D.VIIs flew with different propeller designs from different manufacturers. Despite the differing appearances there is no indication these propellers gave disparate performance. Axial, Wolff, Wotan, and Heine propellers have been noted.
The BMW-engined D-VII had the highest ceiling of any (operational) pursuit aircraft of the war.  
The most admirable quality of the D-VII may have been the fact that it maintained its performance advantage right up to the limit of that performance and did not degrade long before that limit was reached.   It was also an easy aircraft to fly. . .forgiving to the novice, and one that made average drivers seem more qualified than they actually were.

The only plane the D VIII didn't have manoeuvrability on was the Sopwith Camel and that's only with regards to right turning.   Anyways mostly the D VIII was up high where the Camels were mostly low.

The D VIII (BMW) was faster than the Fokker Dr 1, could climb better at higher altitudes, shared the same advantages of the advanced airfoil design.   In short it had it all on the Dr 1 except manoeuvrability, which it didn't need since its enemies on the allied side were not as manoeuvrable as the D VIII.   In addition it was much easier to fly, take off and land than the Dr 1 which in the general scheme of things makes for a superior pursuit force overall.

Later on, Hermann Göring complained about the problem caused by the unbalance of having some D.VIIs with the BMW motors and the rest having Mercedes motors.   He stated, when engaging the high flying allies the Jasta was basically reduced to half engagement strength, since the BMW powered D.VIIs would leave the Mercedes powered D.VIIs in their wake.
    V 11: Prototype
    V 21: Prototype with tapered wings
    V 22: Prototype with four-bladed propeller
    V 24: Prototype with 179 kW (240 hp) Benz Bz.IVü engine
    V 31: One D.VII aircraft fitted with a hook to tow the V 30 glider
    V 34: D.VII development with 138 kW (185 hp) BMW IIIa engine
    V 35: Two-seat development with 138 kW (185 hp) BMW IIIa engine and undercarriage fuel tank
    V 36: D.VII development with 138 kW (185 hp) BMW IIIa engine and undercarriage fuel tank
    V 38: Prototype Fokker C.I
Frontline Strength
Fokker D.VIIs being accepted and being delivered are two different things.
1. When the acceptance flight was made at Schwerin-Gorries Airfield by the Army pilot it is the date listed on the acceptance sheets.
2. Sometime after the acceptance flight the aircraft was disassembled and loaded and blocked on flat cars.   When there are enough flat cars to make up the train, the train departs to the designated Armee Flugpark(en).   There were probably no trains made up and departed from the Fokker Flugzeugwerke in March 1918.   The Front Bestand (Front inventory lists) show 19 Fokker D.VII in the Front Line Inventory on 30 April 1918.   None of these D.VIIs had been delivered to units, all were at the Armee Flugpark being reassembled and test flown.   Jasta 10 of JG Nr1 "Richthofen" did not receive their Fokker D.VIIs until around the 24-25 of May 1918. It is my understanding that Jasta 10 was the first to receive the Fokker D.VII.

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