When the Allies wrote the terms that ended the First World War, they listed what Germany had to hand over in round numbers: 5,000 guns, 25,000 machine guns, 3,000 trench mortars, 1,700 aeroplanes. Not one gun or mortar was named by type. Then, in brackets, came a single exception: “firstly all D. 7’s.”

The aircraft that earned that line was the Fokker D.VII, a square-cut, slightly awkward-looking biplane that had only reached the front in the spring of 1918. In barely six months it convinced the people drafting the Armistice that it was the one German aircraft they could not afford to leave in German hands.

Born at Adlershof

By late 1917 the Allies had regained control of the air over the Western Front with fighters such as the S.E.5 and the SPAD. Germany’s answer was a fighter competition at Adlershof airfield in Berlin in January 1918. For the first time, front-line pilots would test the prototypes and help pick the winner. According to the Smithsonian, 31 aircraft from ten manufacturers took part.

Fokker entered the V 11, the work of chief designer Reinhold Platz. Its secret was a thick, cantilever wing section, which gave it plenty of lift and gentle stall behaviour. The Smithsonian is blunt about who deserved the credit: Platz was the true creative force behind the famous Fokker fighters, while Anthony Fokker’s gift lay in test flying and knowing exactly what to change.

Manfred von Richthofen flew the V 11 on 23 January and found it manoeuvrable but tricky and directionally unstable in a dive. Fokker lengthened the fuselage by 40 cm, added a fixed fin and reshaped the rudder. The Red Baron flew it again, now found it delightful, and his endorsement went far towards the selection of the type. Fokker received an order for 400 aircraft, designated D.VII.

The Smithsonian National Air and Space Museum on its Fokker D.VII and the fighter that gave Germany back the edge in 1918.

Fokker’s factory could not build them fast enough, so the authorities ordered his great rival Albatros to produce the D.VII under licence at Johannisthal and Schneidemühl. Fokker worked from jigs rather than drawings, so Albatros had to measure a finished airframe and draw its own plans. The licence-built aircraft were generally considered better made than Fokker’s own.

The fighter that could hang on its propeller

When the D.VII appeared over the front, Allied pilots at first underestimated it because of its ungainly looks. They revised that view quickly. The thick wing let a D.VII pilot sit below and behind an Allied two-seater, out of reach of the observer’s gun, pull the nose up at full power in a nearly stalled condition, and fire into the unprotected underside. The Smithsonian calls the result “a highly feared opponent.”

Richthofen never flew it in combat: he was killed in April 1918, just before the D.VII reached the Jagdstaffeln. Others, including Hermann Göring and Erich Löwenhardt, scored heavily with it. The US Air Force museum credits German pilots with 565 victories over Allied aircraft in August 1918 alone. The type was not flawless; some aircraft shed upper-wing fabric, and engine heat could ignite phosphorus ammunition until extra cooling louvres were added.

Max Friz and the BMW IIIa

The early D.VII used the Mercedes D.III family of six-cylinder engines, rated at around 160 to 180 horsepower depending on version and source. By summer 1918 that was no longer enough. The breakthrough came from the young Bavarian firm BMW, whose head designer Max Friz had built the BMW IIIa, a 185-horsepower straight-six designed to keep its power at altitude.

Friz used a larger displacement and a higher compression ratio than the engine strictly needed at sea level. A special carburettor with two levers, one for normal flight and one for high altitude, kept the engine alive as the air thinned. The catch was that a pilot could not simply open the throttle on take-off.

According to BMW’s own history, the throttle valves were only opened fully once the aircraft reached 3,500 to 4,000 metres, so the IIIa lost less power at altitude than other engines. Fokker-built aircraft with the BMW were known as the D.VII(F), the F standing for Friz. The US Air Force museum gives the BMW version a ceiling of 21,000 feet against 18,000 for the Mercedes aircraft. Pilots fought over them, but BMW could only make the engine in limited numbers.

The Great War channel explains how the Fokker D.VII changed the balance in the air over the Western Front.

“Firstly all D. 7’s”

Exactly how many D.VIIs were built is one of the type’s small mysteries; published totals range from the Smithsonian’s estimate of about 1,000 to more than 1,700 in the US Air Force museum’s count, and higher still in other references. The Deutsches Museum says more than 760 were in service with 48 German fighter squadrons by 11 November 1918.

What is not in doubt is what the Allies thought of it. Article IV of the Armistice, signed in the railway carriage at Compiègne, demanded the surrender of equipment in good condition, and the only weapon it singled out by type was the D.VII.

The Deutsches Museum describes it as the only aircraft explicitly mentioned in the Armistice agreement. The Smithsonian goes further, saying the clause succinctly attests to the general high regard for the aeroplane. The Allies then carried off their prizes: the US Army and Navy evaluated 142 captured examples, and France, Britain and Canada took their own share.

One of the strangest captures happened two days before the war ended. On 9 November 1918, Leutnant Heinz Freiherr von Beaulieu-Marconnay of Jasta 65 landed his Albatros-built D.VII at a forward American airfield near Verdun used by the 95th Aero Squadron. He said he was lost; the Smithsonian notes it is uncertain whether he simply chose to surrender. His aircraft, U.10, now hangs in the National Air and Space Museum in Washington.

Smuggled to the Netherlands

Anthony Fokker was Dutch, and he had no intention of letting the Armistice end his business. In the chaos after the war he moved aircraft and parts out of Germany to his native Netherlands by rail. According to the Smithsonian, 120 of the 220 aircraft he smuggled out were D.VIIs and 60 were the two-seat Fokker C.I derived from it.

He completed and sold them to a string of new customers. The Dutch, Swiss and Belgian air arms all flew the D.VII after the war, and the Polish Air Force used about 50 of them, mainly for ground attack, during the Polish-Soviet War. The Netherlands naval air service kept its D.VIIs until 1937, almost two decades after the Allies had tried to make the type disappear.

That Dutch navy service produced one of today’s best survivors. A former Dutch naval D.VII was found by a US Army unit in a shed at Vilsbiburg in Bavaria in July 1945 and joined the Deutsches Museum collection in 1948. Its lozenge camouflage is authentic in style, but the museum notes that its serial number is fictional.

Pilot Ken Cassens flies the Fokker D.VII reproduction at Old Rhinebeck Aerodrome in New York State.

The D.VII’s story is a rare thing in aviation history: a verdict written into an international treaty. Generals and diplomats at Compiègne did not bother to name a single German gun. They named one fighter, and in doing so they paid Reinhold Platz the biggest compliment any aircraft designer of the Great War ever received.

Sources: US Department of State Office of the Historian (Foreign Relations of the United States, Armistice terms 1918), Smithsonian National Air and Space Museum, National Museum of the US Air Force, Deutsches Museum, BMW Group Press

Header photo: JustSomePics / Wikimedia Commons, CC0