Blohm & Voss BV 238

The Blohm & Voss BV 238 was a machine of superlatives. A six-engined flying boat with a wingspan of more than 60 metres and a loaded weight approaching 90 tonnes, it was the largest and heaviest aircraft built by any of the Axis powers, and by weight among the largest aircraft to fly anywhere during the Second World War. Beside it a B-17 looked slight.

It was the product of the Hamburg shipbuilder-turned-aircraft-maker Blohm & Voss, whose aircraft division had a long line in maritime flying boats. Where the earlier BV 138 and the six-engined BV 222 Wiking had been large, the BV 238 was conceived on an altogether different scale — a strategic flying boat meant to reach far out across the oceans that Germany, hemmed into Europe, could otherwise not touch.

The design was the work of Richard Vogt, Blohm & Voss’s brilliant and unconventional chief engineer, famous for solutions no one else would try — including the deliberately asymmetric BV 141. His signature appeared here too: a massive tubular steel main spar running the length of the wing that doubled as the aircraft’s fuel tank, a trademark that saved weight and simplified construction across his designs.

Power came from six Daimler-Benz DB 603 inverted-V12 engines, the same family that drove some of Germany’s best fighters, each giving around 1,750 hp and strung along the huge wing. Even with that combined power the sheer bulk of the aircraft held its top speed to about 425 km/h — this was a machine built not for speed but for size, endurance and reach.

The BV 238 was intended for the roles that had always defined Blohm & Voss’s maritime aircraft, scaled up enormously: long-range maritime reconnaissance and patrol far out over the Atlantic, and heavy transport. With a range of some 6,700 km it could in theory cross waters no other German aircraft could reach, shadowing convoys or carrying cargo over distances land-based types could not.

There were more ambitious ideas still — proposals to arm it with defensive turrets of 20 mm and 13 mm guns and to use it as a long-range bomber or minelayer. But these belonged to a Germany that no longer existed by 1944: one with the fuel, the factories and the command of the sea approaches to make use of such a machine. The strategic situation that might have justified the BV 238 had already passed.

Building an aircraft so far beyond existing experience carried real risk, and to explore how it would fly a smaller flying scale model, the FGP 227, was built of wood and fitted with six small engines — so that the giant’s aerodynamics could be studied on a manageable airframe before the full-size boat committed itself to the water and the air.

It was a rare and revealing step, a measure of just how large a leap the BV 238 represented. But by the time the full-size prototype was ready, the effort around it was collapsing. Materials, engines and skilled labour were all being swallowed by more urgent priorities, and Allied bombing was tearing at the German aircraft industry. The giant was being finished into a war already lost.

Only a single BV 238 — the prototype V1 — was ever completed and flown, taking to the air for the first time in 1944. Two further examples were begun but never finished, and a proposed land-based version with a wheeled undercarriage, the BV 250, got no further than the drawing board. The great flying boat existed, in the end, as a single aircraft.

Its life was short. The V1 lay moored on the Schaalsee, a lake east of Hamburg, when in the last weeks of the war it was found by American P-51 Mustangs, strafed at its moorings and sunk. The largest aircraft the Third Reich ever built was destroyed sitting on the water, having never flown a single operational mission.

The BV 238 is one of the great might-have-beens — or perhaps never-should-have-beens — of the air war. It was a genuine engineering achievement, the culmination of Blohm & Voss’s flying-boat tradition and of Richard Vogt’s inventive mind, and for a moment the heaviest aircraft in the world. But it answered a strategic need Germany could no longer act on, at a time when every resource was desperately short.

It belongs to the same late-war category as the other German giants — machines of enormous ambition conceived when the war was already lost. The age of the great military flying boat was itself ending, overtaken by long-range land-based aircraft. The BV 238 was its most extreme expression: a leviathan that flew a handful of times over a defeated country, and was gunned down at its moorings before it could ever show what it was for.

• William Green, Warplanes of the Third Reich (Macdonald & Jane’s).
• J. Richard Smith & Anthony L. Kay, German Aircraft of the Second World War (Putnam).
• Kenneth Munson, German Aircraft of World War 2 (Blandford Press).
• Heinz J. Nowarra, Die deutsche Luftrüstung 1933–1945 (Bernard & Graefe).