Timelines · Aviation · 2 of 9
The Red Baron’s triplane — three stacked wings and an engine that spun with the propeller.
1917·185 km/h·~300 km·1× Oberursel Ur.II 9-cylinder rotary, 110 hp·2.9 min
· THE STORY
The Fokker Dr.I is the little red triplane flown by Manfred von Richthofen, the “Red Baron”. Stacking three short wings gave it a ferocious ability to turn and climb in a dogfight, even though it was slower than most of its enemies. Its engine was one of aviation’s strangest ideas: the whole engine spun around with the propeller.
· WHY IT MATTERED
Three short wings pack a lot of lifting area into a tiny, light airframe. The Dr.I could out-turn and out-climb nearly everything it met — an early lesson that in air combat, manoeuvrability can matter more than straight-line speed.
· WHY IT MATTERED
Its designer Reinhold Platz used thick internal box spars so the wings needed almost none of the usual drag-producing bracing wires. Thick, self-supporting (cantilever) wings became the standard way every later aircraft was built.
· WHY IT MATTERED
The Oberursel rotary bolted the crankshaft to the airframe and spun the entire engine block with the propeller, which kept it cool without a radiator. But 100+ kg of whirling metal turns the aircraft into a gyroscope: the Dr.I snapped right eagerly and turned left reluctantly, and pilots who forgot died young.
· TRY IT
The whole engine rotates with the propeller. Set the rpm and watch what the pilot had to live with: the power that made the Dr.I climb like a lift, and the gyroscopic moment that yanked the nose down in right turns and up in left turns.
That gyroscopic moment rivals the elevator’s full authority: the Dr.I snapped into right turns (nose obligingly dropping) and laboured through left ones. Veterans used it — attacking in right-hand spirals new opponents couldn’t follow. M = Iω·Ω, nothing more.
Timelines · Aviation · go deeper · Fokker Dr.I
The whole engine spun with the propeller — brilliant, mad, and briefly the only right answer.
110 hp·~100 kg at 1,250 rpm·castor — total loss·extinct by 1919
· THE IDEA
For a few years either side of 1917 the standard fighter engine did something no engine has done since: crankcase, cylinders and all, it spun with the propeller while the crankshaft stood still. It was not a stunt. A 1910s aero engine had to shed enormous heat with almost no weight to spare — water cooling weighed as much as a second engine, and stationary air-cooled cylinders of the day simply cooked. If the airflow over the cylinders is too slow, move the cylinders.
· WHY IT MATTERS
Every cylinder whirls through its own permanent gale, even with the aircraft parked — the radiator, pump and plumbing are simply deleted. And a hundred kilograms of spinning engine is a magnificent flywheel, so the rotary ran with a smoothness small engines otherwise could not manage. Lubrication was castor oil flung outward and overboard; the pilot flew in the mist of it.
· WHY IT MATTERS
A heavy mass spinning at 1,250 rpm answers a push with a shove at ninety degrees. Yaw the Dr.I right and the nose dropped; yaw left and it reared. Novices found it lethal, veterans made it a weapon — attacking in right-hand spirals that new opponents could not follow. There was barely a throttle: pilots ran flat out and slowed by blipping the ignition off, the stuttering signature of every rotary landing.
· WHY IT MATTERS
Drag on the spinning cylinders grows with roughly the cube of engine speed, so ever more power went into stirring air instead of pulling the aircraft. Past about 160 horsepower the arithmetic collapsed — and the moment metallurgy let a stationary radial cool itself, the rotary vanished almost overnight. It remains the only mainstream engine that solved its problems by refusing to sit still.
· TRY IT
Spin the engine and watch the gyroscopic moment grow — the sideways shove the pilot had to out-muscle every time the nose moved.
That gyroscopic moment rivals the elevator’s full authority: the Dr.I snapped into right turns (nose obligingly dropping) and laboured through left ones. Veterans used it — attacking in right-hand spirals new opponents couldn’t follow. M = Iω·Ω, nothing more.