No guns at all. Sicily, Normandy, the Hump, Bastogne — the war’s logistics ran on two Twin Wasps.
1943·C-47A·260 km/h·28 troops or 2,700 kg·2× R-1830 Twin Wasp radials, 1,200 hp each·2,600 km·10,174 C-47s (plus ~5,400 licence-built DC-3 derivatives)
1· THE STORY
The airliner that won the war
The C-47 was a DC-3 airliner with a big cargo door, a reinforced floor and benches for 28 paratroopers, and it is on this list because the machines that decide wars are not always the ones with guns. It dropped the paratroops over Sicily and Normandy and Arnhem, flew fuel and ammunition over the Himalayas into China when Japan had closed every road, towed the gliders, brought out the wounded, and kept Bastogne alive. Eisenhower is usually quoted listing it with the bulldozer, the jeep and the truck as the equipment that won the war.
260 km/hCruise28 troops or 2,700 kgPayload
2· WHY IT MATTERED
An airliner with a cargo door
The DC-3 had already made airlines profitable before the war; the C-47 kept its aerodynamics and engines and changed what a war needed: a large cargo door, a reinforced floor with cargo fittings, glider-tow gear and benches for troops. More than ten thousand C-47s were built in the United States; the Soviet Li-2 and the Japanese L2D were licence-built DC-3 derivatives on both sides of the war, related but not C-47s.
From 1942 the only way into China was over the eastern Himalayas at 4,500 to 5,000 m, in weather that killed more crews than the Japanese did. The C-47B was built for that route, with two-speed superchargers that gave its engines back the air the altitude took away. The airlift moved some 650,000 tonnes in three years, carried by a mixed fleet in which the bigger C-46 did much of the tonnage and the C-47 flew from the first day.
4· WHY IT MATTERED
Normandy by air
On the night before D-Day more than 800 C-47s dropped some 13,000 American paratroopers behind Utah beach; by the end of D-Day itself more than 23,000 Allied airborne troops had landed by parachute and glider, most of them delivered by C-47s. Every one of those aircraft was unarmed, flying slow and low through flak.
5· THE ENGINE
The most-produced aero engine in history
The Twin Wasp was not the most powerful radial of the war, nor the most advanced. It was the one that ran: 173,618 were built, more than any other aero engine ever, and they powered the B-24 and the Wildcat as well as the C-47. Two of them made 2,400 hp on take-off and together burned about 400 litres an hour at cruise. The B model’s two-speed supercharger existed for one route, the Hump, where a single-speed engine ran out of air.
2× Pratt & Whitney R-1830-92 Twin Wasp · 14-cylinder two-row radial · 30.0 L · single-stage supercharger (two-speed on the C-47B) · 1,200 hp each
The C-47 carried nothing to defend itself and everything else: paratroopers with their kit, jeeps in pieces, fuel drums, wounded on stretchers. Its speciality was arriving. At 260 km/h it was slower than everything that could shoot at it, and it flew anyway, night after night.
7· TRY IT
Payload against range, and a mountain pass
A C-47 at its maximum take-off weight: the fuel it can carry against the cargo it can carry, along one line, and what a pass at the height you choose leaves in hand from two 1,200 hp engines, with the C-47B’s supercharger in high gear or held in the C-47A’s single low gear.
Readout
Fuel that fits3,070 L
Still-air range2,308 km
Power at the pass2,013 hp
Of the sea-level power87 %
Maximum take-off weight 14,061 kg, empty 8,226 kg, tanks 3,070 L. The Hump route crossed passes near 4,600 m in weather that made the air thinner still.
8· THE LAB
Power, guns and range: the same three models for all ten
Power against altitude from the type of supercharger, weight of fire against the other nine, and Breguet range with the armour and drop-tank trades. Simplified models, each scaled to this aircraft’s published figures, so the shapes are honest and the third decimal is not.
At 3,000 m: 2,102 hp in total, true airspeed 360 km/h.
Readout
Power, 2 engines2,102 hp
Per engine1,051 hp
True airspeed360 km/h
Service ceiling8,000 m
A simplified model calibrated to the published rating and top speed — the shape of the curve is the point, not the third decimal.
Douglas C-47 Skytrain, 7 of 10
Deep dive · Flying the Hump· opened from Douglas C-47 Skytrain
Timelines · WW2 aircraft · go deeper · Douglas C-47 Skytrain
Flying the Hump1942
The only road into China was over the Himalayas at 5,000 m, and the C-47 flew it every day.
4,500–5,000 m·2,700 kg·650,000 t·~1,500
01The idea
Payload against range, and the density altitude of a mountain pass
When Japan closed the Burma Road in 1942 the only way to supply China was to fly over the eastern Himalayas from India: passes at 4,500 to 5,000 m, weather that changed in minutes, ice, no navigation aids and no place to land. The C-47 could carry three tonnes across, or less if it needed the fuel for a diversion, and the C-47B’s two-speed superchargers existed for exactly this run. In three years the Hump airlift, a mixed fleet in which the bigger C-46 carried much of the load, moved 650,000 tonnes and killed about 1,500 aircrew.
02Why it matters
The payload-range line
A transport has a maximum take-off weight; everything above the empty aircraft is fuel or cargo. Fly further and more of it must be fuel. The C-47 could carry 2,700 kg a few hundred kilometres or far less a few thousand, and every planner’s day was spent on that line.
03Why it matters
Density altitude
A hot day at a high airfield is worse than either alone: the engine breathes thin air and the wing has less to push on. An engine that made 1,200 hp at sea level might have 800 at the top of the pass in low blower, and the two-speed supercharger’s high gear was worth several hundred horsepower exactly there.
04Why it matters
Logistics is the war
The C-47 dropped the paratroopers at Normandy, resupplied Bastogne through the snow and flew the Berlin Airlift after the war. None of that has a bang in it, and all of it decided where armies could go. It is the honest reason an unarmed airliner belongs on this list.
05Try it
Payload against range
Trade cargo for fuel, then take the C-47B over a 4,600 m pass in low and high blower.
Readout
Fuel that fits3,070 L
Still-air range2,308 km
Power at the pass2,013 hp
Of the sea-level power87 %
Maximum take-off weight 14,061 kg, empty 8,226 kg, tanks 3,070 L. The Hump route crossed passes near 4,600 m in weather that made the air thinner still.