Modern-Aviation

Helicopters are complex machines, but replacing the transmission system and piston (and later turbine) engines with tip ramjets created a far lighter, more straightforward solution. Indeed, the Hornet enjoyed 90 horsepower (68kW) from two ramjets mounted on the rotor tips, which each only weighed 13 pounds (5.9kg).

The ramjet is the simplest form of jet propulsion as it doesn’t require fans, just the speed of the air itself. Unfortunately, ramjets are also incredibly noisy and thirsty. Though its terrible range made the H-32 an impractical vehicle for military operations, it did much to pioneer US helicopter gunships.

Intriguingly, some consider the YH-32A, nicknamed the Sally Rand (as it was "stripped to the bare essentials" like the Burlesque performer Sally Rand), the first helicopter gunship. Three YH-32As were tested in 1957 with various armaments including combinations of rockets, guided missiles, land-mine detectors, and even a 75mm recoilless cannon.

Despite the inherent issues of tip-jets, many tip-jet helicopter types have been built (or seriously considered), including the Avimech Dragonfly DF-1, the Dornier Do 32, Dornier Do 132, the Fiat 7002, Percival P.74, Sud-Ouest Ariel, Sud-Ouest Djinn and VFW-Fokker H3.