Nederlandse Helicopter Industries TJ-5 Ramjet Engine

In 1952, a Dutch foundation was formed to design and build an experimental rotary-wing aircraft. To keep the design as simple as possible, tip-mounted ramjets eliminated the need for a gearbox and rotor drive shaft. The prototype H-2 first flew in 1955, and, in the same year, the Nederlandse Helicopter Industrie was formed to build and market the H-3 Kolibrie (Humming-Bird). Production began in 1957, and the H-3 was certificated in 1958.

TJ-5 ramjets, built by the Kromhout Company, powered the first 10 H-3 helicopters, with 227 N (51 lb) thrust TJ-5A ramjets used later. A 1.49 kw (2 hp) auxiliary power unit spun the rotor blades to 112 km/hr (70 mph) for ramjet ignition. Due to high fuel consumption of the ramjets, a trailer was developed for road transportation and as a mobile take-off and landing platform. Some uses of the H-3 were crop spraying and survey and exploration work.