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The NHI H-3 ''Kolibrie'' (Dutch for "Hummingbird") was a small helicopter developed in the Netherlands in the 1950s by Nederlandse Helikopter Industrie. ==Design== The H-3 was a two seat general purpose helicopter. It has a duraluminium tube superstructure, an open cockpit and an undergear of metal skids. The design is distinctive because it is ramjet powered. Two ramjets, one at the tip of each rotor blade, power the helicopter. The small tail rotor is powered by the motion of the main rotor. The ramjets could run at any given fuel, which gave the helicopter a certain versatility. The ramjets made a complex engine and gear box unnecessary. Kromhout designed and built the ramjets. Each engine generated 20 kg thrust. The last models had an improved engine, built by Aviolanda, generating 23 kg thrust. In order to start the ramjets, a small 2 hp auxiliary power unit set the main rotor in motion. At a rotor-speed of 70 rpm, the ramjets were to be ignited. Variants with ski’s, floating devices and medical evacuation stretchers were developed and tested, but these versions were never produced. A version as crop duster was developed, and in due time, the H-3 was mainly marketed as crop dusting helicopter. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「NHI H-3 Kolibrie」の詳細全文を読む スポンサード リンク
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