Nederlandse Helicopter Industrie H-3 Kolibrie

11/03/2003. Remarks by Johan Visschedijk: "This ramjet-powered helicopter was of purely Dutch design and the only Dutch helicopter reaching series production. In 1952 the engineers Verhage and Meijer Drees started the development for the SOBEH (a foundation initiating the development and construction of a rotorcraft), with support from the NVI (Dutch Institute for Aircraft construction). Their first product was the SOBEH H-1 (not registered), and Mr. Idzerda conducted initial hovering trials in October 1954. These test proved unsatisfying and eventually the prototype was damaged due to ground resonance.

After redesigning and rebuilding the first airframe the type was designated SOBEH H-2 (PH-NFT, c/n 2001) and flew successfully in March 1955 with Mr. Greve at the controls. Confidence was high and for the series-production a new company was founded in October 1955, the Nederlandse Helicopter Industrie (NHI); the new product became the H-3 Kolibrie (Hummingbird). The first prototype (PH-NHI, c/n 3001) conducted its maiden flight in May 1956, this time with René van der Harten as pilot.

The second prototype (PH-NGS, c/n 3002) flew in November 1956, but was destroyed on April 26, 1957 during ground testing. The first prototype and two more H-3s (PH-NGT, c/n 3003 and PH-NGV, c/n 3004) continued the certification trials and the type gained its Dutch type certificate on March 3, 1958. In total eleven Kolibries were delivered, seven of them going to Israel. The project was halted in 1961 due to lack of funds, two of the engineers, Mr. Meijer Drees and Mr. Kuipers, accepted a leading design job at Bell Helicopters.

The Kolibrie was at the time of its maiden flight the only ramjet-powered helicopter in the world, and despite of the ramjet at the rotor tips of simple but notable construction, which neutralized vibration and considerably lessened maintenance. A disadvantage was the rather high fuel consumption, therefore a trailer was developed called the "helicar". This allowed the transport of the helicopter, its fuel and equipment to the working area; with its boards unfolded it could be used as landing platform. This and the low flying speed made the Kolibrie suited for agricultural operations."

The following data refer to the NHI H-3 Kolibrie.