VFW-Fokker H3
The VFW H-3 Sprinter was in the late 1960s an attempt helicopter of the German manufacturer United Flugtechnische works.
The peculiarity of the helicopter was the driving concept with a cold blade tip drive. For this, the Allison 250 - free shaft turbine powered mechanically to a centrifugal compressor, who directed over a light metal tube and a short flexible hose connection to the compressed air arranged around the rotor head axis air distributor. The rotating part of the air distributor was taken away by a pair of scissors in the rotor head. A sliding surface of the stationary air distribution pipe led the swash plate of the conventional rotor control.
From the air manifold, the compressed air has been passed by means of flexible hoses to the three blades. The air rushed up to the blade tip and was released after being deflected in a slot. The drive concept has been tested in an attempt to support VFW H -2.
For propelling two ducted propeller were provided, which should be driven by a controllable differential gears and shafts. During the testing of the propeller had not yet been mounted. The machines were completed in 1968, the first flight was followed a year later.
The main rotor itself was driven only during the floating phase. Otherwise, the helicopter worked as a gyroplane. He needed therefore no tail rotor. Instead, a V-tail is installed.
Only three prototypes were produced. One was destroyed during load tests, the other two ( registration D - 9543 and D -9544 ) are still preserved; an example is in the Helicopter Museum Biickeburg, the other is privately owned and is at the airfield Meinerzhagen. It is planned that the flight ability of the privately owned helicopter to restore.