McDonnell XH-20 Little Henry

The McDonnell XH-20 Little Henry was a tiny experimental helicopter built by McDonnell Aircraft for the United States Army Air Force and first flown on 29 August 1947. The company called it the Model 38. It was a simple open frame of steel tube carrying one crew member under a rotor of about 20 feet, and its unusual feature was the power: small ramjets mounted at the tips of the rotor blades turned the rotor. Two were built. The ramjets proved noisy and burned a large amount of fuel, so a larger two-seat development, the XH-29 Big Henry, was abandoned before it was built. The first XH-20 survives on display at the National Museum of the United States Air Force.