Image of the Air Force wings with the museum name underneath

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McDonnell XH-20 Little Henry

The XH-20 was essentially a test stand built to research ramjet-propelled helicopter rotor blades. The XH-20 first flew in May 1947, but its fuel was delivered through a flexible line from tanks on the ground. In May 1948, it made its first flight with self-contained fuel tanks. Being a test stand, Little Henry was never intended to fly at any appreciable altitudes or distances.

While the XH-20 proved that a helicopter could use ramjet-propelled rotor blades, it was very loud and consumed fuel at a high rate. The XH-20 on display, the only one built and flown, was obtained by the museum in 1953. 

TECHNICAL NOTES:
Engines:
Two McDonnell-developed ramjets mounted at the rotor tips
Maximum forward speed: About 50 mph
Rotor tip speed: 410 mph
Rotor diameter: 20 feet
Weight: 290 lbs. empty

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