In 1948, Stanley Hiller began to experiment with ramjets mounted on the tips of the main rotor blade. He hoped to make small, ramjet-powered helicopters practical and affordable, and to eventually design and sell giant aerial cranes propelled by ramjets or jet turbine engines. The Hiller HOE-1 became the first production ramjet helicopter, and the Army and Navy flew a small number of these aircraft for a short time to test and evaluate the technology. Highlighted in this image is the cyclic-pitch lever of the Hiller XH-44 Hiller-Copter.