Pentecost CL-1 / Hoppi-Copter
The Pentecost Hoppi-Copter was a 41kg personal helicopter pack designed to be strapped to an infantryman's back to make it possible for him to surmount terrain obstacles, but had no landing gear. Conceived by Horace Pentecost, it first flew in 1945, but landing shock problems proved insurmountable.
This ultra-light individual helicopter had two co-axial contra-rotating two-bladed rotors powered by a small two-stroke horizon-tally opposed engine developing about 20 h.p.
The body consisted of a tubular aluminum frame curved to fit over the pilot's shoulders and attached to the body by harness of the type employed in parachutes; the pilot's legs were used for landing.
Some twenty hops were made with the use of safety cables attached to the pilot, but this strap-on helicopter ended its career at the Smithsonian Institution in Washington.
Capital Helicopter Corp was established January 1954 for continued development of C-1 Hoppi-Copter, took over the patents in 1954, and flew a Hoppi-Copter with rotor blademounted pulse jets.
Horace Pentecost became President of the Capital Helicopter Corporation, founded in 1954, on leaving the Hoppicopter concern and retaining his rights in his inventions.
A new type of helicopter, powered by small pulse-jet engines at the blade tips, was also developed by Horace Pentecost.