hv system

The Herrick HV-2 Vertaplane (Herrick Vertoplane-2) was one of the world's first convertiplanes and was designed by Gerard P. Herrick, a pioneer in the field of VTOL in the 1930s. Herrick's concept called for an aircraft that had a fixed lower wing and an upper wing that could rotate about the vertical axis. The upper rotor wing could be stopped or started both on the ground and in the air. The HV-2 was the first aircraft with an in-flight stoppable rotor to actually use this compound system to generate lift and propulsion in a number of test flights and to perform an in-flight transition.Modern counterparts using a similar propulsion concept include the Sikorsky S-72 and the Boeing X-50.

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