around the periphery of the fan, with mass flow 13 times greater than the gas generators mass flow and increased thrust 3 times over that available using a propelling nozzle. After demonstrating that large amounts of air could be moved through a lift fan, an tip drive fan turned through 90 degrees, driven by a more powerful J79 engine, was built to demonstrate an efficient cruise fan. The concept of a large diameter cruise fan was incorporated in the General Electric TF39 engine, used on the Lockheed C-5 Galaxy. Operational history Two 12,500 lb (maximum gross weight) XV-5A were evaluated in late 1966 by fifteen test pilots (the "XV-5A Fan Club"). One was destroyed in a crash during a public flight demonstration on 27 April 1965, killing Ryan test pilot Lou Everett. The crash investigation believed that the pilot had inadvertently tripped the conventional-to-vertical conversion switch (improperly mounted on the collective), which auto-programmed the horizontal stabilizer to force the nose down almost 45 degrees. (This was to compensate for the lift generated by the nose fan.) Everett initiated a low-altitude rocket ejection, but the ejection seat was improperly rigged and he was killed. As a result of this accident, the conversion switch was changed to a lift-lock toggle and relocated on the main instrument panel ahead of the collective lever control. The aircraft was difficult to control during landing for several reasons. Yaw control was provided by changing the angle of the lift fans in opposing directions, but this proved to have far too little yaw control for precise low speed handling. The duct doors also caused difficulty with control, as even at low speeds opening them caused significant changes in pitch. The aircraft also suffered from very poor acceleration during standard runway takeoffs. Tests and promotional materials proposed a rescue version that could winch a person into a compartment behind the pilots. The second aircraft was extensively damaged on 5 October 1966 during trials as a rescue aircraft, when a suspended "horse collar" survivor sling was ingested into a wing fan. The pilot, Major David H. Tittle, was fatally injured as a result of the ejection seat propelling him out of the craft after it had hit the concrete airport surface, although it was judged that the fan actually still functioned well enough to continue controlled flight. The second aircraft was rebuilt as the modified XV-5B, with tests continuing