Piasecki Helicopter Corporation was a designer and manufacturer of helicopters located in Philadelphia and nearby Morton, Pennsylvania, in the late 1940s and the 1950s. Its founder, Frank Piasecki, was ousted from the company in 1956 and started a new company, Piasecki Aircraft. Piasecki Helicopter was renamed Vertol Corporation in early 1956. Vertol was acquired by Boeing in 1960 and renamed Boeing Vertol. History The Piasecki Helicopter Corporation was founded in 1940 by Frank Piasecki and fellow aeronautics student Harold Venzie as the P-V Engineering Forum (shortened from Piasecki-Venzie); the other partners were F.J. Kosloski, Donald N. Meyers, Elliott Daland, and Walter Swartz. The first design from P-V Engineering was the PV-1, a rotorless-tail design that used a tapering tail cone and pressurized air to suppress main rotor torque. Venzie left the firm in 1943. The PV-2 (NX-37061) was a more conventional design and became the third helicopter flown in the United States (following Igor Sikorsky's VS-300 and Sikorsky R-4). It was designed and flown by Frank Piasecki on April 11, 1943. Piasecki had limited pilot experience; the PV-2 was tethered to the ground as a safety measure, but the clothesline he used broke. He towed the helicopter behind his car in October 1943 to Washington, DC to demonstrate it to federal government officials; because the wheels had no bearings, he had to stop every 10 to 15 minutes to cool them. When asked to show his pilot's license following the demonstration in Washington, Piasecki admitted he did not have one and he was issued the first helicopter pilot's license on October 20, 1943, by the Civil Aviation Administration. Tandem rotor designs With the successful demonstration of the PV-2, Piasecki convinced the United States Navy to fund the development of a follow-on prototype, signing a contract on January 1, 1944; this marked the start of the design and sale of a series of tandem rotor helicopters to the Navy. The resulting PV-3 became the world's first successful tandem rotor design. The PV-3 first flew on March 7, 1945 and bore the Navy designation XHRP-X; it was larger and capable of lifting more than the contemporary Sikorsky designs. Because P-V Engineering lacked the capital to fund production, the company was reorganized and renamed to the Piasecki Helicopter Corporation in 1946, with Laurance Rockefeller and A. Felix du Pont Jr. taking a controlling interest of 51% in exchange for $500,000. After constructing two