Editing Piasecki Helicopter (section)

==History==
The Piasecki Helicopter Corporation was founded in [[1940 in aviation|1940]] by [[Frank Piasecki]] and fellow aeronautics student [[Harold Venzie]] as the '''P-V Engineering Forum''' (shortened from Piasecki-Venzie);<ref name=NYT-08/><ref name=HAI-vertical>{{cite magazine |url=https://www.verticalmag.com/press-releases/hai-is-saddened-by-the-passing-of-frank-piasecki-helicopter-pioneer-html/ |title=HAI is Saddened by the Passing of Frank Piasecki, Helicopter Pioeneer |author=Helicopter Association International |date=February 13, 2008 |magazine=Vertical |accessdate=13 April 2020}}</ref> the other partners were F.J. Kosloski, Donald N. Meyers, Elliott Daland, and Walter Swartz.<ref>{{cite magazine |url=https://books.google.com/books?id=lyEDAAAAMBAJ&pg=RA1-PA29 |title=The Boy Who Grew Flying Bananas |author=White, L. B. |date=August 1951 |magazine=Popular Science |pages=129–132;222 |publisher=Popular Science Publishing Co., Inc. |volume=159 |number=2 |accessdate=13 April 2020}}</ref> The first design from P-V Engineering was the PV-1, a [[NOTAR|rotorless-tail]] design that used a tapering tail cone and pressurized air to suppress main rotor torque.<ref name=Vertical-legacy>{{cite magazine |url=https://www.verticalmag.com/features/a-lasting-legacy/ |title=A Lasting Legacy |date=May 24, 2013 |magazine=Vertical |accessdate=13 April 2020}}</ref> Venzie left the firm in 1943.<ref>{{cite news |url=https://books.google.com/books?id=shwtKbTbEuEC&pg=PA143 |title=Pushing the Envelope: The American Aircraft Industry |author=Pattillo, Donald M. |date=1998 |publisher=The University of Michigan Press |isbn=0-472-08671-5 |accessdate=13 April 2020}}</ref>{{rp|143}}

The [[P-V Engineering Forum PV-2|PV-2]] (NX-37061) was a more conventional design and became the third helicopter flown in the [[United States]] (following [[Igor Sikorsky]]'s [[Sikorsky VS-300|VS-300]] and [[Sikorsky R-4]]). It was designed and flown by Frank Piasecki on April 11, [[1943 in aviation|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.<ref name=NYT-08>{{cite news |url=https://www.nytimes.com/2008/02/15/business/15piasecki.html |title=Frank Piasecki, a Pioneer in Helicopters, Is Dead at 88 |author=Hevesi, Dennis |date=February 15, 2008 |newspaper=The New York Times |url-access=subscription |access-date=13 April 2020}}</ref> 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]].<ref name=NYT-08/><ref name=HAI-vertical/>

===Tandem rotor designs===
[[File:XHRP-1 Piasecki NAN4 47.jpg|thumb|right|XHRP-1 during flight trials (1946)]]
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;<ref name=Vertical-legacy/> this marked the start of the design and sale of a series of [[tandem rotor]] helicopters to the Navy. The resulting [[Piasecki PV-3|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.<ref name=NYT-08/><ref name=HAI-vertical/>

Because P-V Engineering lacked the capital to fund production, the company was reorganized and renamed to the '''Piasecki Helicopter Corporation''' in [[1946 in aviation|1946]],<ref name=NYT-08/> with [[Laurance Rockefeller]] and [[A. Felix du Pont Jr.]] taking a controlling interest of 51% in exchange for $500,000.<ref name=Vertical-legacy/> After constructing two more prototypes (designated XHRP-1),<ref name=Vertical-legacy/> the PV-3 would go into production as the [[Piasecki HRP-1|HRP-1]] in [[1947 in aviation|1947]].<ref name=HAI-vertical/> The HRP-1 was commonly nicknamed the "flying banana" because of the upward angle of the aft fuselage which ensured the large rotors did not hit each other in flight. The nickname would later be applied to other Piasecki tandem-rotor helicopters of similar design.

An evolutionary follow-on design to the HRP-1, designated HRP-2, used an all-metal skin and switched crew seating to side-by-side instead of tandem; however, the limited power meant only five were built, all for the Coast Guard.<ref name=Vertical-legacy/> In 1949, Piasecki provided the [[Piasecki H-21|H-21 Workhorse]] to the [[United States Air Force]], an improved version of the HRP-2 with a more powerful [[Wright R-1820 Cyclone]] radial engine.<ref name=Vertical-legacy/>  Piasecki's tandem-rotor helicopters flew higher than competing single rotor designs, and offered a smoother ride.

At approximately the same time the HRP-1 and HRP-2 were being developed, the Navy commissioned Piasecki to design a smaller tandem-rotor utility helicopter; the resulting prototype, which Piasecki called the PV-14, was designated XHJP-1.<ref name=Vertical-legacy/> These went into production as the [[Piasecki HUP Retriever|HUP-1]] (PV-18), with the first variants delivered to both the Navy and the [[United States Army]] (as the H-25) in 1949; in total, 339 were delivered to the militaries of the United States, Canada, and France by 1954.<ref name=Vertical-legacy/> The HUP was designed with overlapping main rotor blades, which reduced the size so they could be carried on aircraft carrier elevators.<ref>{{cite web |url=http://americanhelicopter.museum/aircraft/piasecki-pv-14-hup-2-retriever |title=Piasecki PV-14 / HUP-2 Retriever |publisher=American Helicopter Museum & Education Center |accessdate=13 April 2020}}</ref>

===Piasecki is forced out===
[[File:Piasecki YH-16 helicopter in flight.jpg|thumb|right|YH-16 prototype in flight]]
[[Donovan Berlin|Don R. Berlin]] was brought in as president and director of Piasecki Helicopters in 1953,<ref name="Miller">{{cite news |author=Miller, Steven |url=http://www.nysun.com/obituaries/frank-piasecki-88-vertical-flight-pioneer/71281/ |title=Frank Piasecki, 88, Vertical Flight Pioneer |newspaper=The New York Sun |date=February 14, 2008 |accessdate=June 2, 2013 |archive-date=October 2, 2013 |archive-url=https://web.archive.org/web/20131002231641/http://www.nysun.com/obituaries/frank-piasecki-88-vertical-flight-pioneer/71281/ |url-status=dead }}</ref> while Frank Piasecki was chairman of the board. Under Piasecki, the company began the PV-15 large transport tandem helicopter project (designated [[Piasecki H-16 Transporter|H-16]]). The prototype PV-15 was first flown in 1953, but a fatal crash in January 1956 led to the cancellation of the project.<ref name=Vertical-legacy/>

The majority owners eventually lost faith in Frank Piasecki's leadership and by May 1956 he was forced out of the company. He had formed a new company, [[Piasecki Aircraft|Piasecki Aircraft Corporation]] to pursue the development of compound helicopters and other rotorcraft. In two successive special stockholders' meetings the board then changed the name of Piasecki Helicopter to '''Vertol''' (for [[vertical take-off and landing]]) Aircraft Corporation and amended the bylaws to bar Piasecki's re-election as a director, on the grounds that he was running a rival company.<ref name="trimble"/>{{rp|257–8}}

===Acquisition by Boeing===
In 1956, Vertol began developing a successor to the HUP with improved lift capacity by using [[turboshaft]] engines. The project was designated [[Boeing Vertol CH-46 Sea Knight|Vertol Model 107 (V-107)]], and a prototype first flew on April 22, 1958. Impressed, the Army awarded a contract for ten production aircraft (then designated YHC-1A) in June and later asked Vertol in March 1959 to produce a larger version, which was designated [[CH-47 Chinook|V-114]]. With the pressure to produce two relatively new designs, Vertol again ran into financial pressure<ref>{{cite web |url=http://www.airvectors.net/avch47_1.html |title=The Boeing Sea Knight |author=Goebel, Greg |date=1 April 2019 |publisher=Air Vectors |accessdate=13 April 2020}}</ref> and was acquired by [[Boeing]] on March 30, 1960,<ref>{{cite book |chapter-url=https://books.google.com/books?id=khBEAQAAMAAJ&pg=PA196 |chapter=Resume of Briefing on Vertol Division, the Boeing Co. |date=February 27, 1964 |title=Department of Defense Appropriations for 1965 |publisher=U.S. Government Printing Office |page=196 |accessdate=13 April 2020}}</ref> who renamed it '''Boeing Vertol'''.<ref name="vert0702-2"/> It became the '''[[Boeing Helicopters|Boeing Helicopter Division]]''' in 1987.