Piasecki HRP Rescuer

{{Short description|Military transport helicopter family}}  {{Infobox aircraft | name = HRP Rescuer | logo = | logo_size = | image = Piasecki HRP-1G US Coast Guard in flight.jpg | alt = | caption = A U.S. Coast Guard HRP-1G | long_caption = | other_names = | aircraft_type = Tandem-rotor transport/rescue helicopter | aim = | outcome = | related = | national_origin = | manufacturer = [[Piasecki Helicopter]] | design_group = | designer = [[Frank Piasecki]] | builder = | issuer = | status = | owners = | primary_user = [[United States Navy]] | more_users = [[United States Coast Guard]]<br/>[[United States Marine Corps]] | service = | major_applications = | proposals = | prototypes = | number_built = 28 | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = [[1947 in aviation|1947]] | retired = | first_flight = 7 March 1945 | initiated = | in_service = | last_flight = | expected = | developed_from = | variants = | developed_into = [[Piasecki H-21]] | preservation = | fate = | predecessors = | successors = | concluded = }}

The '''Piasecki HRP Rescuer''' (also called '''Harp''') is a [[United States]] [[tandem-rotor]] transport or rescue helicopter designed by [[Frank Piasecki]] and built by [[Piasecki Helicopter]]. The Piasecki PV-3 was adopted as the '''HRP-1 Rescuer''' by the [[United States Navy]], [[United States Marine Corps]], and [[United States Coast Guard]].<ref name=":0" /> An improved PV-17 variant was later produced as the HRP-2. As one of the first transport helicopters in military service, the HRP-1 was capable of carrying two crewmen and 8–10 passengers or 2,000 lb. (907 kg) of cargo.

It was first flown in early 1945, entered service in 1947.

== Development == [[File:Piasecki HRP-1 "Flying Banana" (3681949278).jpg|thumb|left|Piasecki HRP-1 "Flying Banana" helicopter at [[Naval Air Station Key West]] minus exterior [[aircraft dope|doped]] fabric skin]]

The prototype helicopter (designated PV-3 by Piasecki, though commonly known to test personnel as "The Dogship") first flew at [[Morton, Pennsylvania|Morton]], [[Pennsylvania]] in 7 March 1945<ref name=":0">{{Cite web |title=Select Products in Boeing History |url=https://www.boeing.com/content/dam/boeing/boeingdotcom/history/pdf/Boeing_Products.pdf |access-date=23 October 2024 |website=Boeing |page=118}}</ref> following a development contract from the [[United States Navy]] in February 1944. The "Dogship" was a novel tandem-rotor helicopter with a fixed tricycle landing gear, powered by a 600 hp (447 kW) [[Pratt & Whitney R-1340-AN-1]] engine.<ref name=":0" /> To ensure that the rotors did not hit each other, the rear end of the fuselage curved upwards so the rear rotor was higher than the forward rotor. The fuselage was constructed of ordinary mild steel tubing, filled out with wooden ribs, and covered with [[aircraft dope|doped]] fabric.<ref name=Day/> [[File:XHRP-1 Piasecki NAN4 47.jpg|thumb|XHRP-1 in 1946]] Following a series of mechanical incidents with the prototype, including stripped transmission gears, it was determined that use of common automotive parts in the helicopter transmission were inadequate to the severe loads imposed by flight; subsequent prototypes built after the war used stronger components.<ref name=Day> {{Cite web | last= Day | first= Dwayne A. | title= Piasecki: The Dogship and the Flying Banana | work= U.S. Centennial of Flight | date= 2003 | url= http://www.centennialofflight.gov/essay/Rotary/Piasecki/HE4.htm | accessdate= 17 June 2012 | url-status= dead | archiveurl= https://web.archive.org/web/20111219125310/http://www.centennialofflight.gov/essay/Rotary/Piasecki/HE4.htm | archivedate= 19 December 2011 }} </ref> Two prototypes designated '''XHRP-1''' were constructed; one was used as a static test aircraft and the other was used for development flying.

The helicopter got the nicknames " Harp" and "flying [[banana]]", a name also carried on by its successor.<ref>{{Cite web |title=HRP-1 (Piasecki PV-3) Rescuer {{!}} Naval Helicopter Association Historical Society |url=https://www.nhahistoricalsociety.org/hrp-1-piasecki-pv-3-rescuer/ |access-date=2024-06-11 |language=en-US}}</ref>

==Operational history== [[File:Piasecki HRP-1.jpg|thumb|left|HRP-1 Rescuer, 1947]] [[File:HRP-1s in flight NAN7-49.jpg|thumb|Fleet of HRP-1 helicopters take flight, 1949]] [[File:USS Palau (CVE-122) with HRPs NAN8-51.jpg|thumb|Eight HRP-1s aboard {{USS|Palau|CVE-122}}, in 1951]] As the first U.S. military helicopter in service with a significant transport capability, the HRP-1 was immediately put to use transporting cargo and personnel. Although referred to officially as the HRP-1, or "Harp", the helicopter's distinctive shape, with no protruding nose beyond the forward rotor's axis, soon earned it the nickname "The Flying Banana". The first HRP-1 Rescuer flew on 15 August 1947, and a second batch of 10 was built later, with the final machine delivered in 1949. All were powered by the {{cvt|600|hp|kW}} Pratt & Whitney R-1340-AN-1 engine.

In all, 20 HRP-1s were ordered by the United States Navy, which passed most of their order to the U.S. Marine Corps and the Coast Guard. Three additional helicopters were delivered to the U.S. Coast Guard with the designation HRP-1G. An improved PV-17 version with an all-metal skin was developed with five ordered in June 1948 as the '''HRP-2'''; all HRP-2s were delivered to the U.S. Coast Guard for use as rescue craft. Nine HRP-1s formed the backbone of the first Marine helicopter transport squadron, HMX-1, and were used in various exercises designed to test the helicopter's ability to deliver troops in beach assault or forward battlefield operations.<ref>Rawlins 1976, p. 20.</ref> In service, the HRP-1 frequently suffered various teething and maintenance troubles such as broken engine mounts and loose fittings; it was not unusual for the fabric covering to rip loose from the helicopter in flight, often entangling the rotor blades.<ref>{{Cite web|last=Close|first=Robert A.|url=https://www.usna.com/SSLPage.aspx?pid=656|title=Helo Operations, Class of 1945|publisher=U.S. Naval Academy Alumni Association & Foundation|work=Helo Operations|accessdate=17 June 2012}}</ref> Despite these issues, the relative success of Piasecki's tandem rotor design would lead to the [[Piasecki H-21]] family of helicopters.<ref>Apostolo 1984, p. 79.</ref> Two surviving aircraft are in storage at the [[American Helicopter Museum & Education Center]] in [[West Chester, Pennsylvania]] and a third is under restoration at the [[Classic Rotors Museum]] in [[Ramona, California]].<ref>{{cite web |title=Aircraft in Storage |url=http://americanhelicopter.museum/aircraft/aircraft-in-storage |website=American Helicopter Museum & Education Center |access-date=12 October 2021}}</ref><ref>{{cite web |title=HRP |url=http://rotors.godaddysites.com/hrp |website=Classic Rotors Museum |access-date=12 October 2021}}</ref>

==Variants== [[File:Piasecki HRP towing tests Jun1953.jpg|thumb|An HRP without skin in 1953]] [[File:HRP-1 with floats NAN3-50.jpg|thumb|HRP-1 with floats]] ;PV-3 :Prototype tandem-rotor helicopter powered by a [[Wright R-975]] piston engine, one built. ;XHRP-1 :Military designation for two further PV-3s, one for static testing and one for flight trials. ;HRP-1 :Production variant, 20 built including three HRP-1Gs. ;HRP-1G :Three United States Navy HRP-1s for the United States Coast Guard. ;HRP-2 :Metal skinned variant, five built.

==Operators== ;{{flag|United States|name=United States of America|1912|size=23px}} *[[United States Coast Guard]]<ref>{{Cite web|url=http://www.helis.com/database/org/us_united_states_coast_guard/History/2|title=USCG History|work=Helis|accessdate=10 January 2013}}</ref><ref>{{Cite web|last=Watkins|first=Ray|url=http://1000aircraftphotos.com/Contributions/WatkinsRay/10649.htm|title=Piasecki PV-3 HRP-1 Rescuer, U.S. Marine Corps|work=1,000 Aircraft Photos|accessdate=10 January 2013}}</ref> *[[United States Navy]]<ref name=" U.S. Navy Aircraft History"/> *[[United States Marine Corps]]<ref name=" U.S. Navy Aircraft History">{{Cite web|last=Thomason|first=Tommy H.|url=https://thanlont.blogspot.com/2010_12_01_archive.html|title=And now for something completely different|work=U.S. Navy Aircraft History|date=29 December 2010|accessdate=26 January 2014}}</ref>

==Specifications (HRP-2)== {{multiple image |perrow = 1 |total_width = 300 | image1 = Piasecki HRP-1 Rescuer 3-view line drawing.png | alt1 = 3-view line drawing of the Piasecki HRP-1 Rescuer | caption1 = 3-view line drawing of the Piasecki HRP-1 Rescuer | image2 = Piasecki HRP-2 Rescuer 3-view line drawing.png | alt2 = 3-view line drawing of the Piasecki HRP-2 Rescuer | caption2 = 3-view line drawing of the Piasecki HRP-2 Rescuer }}

{{Aircraft specs |ref=''The Illustrated Encyclopedia of Aircraft'' 1985, p. 2716. |prime units? = imp |crew=2 |capacity= eight passengers or 2,000 lb. (907kg) cargo or six stretchers |length m=16.46 |length ft=54 |length in=0 |rot number=2 |rot dia m=12.50 |rot dia ft=41 |rot dia in=0 |height m=4.52 |height ft=14 |height in=10 |rot area sqm=245.30 |rot area sqft=2,640.51 |empty weight kg=2404 |empty weight lb=5301 |gross weight kg=3277 |gross weight lb=7225 |eng1 number=1 |eng1 name=[[Pratt & Whitney R-1340-AN-1]] radial engine |eng1 kw=447 |eng1 hp=600 |max speed kmh=169 |max speed mph=105 |range km=483 |range miles=300 |ceiling m=2,600 |ceiling ft=8,530 |cruise speed mph=74<ref name=":0" />}}

==See also== {{aircontent  |see also= |related= *[[Piasecki H-21]] |similar aircraft= |lists= *[[List of United States Navy aircraft designations (pre-1962)]] }}

==References==

===Notes=== {{Reflist|30em}}

===Bibliography=== {{Refbegin}} * {{Cite book|last=Apostolo|first=Giorgio|title=The Illustrated Encyclopedia of Helicopters|location=New York|publisher=Bonanza Books|date=1984|isbn=0-517-439352|url-access=registration|url=https://archive.org/details/illustratedencyc00apos}} * {{Cite book|title=The Illustrated Encyclopedia of Aircraft|date=1985|location=London|publisher=Orbis Publishing}} * {{Cite book|last=Rawlins|first=Eugene W.|title=Marines and Helicopters 1946-1962|location=Washington, D.C.|publisher=History and Museums Division, U.S. Marine Corps|date=1976}} * {{Cite book|last=Taylor|first=Michael J. H.|title=Jane's Encyclopedia of Aviation|location=London|publisher=Studio Editions|date=1989|isbn=0-517-69186-8}} {{Refend}}

==External links== {{Commons category|Piasecki HRP Rescuer}} *[https://web.archive.org/web/20110715083356/http://www.piasecki.com/helicopters_xhrp.php Piasecki XHRP-1 page] *[https://web.archive.org/web/20171004050836/http://www.piasecki.com/helicopters_hrp.php Piasecki HRP-1 page] *[https://web.archive.org/web/20101118032447/http://www.piasecki.com/helicopters_hrp2.php Piasecki HRP-2 page] *[https://books.google.com/books?id=p98DAAAAMBAJ&pg=PA49 "Navies Helicopter For Land or Sea Has Twin Rotors." ''Popular Mechanics'', November 1945, p. 49.] *[https://books.google.com/books?id=p98DAAAAMBAJ&pg=cover "Navies Helicopter For Land or Sea Has Twin Rotors." ''Popular Mechanics'', November 1945, cover art work.]

[[Category:Aircraft first flown in 1945]] [[Category:United States military helicopters]] [[Category:Piasecki Helicopter aircraft]] [[Category:Search and rescue helicopters]] [[Category:Single-engined piston helicopters]] [[Category:Tandem rotor helicopters]] [[Category:1940s United States helicopters]] [[Category:1940s United States military transport aircraft|Piasecki HRP1 Rescuer]]