Piasecki HRP

Piasecki HRP
US Coast Guard HRP-1G
Type:	Transport helicopter
Design country:	United States
Manufacturer:	PV Engineering Forum Inc. , from 1946 Piasecki Helicopter Corporation
First flight:	March 7, 1945
Commissioning:	1947
Number of pieces:	1 XHRP-X, 20 HRP-1, 5 HRP-2

The Piasecki HRP is a transport helicopter from the US manufacturer Piasecki Helicopter Corporation . The prototype XHRP-X was the world's first operational helicopter with a tandem rotor arrangement . A rotary wing aircraft developed by Nicolas Florine that used this propulsion configuration was already flying in the summer of 1933, but it only carried out hover flights with it.

history

development

Prototype XHRP-X Dogship

The United States Coast Guard (USCG) had during the Second World War to save, among others, on the east coast the task castaways from torpedoed ships near the coast. Initial experience with gyroscopes such as the Pitcairn OP-1 did not convince the US Navy that rotary wing aircraft could be a useful instrument for this. In May 1943, however, Piasecki received approval from the Bureau of Aeronautics to develop a tandem helicopter for the USCG, which should be able to carry a load of 816 kg on search and rescue flights. The good performance values ​​of the PV-2, flown for the first time in April 1943, were also decisive for this . Before Frank Piasecki decided on tandem construction, he had carried out systematic tests with four other construction methods. These were the single rotor tail rotor, transverse rotor , coaxial rotor and triple rotor design. He achieved the best results with the tandem design.

After almost a year of development, Piasecki was commissioned to build an experimental tandem helicopter in early 1944, which the Navy designated as the XHRP-X. The first flight of the XHRP-X (factory designation PV-3), whose fuselage was still completely unclad, took place on March 7, 1945 with Frank Piasecki at the controls. The fuselage was later covered with fabric. During the test, a payload of 816 kg could be transported as an external load or 10 people could be taken on board. The maximum speed achieved was 176 km / h. Before the end of the Second World War in August 1945, Piasecki's design office received orders for three work helicopters with the HRP-1, the HUP-1 and the H-16.

HRP-1 (PV-3)

Eight HRP-1s aboard the USS Palau , probably 1949

The production version of the XHRP-X was named HRP-1 and flew for the first time on November 3, 1947. A total of 20 machines were produced, the last of which was delivered in 1949. With the HRP-1, the US Navy developed its doctrines that are still valid today, according to which it uses helicopters for search and rescue tasks, anti-submarine defense, to support amphibious operations of the US Marine Corps, for transporting loads and for mine clearing. The Navy handed over three copies to the US Coast Guard.

On December 1, 1947, the Marine Helicopter Squadron 1 ( HMX-1 ) was the first unit with the HRP. The HMX-1 was also the first helicopter unit of the US Marines. The first HRP-1 received the HMX-1 on August 19, 1948, in April 1949 there were nine machines of this type. A first demonstration of the new operational concept in front of members of the government on May 9, 1949 comprised eight HRPs with 56 fully equipped marines, who took off from a simulated aircraft carrier deck and set down the soldiers in the "combat zone" under the protection of fighter planes. In a second wave, the HRP's hanging howitzers flew into the maneuvering area. HMX-1 took part in exercise PACKARD III from May 22, 1949 with eight HRP on board the escort aircraft carrier USS Palau . Each helicopter carried six soldiers to an area ten miles from the porter; the total transport performance was 230 soldiers and about 6400 kg of cargo. Four HMX-1 HRPs even took part in Cleveland Air Races to demonstrate to the public the use of helicopters as a form of military transport. Between November 25, 1949 and April 5, 1950, all HRP were banned from flying due to mechanical problems with an oil pump.

HPR-1 during experiments with a diving sonar in 1953

On June 15, 1950, the Marine Corps presented the capabilities of the HRP in the context of amphibious operations to President Harry S. Truman and military staff. The HRP-1 remained in use until 1953, after which the remaining machines were taken over by the Navy and used for experiments with diving sonars and airborne mine clearance technology. The fabric covering was removed for weight reasons, as it quickly becomes soaked when floating close to the surface of the water. For safety reasons, floating bodies were attached to the tubular space hull.

HRP-2 (PV-17)

Practically a new design was the HRP-2 (factory designation PV-17), which received a metal-clad fuselage and of which five copies were ordered for the US Coast Guard in June 1948. The first flight took place on November 10, 1949. The pilot and co-pilot sat next to each other in front of the front rotor mast, while the two pilots on the HPR-1 were still accommodated one behind the other. However, the drive remained unchanged, so that this variant was viewed as severely underpowered. At least one copy was later used by a civilian operator. The PV-17 was the starting point for the development of the H-21 Workhorse / Shawnee .

Serial numbers

• XHRP-X (PV-3): Bureau Number 37968/37969, only 37969 flown. 85390 ordered but canceled
• HRP-1 Rescuer (PV-3): 111809 to 828, (111834 to 848) 35 pieces. commissioned, only first lot with 20 copies built
  • HRP-1G: three of these (111821, 111823 and 111826) went to the US Coast Guard
• HRP-2 (PV-17): 111829 to 833, newly constructed metal-clad fuselage, used by the US Coast Guard

production

Acceptance of the Piasecki HRP by the US Navy:

version	1947	1948	1949	1950	TOTAL
PV-3	1				1
XHRP-1	2				2
HRP-1	5	15th			20th
HRP-2				5	5
TOTAL	8th	15th	0	5	28

Technical specifications

Parameter	HRP-1 data
crew	2
Passengers	10 seats
Hull length	14.64 m
Rotor circle diameter	12.51 m
Empty mass	2290 kg
payload	844 kg
Cruising speed	138 km / h
Top speed	165 km / h
Range	420 km
Peak height with normal payload	3170 m
Engines	1 × Pratt & Whitney R-1340 with 600 PS (441 kW) power

See also

• List of helicopter types

literature

• Ryszard Witkowski: Allied Rotorcraft of the WW2 Period. Stratus sc, 2010, ISBN 978-83-8945097-5 , pp. 41-44.
• Eugene W. Rawlins: Marines and Helicopters 1946–1962 , History and Museums Division Headquarters, US Marine Corps, 1976
• Michael JH Taylor: Jane's Encyclopedia of Aviation , London, Studio Editions, 1993 ISBN 1-85170-324-1 , pp. 723 f.
• John M. Andrade: US Military Aircraft Designations and Serials since 1909 , Midland Counties Publ., 1979, ISBN 0-904597-22-9
• Airplanes from A – Z. In: AERO - The illustrated compilation of aviation. Issue 128, pp. 3580 f., Cavendish.
• Aircraft - The new encyclopedia of aviation , issue 172, p. 4816

Web links

Commons : Piasecki HRP  - collection of images, videos and audio files

• XHRP-X on Piasecki.com (accessed March 15, 2017)
• HRP-1 on Piasecki.com (accessed March 17, 2017)
• HRP-2 on Piasecki.com (accessed March 17, 2017)

Individual evidence

1. ↑ Nicolas Florine, pionnier belge de l'hélicoptère (accessed March 19, 2017)
2. ↑ Rawlins, Marines and Helicopters, 1976, pp. 1 f.
3. ↑ "XHR" stood for the prototype status of a transport helicopter from 1944 to 1962, "P" was the abbreviation for Piasecki, the final "X" reinforced, non-compliant, the experimental status of the aircraft (see also the designation system for aircraft of the US Navy from 1922 until 1962 )
4. ↑ Photo of the XHRP-X with fabric covering
5. ↑ Rawlins, Marines and Helicopters, 1976, p. 19 f.
6. ↑ ^{a b c} US Navy Aircraft History (accessed March 19, 2017)
7. ↑ One HRP-2 alongside some HRP-1 on a US Navy light aircraft carrier (accessed March 18, 2017)
8. ↑ Statistical Digest of the USAF 1947, p. 115; 1948II, p. 16; 1949, p. 164 ff.
9. ^ HRP-1 data. (pdf) Accessed August 22, 2020 (English).