Piasecki PV-2
| Piasecki PV-2 | |
|---|---|
|
|
| Type: | Experimental helicopter |
| Design country: | |
| Manufacturer: | |
| First flight: |
April 11, 1943 |
| Number of pieces: |
1 |
The Piasecki PV-2 is an experimental helicopter from the US manufacturer PV Engineering Forum . After the Sikorsky VS-300 flown in September 1939 and the serial version R-4 derived from it (first flight January 1942), it is regarded as the second successfully flown helicopter in the USA. Although the Platt-LePage XR-1 flew in June 1941 in front of the PV-2, it showed major deficiencies and only little development potential on the few flights.
The PV-2 was the first helicopter to use cyclic blade adjustment and dynamically balanced rotor blades.
history
Frank Piasecki founded PV Engineering Forum Inc. together with Harold Venzie and Elliott Daland in early 1943 to build a helicopter. In the name PV-2, "PV" therefore stands for Piasecki and co-designer Venzie. The first project was the PV-1, a helicopter with which a construction without tail rotor similar to today's NOTAR technology was to be tried. However, work on it was soon abandoned in favor of a tail rotor design.
At the beginning of the PV-2 testing, Piasecki had neither experience flying helicopters nor had he ever flown any other aircraft himself. He made his first attempts with a machine anchored to the ground with ropes. But after the ropes broke, he gave up these attempts. After a total of five hours of careful experimentation, he managed to get the PV-2 into the air. The official date of the first flight is given as April 11, 1943, and six months later, on October 20, 1943, Piasecki demonstrated the machine in Washington, DC . Piasecki later became the first American pilot to receive a helicopter license without first having flown a fixed-wing aircraft. Igor Sikorsky had previously received the first helicopter license in the USA .
The good performance of the PV-2 prompted the US Navy to place an order for the US Coast Guard to develop a helicopter that should be able to transport a load of 816 kg on search and rescue flights. This resulted in the development series of the Piasecki tandem helicopter .
The PV-2 is on display at the National Air and Space Museum today .
construction
The fuselage structure is a welded tubular steel grid construction covered with fabric all around. The landing gear consists of a fixed bipod main landing gear and a grinding spur. With the option of folding the rotor blades, the machine can be housed in a normal garage.
The drive consists of a four-cylinder Franklin engine with an output of 90 hp installed vertically behind the pilot's seat, which drives a three-blade rotor . With the exception of the blade root and tip, the rotor blades have a constant width of 24 cm. The leaf structure consists of a tubular steel spar with wooden ribs, front and rear edges. The leaves are covered with fabric. The two-bladed tail rotor is on the right side of the fuselage. When the main rotor rotates at 350 revolutions per minute at cruising speed, the tail rotor has a speed of around 1600 to 1700 min −1 .
The control stick for forward and backward flight and for lateral control (i.e. for cyclic blade adjustment) is attached to the top of the cockpit. Foot pedals change the angle of attack of the tail rotor blades and thus control the movement around the vertical axis , making changes of direction possible. The rotor hub including the blade roots has a circular fabric covering about 1 m in diameter.
Technical specifications
| Parameter | Data |
|---|---|
| crew | 1 |
| Rotor circle diameter | 7.62 m |
| Rotor blade depth | 0.24 m |
| Rotor speed | 350 min −1 |
| Tail rotor diameter | 1.53 m |
| Tail rotor speed | 1600 min -1 |
| Takeoff mass | 454 kg |
| Cruising speed | 104 km / h |
| Top speed | 144 to 160 km / h |
| Range | 240 km |
| Engines | a vertically installed four-cylinder Franklin piston engine with 90 hp |
See also
literature
- Leonard Bridgman (Ed.): Jane's All The World's Aircraft 1945-1946. Samson Low, Marston & Company, London 1946, p. 297c.
- Ryszard Witkowski: Allied Rotorcraft of the WW2 Period. Stratus sc, 2010, ISBN 978-83-8945097-5 , pp. 41-43.
Web links
- PV-2 on piasecki.com (accessed March 3, 2017)
- Video of the first flight attempts in April 1943 on YouTube (accessed March 2, 2017)
- Video of the PV-2 flights in summer 1943 on YouTube (accessed March 2, 2017)
- History summary on aviastar.org (accessed March 2, 2017)
- PV-2 at NASM (accessed March 2, 2017)
Individual evidence
- ^ Eugene W. Rawlins: Marines and Helicopters 1946–1962 , History and Museums Division Headquarters, US Marine Corps, 1976, p. 3
- ↑ Drawing of the PV-1 on piasecki.com (accessed on March 3, 2017)