Platt-LePage XR-1
| Platt-LePage XR-1 | |
|---|---|
|
|
| Type: | Experimental helicopter |
| Design country: | |
| Manufacturer: | |
| First flight: |
May 12, 1941 (tied) |
| Number of pieces: |
2 |
The Platt-LePage XR-1 was the first helicopter of the US Army Air Forces in 1941 and was manufactured by the US company Platt-LePage Aircraft Company . From 1941 to 1947 "R" stood in the then valid designation system for rotary wing .
history
Platt-LePlage received the order to design and build the helicopter, which was largely based on the PL-3 , which was already being planned , on July 19, 1940. The USAAF serial number was 41-001. The XR-1 was tested from 1941 at Wright Field by the Air Technical Service Command , after which the structure of the airframe was judged to be too weak, as the tail unit failed in a static load test of 140 to 150% above the design load. After the necessary repairs, the further tests were carried out very slowly and finally ended completely on June 21, 1946. By then, the XR-1 had only completed about 91 hours of flight.
On October 29, 1941, the order to build a second modified prototype XR-1A with the USAAF serial number 42-6581 was placed. The main differences to the XR-1 were the changed rotor hubs and the complete cladding of the drive system that is guided over the boom. In addition, the tail unit was strengthened and the bow received a plexiglass paneling all around. The XR-1A also underwent a test program on Wright Field until 1946, after which the machine was taken out of stock by the USAAF. It then bought the Camden, New Jersey- based Helicopter Air Transport Co. and, after an overhaul and conversion, used it for commercial use. For this she received the civil aircraft registration NX6950.
construction
The XR-1 was powered by a 440 hp Pratt & Whitney R-985-21 radial engine , which was housed in the fuselage and powered two three-blade rotors rotating in opposite directions. The rotors were located at the end of arms designed as narrow wings on both sides of the fuselage. The design of the XR-1 was very similar to the design that was already used by Focke-Wulf for the Fw 61 . There was also a conventional tail unit with a braced horizontal tail unit and a fixed landing gear. The crew sat behind one another on two seats under a heavily glazed cockpit cover, with additional glazing in the lower bow area also allowing a good view downwards. The helicopter was a total in composite construction designed with a fabric covering.
The drive of the XR-1A was slightly more powerful than that of the XR-1 with a 450-hp R-985-AN-1 radial engine.
Technical specifications
| Parameter | XR-1 | XR-1A |
|---|---|---|
| crew | 2 | |
| length | 8.94 m | |
| Rotor diameter | 9.3 m | |
| Takeoff mass | 2145 kg | 2404 kg |
| Top speed | 177 km / h | 161 km / h |
| Engines | a Pratt & Whitney R-985-21 star engine in the fuselage, 440 hp | a Pratt & Whitney R-985-AN-1, 450 hp |
Whereabouts
The XR-1 is currently (2014) stored in the National Air and Space Museum , but not on display. Nothing is known about the ultimate whereabouts of the XR-1A.
See also
literature
- René J. Francillon: McDonnell Douglas Aircraft since 1920 , Putnam & Company, 1979, ISBN 0-370-00050-1 , p. 317 ff.
