Bell L-39 Sweep Cobra
After the capitulation of Germany in 1945, US forces captured large amounts of documents on all types of new aeronautical developments. One of these which were tested extensively by German scientists was the swept wing configuration. To test such a configuration at low speeds, Bell received from the U.S. naval air service a contract for the development and construction of two flying test models based on the existing Bell P-63 Kingcobra fighter.
Because of centre of gravity problems with the swept wing configuration, it was decided to replace the original P-63 propeller by the lighter and smaller propeller of the P-39 Airacobra fighter. The conversion of the P-63 was designated by Bell as the L-39 with the appropriate name Sweep Cobra. Both Sweep Cobras were fitted with completely new designed wings with 35° sweep. As such, they were in fact the first US planes with swept wings. The Sweep Cobra was flown in by test pilot Tex Johnson. Later, also Bell test pilots Slick Goodman and U.S. Navy test pilot Robert Champine flew the Sweep Cobra at NACA’s Langley airfield. The Sweep Cobra was regularly flown fitted with the well-known wool tufts for turbulence research.
According to existing pictures, the Sweep Cobra no. 1 flew initially with a 3-bladed propeller. Later, it was replaced by a 4-bladed prop. The Sweep Cobra was also fitted with an additional small vertical stabilizer under the rear fuselage. Flight trials revealed that the flight efficiency decreased quickly at lower speeds. This was later improved by fitting leading edge slats and a larger wing area.
Nico Braas
Photos- Nico Braas, NASA Langley Color profile- Srecko Bradic
This is a very nice site, and needed to see what is on the INternet.
I’m completing a soft-cover XP/YP-59A Airacomet booklet 8,000 words, 35 plus photos.
I’m searching for a photo of YP-59A “Mystic Mistress,” used in the robot plane research program, and whether or not it had a name, or caracature on the side of the nose or not, and any shots at Ladd Field of the P-59 named Smokey Stover, that flew up the ALSIB route to Ladd’Field’s Cold Wx Test Unit to test the plane in arctic weather.
I spenjt 24 years in Alaska, flew the bush in a Brantly B-2, salvaged aircraft parts, gold panned, and saw one wrecked Russian marked P-39 crash and photographed what reamined.
I have a wide-variety of planes, spacecraft projects, Dyna Soar stuff, Navaho, and a box of plans from Boeing of their aircraft for sale or trade.
Drop a line if we can swap photos or needs/wants. Thanks and have a good day.
Dave
Renton, WA
Dyna Soar writer and researcher. My unusual projects are written up for QUEST Spaceflight history quarterly.
Regarding the Bell L-39-1 and -2, does anyone have documentation to prove what colour these aircraft were painted?
A colour photo has finally surfaced, of the L-39-1. It was navy Blue! I have a copy if anyone is interested.