We on occasion post interesting aircraft related photos and after seeing the photo (above) at the USC Digital Library, we felt you would enjoy viewing photos of this impressive wind tunnel. It was built at Langley Field, in Hampton, Virginia, in 1934, by the National Advisory Committee for Aeronautics, or NACA and at the time was the largest wind tunnel in the world. The photo dated Feb. 2, 1935, shows a Douglas Army observation plane mounted for testing.
The photo (below) shows the building atop of which the aircraft were fastened to for testing. Shown here in a LOC photo dated 1938, is a “Brewster Buffalo” in the tunnel for drag-cleanup studies. More photos of the Langley Field wind tunnel can be found here.
A very interesting United News Newsreel film (below), dated 1944, shows a wind tunnel built for testing airplane propellors. In the film you will see a propeller over sixteen feet in diameter mounted onto a 2200 h.p. radial engine used for testing.
That top photo appears to show a version of the Douglas YO-31A in the cradle (“O” for Observation). Note the unusual tail area, with the “slightly smaller than you might expect” vertical rudder. The early versions were noted for instability, and the tail section was frequently modified. Note also the open cockpit, plus a “greenhouse” (canopy) for the observer. The non-retractable landing gear, even with fairings, helps us appreciate the aerodynamic efficiencies of aircraft that could retract gear into wing or fuselage.
Tom, thanks again.
Tom,
Would you know what type of engine this Douglas had ? It looks to be water cooled, an Allison maybe?
Dick, Sorry we don’t but hopefully a reader will know.
Dick – the engine is likely a Curtiss V-1570-53 Conqueror. Note that during testing, various engine and prop configurations could be used; the Conqueror was the production choice.
There’s no specific date given for the photo, but NACA did much testing of the airframe for drag, caused by the oil radiator (bottom of cowling) and coolant radiator (under fuselage). NACA found that the radiators accounted for ca. 11% of the drag. If the top speed with radiators was 188 mph, it would be closer to 199 mph with radiators removed.
You can see many more photos of this aircraft during testing at:
http://crgis.ndc.nasa.gov/historic/643_Test_8_-_Douglas_YO-31A
Original documentation of that test is at:
http://ia700607.us.archive.org/14/items/nasa_techdoc_19930081346/19930081346.pdf
I’m a researcher at the New England Air Museum. When David posts photos of classic cars and classic aircraft, I go into overdrive.
Tom