Official paint colors:
Gray Paint - Originally provided by Kay and Ess Company of Dayton, Ohio. "No. 839 Blue Gray Airdry Enamel", Military Specification: MIL-E-7729, Enamel, Gloss, For Aircraft Use, Gray
Black Paint - Military Specification: MIL-E-5557, Enamel, Heat Resisting, Glyceryl-Phthalate, Black
Discussion of all the R-1340 variants at
Appears to be authoritative!
From aerofiles.comSpecial thanks to P&W Archives volunteer Jesse Hendershot for researching data for me!
P&W company history from the Aviation Engine Historical Society atR-1340 Wasp (Wasp CG) 1926 (ATC 55, 5E-2) = 410-600hp 1344ci 9RA. George Mead, Andrew Willgoos. The first P&W.
While not the first radial aircraft engine—that was an operating six-cylinder with two banks of three cylinders and a double-throw crankshaft built in 1913 by J W Smith in Cicero IL—the Pratt & Whitney was certainly the most successful.
When Frederick B Rentschler and a group of Wright engineers left that company and formed their own group in 1925 to produce the nine-cylinder R-1340 Wasp, they had neither official organization nor name when the prototype was submitted to USN for evaluation.
The very un-aviation Pratt & Whitney Machine Tool Division of Niles-Bement-Pond Corp (Hartford CT) had made castings for the prototype and cast its name in the metal housing. Navy evaluators dutifully transcribed this name into their records and a company was born, even though there was no actual connection with the original tool manufacturer. The first Wasp (410hp), designed by George Mead and Andy Willgoos, was completed on Christmas Eve 1925, passed USN tests in March 1926, and a Boeing F2B-1 was selected as the first operational plane to use the new motor.
The company was famous for making a comparator that could measure to .050". Later they touted that they could mill engine parts, when necessary, to .0002".