P/b, approximately 14 x 20cm, 100pp. 2nd edition. Published by Pratt & Whitney Aircraft division of United Aircraft Corporation, December 1940. The Pratt & Whitney R-1830 Twin Wasp was a 14 cylinder, double-row, air-cooled radial engine used in a range of aircraft that included the Douglas DC-3 DST, B-24 Liberator, Grumman F4F Wilcat and Curtiss P-36. The handbook covers the operation and routine servicing of these engines. Illustrated with diagrams/charts and photographs. Wear and fading to the covers, pages generally quite good and perfectly legible. Stock code P22770.