Editing Allison V-1710 (section)

==Design and development==
The [[Allison Engine Company|Allison]] Division of [[General Motors]] began developing an [[ethylene glycol]]-cooled engine in 1929 to meet a USAAC need for a modern, {{convert|1000|hp|kW|abbr=on}}, engine to fit into a new generation of streamlined bombers and fighters. To ease production, the new design could be equipped with different propeller gearing systems and superchargers, allowing a single production line to build engines for various [[fighter aircraft|fighters]] and [[bomber]]s.

The [[United States Navy]] (USN) hoped to use the V-1710 in its rigid airships [[USS Akron (ZRS-4)|''Akron'']] and [[USS Macon (ZRS-5)|''Macon'']], but both were equipped with German-built [[Maybach VL II]] engines<ref>Smith, 1965 p. 182</ref> as the V-1710 was still in testing when the ''Macon'' was lost in February 1935 (the ''Akron'' having been lost in April 1933).<ref>Smith 1965, p. 178</ref> The USAAC purchased its first V-1710 in December 1932. The [[Great Depression]] slowed development, and it was not until December 14, 1936, that the engine next flew in the [[Consolidated XA-11A]] testbed. The V-1710-C6 successfully completed the USAAC ''150 hour [[Type certificate|Type Test]]'' on April 23, 1937, at {{convert|1000|hp|kW|abbr=on}}, the first engine of any type to do so. The engine was then offered to aircraft manufacturers where it powered the prototype [[Curtiss XP-37]]s. All entrants in the new pursuit competition were designed around it, powering the [[Lockheed P-38]], [[Bell P-39]] and [[Curtiss P-40]]. When war [[British Purchasing Commission|material procurement agents from the United Kingdom]] asked [[North American Aviation]] to build the P-40 under license, NAA instead proposed their own improved aircraft design, using the V-1710 in their NA-u73, which became the famed [[North American P-51 Mustang|P-51 Mustang]].