Editing Curtiss P-40 Warhawk (section)

===Origins===
[[File:Curtiss XP-40 in flight, circa in 1939.jpg|thumb|Curtiss XP-40 "11" used for test purposes by the [[Air Force Materiel Command|Materiel Division]] of the US Army Air Corps]]

On 14 October 1938, Curtiss test pilot Edward Elliott flew the prototype XP-40 on its first flight in Buffalo.<ref>[https://web.archive.org/web/20110223210821/http://www.airforcehistory.hq.af.mil/PopTopics/chrono1.htm "Chronology: The Army Air Corps to World War II".] ''Air Force Historical Studies Office''. Retrieved: 20 July 2011.</ref> The XP-40 was the 10th production Curtiss P-36 Hawk,<ref name="Famous Fighters">Green 1957, p. 43.</ref> with its [[Pratt & Whitney R-1830 Twin Wasp]] 14-cylinder air-cooled [[radial engine]] replaced at the direction of Chief Engineer [[Don R. Berlin]] by a liquid-cooled, supercharged Allison V-1710 [[V12 engine|V-12]] engine. The first prototype placed the glycol coolant radiator in an underbelly position on the fighter, just aft of the wing's trailing edge.<ref name=Merriam>Merriam 2000, p. 15.</ref> USAAC Fighter Projects Officer Lieutenant [[Benjamin S. Kelsey]] flew this prototype some 300 miles in 57 minutes, approximately {{convert|315|mph}}. Hiding his disappointment, he told reporters that future versions would likely go {{convert|100|mph}} faster.<ref>''American Aviation'', Volume 3, 1939, p. 2.</ref> Kelsey was interested in the Allison engine because it was sturdy and dependable, and it had a smooth, predictable power curve. The V-12 engine offered as much power as a radial engine but had a smaller frontal area and allowed a more streamlined cowl than an aircraft with a radial engine, promising a theoretical 5% increase in top speed.<ref name=Wilson1997>Wilson, Randy. [http://rwebs.net/dispatch/output.asp?ArticleID=19 "The Heart of the Cobra: Development of the Allison V-1710 Engine".] {{webarchive |url=https://web.archive.org/web/20160304061418/http://rwebs.net/dispatch/output.asp?ArticleID=19 |date=4 March 2016 }} ''Allison Press Release on the Certification of its V-1710 Engine by the Air Corps'' via ''The Dispatch'', Volume 22, Number 1, Spring, 1997. Retrieved: 20 July 2011.</ref>

Curtiss engineers worked to improve the XP-40's speed by moving the radiator forward in steps. Seeing little gain, Kelsey ordered the aircraft to be evaluated in a [[NACA]] wind tunnel to identify solutions for better aerodynamic qualities. From 28 March to 11 April 1939, the prototype was studied by NACA.<ref>Wagner, Ray. [http://www.americancombatplanes.com/p40_1.html "P-40".] {{Webarchive|url=https://web.archive.org/web/20150521015346/http://www.americancombatplanes.com/p40_1.html |date=21 May 2015 }} ''American Combat Planes of the 20th century''. Retrieved: 20 July 2011.</ref> Based on the data obtained, Curtiss moved the glycol coolant radiator forward to the chin; its new air scoop also accommodated the oil cooler air intake. Other improvements to the landing gear doors and the exhaust manifold combined to give performance that was satisfactory to the USAAC.<ref name=Merriam/> Without beneficial tail winds, Kelsey flew the XP-40 from [[Wright-Patterson Air Force Base|Wright Field]] back to Curtiss's plant in Buffalo at an average speed of {{convert|354|mph|abbr=on}}.{{refn|Due to the reporter's unfamiliarity with the type, the XP-40 was inaccurately identified as an upgraded P-36.<ref>"America Creeps Up". ''The Aeroplane'' (Temple Press), Volume 56, 1938, p. 730.</ref>|group=N}} Further tests in December 1939 proved the fighter could reach {{convert|366|mph|abbr=on}}.<ref>Molesworth 2008, p. 10.</ref>

An unusual production feature was a special truck rig to speed delivery at the main Curtiss plant in Buffalo, New York. The rig moved the newly built P-40s in two main components, the main wing and the fuselage, the eight miles from the plant to the airport where the two units were mated for flight and delivery.<ref>[https://books.google.com/books?id=ftkDAAAAMBAJ&pg=PA91 "New Army Warplane Rides a Trailer on Its First Trip to Airport".] ''Popular Mechanics'', January 1941, p. 91.</ref>