History
The XP-40Q development began in 1943 to improve the P-40 and its performance ahead of newer fighter aircraft. The management at Curtiss acknowledged that the P-40 was not up to the standards of the North American P-51 Mustang, Republic P-47 Thunderbolt, or Lockheed P-38 Lightning. The P-40 was woefully outmatched in terms of high-altitude performance, as it only had a single-stage supercharger and fell behind these superior fighters and Chance Vought F4U Corsair and Grumman F6F Hellcat.
Fearing Curtiss’ P-40 production lines being shut down and going out of business, the program built and designated the three prototypes as the XP-40Qs. These prototypes were built from other P-40 airframes (P-40K-10, P-40K-1, and P-40N-25, respectively). They all had four .50-cal. machine guns with 235 rounds per gun. All were powered by two-stage supercharged Allison V-1710 engines and a four-blade propeller.
Per my suggestion, we focus on a specific airframe of the second P-40Q variant - the XP-40Q-2A of P-40K-1 with a serial number 42-45722 and a long fuselage design.
The XP-40Q-1, with its ancient features, flew its test flights in June 1943, but Curtiss concluded they could do better and proceeded with the second prototype - XP-40Q-2 - in November 1943.
The XP-40Q-2 was fitted with a bubble canopy and had a chin scoop, including the oil cooler and air intake, under the nose in a slimmer configuration than the typical P-40. The radiators had been incorporated and remained in the leading edge of the wings. This aircraft originally had rounded wing tips like those on the typical Warhawks, but these were later clipped by one foot, giving them a square appearance. This model originally retained the olive drab paint.
The XP-40Q-2 had its first flight testing at Eglin Field, Florida, in January 1944 and completed a series of flight tests in Buffalo, New York, in March 1944. With a more powerful V-1710-121 engine, it produced 1,425 hp at takeoff and 1,800 hp with water injection at 20,000 feet. This model recorded a top speed of 422 mph (679 km/h) at 20,000 ft (6,096 meters). Test pilots noted the Q-2 had excellent visibility and handling, as it was very maneuverable and capable of pulling a tight turn radius. The test flights were recognized and praised, which prompted a recommendation for two additional prototypes to be constructed.
The XP-40Q-2 was damaged in an accident during testing on March 24, 1944, when the aircraft was nosed over. The aircraft was repaired and sent to Wright Field, Ohio, in the middle of 1944 for further testing.
The focus switched to testing on the next model - XP-40Q-2A - almost entirely identical to the XP-40Q-2. The XP-40Q-2A was built on a P-40K-1 airframe with serial 42-45722 and had an unpainted natural metal finish. The Q-2A had different modifications to its cockpit and canopy, and it incorporated automatic cooling shutters for the inner wing intakes. This aircraft had a P-51ish look; however, the wings on the aircraft were the original P-40 thickness and not the laminar types used on the P-51 Mustang.
The Q-2A’s first flight occurred before the end of March 1944, and the flight testing showed performance to be broadly comparable to the original Q-2. Suddenly, the Q-2A was plagued with Allison engine problems, and the Q-2A spent a long time being repaired instead of undergoing testing.
The original Q-2 was damaged again when it ground looped while landing on July 31, 1944. It is unknown if the aircraft was repaired again or damaged beyond repair.
As a result, the US Army Air Forces moved on to the next prototype, the Q-3, and loaned the Q-2A to Allison for further engine tests. Unfortunately, the USAAF lost interest in continuing the development of the production P-40Q and did not place orders because other aircraft with superior performance were already available in the inventory. Even with these modifications, the XP-40Q prototype was still inferior to modern fighters, and the project was canceled.
Warhawk production finally ceased in November 1944, although the war was not over. It marked the beginning of the end for Curtiss as a business.
The XP-40Q-2A survived the end of the war in the possession of Allison. This aircraft was declared surplus and sold to Joe Ziegler. He acquired and registered it as NX300B as the racing aircraft. The Q-2A entered and competed in the 1947 Thompson Trophy Race as an unqualified racer. Sadly, when it was running in fourth place, it caught on fire and was destroyed in the ongoing race, with the pilot bailing out and suffering a broken leg. It appeared that its unsolved reliability issues with the engine struck once again and ended the legendary Warhawk of P-40Q as we know it.
With a top speed of 422 mph (679 km/h) at 20,000 ft (6,096 meters), the XP-40Q was faster than every variant, even the P-40N-1. No P-40 Warhawk with a single-speed supercharger could ever approach at 400 mph (640 km/h).
