EXPERIMENTS IN FAILURE

Air Classics, Apr 2004 by O'Leary, Michael

AN AMAZNG STRING OF SUB-STANDARD FIGHTER AIRCRAFT HELPED PUT THE ONCE-DOMIHANT CURTKi OUT OF THE BUSINESS OF BUILDING COMBATAIRCRAFT

There can be no doubt that the Curtiss P-40 series of fighters deserve the title of classic (see Air Classics V39/N10). Though heavily influenced by 1930's thinking and showing little brilliance, the P-40s were available in considerable numbers when they were most needed. However, during and after the P-40, virtually every aircraft in the fighter category produced by Curtiss was a failure. Not only were they failures but they were also some of the ugliest aircraft ever made. A perfect example of the rapid drop in the fortunes of Curtiss was the XP-46.

Observers from Curtiss who had been sent to England and Europe before the outbreak of World War Two returned to the parent company with a number of suggestions as to future directions for purposed fighters. Heavily influenced by the early Spitfires and Messerschmitt Bf 109s, a smaller fighter than the P-40 with a battery of at least eight .30-cal weapons and a slotted wing to improve handling during combat was suggested. Preliminary work on the aircraft, which was hoped to be a successor to the P-40, was handed over to the Army Air Corps who approved of what they saw and issued a production contract for two prototypes on 29 September 1939. The original Curtiss designation for the project was CP-39-13 because it was designed to Army Circular Proposal 39-13 and the Army designated the new plane as the XP-46.

Production for the P-40 was rapidly building up when the order for the new fighter prototypes was received and Curtiss planned to use an uprated Allison - a V-1710-39 of 1150-hp - to power the new design, thus assuring a common engine design for the two types.

With the liquid-cooled Allison and a smaller airframe than the P-40, Curtiss predicted a top speed over 400-mph - how they came up with this unrealistic figure is open to conjecture. The quality of work coming from the Curtiss design department also leads to interesting speculation on the creation of the North American NA-73X - the aircraft that led directly to the Mustang.

It must be remembered that North American Aviation was a new company at the time. The NA-73X stemmed from a British requirement and the Brits knew NAA had never built a fighter and were concerned about the company's capabilities. NAA President James "Dutch" Kindelberger placed Edgar Schmued in charge of the project, but the British also put in a requirement that NAA purchase wind tunnel and other data from Curtiss on their XP-46.

Curtiss made a quick $56,000 profit from the sale and NAA chief engineer Lee Atwood went to Buffalo, New York, to collect the papers and data. In correspondence with Sir Henry Self, Atwood would write on 1 May 1940, "We have reached an extremely satisfactory agreement with the Curtiss Aeroplane Company of Buffalo whereby they are furnishing to us data covering a comprehensive series of wind tunnel, cooling and performance tests of a similar airplane, which data will assist us in the design and manufacture of these airplanes." Chief aerodynamicist Ed Horkey examined the data and found it virtually useless. Schmued would later claim he never even saw the Curtiss data.

In conjunction with NACA, a fullscale XP-46 wind tunnel model was made, tested, and fitted with numerous modifications in the hope of achieving the desired performance.

Oddly, the second XP-46 (AAC s/n 40-3054) was the first to fly - this event taking place on 15 February 1941. In order to save time, this aircraft was delivered to military minus armament and radio so that testing could proceed in the most timely manner. Without this equipment, the Air Corps felt that a designation change should take place and the plane became the XP-46A.

The first XP-46 (40-3053) had its armament increased to eight .30-cal guns in the wing along with two .50-cal weapons in the nose, making it the most heavily armed US fighter of the time. Automatic leading edge slats were fitted on the outer portions of the wing. Testing revealed that the P-46 had no advantage over the P-40 except for more firepower and the Army terminated the program.

ENTER THE PROTRACTED P-60

Perhaps no other aircraft outlines the Curtiss downfall better than the P-60, a series of unattractive fighters whose history is as complex as their performance was poor.

During 1940, Curtiss was pleased with the numbers of P-40s that were beginning to pour from the Buffalo, New York, factory but, realizing that times were rapidly changing, work was instigated on the production of a superior fighter that could eventually take over where the P-40 left off.?

In order to speed the production of a new fighter, it was planned to use a wing based on the new laminar flow airfoil (as used on the new P-51) with a fuselage that was basically that of an updated P-40D. Power was to be supplied by a Rolls-Royce Merlin V-1650-1 built by Packard in the United States. An eight-gun .50-cal armament was to be fitted and the new craft was designated XP-60 (Curtiss Model 90, 9OA). The XP-60 owed much of its design to the earlier uncompleted XP-53 which was to have been a follow-on to the unsuccessful XP-46. The XP-53 was to have had a laminar flow wing and was to have been powered by the Continental XIV-1430-3 but problems with the engine led to the project being dropped. However, the partially completed XP-53 airframe was used for static and equipment tests for the XP-60.