A conception of pre-war years, the Lockheed XP-49, was designed in 1939 with the goal of attaining 761km/h in level flight at 4572m. The XP-49 was to be armed with two 20mm cannon and four 12.7mm machine-guns.
The XP-49 was an outgrowth of the P-38 Lightning but in most respects was an entirely new design by the Lockheed-Burbank fighter team under H. L. Hibbard and Clarence (Kelly) Johnson.
Ordered by the US Army on 3 August 1939 to meet a twin-engine fighter requirement (which also produced the Grumman XP-50) the sole XP-49 was expected to attain unprecedented performance by mating the Lightning's familiar twin-boom layout with two 1715kW Pratt & Whitney X-1800 24-cylinder inline engines.
When plans to develop the powerplant proved too ambitious, twin 1006kW Continental XIV-1430-1 engines had to be substituted, reducing speed to 737km/h, although this was reached because the test ship lacked the added weight of protective armour which would have been fitted on a production variant. "We still felt we had a winner," says a Lockheed engineer. "We had a roomy, pressurised cabin, good handling characteristics and, eventually, good manoeuvrability."
The XP-49 first flew 11 November 1942 at Burbank. When it became necessary to increase the vertical fin area to improve yaw characteristics, the result was an unusual set of markings: Army directives called for 13 alternating red and white horizontal stripes on the rudder, symbolic of the original 13 American colonies. When the tail was heightened, painters simply added non-regulation extra stripes.
repaired, and was ferried to Wright Field, Ohio, on 25 June 1943. Though it was a clear improvement over the P-38, able to "fly rings around the Lightning" in the words of one pilot, minor but troublesome fuel leakage problems led to XP-49 tests being discontinued and the airframe being scrapped, just when Mustangs with long-range drop tanks were appearing over Berlin.
Engine: 2 x Continental XIV-1430-13/15, 1010kW
Max take-off weight: 9047-9977 kg / 19945 - 21996 lb
Empty weight: 7013 kg / 15461 lb
Wingspan: 15.85 m / 52 ft 0 in
Length: 12.22 m / 40 ft 1 in
Height: 2.98 m / 9 ft 9 in
Wing area: 30.42 sq.m / 327.44 sq ft
Max. speed: 650 km/h / 404 mph
Cruise speed: 600 km/h / 373 mph
Ceiling: 11400 m / 37400 ft
Range: 1095 km / 680 miles