Lockheed XP-49


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Lockheed XP-49

The Lockheed XP-49, its designation seemingly out of sequence in that it was a conception of pre-war years, was designed in 1939 with the ambitious goal of attaining 761km/h in level flight at 4572m. The XP-49 would have been a veritable flying arsenal in its day as it was to be armed with two 20mm cannon and four 12.7mm machine-guns. It was rigorously and exhaustively tested at Burbank, California, and Wright Field, Ohio, and the XP-49 was denied production status because of an engine substitution and the appearance of the Thunderbolt and Mustang.

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 a still-impressive 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." US Army planners saw the XP-49 as a possible 'convoy fighter' able to escort bombers on deep penetration raids. It might have been accorded higher priority had England been lost as a base from which to mount the air assault on the Third Reich.

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.

At Burbank, the XP-49 survived a crash-landing caused by hydraulic failure, was 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. The 'convoy fighter' concept was studied later with the Lockheed XP-58 but never produced an operational aircraft.

Lockheed XP-49A three-view drawing (1278 x 778)

 ENGINE2 x Continental XIV-1430-13/15, 1010kW
  Take-off weight9047-9977 kg19945 - 21996 lb
  Empty weight7013 kg15461 lb
  Wingspan15.85 m52 ft 0 in
  Length12.22 m40 ft 1 in
  Height2.98 m10 ft 9 in
  Wing area30.42 m2327.44 sq ft
  Max. speed650 km/h404 mph
  Cruise speed600 km/h373 mph
  Ceiling11400 m37400 ft
  Range1095 km680 miles

Ron, e-mail, 18.04.2020 02:47

I would have like the P-38 adopt the twin cannons of the XP-49 [and perhaps reduce 12.7mm guns to 3]. One would assume that all the advances in the P-49 should benefit the P-38 since the Lightning was not replaced when the XP-49 was cancelled. If so, obviously the twin 20mm cannons were not adopted. Maybe I should not assume anything was transferred from the failed replacement, over to the P-38 that soldered on by default.

I can understand why the improved XP-49 had a back-up cannon. These US HS were maybe the least reliable 20mm cannons of WW2. Thankfully, they could be recharged in flight since they were nose-mounted. Of course the far more reliable RAF version would be much preferred. Still I would want 2 and not just 1 HS cannon, and if this meant cutting 1 or 2 Browning 12.7mm guns to alleviate some weight gain, why not? This should help keep the old P-38 competitive with the newer fighters. The XP-49 should not be a total loss. It was a sweet looking fighter! Too bad about the disappointing engines.


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