The Douglas XB-43 was the first American jet bomber. It was a development of the XB-42 Mixmaster twin-engined bomber, with turbojet engines replacing the twin inline Allison piston engines.
The XB-43 had its origin back in October of 1943, when first consideration was given to fitting turbojets to the XB-42. Preliminary studies indicated that the scheme was practical, and on March 31, 1944 Douglas received a change order to the original XB-42 contract which called for the production of two jet-powered versions under the designation XB-43. The USAAF wanted the XB-43 to have a gross weight of 40,000 pounds.
Two General Electric TG-180 (later redesignated J35-GE-3) axial-flow turbojets were mounted in the forward fuselage bays that were previously occupied by the Allison piston engines of the XB-42. Flush intakes were incorporated in the upper fuselage sides immediately behind the two-seat pressurized cockpit. The hot gases from the engines were exhausted via long tail pipes which extended all the way down the fuselage to side-by-side openings in the tail. Since there was no longer any rear propeller which had to be protected against hitting the ground, the lower ventral fin of the XB-42 could be omitted. This omission required that the upper vertical fin be increased in area to provide adequate lateral control.
Assuming tests on the prototypes to be satisfactory, plans were made for an initial production order of 50 B-43s for the USAAF, while Douglas subitting a proposal for an eventual production rate of as many as 200 per month. The production B-43 would have had a conventional canopy in place of the two small bug-eye canopies of the XB-42. Two versions were planned--a bomber version with a transparent nose and a maximum bombload of 6000 pounds and an attack version with 16 forward-firing 0.50-inch machine guns with an unglazed nose and an armament of 35 5-inch rockets. Both versions were to be fitted with a remotely-controlled, radar-directed tail turret with two 0.50-inch machine guns. However, no bombs were ever carried and the defensive armament was never installed on the XB-43 prototypes.
The end of the war resulted in a slowdown in the B-43 program, since a jet bomber was no longer urgently needed. In addition, late delivery of the turbojets resulted in a delay of several additional months. During a engine run-up test at Clover Field in October of 1945, the starboard engine shed some of its first-stage compressor blades, causing an instantaneous separation of all blades and damaging the engine casing and fuselage skin. The repairs that were required delayed the first flight by another seven months.
The first XB-43 (44-61508) finally took off on its maiden flight on May 17, 1946, with test pilot Bob Brush and engineer Russell Thaw in the cockpit. Performance was generally satisfactory, but the aircraft was somewhat underpowered. During flight trials, the Plexiglas nose cracked due to temperature changes, and had to be replaced by a plywood cone.
However, by the time of the XB-43's first flight, the USAAF had already decided against ordering the B-43 into production. USAAF thinking now favored a four-engined rather than a twin-engined configuration for its future jet bombers, and had already decided to order the North American B-45 Tornado into production. The XB-43 program would still continue, but it would now be relegated to the status of a flying testbed.
The second aircraft (44-61509) was fitted with a single canopy and was delivered to Muroc in May of 1947. It was used there as an engine testbed. For this purpose, one of its J35s was replaced by a General Electric J47. This plane was kept flying by cannibalizing the first XB-43, which had been damaged in an accident on February 1, 1951. In late 1953, the second XB-43 was finally retired. The plane is now owned by the National Air and Space Museum. It is now sitting in one of the hangars of the Paul Garber restoration facility at Suitland, Maryland, awaiting restoration. However, the plane stored there has the original twin-canopy cockpit.
Serials of the two XB-43s were 44-61508 and 44-61509.
Two General Electric J35-GE-3 turbojets, 4000 lb.s.t. each. Performance: Maximum speed 515 mph at sea level. Cruising speed 420 mph. Service ceiling 38,200 feet, Absolute ceiling 41,800 feet, Initial climb rate 2470 feet per minute. Range 1100 miles with 8000 pounds of bombs. Maximum range 2840 miles. Weights: 21,755 pounds empty, 37,000 pounds loaded, 39,553 pounds maximum takeoff. Dimensions: Wingspan 71 feet 2 inches, length 51 feet 2 inches, height 24 feet 3 inches, wing area 563 square feet. Armament: Neither XB-43 was ever fitted with any armament.