To understand America's first jet bomber, the XB-43 Jetmaster, you have to understand the XB-42 Mixmaster, an aircraft that was equally as impressive and even more exotic. Even though neither of these amazing aircraft made it to the front lines, many of their unique innovations and lessons learned from operating them did.

The Douglas XB-42 Mixmaster started as a corporate project exploring the idea of very fast and high-flying attack aircraft. After showing it to the Army Air Force they wanted it as a possible lower-cost, smaller hedge against the incredibly complex and costly B-29 Superfortress program. In their minds, if the B-29 did not end up being the bomber that could could attack the Japanese homeland, the smaller B-42 would have to do.

The XB-42's design was anything but standard, with a cylindrical fuselage and a huge cruciform tail with a coaxial pusher propeller emanating out the back of it. The aircraft sat on a tricycle gear, which was somewhat exotic for the time, and the pilot and copilot sat abreast one another under separate bubble canopies. The bombadier was seated in the aircraft's glazed nose section. Defensive armament consisted of a pair forward firing .50 caliber machine guns and a quartet of rear firing machine guns that emanated from the rear of the XB-42's wings. They were controlled by the copilot via an elaborate aiming mechanism and had a limited field of fire. The idea was that the XB-42 should be fast enough that no fighter could catch up with it from behind.

A pair of Allison V-1710 inline V-12s that were coupled together through a complex drivetrain powered the XB-42, with each V-12 powering one of the aircraft's stacked props. The pusher-prop design gave the aircraft clean wings and a smooth fuselage, which helped it hurtle through the air at a remarkable high speed.

The first of two prototype XB-42 took to the air for the first time on May 6th 1944. The aircraft had major handling issues from the start, with the low-slung tail being a serious issue to contend with during takeoff and landing. In flight, the aircraft suffered from excessive yaw, intense vibration and cooling issues for its twin V-1710s, but beyond these peculiarities, many of which could have been worked through fairly easily via a light redesign, the aircraft was fast, just as promised.

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It could cruise at over 300 mph and it could hit 410mph during a dash. Considering that the aircraft could carry 8,000 lbs of weapons and had a range approaching 2,000 miles, the Mixmaster looked like it would become a huge success. But the tide of World War II was changing and the B-29 ended up being everything that it promised. Jet engine technology was emerging as the wave of the future, leaving little room for piston engine-based designs. This left the XB-42 without a production contract.

In December of 1945, at the hands of famed pilot Glen Edwards, one of the Mixmasters flew a speed record across the US, taking off from Long Beach and flying to Washington, D.C. in just 5 hours and 17 minutes. This same aircraft ended up being destroyed do to a gear failure, but its sister ship was migrated to other test programs. One of these programs was to fit a pair of Westinghouse tubrojets with a paltry 1,600lbs of thrust each under the XB-42's clean wings. This configuration was known as an XB-42A.

The XB-42A flew many test flights to prove jet engine technology and hit a top speed of 488mph, but was damaged after a hard landing and never flew again. By 1949 the aircraft was removed from the Army Air Force's official inventory.

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Oddly enough, this was not the end of such an exotic design. In 1944, the Army Air Force amended the XB-42 contract so that Douglas could also build a jet powered prototype based on the XB-42 core design. Because of where the aircraft's engines were located, internally within the aircraft's smooth fuselage, and its pusher prop design, the Mixmaster was seen as a perfect place to start experimenting with a dedicated jet bomber concept.

Two prototypes were ordered, these aircraft were known as XB-43s. One of these was the XB-42's static test airframe that was reworked into the XB-43 configuration by removing the Allison V-1710 V-12 engines and replacing them with a pair of General Electric J35 turbojets. Two inlets were cut into the sides of the XB-42 just behind the cockpit and long exhaust ducts was snaked back to where the coaxial propellers once were. Because there were no props included in the design, the bottom stabilizer of the big cruciform tail could be removed, which eliminated the aircraft's issues with ground handling. The aircraft's vertical stabilizer was enlarged to compensate for the loss of the bottom one.

Although Douglas thought they were on to something big and pushed the Army Air Force to rush the design into production so that it could affect the War effort, pushing for both a bomber as well as an attack version that was bristling with 16 guns, the jet had not even flown yet and the Army Air Force took a wait-and-see position.

In the end, this position was well founded, as the arrival of the XB-43's J35 powerplants was frequently delayed. When they finally arrived and were ran after installation, one of the jets had a major containment failure and detonated, sending compressor blades flying through the aircraft's fuselage. The damage resulted in a half year delay in the program, by which time the war was over.

America's first jet bomber finally flew for the first time at Muroc Army Air Base (now Edwards AFB, named after the aforementioned Glen Edwards) on May 17, 1946. The aircraft performed remarkably well, with a top speed of over 500mph and a range of almost 2,500 miles. Handling qualities were said to have been exceptional. Still, the Army Air Force treated the X-43 as a testbed instead of a possible production aircraft, concentrating on the more substantial B-45 Tornado as its first operational jet bomber.

The second XB-43 prototype joined the test program in 1948. Both aircraft were upgraded with the more capable J47 turbojet for continued testing. Many of the procedures, processes and tactics used for flying and employing future jet bombers were born from the XB-43s' hundreds of hours of test flights, which continued until 1953 even though the first XB-43s was grounded do to a mishap that occurred in 1951. Parts from it were cannibalized to keep the second prototype, nicknamed "Versatile II" flying another two years.

Today, the only remaining XB-43 and XB-42 are located at the USAF museum at Wright Patterson Air Force Base near Dayton, Ohio. Both are awaiting restoration (see the XB-43's condition here), after which time they will be displayed together in the museum, and rightfully so. In the end the XB-42 and XB-43 ushered in a new era of speed and helped developed the playbook for jet aircraft operations, with the XB-43 being the first American jet bomber ever flown. Both types' work as test aircraft paved the way for America's ever-evolving Cold War-era jet bomber fleet, a deterrent capability that was a major contributing factor in ending the Cold War.

Tyler Rogoway is a defense journalist and photographer who maintains the website Foxtrot Alpha for Jalopnik.com You can reach Tyler with story ideas or direct comments regarding this or any other defense topic via the email address Tyler@Jalopnik.com