The Douglas XB-42 Mixmaster was an unconventional prototype aircraft initially developed by the company as a private project. It was only once they showed the designs to the United States Army Air Force in May 1943 that the military got involved. The USAAF ordered two prototypes and one static test airframe. The air force were sold on the design as it promised the same sort of range as the Boeing B-29 Superfortress, but didn’t come with the B-29’s massive size or cost.
The Douglas XB-42 Mixmaster was powered by a pair of Allison V-1710-125 liquid-cooled V12 engine which were mounted behind and below the cockpit. Each engine was responsible for powering one set of the contra-rotating pusher propellers. Air intakes in the leading edge of the wings fed the engines, but other than that the aircraft was devoid of almost any drag-inducing apertures. The rear mounted propellers were vulnerable to damage during take-off and landings, so there was a long fin under the tail to prevent them from striking the ground. For some unknown reason the designers chose to fit the aircraft with two individual bubble canopies, one for the pilot and one for the co-pilot. However after the first flight this was replaced with a more practical large single canopy which allowed for much better communication between the two. The bombardier sat at the very front of the aircraft behind a plexiglass nosecone.
The Douglas XB-42 Mixmaster’s defensive armament consisted of two rear facing 0.50 inch (12.7 mm) machine guns which were aimed by the copilot from a sighting station at the rear of the cockpit. These guns only had a limited field of fire, but as the aircraft’s top speed was so impressive it was thought any attacking fighters would almost certainly have to approach from behind. The second prototype was ordered in different configuration to the first aircraft – which had been conceived primarily as a bomber. This model was designed as an attack aircraft, and if it went into combat would have been fitted with no less than 16 machine guns, or a 75 mm (2.95 in) cannon and a pair of machine guns.
The Douglas XB-42 Mixmaster first flew on 6th May 1944. It proved to be a superb aircraft and lived up to its expectations. It was faster than its competition and could carry more weaponry. Testing did reveal a few flaws with the aircraft, including some instability during excessive yaw, vibrations and engine cooling issues. However with time these could all have been rectified.
When the Second World War ended, America’s need for long range bomber aircraft was no longer a priority. At the same time jet-powered aircraft were just starting to take-off – both literally and figuratively! So while the XB-42 was a highly advanced and capable propeller-driven aircraft, it just couldn’t compete with the sort of performance numbers the first generation of jet aircraft were producing.
That doesn’t mean the Douglas XB-42 Mixmaster didn’t have its moment of glory though. In December 1945, Capt. Glen Edwards (after whom Edwards Air Force Base is named) and Lt. Col. Henry E. Warden set a new transcontinental speed record by flying the prototype XB-42 from Long Beach, California to Bolling Air Force Base in Washington DC in 5 hours, 17 minutes.
The same aircraft was later destroyed in a crash attributed to the failure of the tricycle landing gear. However the other XB-42 Mixmaster continued flying up until 1947. During its time it was used to test new engines and underwing Westinghouse axial-flow turbojets. It too was put out of action due to a hard landing, which severely damaged the rudder and stabilizer. Despite being repaired it never flew again. It currently sits in storage awaiting restoration at the National Museum of the United States Air Force in Dayton, Ohio.