Douglas B-42

XB-42 Mixmaster
XB-42
Role	Medium Bomber
Manufacturer	Douglas Aircraft Company
First flight	6 May 1944
Status	Cancelled in 1948
Primary users	United States Army Air Forces (intended) United States Air Force (intended)
Number built	2
Unit cost	US$13.7 million for the program, including B-43
Developed into	Douglas XB-43 Jetmaster Douglas DC-8 (piston airliner)

The Douglas XB-42 Mixmaster was an experimental bomber aircraft, designed for a high top speed. The unconventional approach was to mount the two engines within the fuselage driving a pair of contra-rotating propellers mounted at the tail in a pusher configuration, leaving the wing and fuselage clean and free of drag-inducing protrusions.

Two prototype aircraft were built, but the end of World War II changed priorities and the advent of the jet engine gave an alternative way toward achieving high speed.

The XB-42 was developed initially as a private venture; an unsolicited proposal was presented to the United States Army Air Forces in May 1943. This resulted in an Air Force contract for two prototypes and one static test airframe, the USAAF seeing an intriguing possibility of finding a bomber capable of the Boeing B-29 Superfortress' range without its size or cost.

The aircraft mounted a pair of Allison V-1710-125 liquid-cooled V-12 engines behind the crew's cabin, each driving one of the twin propellers. Air intakes were in the wing leading edge. The landing gear was tricycle and a full, four surface cruciform tail was fitted, whose ventral fin/rudder unit prevented the coaxial propellers from striking the ground. The pilot and co-pilot sat under twin bubble canopies, and the bombardier sat in the extreme front behind a plexiglass nose.

Defensive armament was two 0.50 in (12.7 mm) machine guns each side in the trailing edge of the wing, which retracted into the wing when not in use. These guns were aimed by the copilot through a sighting station at the rear of his cockpit. The guns had a limited field of fire and could only cover the rear, but with the aircraft's high speed it was thought unlikely that intercepting fighters would be attacking from any other angle.

Two more guns were fitted to fire directly forward. Initially ordered as an attack aircraft (XA-42) in the summer of 1943, this variant would have been armed with 16 machine guns or a 75 mm (2.95 in) cannon and two machine guns.