Douglas XB-42 Mixmaster

https://en.wikipedia.org/wiki/Douglas_XB-42_Mixmaster

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's 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.


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 first XB-42 was delivered to the USAAF and flew at Palm Springs, California
on 6 May 1944. Performance was excellent, being basically as described in the
original proposal: as fast or faster than the de Havilland Mosquito but with
defensive armament and twice the bombload. The twin bubble canopies proved a bad
idea as communications were adversely affected and a single bubble canopy was
substituted after the first flight.

Testing revealed that the XB-42 suffered from some instability as excessive yaw
was encountered, as well as vibration and poor engine cooling - all problems
that could probably have been dealt with. Due to the ventral vertical stabilizer
and rudder surface set's tip being located underneath the fuselage, careful
handling during taxiing, takeoff, and landing was required because of limited
ground clearance.

The end of World War II allowed the Air Force to consider possibilities with a
little more leisure and it was decided to wait for the development of better jet
bombers rather than continue with the B-42 program.

In December 1945, Captain Glen Edwards and Lt. Col. Henry E. Warden set a new
transcontinental speed record when they flew the XB-42 from Long Beach,
California to Bolling Air Force Base in Washington, D.C. (c. 2,300 miles). In
just 5 hours, 17 minutes, the XB-42 set a speed record of 433.6 mph (697.8
km/h).

Specifications (XB-42)

General characteristics
Crew: Three (pilot, copilot/gunner, bombardier)
Length: 53 ft 8 in (16.36 m)
Wingspan: 70 ft 6 in (21.49 m)
Height: 18 ft 10 in (5.74 m)
Wing area: 555 sq ft (51.6 m2)
Empty weight: 20,888 lb (9,475 kg)
Max. takeoff weight: 35,702 lb (16,194 kg)
Powerplant: 2 × Allison V-1710-125 V12 engines, 1,325 hp (988 kW) each

Performance
Maximum speed: 410 mph (357 knots, 660 km/h) at 23,440 ft (7,145 m)
Cruise speed: 312 mph
Range: 1,800 mi (1,565 nmi, 2,895 km)
Ferry range: 5,400 mi (4,696 nmi (8,690 km))
Service ceiling: 29,400 ft (8,960 m)

Armament

Guns: 6 × .50 in (12.7 mm) machine guns, two twin rear-firing turrets and two
fixed forward-firing
Bombs: 8,000 lb (3,629 kg)





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