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.

XB-42 Mixmaster
B-42 Mixmaster
XB-42
Role Medium bomber
Manufacturer Douglas Aircraft Company
First flight 6 May 1944
Status Canceled 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[1]
Developed into Douglas XB-43 Jetmaster
Douglas DC-8 (piston airliner)

Design and development

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.[2]

Defensive armament consisted of 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 attack from any other angle.[2]

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.[2]

Operational history

Douglas XB-42 rear
View of the contraprop and cruciform tail.
Douglas XB-42A Mixmaster rear view
Rear view of the XB-42A in May 1947
Douglas XB-42a side view
XB-42A with podded 19XB-2 jets.[3]
Douglas XB-42A
XB-42A

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.[4]

Testing revealed that the XB-42 suffered from some instability as excessive yaw was encountered,[4] 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).[5]

The record-breaking XB-42 prototype had been destroyed in a crash at Bolling Field. The second of two prototypes of the Douglas XB-42, 43-50225, on a routine flight out of Bolling Field, Washington, D.C., suffered in short order, a landing gear extension problem, failure of the port engine, and as coolant temperatures rose, failure of the starboard engine. Maj. Hayduck bailed out at 1,200 feet, Lt. Col. Haney at 800 feet, and pilot Lt. Col. (later Major General) Fred J. Ascani, after crawling aft to jettison the pusher propellers, at 400 feet – all three survived. The aircraft crashed at Oxon Hill, Maryland. Classified jettisonable propeller technology caused a problem for authorities in explaining what witnesses on the ground thought was the aircraft exploding. Possible fuel management problems were speculated, but this hypothesis was never proven by subsequent investigation. The remaining prototype was used in flight test programs, including fulfilling a December 1943 proposal by Douglas to fit uprated engines and underwing Westinghouse 19XB-2A axial-flow turbojets of 1,600 lbf (7.1 kN) thrust each, making it the XB-42A.[6]

In this configuration, it first flew at Muroc (now Edwards Air Force Base) on 27 May 1947. In testing, it reached 488 mph (785 km/h). After 22 flights, the lower vertical stabilizer and rudder were damaged in a hard landing in 1947. The XB-42A was repaired but never flew again, and was taken off the USAF inventory on 30 June 1949.[6]

Surviving aircraft

Specifications (XB-42)

Data from Francillon 1979[8]

General characteristics

  • Crew: three (pilot, co-pilot, 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 liquid-cooled V12 engines, 1,325 hp (988 kW) each

Performance

  • Maximum speed: 410 mph (660 km/h, 360 kn) at 23,440 feet (7,140 m)
  • Range: 1,800 mi (2,900 km, 1,600 nmi)
  • Ferry range: 5,400 mi (8,700 km, 4,700 nmi)
  • Service ceiling: 29,400 ft (9,000 m)
  • Power/mass: 0.16 hp/lb

Armament

  • Guns: 6 × .50 in (12.7 mm) machine guns, two in twin rear-firing turrets and two fixed forward-firing[9]
  • Bombs: 8,000 pounds (3,600 kg) in internal bay

See also

Related development

Related lists

References

Citation

  1. ^ Knaack, Marcelle Size. Post-World War II bombers, 1945-1973. Washington, D.C.: Office of Air Force History, 1988. ISBN 0-16-002260-6.
  2. ^ a b c Winchester 2005, p. 27.
  3. ^ Francillon 1979, p. 376.
  4. ^ a b Winchester 2005, p. 26.
  5. ^ O'Leary 1994, p. 10.
  6. ^ a b Francillon 1979, pp. 376–377.
  7. ^ "XB-42 Mixmaster/43-50224." Archived December 3, 2008, at the Wayback Machine National Museum of the USAF. Retrieved: 10 May 2013.
  8. ^ Francillon 1979, p. 377.
  9. ^ "Factsheet: Douglas XB-42". Archived 2008-02-08 at the Wayback Machine National Museum of the United States Air Force. Retrieved: 9 June 2010.

Bibliography

  • Boyne, Walt (September 1973). "The First, The Last, And The Only: The Douglas XB-42/42A/43". Airpower. Vol. 3 no. 5. pp. 13–14.
  • Francillon, René J. (1979). McDonnell Douglas Aircraft since 1920. London: Putnam. ISBN 0-370-00050-1.
  • O'Leary, Michael, ed. "Elegant Failure." America's Forgotten Wings, Volume 1, 1994, pp. 4–11.
  • Winchester, Jim (2005). The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books. ISBN 1-904687-34-2.

External links

Allison V-1710

The Allison V-1710 aircraft engine designed and produced by the Allison Engine Company was the only US-developed V-12 liquid-cooled engine to see service during World War II. Versions with a turbocharger gave excellent performance at high altitude in the twin-engined Lockheed P-38 Lightning, and turbo-superchargers were fitted to experimental single-engined fighters with similar results.

The United States Army Air Corps (USAAC) preference for turbochargers early in the V-1710's development program meant that less effort was spent on developing suitable mechanically-driven centrifugal superchargers for the Allison V-12 design, as other V-12 designs from friendly nations like the British Rolls-Royce Merlin were already using.

When smaller-dimensioned or lower-cost versions of the V-1710 were desired, they generally had poor performance at higher altitudes. The V-1710 nevertheless gave excellent service when turbocharged, notably in the P-38 Lightning, which accounted for much of the extensive production run.

Buzz number

A buzz number was a large letter and number combination applied to United States Air Force military aircraft in the years immediately after World War II, through the early 1960s. They were applied for general aerial identification of aircraft, but particularly for the identification of aircraft guilty of "buzzing" (very-low-altitude high-speed passes) over populated areas.

The first two letters of a buzz number indicated the type and designation of an aircraft while the last three were generally the last three digits of the aircraft serial number. Air Force fighters used buzz numbers starting with the letter F (or P, when fighters were designated as "pursuit" aircraft before June 1948), while bombers started with the letter B. For example, a P-51 Mustang would have a buzz number such as FF-230 while an F-86 Sabre might be FU-910. A B-66 Destroyer would have a buzz number such as BB-222. One of the last Air Force fighters to carry a buzz number was the F-4 Phantom II (FJ), then called the F-110 Spectre by the Air Force.

Contra-rotating propellers

Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston or turboprop engine to drive two coaxial propellers in contra-rotation (rotation about the same axis in opposite directions). Two propellers are arranged one behind the other, and power is transferred from the engine via a planetary gear or spur gear transmission. Contra-rotating propellers are also known as counter-rotating propellers, although counter-rotating propellers is much more widely used when referring to airscrews on separate shafts turning in opposite directions.

Douglas Aircraft Company

The Douglas Aircraft Company was an American aerospace manufacturer based in Southern California. It was founded in 1921 by Donald Wills Douglas Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas, when it then operated as a division of McDonnell Douglas. McDonnell Douglas later merged with Boeing in 1997.

Douglas Cloudster II

The Douglas Cloudster II was an American prototype five-seat light aircraft of the late 1940s. It was of unusual layout, with two buried piston engines driving a single pusher propeller. Only a single example was built, which flew only twice, as it proved too expensive to be commercially viable.

Douglas DC-8 (piston airliner)

The Douglas DC-8 was an American piston-engined airliner project by Douglas Aircraft. A concept developed more than a decade before the DC-8 jetliner, the piston-engined DC-8 was to have propellers in the tail, an idea first used at Douglas by Edward F. Burton on a fighter project. The airliner project was canceled after development costs made it commercially unviable.

Douglas XB-43 Jetmaster

The Douglas XB-43 Jetmaster is an American 1940s jet-powered prototype bomber. The XB-43 was a development of the XB-42, replacing the piston engines of the XB-42 with two General Electric J35 engines of 4,000 lbf (17.8 kN) thrust each. Despite being the first American jet bomber to fly, it suffered stability issues and the design did not enter production.

Earl Schuyler Kleinhans

Earl Schuyler (Sky) Kleinhans (February 3, 1905 – September 21, 1996) was an airplane and flying boat aeronautical engineering pioneer with primary experience at Sikorsky and Douglas Aircraft where he advanced over a 36-year career to become chief engineer and retired as the chairman of the scientific advisory board in 1969 for McDonnell Douglas.

List of accidents and incidents involving military aircraft (1945–1949)

This is a list of accidents and incidents involving military aircraft which occurred between 1945 and 1949, grouped by the year in which the accident or incident occurred. Not all of the aircraft were in operation at the time. For more exhaustive lists, see the Aircraft Crash Record Office or the Air Safety Network or the Dutch Scramble Website Brush and Dustpan Database. Combat losses are not included except for a very few cases denoted by singular circumstances.

List of pusher aircraft by configuration

A pusher aircraft is a type of aircraft using propellers placed behind the engines and may be classified according to engine/propeller location and drive as well as the lifting surfaces layout (conventional or 3 surface, canard, joined wing, tailless and rotorcraft),

Some aircraft have a Push-pull configuration with both tractor and pusher engines. The list includes these even if the pusher engine is just added to a conventional layout (engines inside the wings or above the wing for example).

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