Douglas XB-43 Jetmaster

https://en.wikipedia.org/wiki/Douglas_XB-43_Jetmaster

The Douglas XB-43 Jetmaster was 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.

United States Army Air Forces (USAAF) leaders in the Air Materiel Command began
to consider the possibilities of jet-propelled bombers as far back as October
1943. At that time, Douglas Aircraft was just beginning to design a promising
twin-engine bomber designated the XB-42. Reciprocating engines powered this
aircraft but they were buried in the fuselage, leaving the laminar flow-airfoil
wing clean of any drag-inducing pylon mounts or engine cowlings. The airframe
appeared ideally suited to test turbojet propulsion. Douglas confirmed the
feasibility of the concept and the USAAF amended the XB-42 contract in March
1944 to include the development of two turbojet-powered XB-43 prototypes,
reduced from an initial order of 13 test aircraft.

The Douglas design team convinced the Army that modifying the XB-42 static test
airframe into the first XB-43 was a relatively straightforward process that
would save time and money compared to developing a brand new design. Douglas
replaced the two Allison V-1710 engines with a pair of General Electric (GE) J35
turbojets (the first American axial-flow jet engines ever used), then cut two
air intakes into each side of the fuselage, aft of the pressurized cockpit.
Removing the propellers and drive shafts freed enough space for two long jet
exhaust ducts. Without any propellers present, there was no chance of striking
the blade tips on the runway, so the entire ventral fin/rudder unit of the
earlier XB-42's full four-surface cruciform tail was omitted. Douglas
compensated for the loss of yaw stability by enlarging the dorsal fin/rudder
unit.

Douglas Aircraft was keen to mass-produce the new bomber and the USAAF
considered ordering 50. The company was poised to roll out as many as 200 B-43s
per month in two versions: a bomber equipped with a clear plastic nose for the
bombardier, and an attack aircraft without the clear nose and bombing station
but carrying 16 forward-firing .50 in (12.7 mm) machine guns and 36 5 in (127
mm) rockets. Nothing came of these plans. The USAAF was already moving ahead
with a new bomber, the XB-45 Tornado, designed from the outset for turbojet
power and promising major improvement in every category of performance.


Role
Prototype bomber aircraft

Manufacturer
Douglas Aircraft Company

First flight
17 May 1946

Introduction
n/a

Number built
2

Developed from
Douglas XB-42 Mixmaster

As Douglas predicted, the work itself was not overly complex but almost two
years were required to ready the aircraft for flight due to delays in obtaining
the J35 powerplants. The end of World War II caused a general slowdown within
the aviation industry and GE was late delivering the engines. When they were at
last installed and tested on the ground, one of the units failed
catastrophically. Compressor blades exploded through the engine casing, damaging
the surrounding airframe and injuring a ground technician. Another seven-month
delay ensued for repairs. America's first turbojet bomber finally flew from
Muroc Army Air Base on 17 May 1946, piloted by Douglas test pilot, Bob Brush,
accompanied by engineer Russell Thaw.

Caught in a momentous technological shift, the XB-43 contributed to developing
procedures for flying the new jet bombers, and it gave yeoman service testing
new turbojet engines. Douglas completed the second prototype, AAF serial number
44-61509, flying on 15 May 1947 and delivered it to Muroc Air Force Base,
California, in April 1948. The USAAF soon replaced one J35 turbojet engine with
a General Electric J47. Douglas delivered the second prototype, designated
YB-43, in April 1948. That aircraft was nicknamed Versatile II by USAAF
personnel. When the clear plastic nose began to crack from variations in
temperature at high and low altitudes, mechanics fashioned a more durable
replacement made from plywood. To keep it flying, the US Air Force cannibalized
parts from the first XB-43 after it was damaged in February 1951. Versatile II
flew more than 300 hours until its retirement in December 1953.

Specifications (XB-43)

General characteristics
Crew: three
Length: 51 ft 5 in (15.7 m)
Wingspan: 71 ft 2 in (21.7 m)
Height: 24 ft 3 in (7.4 m)
Wing area: 563 ft² (52.3 m²)
Empty weight: 22,890 lb (10,380 kg)
Loaded weight: 40,000 lb (18,000 kg)
Powerplant: 2 × General Electric J35-GE-3 turbojets, 4,000 lbf (18 kN) each

Performance
Maximum speed: 507 mph (440 kn, 816 km/h)
Range: 2,500 mi (2,200 nmi, 4,000 km)
Service ceiling: 38,500 ft (11,700 m)
Rate of climb: 2,470 ft/min (753 m/min)
Wing loading: 71 lb/ft² (350 kg/m²)
Thrust/weight: 0.20

Armament

Guns:
2 × 0.50 in (12.7 mm) machine guns in a remotely operated tail mount, never
installed.
Planned attack variant: 8 × 0.50 in (12.7 mm) machine guns in solid nose

Bombs: 8,000 lb (3,629 kg)




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