XB-39 Superfortress
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| Boeing XB-39 Superfortress | |
|---|---|
| Type | Test-bed bomber aircraft |
| Manufacturer | Boeing |
| Maiden flight | 1944 |
| Status | Never mass-produced |
| Primary user | United States Army Air Forces |
| Produced | 1944 |
| Number built | 1 |
The Boeing XB-39 Superfortress was a prototype bomber aircraft, a single example of the B-29 Superfortress converted to fly with alternative powerplants. It was intended to demonstrate that the B-29 could still be put into service even if the first choice of engine, the Wright R-3350, ran into development or production difficulties.
Starting life as the first YB-29 delivered to the United States Army Air Forces, it was modified by General Motors to use Allison V-3420-17 liquid-cooled inline engines. Testing on it began in early 1944. Since no problems with the R-3350 developed, and most flaws of the B-29 were worked out by the time production began, the XB-39 was never ordered.
[edit] Specifications (XB-39)
General characteristics
- Crew: 10: pilot, co-pilot, flight engineer, bombardier, navigator, radio operator, side gunners (two), top gunner, and tail gunner
- Length: 99 ft 0 in (30.18 m)
- Wingspan: 141 ft 3 in (43.05 m)
- Height: 27 ft 9 in (8.46 m)
- Wing area: 1736 ft² (161.3 m²)
- Empty weight: 74,500 lb (33,800 kg)
- Loaded weight: 120,000 lb (54,000 kg)
- Max takeoff weight: 133,500 lb (60,560 kg)
- Powerplant: 4× Allison V-3420-11 liquid-cooled V24 engines, 2,100 hp (1,600 kW) each
Performance
- Maximum speed: 405 mph (351 knots, 648 km/h)
- Range: 6,290 mi (5,460 nm, 10,060 km)
- Service ceiling: 35,000 ft (11,000 m)
- Wing loading: 69.12 lb/ft² (337.5 kg/m²)
- Power/mass: 0.073 hp/lb (121 W/kg)
Armament
- Guns:
- 8× .50 in (12.7 mm) Browning M2 machine guns in remote controlled turrets
- 2× .50 in (12.7 mm) machine guns in manual turrets
- 1× 20 mm (0.787 in) M2 cannon in tail
- Bombs: 20,000 lb (9,000 kg)
[edit] References and external links
[edit] Related content
Related development
Designation sequence
| 345 (B-29) | - 367 - 377 - 400 | |
| 345 (B-39) | ||
| 345 (B-44) | ||
| 345 (B-50) |
Related lists
See also
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