Boeing XB-15
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Image:XB-15 Bomber.jpg The Boeing XB-15 (Boeing 294) was a bomber aircraft first designed in 1934 as a test for the United States Army Air Corps to see if it was possible to build a heavy bomber with a 5,000 mile (8,000 km) range. It was originally designated the XBLR-1 (experimental bomber, long range). When it first flew, it was the most massive and most voluminous airplane ever built in the United States. It set a number of load-to-altitude records, including a 31,205-pound flight to 8,200 feet (July 30 1939).
The aircraft's immense size allowed for passages within the wing, which the crew could use to make minor repairs in flight. Due to the technology of the time, a 5,000 mile flight took several days; the crew was made up of several shifts, and bunks allowed them to sleep when off duty.
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Development
The XB-15 was designed around liquid-cooled 1,000 hp (750 kW) engines. Unfortunately, these were not available, and 850 hp (637 kW) engines were used instead. These engines left the bomber significantly underpowered; its top speed of 200 mph (322 km/h) was far too slow for a combat aircraft, and the project was abandoned. No B-15s were put into service; the Army Air Corps converted the only prototype into a transport designated the XC-105.
Technological achievements
Despite its cancellation, the XB-15 did feature a number of significant innovations:
- Automatic Pilot
- De-icing equipment
- Auxiliary power units independent of the main engines to power the electrical system
- Engines serviceable in flight using an access tunnel inside the wing
- Crew compartment with rest bunks, galley and lavatory
- Double-wheel main landing gear.
Specifications (XB-15)
{{airtemp
|plane or copter?=plane |jet or prop?=prop
|crew=10 |length main=87 ft 7 in |length alt=32.6 m |span main=149 ft 0 in |span alt=45.5 m |height main=18 ft 0 in |height alt=5.5 m |area main=2,780 ft² |area alt=258 m² |empty weight main=65,000 lb |empty weight alt=30,000 kg |loaded weight main=69,000 lb |loaded weight alt=31,000 kg |max takeoff weight main=77,000 lb |max takeoff weight alt=37,000 kg
|number of props=4 |engine (prop)=Pratt & Whitney R-1830-11 |type of prop=radial engines |power main=850 hp |power alt=640 kW
|max speed main=200 mph
|max speed alt=170 kt, 320 km/h
|cruise speed main=152 mph
|cruise speed alt=132 kt, 245 km/h
|range main=
- Combat Range: 3,400 mi
|range alt=3,000 nm, 5,500 km)
- Ferry Range: 5,130 miles (4,460 kt, 8,250 km
|ceiling main=18,900 ft |ceiling alt=7,830 m |climb rate main=670 ft/min |climb rate alt=3.4 m/s |loading main=25 lb/ft² |loading alt=120 kg/m² |power/mass main=0.049 hp/lb |power/mass alt=81 W/kg
|guns=
- 3× .30 in (7.62 mm) machine guns
- 3× .50 in (12.7 mm) machine guns</ul>
|bombs=12,000 lb (5,400 kg) }}
External links
- Boeing's description of the XB-15
- Encyclopedia of American aircraft
- USAF Museum description of XB-15
Related content
{{aircontent
|sequence=
- Military XBLR- series: XBLR-1 - XBLR-2 - XBLR-3
- Military B- series: B-12 - XB-13 - XB-14 - XB-15 - XB-16 - B-17 - B-18
- Boeing: 248 - 266 - 281 - 294 - 299 - 314 - 316
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|similar aircraft=
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