B-18 Bolo

Infobox Aircraft
name= B-18 Bolo


caption=Douglas B-18A airplane in flight.
type=Light bomber
manufacturer=Douglas Aircraft Company
designer=
first flight= April 1935
introduced=1936
retired=1940s
status=
primary user= United States Army Air Corps
more users= United States Army Air Forces Royal Canadian Air Force Brazilian Air Force
produced=1936-
number built=350
unit cost=US$58,500 (1935)
variants with their own articles=Douglas XB-22 C-58 BoloThe Douglas B-18 Bolo was a United States Army Air Corps and Royal Canadian Air Force bomber of the late 1930s and early 1940s. The Bolo was built by Douglas Aircraft Company and based on its DC-2. Although not the latest or most advanced design, the B-18 was pressed into service where it performed wartime patrol duties early in World War II.

Design and development

In 1934, the United States Army Air Corps put out a request for a bomber with double the bomb load and range of the Martin B-10, which was just entering service as the Army's standard bomber.In the evaluation at Wright Field the following year, Douglas showed its DB-1. It competed with the Boeing "Model 299" (later the B-17 Flying Fortress) and Martin Model 146. While the Boeing design was clearly superior, the crash of the B-17 prototype (caused by taking off with the controls locked) removed it from consideration. During the depths of the Great Depression, the lower price of the DB-1 ($58,500 vs. $99,620 for the Model 299) also counted in its favor. The Douglas design was ordered into immediate production in January 1936 as the B-18.

The DB-1 design was essentially the same as the DC-2, with several modifications. The wingspan was 4.5 ft (1.4 m) greater. The fuselage was deeper, to better accommodate bombs and the six-member crew; the wings were fixed in the middle of the cross-section rather than to the bottom, but this was due to the deeper fuselage. Added armament included nose, dorsal, and ventral gun turrets.

Operational history

The initial contract called for 133 B-18s (including DB-1), using Wright R-1820 radial engines. The last B-18 of the run, designated DB-2 by the company, had a power-operated nose turret. This design did not become standard. Additional contracts in 1937 (177 aircraft) and 1938 (40 aircraft) were for the B-18A, which had the bombardier's position further forward over the nose-gunner's station. The B-18A also used more powerful engines.

By 1940, most US Army Air Force bomber squadrons were equipped with B-18s or B-18As. Many of those in the 5th Bomb Group and 11th Bomb Group in Hawaii were destroyed in the attack on Pearl Harbor.
B-17s supplanted B-18s in first-line service in 1942. Following this, 122 B-18As were modified for anti-submarine warfare. The bombardier was replaced by a search radar with a large radome. Magnetic anomaly detection (MAD) equipment was sometimes housed in a tail boom. These aircraft, designated B-18B, were used in the Caribbean on anti-submarine patrol. Two aircraft were transferred to Força Aérea Brasileira in 1942. The Royal Canadian Air Force acquired 20 B-18As (designated the "Douglas Digby Mark I"), and also used them for patrol duties.

On 2 October 1942, a B-18A depth charged and sank the German u-boat U-512 north of Cayenne, French Guiana. [Uboat.net: [http://uboat.net/boats/u512.htm B-18 sinks U-512] ] Bolos and Digbys sank an additional two submarines during the course of the war. RCAF Eastern Air Command (EAC) Digbys carried out 11 attacks on U-boats. U-520 was confirmed sunk by Flying Officer F. Raymes' crew of No 10 (BR) Sqn, on 30 October 1942 [ [http://www.rcaf.com/aircraft/patrol/digby/index.php Douglas Digby] ] east of Newfoundland. [Uboat.net: [http://uboat.net/boats/u520.htm Canadian Digby sinks U-520] ]

Variants

;DB-1:Prototype, first of B-18 production run, 1 built.;B-18:Initial production version, 131 or 133 built. [ [http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2457 "B-18" entry at the "National Museum of the USAF" website] ] ;;B-18M::Bomb gear removed from B-18 to serve as trainer.;;DB-2::Powered nose turret prototype; last of B-18 production run, 1 built.;B-18A:B-18 with more powerful Wright R-1820-53 engines and moved bombardier's station, 217 built. [ [http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2458 "B-18A" entry at the "National Museum of the USAF" website] ] ;B-18AM:Bomb gear removed from B-18A to serve as trainer.;B-18B:Antisubmarine conversion, 122 converted. [ [http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2459 "B-18B" entry at the "National Museum of the USAF" website] ] ;B-18C:Antisubmarine conversion, 2 converted.;XB-22:Improvement on B-18 using Wright R-2600-3 radial engines (1,600 hp, 1194 kW). Never built, largely due to better light bombers such as the B-23 Dragon. [ [http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2492 "XB-22" entry at the "National Museum of the USAF" website] ] ;C-58:Transport conversion.;Digby I:Royal Canadian Air Force modification of B-18A.

Operators

;BRA
*Brazilian Air Force;flag|Canada|1921
*Royal Canadian Air Force;flag|United States|1912
*United States Army Air Corps
*United States Army Air Force

urvivors

Only five B-18s still exist, preserved in museums in the United States: [ [http://aeroweb.brooklyn.cuny.edu/locator/manufact/douglas/b-18.htm AeroWebs: "List of survivorr B-18s on display"] ] ;B-18 s/n "37-0029":On display at Castle Air Museum, Atwater, California.;B-18A s/n "37-469":On display at National Museum of the United States Air Force, Wright-Patterson AFB, Ohio.;B-18A s/n "39-25/64":On display at Wings Over the Rockies Air and Space Museum, Denver, Colorado.:See the [http://members.aol.com/cba1974/myhomepage/B18walkaround.html Wings' B-18 Bolo Walk Around Site] with aircraft history.;B-18B s/n "37-505":On display at McChord Air Museum [http://www.mcchordairmuseum.org/] , McChord AFB, Washington.;B-18B s/n "38-593":On display at Pima Air & Space Museum Tucson, Arizona.;B-18 s/n "36-446":Sitting in a gulch on Laupahoehoe Nui LLC property, Hamakua, Hawai'i.:Hopefully soon to be rescued by the Pearl Harbor Aviation Museum.

pecifications (B-18A)

aircraft specifications

plane or copter?=plane
jet or prop?=prop

crew=6
length main=57 ft 10 in
length alt=17.6 m
span main=89 ft 6 in
span alt=27.3 m
height main=15 ft 2 in
height alt=4.6 m
area main=959 ft²
area alt=89.1 m²
empty weight main=16,321 lb
empty weight alt=7,400 kg
loaded weight main=22,123 lb
loaded weight alt=10,030 kg
max takeoff weight main=27,500 lb
max takeoff weight alt=12,600 kg
engine (prop)=Wright R-1820-53
type of prop=radial engines
number of props=2
power main=1,000 hp
power alt=750 kW
max speed main=215 mph
max speed alt=197 knots, 346 km/h
combat range main=999 nm
combat range alt=1,150 mi, 1,850 km)
ferry range main=1,800 nm
ferry range alt=2,100 mi, 3,400 km
ceiling main=23,900 ft
ceiling alt=7,280 m
climb rate main=1,030 ft/min
climb rate alt=5.2 m/s
loading main=23.1 lb/ft²
loading alt=113 kg/m²
power/mass main=0.09 hp/lb
power/mass alt=150 W/kg
guns=3× .30 in (7.62 mm) machine guns
bombs=4,500 lb (2,200 kg)

ee also

aircontent
related=
* Douglas DC-2
sequence=
lists=
* List of bomber aircraft
* List of military aircraft of the United States
see also=

References

Notes

Bibliography

* Francillon, René. "McDonnell Douglas Aircraft Since 1920: Volume I". London: Putnam, 1979. ISBN 0-87021-428-4.
* Kostenuk, Samuel and Griffin, John. "RCAF Squadron Histories and Aircraft: 1924–1968". Toronto: Samuel Stevens, Hakkert & Company, 1977. ISBN 0-88866-577-6.

External links

* [http://home.att.net/~jbaugher2/b18.html Baughers: "B-18 Bolo" main page]
* [http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2457 USAF Museum Factsheet: "B-18 Bolo" with gallery]