Douglas B-18 Bolo
| Douglas B-18A Bolo | ||
|---|---|---|
| Douglas B-18A Bolo
| ||
| Description | ||
| Role | Bomber | |
| Crew | 6 | |
| First Flight | April, 1935 | |
| Entered Service | February 23, 1937 | |
| Manufacturer | Douglas Aircraft Company | |
| Dimensions | ||
| Length | 57ft 10in | 17.6 m |
| Wingspan | 89ft 6in | 27.3 m |
| Height | 15ft 2in | 4.6 m |
| Wing Area | 959 ft² | 89.1 m² |
| Weights | ||
| Empty | 16,321 lbs | 7,400 kg |
| Loaded | 22,123 lbs | 10,030 kg |
| Maximum takeoff | 27,673 lbs | 12,550 kg |
| Powerplant | ||
| Engine | 2 × Wright R-1820-53 | |
| Power (each) | 1,000 hp | 750 kW |
| Performance | ||
| Maximum speed | 215mph @ 15,000ft | 346km/h @ 4,570m |
| Combat range | 1,150 miles | 1,850 km |
| Ferry range | 2,100 miles | 3,380 km |
| Service ceiling | 23,900 ft | 7,280 m |
| Rate of climb | 1,030 ft/min | 310 m/min |
| Wing loading | 23.1 lb/ft² | 112.6 kg/m² |
| Power/Mass | 0.09 hp/lb | 0.15 kW/kg |
| Armament | ||
| Guns | 3 × 0.303in machine guns | |
| Bombs | 4,500 lbs | 2,200 kg |
The Douglas B-18 Bolo was a USAAC and RCAF bomber of the late 1930s and early 1940s that was based on the Douglas DC-2.
In 1934, the Army Air Corps put out a request for a bomber with double the bomb load and range of the Martin B-10, then the USAAC's standard bomber. In the evaluation at Wright Field the following year (where Boeing demonstrated its Model 299 that became the B-17 Flying Fortress), Douglas showed its Douglas DB-1. The Douglas design was ordered into immediate production in January 1936 as the B-18.
The DB-1 design was basically the same as the DC-2, but the wingspan was an additional 4.5 ft, and with a a mid-wing instead of a low-wing position on a deeper fuselage, so as accommodate both bombs and 6-member crew. Armament included dorsal and nose turrets, plus a ventral gun. The engines were two Wright R-1820-45 Cyclone 9s, developing 930 hp (694 kW) each.
The initial contract called for 133 B-18s (including the single prototype DB-1), using Wright radial engines. The last B-18 of the run had a power-operated nose turret and was designated DB-2 by the company, but did not become standard. Additional contracts in 1937 (177 aircraft) and 1938 (40) were for the B-18A, which has the bomb-aimer's position further forward (over the nose-gunner's station), and Wright R-1820-53 Cyclone 9 engines (1,000 hp, 746 kW).
By 1940, most USAAC 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. 122 B-18As were equipped with search radar and magnetic anomaly detection (MAD) equipment, designated B-18B, and used in the Caribbean on anti-submarine patrol. The RCAF acquired another 20, called them the "Douglas Digby Mk I", and used them for patrols also.
The B-22 was a proposed followon using Wright R-2600-3 radial engines, but it was never built.
Variants
- DB-1 - prototype
- B-18 - initial production version
- DB-2 - powered nose turret prototype
- B-18A - more powerful engines
- B-18AM - trainer, bomb gear removed from B-18A
- B-18B - antisubmarine conversion
- B-18C - similar, two aircraft only
- B-18M - trainer version of B-18
- B-22 - projected followon
- C-58 - transport conversion
- Digby Mk I - RCAF B-18A
| Related content | |
|---|---|
| Related Development | Douglas DC-2 |
| Similar Aircraft | |
| Designation Series |
XB-15 - XB-16 - B-17 - B-18 - XB-19 - Y1B-20 - XB-21 - B-22 - B-23 - B-24 - B-25 |
| Related Lists |
List of military aircraft of the United States - List of bomber aircraft |