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Douglas A-20 Havoc / Boston Light Bomber / Night-Fighter (1941)

Authored By Dan Alex | Last Updated: 8/3/2013

The Douglas A-20 Havoc proved a suitable and adaptable light bomber and night-fighter for Allied forces.

The Douglas A-20 Havoc served Allied forces through most of World War 2, fighting for British, American and Soviet forces. The type saw extensive use, proving itself a war-winner capable of withstanding a great deal of punishment but living up to its namesake in turn thanks to its speed and inherent firepower. Her crews put the aircraft through its paces with production topping over 7,000 units and several major production variants. Built as a light bomber but operated more or less as a heavy fighter, the Havoc proved a successful addition to the Douglas company line and the Allied war effort as a whole before being eventually replaced by the more capable Douglas A-26 Invader in the attack/light bombing role and Northrop P-61 Black Widow in the night-fighter role.

Development

The A-20 series began life as the Douglas Model 7B design, a light bomber attempt originally put to the paper as early as 1936. The United States Army Air Corps (USAAC) showed enough interest after a design review in 1938 that it ordered an operational prototype to be constructed under contract. The first flyable model took to the air on October 26th, 1938, and displayed extremely promising potential for such a design. The aircraft was fast on its twin engines and responsive to the controls with very few negative aspects to her overall design. At any rate, the future of the Model 7B was showing great promise.

With America still in an isolationist mentality despite the worsening situation in Europe (and the world for that matter), the Model 7B was not followed upon by the USAAC and shelved for the time being. Despite this setback, the French and Belgium governments came calling - with some desperation one can imagine - and ordered several hundred Model 7B's for immediate production in February of 1940. These were assigned the official designation of DB-7 and construction covered two distinct production models to become the DB-7A and the DB-7B. An initial batch of 100 DB-7's were constructed and an extended order for 270 more was put into action to help strengthen the ranks. Despite the initiative, only 115 DB-7;s were ultimately delivered to French forces before the collapse of France under German power. Some 95 French-operated DB-7's escaped to North Africa while the remaining models in American hands - and the contract to go along with them - were diverted to British ownership who took over operation of the type as the "Boston". The British Boston series covered three distinct marks as the Boston Mk.I (DB-7), Boston Mk.II (DB-7A) and Boston Mk.III (DB-7B).

RAF Bostons were fielded as day bombers initially, though these met with disastrous results. The type was found to be unsuitable for such a dangerous role and therefore modified into a dedicated night-fighter form. The RAF selected roughly 100 of these Boston light bombers and produced the converted "Havoc", intruder aircraft fitted with the AI Mk IV series of radar in the nose housing and as many as 12 x 7.7mm machine guns to handle the offensive dirty work. Additionally, these converted Bostons were given increased armor protection for the crew and specialized exhaust piping to dampen the flame effects of the engines at night. Essentially, the British RAF gave birth to the "Havoc" series by default, despite its origins as an American airplane. Havocs were first fielded by No. 23 Squadron.

With its newfound weapon, the RAF initiated several interesting - yet costly - projects involving the Havoc. One such initiative involved the "Turbinlite", night-fighting Havoc Mk I models fitted with a 2,700-million candlepower spotlight taking up most of the space in the nose housing. Up to 10 squadrons and 18 months of valuable time and resources went into this project which ultimately proved a failure.

In 1939, the USAAC returned to the DB-7 and re-evaluated its potential for use in the American military. The aircraft was given an extended life now with the initial order of 63 DB-7B platforms. The initial requirement of the USAAC specified a high-altitude capable airframe in the attack bomber role. As such, Douglas produced the design (designated as the A-20) with 2 x turbosupercharged R-2600-7 Wright Cyclone radial engines of 1,700 horsepower each. These initial A-20s were to feature a battery of 4 x 7.62mm (.30 caliber) machine guns in fuselage blister positions. An additional 2 x 7.62mm machine guns would be manned from a dorsal position while a single 7.62mm machine gun was allotted to a manned ventral gun position. Interestingly, rearward-firing 7.62mm machine guns were also introduced in this design, with these being mounted in each engine nacelle. Bombload was a reported 1,600lbs of internal ordnance. Crew personnel amounted to four specialists - a pilot, navigator, bombardier (in a glassed-in nose position) and gunner. Performance specs allowed for a top speed of 385 miles per hour (comparable to fighter performance) and a ceiling of up to 31,500 feet and range totaling some 1,100 miles (ferry range).

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Specifications for the
Douglas A-20 Havoc / Boston
Light Bomber / Night-Fighter


Focus Model: Douglas A-20G Havoc
Country of Origin: United States
Manufacturer: Douglas Aircraft Company - USA
Initial Year of Service: 1941
Production: 7,478


Crew: 3


Length: 48.00ft (14.63m)
Width: 61.32ft (18.69m)
Height: 17.59ft (5.36m)
Weight (Empty): 15,984lbs (7,250kg)
Weight (MTOW): 27,201lbs (12,338kg)


Powerplant: 2 x Wright Cyclone R-2600-23 14-cylinder air-cooled radial piston engines generating 1,600hp.


Maximum Speed: 339mph (545kmh; 294kts)
Maximum Range: 1,091miles (1,755km)
Service Ceiling: 25,098ft (7,650m; 4.8miles)
Rate-of-Climb: 1,500 feet per minute (457m/min)


Hardpoints: 2
Armament Suite:
Dependent upon specific Havoc Model. Can include:

4, 6 OR 8 x 12.7mm machine guns in nose
4 x 20mm cannons in nose

OPTIONAL:
2 x 12.7mm machine guns in lower-fuselage position.
2 x 7.62mm OR 12.7mm machine guns in flexible rear dorsal position.
1 x 7.62mm OR 12.7mm machine gun in flexible ventral position.
4 x 7.62mm machine guns in fuselage blisters (2 to a side).
6 x 12.7mm machine guns in fuselage blisters (3 to a side).
2 x 7.62mm machine guns in fixed rear-firing engine nacelle positions (1 per nacelle).

1,600lbs to 4,000lbs of bombs including four held in an internal bay and (later) two external pylons outboard of the nacelles.

1 x 374-gallon fuel tank in place of some of the internally-held bombs.


Variants:
Model 7 - Private Douglas venture design to replace current US Army single-engine attack aircraft.


Model 7A - Proposed light bomber with improved 450hp radial engines.

Model 7B - Followup proposed light bomber with Pratt & Whitney R-1830 radial engines devlivering 1,100hp.

DB-7 - (Douglas Bomber 7) Original French order placed featuring R-1830-S3C4-G radial engines and longer fuselage.

DB-7A - Wright R-2600-A5B radial engines; Improved variant.

DB-7B - Redesigned with British equipment; Enlarged vertical tail surface structure; Redesignated Boston Mk III.

DB-73

DB-7C

A-20A - Initial production model to go in service with Britain and Commonwealth nations; "Havoc" name officially adopted; 143 examples produced.

A-20B - First major order in terms of overall numbers for Soviet Lend-Lease Act; 999 produced.

A-20C - "Improved" A-20A model; 4 x 7.62mm machine guns in nose; improved Wright engines of 1,600 horsepower; self-sealing fuel tanks; increased armor plating; 948 total produced by/for Douglas including 140 by Boeing.

A-20D - Proposed high-altitude version; intended powerplant of turbosupercharged Wright Cyclone radial engines; canceled before production.

A-20E - Test Models converted from A-20A models; all fitted with Wright R-2600-11 Cyclone engines; 17 total conversion ecamples.

XA-20F - Single A-20A model example set aside for nose armament and powered-turret tests; 1 x37mm nose cannon trialed along with 2 x 12.7mm machine guns in powered dorsal and ventral turrets.

A-20G - Sans-bomb aimer in nose; Solid nose with 8 x machine gun battery; Highest production rate of entire A-20 series; production blocks of A-20G-5 to A-20G-15, A-20G-20 to A-20G-45 with various minor changes throughout; 2,850 examples produced.

A-20H - Similar to A-20G-45 block model with increased MTOW and upgraded engines (Wright R-2600-29 series radials); 412 examples produced.

A-20J - "Lead Ship" aircraft model based on A-20G with glassed-in nose and bombardier position; 450 examples produced.

A-20K - "Lead Ship" aircraft model with glassed-in nose and bombardier position based on A-20H models; improved powerplant, improved armament capabilities and updated onboard equipment; Represents final production version; 413 examples produced.

Boston Mk.I - British redesignation of DB-7.

Boston Mk.II - British redesignation of DB-7A.

Boston Mk.III - British redesignation of DB-7B; DB-7B model with enlarged vertical tail surface and featuring British equipment internally.

Boston Mk.IIIa - A-20C models via Lend-Lease

Boston Mk.IV

Boston Mk.V

XP-70 - Converted A-20 to Night-fighter with glass-nose section painted black housing 4 x 20mm cannons.

P-70 - Night-fighter Variant Conversion base model.

P-70A-1 - Converted A-20C model to Night-fighter role.

P-70A-1 - Converted A-20G model to Night-fighter role.

P-70B-1 - Converted A-20G-10-DO Night-fighter.

P-70B-2 - A-20G / A-20J converted trainers for Northrop P-61 crewmembers.

F-3 - Base A-20 conversion to Night-time photography and reconnaissance.

F-3A - Night-time Photography and Reconnaissance Conversion of A-20J and A-20K models.


Operators:
Australia; Brazil; Canada; France; Netherlands; New Zealand; South Africa; Soviet Union; United Kingdom; United States