Douglas A-20/DB-7 Havoc – Upward Guns?

The Havoc is one of the most famous if somewhat forgotten planes of the Second World War and had some very unusual modifications. Built by Douglas as the A-20 and in RAF service, more commonly known as the Boston by day and the Havoc by night.

The DB-7 was an excellent aircraft at the start of the war.
Douglas’ creation went by many names including A-20, Havoc, Boston and DB-7.

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The origins of the Havoc begin in the US with the Douglas model 7A in between 1936 and 1938. Designed as a light twin-engine bomber, after testing it proved to be fast, nimble, and have excellent handling characteristics, yet initially was somewhat slow and had a meagre payload, leading to the American air force at the time declining to put it into production.

Read More: Focke-Wulf Fw-190 – Butcher Bird

Douglas would carry on development as they saw potential and produced the more powerful 7B variety which caught the attention of the French and Belgians who with the inevitability of war in Europe beginning placed an order for some 170 aircraft, albeit with modification to the armament, layout and fuselage shape. These would be christened DB-7 or Douglas Bomber 7 for French use and first flew in 1939 on the eve of World War 2.

The UK was also interested and would order 300 while taking those that could not be delivered to the French once the war had begun. In British service, they were given the name Boston keeping in line with the naming convention of bombers after cities, while the US had once again taken an interest as a strike bomber under the name A-20.

The A-20/DB-7/Havoc was relatively inecpesnive and easy to build
A-20s were built in relatively large numbers – almost 7,500.

Bomber or Attacker?

The British however felt that her relatively short range did not make for the type of bomber they needed. However they did need night fighters and intruders, and so the Boston was given a new paint job, flame-dampening exhausts, and fitted with radar she became a dedicated night fighter under the name Havoc Mk.1 while a heavier armed version became the intruder version. 

These aircraft were particularly effective in this role, due to their high speed, maneuverability, and firepower, only surpassed by the much-maligned Bolton Paul defiant in the number of aircraft shot down.

Another role, fitting for its name, was night attacks on enemy airfields in France and Holland.

The Havocs would tail the German flights back to their runways and wait until they began to land, and then flicking on and off its landing lights and acting in the way a damaged plane would entice Jerry to help their struggling colleague by turning on the lights.

The nighttime tactics used by the Havoc pilots were genius.
When painted in dark colours and at night, the Germans would struggle to tell the difference between friend and foe.

This would reveal all the landed aircraft only for the Havoc to gun its engines and swoop in to bomb the crews and aircraft, this resulted in frightened German gunners later shooting down their own aircraft thinking they were Havocs. 

Meanwhile, the American version would go on to become one of the most fearsome attack aircraft of the war, singlehanded shortening the war in the pacific, from low-level attacks on enemy shipping and skipping bombs into their targets across the waves, to flying at tree-top height to strafe Japanese airfields and drop bombs.

The A-20 would score numerous victories, while DB-7’s fought to help the Americans at the Kasserine pass.

The Havoc was a capable low level attacker.
An A-20 flying a tree top level attacking Japanese targets.

Upward Guns?

During the battle of Britain however two odd adaptions to the Havoc would take place, the first and by far the most commonly known is the fitting of large searchlights to the nose of some Havocs, this was done to spot the enemy bombers for the fighters when flying above cloud level.

This adaption known as turbanlight with some 2.7 million candle power would in theory light up German bombers and 31 aircraft had it fitted, yet in reality, proved to be less successful as the host plane was also lit up for every German gunner in a large area, and later improvements to radar rendered it obsolete. 

Read More: Bristol Beaufighter – Night Stalker

The other adaption was the fitting for upwards firing guns, a method later copied by both the Germans and Japanese later on.

Initially small calibre guns were used in the Havoc.
With the guns pointing upwards the Havoc could be in the bomber’s blind spot.

The idea was quite simple, in that by detecting an enemy bomber using its AI Mk IV radar it would attack an enemy bomber from below, in this case, reported as 1,000 feet astern and 500 feet below the Havoc was essentially in the bomber’s blind spot and was, in theory, able to rake his soft unarmoured belly and approach undetected, while being relatively immune to counter fire, and introducing the German plane to a rather brief but terminal introduction to the English channel. 

To this end 3 Havoc Mk.1s were fitted with a Frazer Nash F.N.72 gun mounting in the opening behind the pilot’s cockpit. This device which remained closed in flight would then open up to reveal six browning .303 machine guns with 1,000 rounds each.

It was critical to attack the most vulnerable spots of the bombers with limited ammo.
An example of a diagram given to Havoc pilots to attack a He-111.

These guns could be angled between 30 and 50 degrees and had limited traverse to either side (initially 19 degrees due to a draftsman error) and would fire into the enemy bomber above, with night tracer fire (1:5) rounds to help the gunner who was located in the glazed nose direct his fire vis a reflector gun sight. All 6 guns would be empty after 45 seconds of fire.

The initial aircraft given was a somewhat war-weary Havoc Mk.1 with the registration BD.126, but this was not deemed a happy partnership as the aircraft was essentially recorded as being in a very bad state and would need a significant overhaul, yet the ministry was critically short of pilot’s material and supplies was not in the mood for pandering and essentially told the team to make do.

The Havoc only used .303s which didn't have enough power to quickly shred bombers.
These weapons were not the easiest to aim.

The first trials were not overtly successful and a list of complaints, primarily in the linkages, and sighting system was given back to Frazer Nash who quickly came out with an improved Mk 2 version around July 1941. 

This would include several changes, including a ring sight for the pilot, heated clothing for the gunner and oxygen bottles, and most importantly a modified safety system to prevent the guns from firing while enclosed in the hull or the hatch shutting when the guns were exposed while the angles were altered to 15 degrees to 48 degrees and 25 degrees either side.

The feed system was also extensively overhauled due to it causing stoppages and post fix none were recorded.

The Havoc had its own defensive armament.
A close-up of the cockpit and front gunner view.

The Havoc could also retain its original weapons if required of fixed .303’s in the nose, a dorsal gunner and its original payload if needed, albeit the latter was not required in this role and the former not used in the trials.

Around this time, the plane is also referred to as the DB7 Melvill Jones night fighter, or Havoc M.J, after Sir Bennett Melvill Jones, a professor at Cambridge, whose work pioneered streamlining aircraft and gyroscopic gun sights and who was closely involved in the design.

The concept was used against a towed target canvas screen worked and Frazer Nash was giving it the go-ahead. The next request was to have it mounted into 3 Havoc Mk 2 aircraft, these were considerably more powerful and faster than the original vehicle with heavier firepower, in fact, had it all gone to plane the new Havoc II MJ would have had no less than 19 .303 machine guns fitted in a full configuration arguably making it the heaviest armed aircraft of its time.

The nose gunner on the Havoc was fairly cramped but with a great view.
At the time, this Havoc had the heaviest armament of any aircraft.

And this is before it was recommended that the weapons be also fitted with 20 mm cannons!

Innovation Cancellation

However, with the war changing, delays in getting parts, and the ever-present bane of British wartime design, the ‘Committee’ along with the fact that a large number of German bombers were now littering the English countryside and decided to cancel the order. Newer planes such as the Mosquito with its cannon armament were coming into play and striking what was left of the Luftwaffe from below was no longer needed resulting in the project being canceled.

Missed Russian Mi-26 Heavy Transpor...
Missed Russian Mi-26 Heavy Transport Helicopter
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Post-war the design and devices were all but forgotten and now only a few single lines of text remain in some books, however, the rediscovery of the photos and text in the national archives by Historian Ed Francis has given an interesting insight into this forgotten project.

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Specification

  • Crew: 3
  • Length: 47 ft 11+78 in (14.63 m)
  • Wingspan: 61 ft 3.5 in (18.68 m)
  • Height: 18 ft 1+12 in (5.52 m)
  • Wing area: 464 sq ft (43.1 m2)
  • Empty weight: 16,031 lb (7,272 kg)
  • Gross weight: 24,127 lb (10,944 kg)
  • Powerplant: 2 × Wright R-2600-23 Twin Cyclone 14-cylinder air-cooled radial piston engines, 1,600 hp (1,200 kW) each
  • Maximum speed: 317 mph (510 km/h, 275 kn) at 10,700 ft (3,300 m)
  • 325 mph (282 kn; 523 km/h) at 14,500 ft (4,400 m)
  • Range: 945 mi (1,521 km, 821 nmi)
  • Service ceiling: 23,700 ft (7,200 m)
  • Rate of climb: 2,000 ft/min (10 m/s)