Douglas A-20 Havoc

Douglas A-20 Havoc ou aussi DB-7 Boston

La partie Havoc à raccorder avec le DB-7 Boston, sur Wikipedia.Fr


Le Douglas A-20 Havoc (« ravage ») est un bombardier léger américain de la [Vous devez être inscrit et connecté pour voir ce lien].

Il est aussi connu sous les noms DB-7 et Boston.


Conception

Le projet démarra en [Vous devez être inscrit et connecté pour voir ce lien], dirigé par [Vous devez être inscrit et connecté pour voir ce lien] et [Vous devez être inscrit et connecté pour voir ce lien], le prototype (7B pour Douglas) fut prêt en [Vous devez être inscrit et connecté pour voir ce lien].

Le premier vol eu lieu le 26 octobre 1938.

La première commande vint de la [Vous devez être inscrit et connecté pour voir ce lien] pour un total de 960 appareils, mais la plupart furent récupérés par le [Vous devez être inscrit et connecté pour voir ce lien] après la [Vous devez être inscrit et connecté pour voir ce lien].

D'abord équipé de moteur Pratt et Withney R-1830 (Twin Wasp) de 1100cv (820kw) la plupart reçoivent un au Wright R-2600 Cyclone de 1600cv (1190 kw), voire de 1700cv (1268 Kw) pour l'A-20H, bien plus puissant.

Très apprécié pour sa robustesse et sa rapidité, il fut utilisé comme bombardier de jour et de nuit, avion d'appui tactique, avion-torpilleur et même chasseur de nuit.

De nombreux pays l'ont utilisé comme les [Vous devez être inscrit et connecté pour voir ce lien] (1962 avions), la [Vous devez être inscrit et connecté pour voir ce lien] (1800 avions),
l'[Vous devez être inscrit et connecté pour voir ce lien] (3125 avions) ou même la [Vous devez être inscrit et connecté pour voir ce lien] en 1940 et par la suite Les Français Libres.

7 478 exemplaires furent construits dont 7385 par Douglas.

Le dernier exemplaire produit sort le 20 septembre 1944.

Engagements


Un des bombardiers légers et d'attaque au sol les plus répandus, il reçut de nombreux noms :
Boston pour les britanniques,
Havoc pour les américains les modèle d'assaut (A) et de chasse nocturnes (P) ,
DB-7 en France pour Douglas Bombardier modèle 7,
il servit sans interruption sur tous les fronts jusqu'à la fin de la guerre dans des rôles très variés.

Des Havoc sur la base d'Elmendorf, Alaska

[Vous devez être inscrit et connecté pour voir cette image]

Les A 20 et Boston sur Wikipedia en langue anglaise :


The [Vous devez être inscrit et connecté pour voir ce lien] A-20/DB-7 Havoc was a family of [Vous devez être inscrit et connecté pour voir ce lien] attack, light bomber and night fighter aircraft of World War
II, serving with several [Vous devez être inscrit et connecté pour voir ce lien] air forces, principally those of the
[Vous devez être inscrit et connecté pour voir ce lien],
[Vous devez être inscrit et connecté pour voir ce lien], and
[Vous devez être inscrit et connecté pour voir ce lien].

The DB-7 was also used by the air forces of [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien], and [Vous devez être inscrit et connecté pour voir ce lien] during the war, and [Vous devez être inscrit et connecté pour voir ce lien] afterwards.

The bomber aircraft was known as Boston among [Vous devez être inscrit et connecté pour voir ce lien] air forces, while the [Vous devez être inscrit et connecté pour voir ce lien] night fighter variants were given the service name Havoc.

The [Vous devez être inscrit et connecté pour voir ce lien] assigned the DB-7 the designation "A-20" and gave it the popular name "Havoc".


Design and development


In March 1937, a design team headed by [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] produced a proposal for a light bomber powered by a pair of 450 hp (336 kW) [Vous devez être inscrit et connecté pour voir ce lien] Wasp Junior [Vous devez être inscrit et connecté pour voir ce lien] mounted on a high-mounted wing.

It was estimated it could have carried a 1,000 lb (454 kg) bomb load at 250 mph (400 km/h).

Reports of aircraft performance from the [Vous devez être inscrit et connecté pour voir ce lien] indicated that this design would be seriously underpowered and, subsequently, it was cancelled.

In the autumn of the same year, the [Vous devez être inscrit et connecté pour voir ce lien] issued its own specification for an attack aircraft.

The Douglas team, now headed by Heinemann, took the Model 7A design, upgraded to 1,100 hp (820 kW) [Vous devez être inscrit et connecté pour voir ce lien] S3C3-G Twin Wasp engines, and submitted the design as the Model 7B.

It faced competition from the [Vous devez être inscrit et connecté pour voir ce lien], the [Vous devez être inscrit et connecté pour voir ce lien] and the [Vous devez être inscrit et connecté pour voir ce lien].

The Model 7B was maneuverable and fast, but did not attract any US orders.

The model did, however, attract the attention of a [Vous devez être inscrit et connecté pour voir ce lien] Purchasing Commission visiting the USA.

The French discreetly participated in the flight trials, so as not to attract criticism from U.S.[Vous devez être inscrit et connecté pour voir ce lien], but the secret was blown when the 7B crashed on 23 January 1939, while demonstrating single-engine performance.

The French were still impressed enough to order 100 production aircraft, with the order increased to 270 when the war began.
Sixteen of those had been ordered by [Vous devez être inscrit et connecté pour voir ce lien] for its [Vous devez être inscrit et connecté pour voir ce lien].

Although not the fastest or longest-legged in its class, the Douglas DB-7 series distinguished itself as a tough, dependable combat aircraft with an excellent reputation due to its speed and manoeuvrability.

In a report to the [Vous devez être inscrit et connecté pour voir ce lien] (AAEE) at [Vous devez être inscrit et connecté pour voir ce lien], test pilots summed it up as "has no vices and is very easy to takeoff and land.

The aeroplane represents a definite advantage in the design of flying controls extremely pleasant to fly and manoeuvre." Ex-pilots often consider it their favorite aircraft of the war due to the ability to toss it around like a fighter.
Its true impact was that the Douglas bomber/night fighter was extremely adaptable and found a role in every combat theater of the war and excelled as a true "pilot's aeroplane."

When DB-7 series production finally ended on 20 September 1944, a total of 7,098 had been built by Douglas and a further 380 by [Vous devez être inscrit et connecté pour voir ce lien].

Operational history


The French order called for substantial modifications, and the new designation DB-7 (for Douglas Bomber 7) was introduced.
It had a narrower, deeper [Vous devez être inscrit et connecté pour voir ce lien], 1,000 hp (746 kW) Pratt & Whitney R-1830-SC3-G radials, French-built guns, and metric instruments.
Midway through the delivery phase, engines were switched to 1,100 hp (820 kW) Pratt & Whitney R-1830-S3C4-G.

The French designation was DB-7 B-3 (the B-3 signifying "three-seat bomber").

The DB-7s were shipped in sections to [Vous devez être inscrit et connecté pour voir ce lien] for assembly and service in France and French North Africa.

When the Germans [Vous devez être inscrit et connecté pour voir ce lien] on 10 May 1940, the 64 available DB-7s were deployed against the advancing [Vous devez être inscrit et connecté pour voir ce lien].

Before the [Vous devez être inscrit et connecté pour voir ce lien] they were evacuated to North Africa to avoid capture by German forces.

Here, they fell under control of the [Vous devez être inscrit et connecté pour voir ce lien], but saw practically no action against the Allies except briefly during [Vous devez être inscrit et connecté pour voir ce lien].

After French forces in North Africa had sided with the Allies, DB-7 were used as trainers and were replaced in frontline units by [Vous devez être inscrit et connecté pour voir ce lien].

In early 1945, a few DB-7s were sent back to France where they saw action against the remaining isolated German pockets on the Western coast.

Through [Vous devez être inscrit et connecté pour voir ce lien], Soviet forces received more than two-thirds of A-20B models manufactured and a significant portion of versions G and H.

These aircraft were armed with fixed-forward cannons and found success in the ground attack role.

Variants


Boston I & II

The [Vous devez être inscrit et connecté pour voir ce lien] agreed to take up the balance of the now-frustrated French order which was diverted to Britain, and the aircraft were given the service name Boston with the further designation of "[Vous devez être inscrit et connecté pour voir ce lien]" or "Mark II" according to the earlier or later engine type.

Havoc I

The aircraft was generally unsuited for RAF use as its range was too limited for daylight raids on Germany.
Many of the Boston Mk II, plus some re-engined Mk Is, were converted for night time duties - either as
intruders with 2,400 lb (1,100 kg) bombs, or as [Vous devez être inscrit et connecté pour voir ce lien] with AI Mk IV [Vous devez être inscrit et connecté pour voir ce lien]. These were known collectively as Havoc Mk I. A total of 181 Bostons were converted to Havocs. In interdiction raids, Havoc intruders caused considerable damage to German targets.

Havoc-Pandora

Twenty Havocs were converted into intruder aircraft, utilizing the Long Aerial Mine (LAM), an explosive charge trailed on a long cable in the path of enemy aircraft in the hope of scoring a hit. Trials conducted with lone [Vous devez être inscrit et connecté pour voir ce lien] dropping LAMs into the stream of German bombers were not successful, consequently, the Havocs were converted back to Mk I intruders.

Havoc I [Vous devez être inscrit et connecté pour voir ce lien]

A further 31 Havocs were fitted with a 2,700 million [Vous devez être inscrit et connecté pour voir ce lien] (2.7 Gcd) searchlight in the nose.
They were unarmed and were supposed to illuminate targets for accompanying [Vous devez être inscrit et connecté pour voir ce lien] fighters, but in practice the conspicuous light made them ready targets for German gunners.

DB-7A / Havoc II

The French Purchasing Commission ordered a further 200 bombers, to be fitted with 1,600 hp (1,195 kW) [Vous devez être inscrit et connecté pour voir ce lien]-A5B Double Cyclone engines. This variant was designated DB-7A by Douglas.
None had been delivered before the fall of France, and they served instead as night-fighters with the RAF under the name of Havoc Mk II.
They had an impressive top speed of 344 mph (550 km/h) at altitude. A total of 39 were used briefly in [Vous devez être inscrit et connecté pour voir ce lien] roles.

DB-7B / Boston III

The DB-7B was the first batch of the series to actually be ordered by Britain, in February 1940. Powered by the same engines as the DB-7A, with better [Vous devez être inscrit et connecté pour voir ce lien] and, crucially, larger fuel tanks, these were at last suitable for British use in the light bomber role. This was the batch for which the name "Boston" was first reserved, but since the commandeered DB-7s entered service first, this batch became known as the Boston Mk III. Amongst other operations, they took part in the attacks on the [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] during their dash
through the English Channel (Operation Cerberus) and the infamous [Vous devez être inscrit et connecté pour voir ce lien] (Operation Jubilee). Three hundred
were delivered and some were converted for use in intruder and night fighter roles.

DB-73

A French variant very similar to BD-7B, which again were diverted to England as Boston Mk IIIs. Many of these were built under licence by [Vous devez être inscrit et connecté pour voir ce lien]. Events further overtook this shipment after the [Vous devez être inscrit et connecté pour voir ce lien] on the Soviet Union and the [Vous devez être inscrit et connecté pour voir ce lien], when many Bostons were sent to the USSR and many more retained by the USAAF for its own use. Twenty-two were also sent to the [Vous devez être inscrit et connecté pour voir ce lien] by the British.

Variantes, suite :

DB-7C

A [Vous devez être inscrit et connecté pour voir ce lien] variant intended for service in the[Vous devez être inscrit et connecté pour voir ce lien], but the [Vous devez être inscrit et connecté pour voir ce lien] invasion was complete before they were delivered.
Part of this order was stranded in Australia on the so-called "lost convoy" and the first 31 Bostons were assembled at Richmond Airbase (NSW) and operated by [Vous devez être inscrit et connecté pour voir ce lien] during the campaign against Buna/Gona and Lau on New Guinea.
The assembley of these 31 was hampered by the manuals and instrument panels being completely in Dutch.
The remaining aircraft in this order were sent to the Soviet Union under [Vous devez être inscrit et connecté pour voir ce lien] which would receive 3,125 examples of different variants of the Douglas DB-7 series.

When shipments to the UK finally resumed, they were delivered under the terms of Lend-Lease. These aircraft were
actually refitted A-20Cs known as the Boston IIIA.

A-20

The original American indifference to the Model 7B was overcome by the improvements made for the French and British, and the [Vous devez être inscrit et connecté pour voir ce lien] ordered two models, the A-20 for high-altitude bombing and the A-20A for lower-altitude work.
Both were similar to the DB-7B, the A-20 was to be fitted with turbosupercharged Wright R-2600-7 engines, but these were bulky and the prototype suffered cooling problems, so the remainder were completed with the un-supercharged R-2600-11, 59 as P-70 fighters and 3 as F-3 reconnaissance planes (described below).

One A-20 was evaluated by the US Navy as the BD-1, while the US Marine Corps operated eight examples as the BD-2.

A-20A

The U.S. Army ordered 123 A-20As with R-2600-3 engines, and a further 20 with more powerful R-2600-11. They entered service in spring 1941. The Army liked the A-20A because of its excellent performance and because it had no adverse handling characteristics. Nine of them were transferred to Australia in 1943. The British name "Havoc" was adopted for the A-20A.

A-20B

The A-20B received the first really large order from the US Army Air Corps: 999 aircraft. They resembled the DB-7A
rather than the DB-7B, with light armor and stepped rather than slanted glazing in the nose. In fact, 665 were exported to the Soviets, so relatively few actually served with the USAAC.


A-20C

The A-20C was an attempt to standardize a common British and American version, produced from 1941. It reverted to the slanting nose-glass and had RF-2600-23 engines, [Vous devez être inscrit et connecté pour voir ce lien] and additional armor.
They were equipped to carry an external 2,000 lb (907 kg) naval torpedo.
A total of 948 were built for Britain and the Soviet Union, but many were retained by the USAAF after Pearl Harbor. The Soviet A-20s were often fitted out with turrets of indigenous design.


The A-20G, delivered from February 1943, would be the most produced of all the series - 2850 were built. The glazed nose was replaced by a solid nose containing four 20 mm (.79 in) [Vous devez être inscrit et connecté pour voir ce lien] and two .50 in [Vous devez être inscrit et connecté pour voir ce lien], making the aircraft slightly longer than previous versions.
After the first batch of 250, the unreliable cannon were replaced by more machine guns. Some had a wider fuselage to accommodate a power driven gun turret. Many A-20Gs were delivered to the Soviet Union. The powerplant was the 1,600 hp (1,200 kW) R-2600-23. US A-20Gs were used on low-level sorties in the [Vous devez être inscrit et connecté pour voir ce lien] theatre.

A-20H

The A-20H was the same as A-20G, continued with the 1,700 hp (1,270 kW) R-2600-29. 412 of these were built. The takeoff weight was raised to 24,170 lb (10,960 kg).

A-20J / Boston IV

The A-20J carried an additional bombardier in an extended [Vous devez être inscrit et connecté pour voir ce lien] nose section. These were intended to lead bombing formations, with the following standard A-20s dropping their bombs when signaled by the leader. A total of 450 were built, 169 for the RAF which designated them Boston Mk IV from summer 1944.


A-20K / Boston V


The A-20K (Boston Mk V in RAF parlance) was the final production version of the A-20 series, the same as the A-20J
except for R-2600-29s instead of -23s.

P-70

In October 1940, the USAAC felt a need for long-range fighters more than attack bombers, so some of the production run of A-20s were converted to P-70 and P-70A night-fighters. They were equipped with SCR-540 radar (a copy of British AI Mk IV), the glazed nose often painted black to reduce glare and hide the details of the radar set, and had
four 20 mm (.79 in) forward-firing cannon in a ventral bomb bay tray. Further P-70 variants were produced from A-20C, G and J variants.
The singular airframe P-70B-1 (converted from an A-20G) and subsequent P-70B-2s (converted from A-20Gs and Js) had American centimetric radar (SCR-720 or SCR-729) fitted. The P-70s and P-70As saw combat ONLY in the Pacific during World War II and only with the USAAF. The P-70B-1 and P-70B-2 aircraft never saw combat but served as night fighter aircrew trainers in the US in Florida and later in California.
All P-70s were retired from service by 1945.


F-3A

The F-3A was a conversion of 46 A-20J and K models for night-time photographic reconnaissance (F-3 were a few conversions of the original A-20).
This variant was employed in the European Theatre by the 155th Photo Reconnaissance Squadron which began its deployment as the 423rd Night Fighter Squadron. The 423rd was converted to its photo mission as the 155th Night Reconnaissance Squadron in part because of knowledge of night fighter tactics which could be used to defend against German aircraft.
Although armament was removed, the crew of three was retained consisting of, pilot, observer, and navigator. The first Allied aircraft to land at Itazuke, Japan after the August 1945 surrender was an F-3A.

DB-1

One A-20A was bought in 1940 by the United States Navy for evaluation for use by the United States Marine Corps. The Navy/Marine Corps did not have any priority on the production lines, so the DB was not put into service.

DB-2

In 1942, eight former Army A-20Bs were diverted to the United States Navy for use as high-speed target tugs. Despite the addition of the target-towing equipment and the removal of all armament and the provision to carry bombs the aircraft were still designated DB in the Bomber sequence. They were withdrawn from service in 1946.

O-53

An observation/reconnaissance version of the A-20B powered by two 1,700 hp (1,268 kW) R-2600-7 engines, order for
1,489 aircraft was cancelled and none were built.