Boulton Paul Defiant

Le famaeux P 82 Boulton Paul sur Wikipedia de langue anglaise :

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The Boulton Paul Defiant was a [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] used early in the [Vous devez être inscrit et connecté pour voir ce lien].

The Defiant was designed and built by [Vous devez être inscrit et connecté pour voir ce lien] as a "turret fighter" and served with the [Vous devez être inscrit et connecté pour voir ce lien] (RAF).

Contemporary with the[Vous devez être inscrit et connecté pour voir ce lien]'s [Vous devez être inscrit et connecté pour voir ce lien], the concept of a turret fighter was somewhat similar to the First
World War-era [Vous devez être inscrit et connecté pour voir ce lien].

In practice, the Defiant was found to be vulnerable to the [Vous devez être inscrit et connecté pour voir ce lien]'s more agile, single-seat [Vous devez être inscrit et connecté pour voir ce lien] fighters;
crucially, the Defiant did not have any forward-firing guns.

It was later used successfully in the [Vous devez être inscrit et connecté pour voir ce lien] role, before it was phased out of combat service in favour of the [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].

The Defiant finally found use in gunnery training, target towing, [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].

Among RAF pilots, it had the nickname "Daffy", probably a dimunitive of the word "Defiant".

Design and development

Evolution

The concept of a turret-armed defensive fighter emerged in 1935, at a time when the RAF anticipated having to defend [Vous devez être inscrit et connecté pour voir ce lien] against massed formations of unescorted enemy bombers.

Advances in aircraft design during the 1920s and 1930s resulted in a generation of multi-engined bombers that were faster than the single-engined [Vous devez être inscrit et connecté pour voir ce lien] fighters then in service.

The RAF believed that its own turret-armed bombers, such as the [Vous devez être inscrit et connecté pour voir ce lien], would be able to penetrate enemy
airspace and defend itself without fighter escort and also that the German Luftwaffe would be able to do the same.

In theory, turret-armed fighters would approach an enemy bomber from below or from the side and coordinate their fire.

The separation of the tasks of flying the aircraft and firing the guns would allow the pilot to concentrate on putting the fighter into the best position while the gunner could engage the enemy.

Previously the [Vous devez être inscrit et connecté pour voir ce lien] had tested the concept with 59 of the biplane fighters manufactured by Boulton Paul under a sub-contract, equipped with a powered rear turret while the remainder of the series already manufactured were similarly converted.

[Vous devez être inscrit et connecté pour voir ce lien] required a two-seater day and night "turret fighter" capable of 290 mph at 15,000 ft.

It followed the earlier F.5/33 which was for a pusher design with a front turret. F.5/33 had been abandoned as it offered
little over existing fighters and the Armstrong Whitworth AW.34 design which had been ordered was not completed.

P.82


Boulton Paul, who had considerable experience with turrets from their earlier [Vous devez être inscrit et connecté pour voir ce lien] bomber, submitted their P.82 design.

Of the seven designs tendered, the P.82 was ranked second after Hawkers, but ahead of Armstrong Whitworths twin-engined design.

The Air Ministry wanted several designs investigated and two prototypes of each.

The Treasury acquiesced to seven prototypes (2 Hawker, 2 Boulton Paul, 2 Fairey and 1 Armstrong Whitworth).

In the event only prototypes of the P.82 and Hawker would be built.

Production orders were prepared for the Hawker but the Boulton Paul turret had the Air Ministry's attention.

Delays by Hawker who were more focussed on the Hurricane led to the P.82 receiving a production order in 1937 and the Hotspur order was cancelled in 1938.

The P.82 was a monocque design constructed by bolting the sections together.

This was the same as BP had used on other aircraft.

The tendered design had room for small bombs in recesses in the outer wing.

Some of the development work from their B.1/35 tender carried over into the P.82

The central feature of the P.82 was the four-gun turret based on a design by French aviation company [Vous devez être inscrit et connecté pour voir ce lien] which had been licensed by Boulton Paul for use in the earlier [Vous devez être inscrit et connecté pour voir ce lien] bomber, but eventually installed in the "follow-up" design, the [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] naval fighter.

The turret, the Type A, was an electro-hydraulically powered "drop-in" unit with a crank-operated mechanical backup.

The Defiant was armed with a powered dorsal turret, equipped with four [Vous devez être inscrit et connecté pour voir ce lien].

The [Vous devez être inscrit et connecté pour voir ce lien] was fitted with [Vous devez être inscrit et connecté pour voir ce lien] that helped alleviate the drag of the turret; they were pneumatically powered and could be lowered into the fuselage so that the turret could rotate freely.

The Browning guns were electrically fired, and insulated cut-off points in the turret ring prevented the guns from being activated when they were pointing at the propeller disc or tailplane.

The gunner could rotate the turret directly forward and transfer firing control of the guns to the pilot, with the guns firing along each side of the cockpit canopy.

However, in practice this was rarely done as the turret's minimum forward elevation was 19° and the pilot did not have a gunsight.

The gunner's hatch was in the rear of the turret, which had to be rotated to one side or the other to enable entry or exit.

There was not enough room in the turret for the gunner to wear a seat-type or back pack parachute, so gunners were provided with a special all-in-one garment nick-named the "rhino suit".

To quote Frederick "Gus" Platts, air gunner in 230, 282 and 208 squadrons, "The Rhino suit we had to wear on Defiants was a bear, but I couldn't come up with an alternative, even though it killed dozens of us.

I forget the details of it, but we could not have sat on our chute or even keep it nearby as in other turrets, so you wore - all in one - an inner layer that fitted a little like a wetsuit of today.

The chute fitted around this, and then the dinghy and the outer clothing.

There was inner webbing and pockets that literally fell apart (I presume) when one bailed out".

The first P.82 prototype (K8310) was rolled out in 1937 without its turret, looking superficially like the [Vous devez être inscrit et connecté pour voir ce lien], although it was at least 1,500 lb (680 kg) heavier.

A clean, simple and compact [Vous devez être inscrit et connecté pour voir ce lien] structure had been achieved with [Vous devez être inscrit et connecté pour voir ce lien] retracting into a broad mainplane section.

The pilot's [Vous devez être inscrit et connecté pour voir ce lien] and rear turret were faired into a streamlined upper fuselage section.

Fuel was carried in the wing centre section along with a large ventral [Vous devez être inscrit et connecté pour voir ce lien] that completed the resemblance to the Hawker fighter.

With a 1,030 hp (768 kW) [Vous devez être inscrit et connecté pour voir ce lien] I installed, the newly named "Defiant" prototype first flew on 11 August 1937, nearly a year ahead of the Hotspur.

A second prototype, K8620, equipped with a turret, was modified with telescopic radio masts, revision to the canopy
and changes to the undercarriage fairing plates.

Completing its acceptance tests with the turret installed, the Defiant reached a top speed of 302 mph (486 km/h) and subsequently was declared the victor of the turret fighter competition.

Apart from detail changes, the production Defiant Mk I looked similar to the two Defiant prototypes.

However, as Boulton Paul were busy producing the [Vous devez être inscrit et connecté pour voir ce lien] naval turret fighter, the Defiant's service entry was delayed to such an extent that only three aircraft had reached the RAF by the start of the war in September 1939.

The Mk I was powered by the Rolls Royce Merlin III (1,030 hp/768 kW or 1,160 hp/865 kW) with a total of 713 aircraft built.

P.85


The P.85 was Boulton Paul's tender to Specification O.30/35 for the naval turret fighter.

A version of the Defiant for [Vous devez être inscrit et connecté pour voir ce lien] (FAA); it had a deeper fuselage and leading edge slats for lower landing speeds required of carrier aircraft.

The engine would be either a Bristol Hercules radial or the Merlin.

Despite a higher estimated top speed, the Blackburn Roc was selected.

With Blackburn already busy producing other projects, the detail design and production of the Roc was given to Boulton Paul.

The only FAA use of the Defiant was as the target tug version.