BP Defiant: any plausible evolution?

[tomo pauk]

The plane that received plenty of bad rap, the Boulton Paul Defiant, was one of RAF's single engined fighters in combat use during the 1st half of WW2. What kind of development and roles could you envisage for it? Some minor change to go into effect some time in 1941, and another for maybe 1943? A comment that goes beyond of 'build Spitfires instead' is encouraged

[Shortround6]

Build Hurricanes????

While Defiants may have had a role in 1941 in any of several versions/modifications building them in 1943 is just a waste.

Very few fighter planes designed in 1935-36 were still viable in 1941 let alone 1943. Just because the Spitfire and the 109 did it and beyond doesn't mean there is any shame in another design not making it that far. Don't forget that the Typhoons 1937 wing had some real problems with high speed drag.

The Defiant was actually just a tiny bit smaller than a Hurricane but weighed a lot more. While you can pull the turret and fair over the opening, getting rid of the extra structural weight that supported the turret ( and the heavier wings that allowed for the same "G" loads at the higher weight) is a lot harder. You may be able to streamline the plane to get speed but climb is always going to suffer without a thorough re-stressing and redesign to lighten it up. And then you are spending scarce resources (engineering man hours) to up date an old design rather than going for a new airplane that can more easily incorporate new knowledge of airfoils, structure, manufacturing techniques and so on.

[oldcrowcv63]

The plane looks like it would be a good candidate for becoming a decent interceptor, if not a fighter. It's got clean lines, and is nicely streamlined. It possesses the modern features of the time such as retractable gear and a Merlin engine. To some extent, that's all you need to make a superior aircraft isn't it?

The old saw if it looks good it should fly good might apply here and that may also be worth a separate thread although to make it interesting it should be relative flying qualities compared to aesthetic appeal. The Barracuda looked a monstrosity (to me) but it appears to have got the job done. The Buffalo has always remined me of a US Polikarpov I-16.

From wikipedia (my favorite source for non US aircraft )

Boulton Paul Defiant - Wikipedia, the free encyclopedia

"In 1940, Boulton Paul removed the turret from the prototype as a demonstrator for a fixed gun fighter based on Defiant components. The armament offered was either 12 .303 in (7.7 mm) Browning machine guns (six per wing) or 4 20mm Hispano replacing 8 of the Brownings. The guns could be depressed for ground attack. By that time, the RAF had sufficient quantities of Hawker Hurricanes and Supermarine Spitfire and did not require a new single-seat fighter. With a calculated top speed of about 360 mph (579 km/h) at 21,700 ft, the P.94 was almost as fast as a contemporary Spitfire although less manoeuvrable."

The capability for depressing the guns sounds like it might make a very good Fighter bomber. Range is a bit limited by US standards but not by European. I'd say trade a set of guns for some extra gas and give it longer legs. I am a believer in 4 x .50's as being quite sufficient.

[michaelmaltby]

Hang rockets under the wings (as with the Hurricane) and use it for Coastal Command shipping strikes ... freeing up Beaufighters for other missions.

MM

[davebender]

WWII Britain never had enough aluminum or Merlin engines. That's why large quantities of both were imported from North America.

The Defiant was made of aluminum and powered by a Merlin engine.

How many Spitfires or Lancaster bombers are you willing to forego to keep the Defiant in production?

If the choice is mine then the Defiant program dies without producing any aircraft at all. That frees up resources for additional Spitfires, a much more valuable aircraft.

[fastmongrel]

It doesnt have to be a combat aircraft. The Defiant could have been turned into an advanced trainer with a performance almost up with contemporary fighters. We always forget trainers but you can never have too many.

[oldcrowcv63]

Found on another forum

From Tony Buttler’s ‘British Secret Projects, Fighters and Bombers 1935-1950.

Prototype Defiant K8310 eventually had its turret removed and in August 1940 was flown as an unarmed flying demonstrator for a fixed-gun version called P.94, which was intended for rapid production using many complete Defiant components. The P94 had the turret replaced by 12 0.303” MG disposed in each side of the wing centre section in nests of six – 4 20mm cannon replacing 8 of the 0.303” in two nests of two each were an alternative while the MG could also be depressed 17 degrees for ground attack work. P.94 had a 1,100hp Merlin XX, which offered a maximum speed of 360mph at 21.700ft, a sea level climb of 3,250ft.min and would get to 25,000ft in 8.1 minutes. To allow the type to act as a long range fighter two 30-gallon auxiliary tanks could be carried and in production the aircraft would use standard Defiant jigs. The P94 was never ordered but Boulton Paul also proposed to convert the now single seat Defiant prototype into a 4 cannon fighter demonstrator. The Air Ministry’s rejection of this idea was recorded at a company board meeting on 26th September 1940.

[Kryten]

foreward firing armament would have been a good idea, maybe binning the 4x.303 for 2x20mm to increase range, but as pointed out above, not really a practical design for post 43?

[tomo pauk]

How about a fighter for FAA?

[oldcrowcv63]

How about a fighter for FAA?

Would it have been as robust as the Sea Hurricane or as long legged as the F4F-4? Without that ball turret, it's possible there would have been ample space for fuel and with the engine, similar fuel consumption efficiencies ... reducing armament to 4 .50's, should have help maintain a reasonable climb rate, assuming any CoG issues are overcome.... I suppose its possible and that would have made it worthwhile to produce assuming its overall characteristics were superior to any of the Martlet series.

[Shortround6]

The 360mph speed appears to be calculated and not proven.

The prototype, according to one account, hit 302mph without the turret. production versions hit 304mph. with the turret. The MK II with the Merlin XX was only about 8-12mph faster than the MK I which leaves one wondering where the extra 45mph to hit 360 was going to come from?
A loaded MK I was about 32% heavier than a MK I Hurricane, not all the weight was the turret.

Using it as rocket firing strike aircraft means it has around 50% more strike radius than a Hurricane II, useful perhaps but still very limiting.

Operational conversion trainers are nice to have ( two seat fighters to accustom pilots to service fighters). Merlin powered advanced trainers that DO NOT fly like an operational type and still require conversion trainers are a VERY expensive luxury.

[stona]

The RAF already had the Miles Master as it's advanced two seat trainer with the Bristol Mercury engine and later a U.S.Pratt and Whitney power plant. Why on earth would they want another one using the engine needed for front line aircraft.
This is just one of many dead ends for the Defiant,despite the efforts of Boulton-Paul to find a role for it.
It was designed as a turret fighter to meet a specification dreamed up by people who envisaged aerial combat rather like a 19th century naval engagement with the fighter flying alongside the bomber formation engaging it with its turret mounted armament. It was obsolete before the first one was built.
Cheers
Steve

[rank amateur]

It doesnt have to be a combat aircraft. The Defiant could have been turned into an advanced trainer with a performance almost up with contemporary fighters. We always forget trainers but you can never have too many.

If I'm not mistaken, Miles had a prototype in 1938 for an advanced trainer, the Kestrel with nearly the speed of the Hurricane but with a Rolls Royce Kestrel engine of only 745 hp. This eventualy went in to production as the Master but the Master turned out a lot slower. I wonder why that was but appearantly the RAF did not see any need for a high speed trainer

[stona]

The M.9 Kestrel first flew in 1937 with the 745 hp Kestrel XVI engine and could reach 290 mph but it never entered production. The Master I first flew in early 1939 with the Kestrel XXX power plant with 30hp less than the M.9 so it was slower but nonetheless fast for a trainer of that era. It was considered adequate by the RAF as an advanced trainer.
The Bristol Mercury powered MkII had 870 hp but I haven't got a speed for it. The Pratt and Whitney powere MkIII had 825 hp. These were powerful engines for a trainer of the time.
Steve

[pbfoot]

It was used extensively by the RCAF as a target tug (the drogue operator was the only ground crew rated for flight pay)