Boulton Paul Defiant Rationale

It was the development of such weapons by other powers which convinced the British in 1935/6 to adopt them for themselves.

The fact that a single 1" gun was built, presumably a prototype, does not mean that the British were ready to abandon the convention. Some of the suggested ammunition would fall within the convention and we don't know the weight of the proposed HE shell. If it was kept under 400g that too would not be an issue.

The fact remains that until 1935 the Air Ministry showed no interest in weapons that did not comply with the Convention. RFC/RAF aircraft were designed for, or equipped with, machine guns or cannon like the Vickers QF (in WW1) or, later, the COW gun that complied.

Cheers

Steve

The slipper tanks I was referring to were those that fitted flush to the underside of the wings. There are pictures online showing one under the port wing for long range duties. Maybe these weren't called slipper tanks, as those under the fuselage were. I recall reading yonks ago that slipper tanks were those that fitted flush to the aircraft, but I accept the mists of time may have clouded my recollection.

In answer to those saying that forward firing guns in the wings were not in the specification, I agree. However, Boulton Paul did make provision for them and had proffered up a single seat conventional fighter that was developed into the Defiant (according to Warpaint #42). There are pictures of this too. Also, the Hawker Hotspur has been mentioned, which had a forward firing .303 in the fuselage as well as the turret.
Yes, performance would have been compromised by an extra four guns, but it has already been said that the Defiant was intended to be a bomber destroyer. I did say that it could have been used as a WW2 "Brisfit" ie a conventional fighter with a sting in the tail. It is a matter of record that Defiants did actually shoot down opposing fighters and that their vulnerability was an attack from the front.

All this is conjecture of course, but so is suggesting Boulton Paul could have built Spitfires. Blackburn could have built Spitfires too, instead of its useless and equally dangerous (to its crew) Botha. Which brings me back to my assertion that the Defiant was a missed opportunity. I still maintain it was, but just about all of the UK's weapons procurement in WW2 was a missed opportunity. When the Avro Manchester failed, it was strongly suggested by officials that Avro build Halifaxes and not not bother developing the Manchester II (Lancaster). The Mosquito was supposedly rejected initially and the Hornet could have been in production in 1941, according to some sources. The reason De Havilland didn't make the Hornet in 1941 is stated as being "We weren't asked to."

The Boulton Paul P.94 (turretless Defiant) did have exceptional performance and had a provision of up to 12 MG (6 per wing) or a combination of cannon and MGs.

The problem was, that the P.94 was not as maneuverable as the Spitfire and it was decided that the P.94 was not needed.

Not a bad looking aircraft, really and looks a little like the Hurricane.

The picture is of K8310, one of the Defiant prototypes. It is a mock up to show what a turretless version might look like. It is not a prototype of a turretless Defiant with forward firing armament. It was made in early 1940 (I don't have the date to hand) long after the superior Spitfire and comparable Hurricane had entered service.
This is the same aircraft in 1938.



The P.94, an even more heavily modified design, derived from the Defiant, never left the drawing board.

In 1941 the Mosquito was still being developed, so it is hard to see how the Hornet could have been produced. By November 1942 (a year later) there had been just 415 Mosquitoes produced in the UK, with just 204 at operational units.

Production has to be rationalised and hard decisions need to be made. If not you can end up in the sort of mess in which the RLM/Luftwaffe found itself.

It seems that not just hindsight but now time machines must be used! The first mock up of the DH 103, which would become the Hornet, was not completed until the end of 1942. This was a private venture by the company and remained so until the Air Ministry issued F.12/43 in June 1943, built around the DH. 103. The first prototype began construction in late 1943/early 1944, depending who you believe. It could not possibly have been in production in 1941.

Cheers

Steve

K8310, as the P.82, made it's first flight in August 1937 without it's turret, as the turret was not yet ready to be fitted
It was the test data from that first turretless flight that led BP to consider a single-seat version and the turret was removed from K8310 in 1940 and was used as a demonstrator for a P.94 model.

But by mid-1940, Britain already had the Hurricane, Spitfire, Whirlwind and the Typhoon was in the works.

Also my mid-1940, the Battle of Britain was getting underway and the last thing the RAF needed, was diverted production on a new fighter that was no better than the Spitfire.

And I used that early photo of K8310 because it was the basis for the P.94 as well as the P.94's demonstrator.

The same quote of the Defiant was nice to fly also said a ground attack version could have been a RAF Shturmovik in single seat and a better bet than the Hurricane.

The Basket said:

The same quote of the Defiant was nice to fly also said a ground attack version could have been a RAF Shturmovik in single seat and a better bet than the Hurricane.

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But not the Typhoon, which, though delayed, was already in the pipeline long before the Defiant became obsolescent (or even obsolete). The Whirlwind would have been a better ground attack aircraft, if its engines were not cancelled, so too the Mustang (I-III). You could even argue that the Tomahawk/Kittyhawk did a decent job in North Africa.

I can't see any justification for keeping another Merlin engine aircraft in production on the grounds that it could be used for ground attack, which was hardly an RAF priority in 1940 anyway.

When the Defiant failed in its intended role it found some use a a makeshift night fighter (though, unlike the Bf 110, only a short reprieve) before being seen for what it was; a dead end.

Cheers

Steve

The Defiant could have been a better bet than the Battle.

The Basket said:

The Defiant could have been a better bet than the Battle.

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The Battle was built to a completely different specification.

It was ordered as a day bomber.

It's specification (P.27/32) pre-dates that for the Defiant (F.9/35) by several years.

The Battle was to carry a 1,000lb bomb load for 1,000 miles. The Defiant had a range of under 500 miles. We are in 'apples and oranges' territory here, comparing an aircraft designed as a fighter/interceptor to one designed as a day bomber replacement for the Hart/Hind.

Cheers

Steve

The Battle and Defiant were in the end contemporary and were both failures in their allotted roles. The logic to try and extend the life of the Defiant is to make it a single seat bomber to undertake the same roles as the Battle. Since this didn't happen and the true potential of the Defiant design was never met then this is moot. However, the RAF did use Hurricanes and Warhawks in a ground attack role which they were not well suited to or designed for. I doubt that anyone could argue that the Defiant could be a better fighter than A Spitfire but a single seat Defiant without a turret may have been a better ground attack/bomber than contemporary aircraft. The RAF guy who said the Defiant was nice to fly also said he felt it a shame that the Defiant was wedded to the turret and so became a one trick pony and its true potential was never explored. Was the Defiant worse than a Fulmar?

The Defiant had considerably less range than the Fulmar, far from ideal for maritime operations.

If you are looking for something purely for fleet defence, where range might not be so much an issue, then the Sea Hurricane was a better option.

Cheers

Steve

I would wager the Defiant was better than the Roc. Of course we could wax on about the P.94 but since nothing came of it then there is actual not much to say other than moonbeams and wishdreams.

Yes.
I can't find the text of the Fulmar specification (O.8/38), but it did emphasise endurance. The Admiralty wanted six hours, but got four and three quarter hours (MkI) and five and a half hours (Mk II).
British carrier aircraft were not expected to meet enemy fighters, the Germans having no carriers themselves, and operations expected to be beyond the range of land based fighters.
The situation as it developed in the Mediterranean was not foreseen, crystal balls only working in fantasy novels and films, but not at the Admiralty or Air Ministry.
Cheers
Steve

There seems to be a bit of confusion here.
The Defiant was designed as a two seat turret fighter and actually had a slightly smaller wing than the Hurricane (250sq ft). It also weighed around 1500lbs more but only around 800lbs of this was the actual turret, guns ammo and gunner so just wanking the turret out and plating over the opening still leaves the plane hundreds of pounds heavier. Without going back and redoing the stress calculations and redesigning structural components and even skin thickness that weight is not going to magically disappear.
The Battle was a three seat light strategic bomber. It carried twice the payload of a Hart bomber twice as far. It was designed to get around a possible treaty restriction on the size/weight of bombers that never was implemented. It is a large single engine plane (422sq ft wing) , The Fulmar was based on a smaller two seat dive bomber derivative of the Battle that carried 1/2 the bomb load about 1/2 as far. The Fulmar had 8 feet less wingspan and a shorter/skinner fuselage and a 342sq ft wing.
Trying to squish things around in these rather different airframes to try to do each others jobs is not really going to end well. That is give you a really useful airplane instead of one that fills a slot on paper and takes up hanger/apron space.
A lot depends when you try to use the soft clay to squeeze the planes into different roles. For instance radios changed fairly quickly in the late 30s and first few years of the 40s. SOme accounts cali that the Defiant didn't use the same radios as the Hurricanes and Spitfires and could not communicate with them. Long range radios (as needed by bombers and planes flying over water) often needed a dedicated operator but just a few years later newer radios that were easier to operate and longer ranged did away with the need for the 2nd crew man.

Trying to adapt land planes to carriers is also a can of worms.

Granted this is the HMS Argus but non-folding wings presented a lot of problems on carriers.
take-off speeds and landing speeds were also critical. A 10% increase in landing speed (from say 70mph to 77mph) is actually 21% higher in the energy the arresting system has to deal with. On a moving carrier it is worse. Assuming the carrier is moving at 20mph the difference in relative energy of the 70mph airplane and the 77mph airplane is just under 30%.
The Defiant had a higher landing speed than the Hurricane or Spitfire, adding another fighter to the FAA that didn't have folding wings (the Fulmar did) doesn't solve any problems for the FAA.
The whole P.94 story seems to have a few holes. The Defiant was about 20mph slower than a Hurricane using the same engine, The P. 94 was supposed to be 20mph faster by dropping the turret? The 360mph speed for the P. 94 was an estimate based off the trials of the prototype Defiant. However the Defiant II with Merlin XX engine didn't quite meet the estimates for it. How much of that was due to the flat black paint and radar aerials, how much was due to a high drag radiator (larger than the radiator for the Merlin III) or for other reasons I don't know but getting 40mph just for dropping the turret seems a bit much. (it also takes no account of sticking guns in the wings?)

The P.94 was probably the only place the Defiant could go. Whether this would have been bad good or ugly is not the point.
The Spitfire and Hurricane weren't naval fighters either.
Not sure your point here. Yes the Defiant or P.94 were never going to be good at much but that hasn't stopped military before! In the perfect world the Defiant wouldn't even had been a turret fighter. But if push comes to shove and the Defiant was the only game in town then what was it's potential?

The Basket said:

In the perfect world the Defiant wouldn't even had been a turret fighter.

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It was only ever going to be a turret fighter. That's the specification it was built to. That's the only way the company could obtain public money for its development.

The only other alternative would have been a private venture, and we know what happened to the P.94 after it was rejected by the Air Ministry in late (September I think) 1940. The company was not prepared to pursue the project on its own.

Thankfully it wasn't the only game in town. In the mid 1930s the Air Ministry had the Supermarine fighter (Spitfire) and the Hawker fighter (Hurricane) as their front runners. The 'fall back' should both these fail was expressly the Gloster F.7/30, so it's just as well that both Supermarine and Hawker delivered!
The Defiant was never in the running as anything but an interceptor armed with a turret. Anything else is pure 'what iffery'.

Cheers

Steve

The Basket said:

The P.94 was probably the only place the Defiant could go. Whether this would have been bad good or ugly is not the point.
The Spitfire and Hurricane weren't naval fighters either.
Not sure your point here. Yes the Defiant or P.94 were never going to be good at much but that hasn't stopped military before! In the perfect world the Defiant wouldn't even had been a turret fighter. But if push comes to shove and the Defiant was the only game in town then what was it's potential?

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The Defiant was never going to be the only game in town in any role. Even in the role of "turret fighter" it had to complete against the Hawker Hotspur.


The Fulmar was an emergency fighter ordered off the prototype P.4/34 dive bomber


which had competed with the Hawler Henley.


The Hurricane and Seafire were probably the most successful adaptations of land mono-planes to carrier use, in large part because they were designed to fly out of small airfields using fixed pitch props at part throttle. By the time they stuck them on carriers they had constant speed props which helped take-off enormously and they still had the big wings and low stalling speed for landing.

A "Defiant" designed without a turret would have been much different, construction would have been different (lighter) and perhaps it would have used a smaller wing? Being a bit later in timing different flaps (?) Hurricane and Spit flaps were mostly airbrakes and provided very little, if any, lift when deployed on the early aircraft (there were no intermediate settings, either flap up or flap down).
The Defiant went into service with it's first squadron 2 years after the Hurricane. Those two years of start and development time saw a number of changes in aerodynamic and structural knowledge. For instance no Defiant ever had to struggle with a fixed pitch prop (although the two pitch was a far cry from what was needed/wanted by pilots)

Shortround6 said:

...
The Defiant went into service with it's first squadron 2 years after the Hurricane. Those two years of start and development time saw a number of changes in aerodynamic and structural knowledge.

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People at Boulton-Paul design shop decided that changes/advances in aerodynamics are not applicable for their new fighter, whether it is about wing profile & thickness, layout of radiator, slope of windscreen, high-lift devices, or 'retractability' of the tailwheel.

True Tomo.
I would also note that the Hawker Tornado flew several months before the Defiant was issued to a service squadron.

developments of "improved" Defiants or other types have to be looked at in the light of the Tornado/Typhoon development (or potential).

If a single seat Defiant offers no real improvement over the Hurricane and Spitfire and there are thousands of Tornado/Typhoons on order the need for a single seat Defiant rather fades away.

Lets also remember that the P.94 was supposed to use a Merlin XX which puts it at the fall/winter of 1940 and up against the Hurricane II and Spitfire II and V.

UK was handily out-producing Germany in aircraft numbers, airframe weight and number of engines already in 1939, let alone in 1940. Granted, a good deal of those aircraft were of dubious utility for war of 1940 - Defiant, Battle, Lysander, Botha, Blenheim. RAF needed better fighters than what was in inventory, not yet another hundreds of so-so performers. Investing a Merlin XX in Spitfire (= Spitfire III of 390-400 mph, depending whether armament is installed?) is a much better thing than installing them in the Defiant's off-spring that was supposed to posses performance of Spitfire I, 2 years later.