Boulton Paul Defiant

[Conspirator]

The Defiant has always been one of my favorite WW2 misfits aircraft. it was an incredible idea that (possibly) didnt get the right company to develop it. if you look at the pictures the edges around the turret were almost air scoops. the fuselage was just slashed open to make it fit. the drag was horrible. if possibly it was like an (correct me if im wrong) F4F Wildcat? the dual LMGs back there? they folded down to make room and were in a more aerodynamic cabin. could it be possible to do something like that and still have the same quad .303 system?

 

[Archibald]

I think the 4*7.7 mm MG (0.303) were hopeless. But how about two 12.7 mm in the turret (like a B-17 turret) and 2*20 mm gun in the wings ? Now that would have been a decent firepower. Add a Griffon in place of the Merlin, and now we are up to something. Must be possible: see Fulmar / Firefly.
Next step is 1*20 mm in the turret, but this has already been discussed.

Yeah, I kind of like it. Firefly's Griffon, two 20 mm in the wing, two 12*7 in the turret.

I'm tempted by a line-profile, if only I can find a Firefly matching a Defiant...

 

[Nick Sumner]

Archibald, what you are describing is pretty much what BP did with their P.96 project.

https://www.secretprojects.co.uk/threads/boulton-paul-p-96-single-engine-fighter-project.20993/

 

[EwenS]

The Defiant has always been one of my favorite WW2 misfits aircraft. it was an incredible idea that (possibly) didnt get the right company to develop it. if you look at the pictures the edges around the turret were almost air scoops. the fuselage was just slashed open to make it fit. the drag was horrible. if possibly it was like an (correct me if im wrong) F4F Wildcat? the dual LMGs back there? they folded down to make room and were in a more aerodynamic cabin. could it be possible to do something like that and still have the same quad .303 system?

If you think the Defiant is bad just look at what Bolton Paul did to the Skua when they turned it into the Roc for Blackburn.

Blackburn Roc - Wikipedia

en.m.wikipedia.org

Biggest problem for both to overcome is the weight of that turret.

 

[Conspirator]

The Defiant has always been one of my favorite WW2 misfits aircraft. it was an incredible idea that (possibly) didnt get the right company to develop it. if you look at the pictures the edges around the turret were almost air scoops. the fuselage was just slashed open to make it fit. the drag was horrible. if possibly it was like an (correct me if im wrong) F4F Wildcat? the dual LMGs back there? they folded down to make room and were in a more aerodynamic cabin. could it be possible to do something like that and still have the same quad .303 system?

If you think the Defiant is bad just look at what Bolton Paul did to the Skua when they turned it into the Roc for Blackburn.

Blackburn Roc - Wikipedia

en.m.wikipedia.org

Biggest problem for both to overcome is the weight of that turret.

ok thank you for ruining my outlook on Boulton Paul...... JK

 

[Archibald]

The Defiant has always been one of my favorite WW2 misfits aircraft. it was an incredible idea that (possibly) didnt get the right company to develop it. if you look at the pictures the edges around the turret were almost air scoops. the fuselage was just slashed open to make it fit. the drag was horrible. if possibly it was like an (correct me if im wrong) F4F Wildcat? the dual LMGs back there? they folded down to make room and were in a more aerodynamic cabin. could it be possible to do something like that and still have the same quad .303 system?

If you think the Defiant is bad just look at what Bolton Paul did to the Skua when they turned it into the Roc for Blackburn.

Blackburn Roc - Wikipedia

en.m.wikipedia.org

Biggest problem for both to overcome is the weight of that turret.

And if you think the Roc was bad, just consider the fact they pondered about a variant with floats - just to make it even more slower, ugly, unaerodynamic, and a perfect giant training target for the LW.
This was in the days of Norway, 1940, where the Skuas already suffered against the LW.

 

[Arjen]

And if you think the Roc was bad, just consider the fact they pondered about a variant with floats - just to make it even more slower, ugly, unaerodynamic, and a perfect giant training target for the LW.
This was in the days of Norway, 1940, where the Skuas already suffered against the LW.

Not just pondered - built it.

https://www.secretprojects.co.uk/threads/british-ww2-turret-fighter-projects.3537/#post-315511

 

[Justo Miranda]

When the Defiant was designed, no one expected that German bombers could attack from French bases with fighter escorts. Bombers were supposed to take off from German bases and reach England without escort.

 

[tomo pauk]

When the Defiant was designed, no one expected that German bombers could attack from French bases with fighter escorts. Bombers were supposed to take off from German bases and reach England without escort.

I always find the notion that German bombers are supposed to fly from Germany ... short-sighted from the powers that were. 20+ years before Defiant was mooted, Germans have had air bases in Belgium, for crying out loud.
Defiant was also sporting half the firepower of Hurricane or Spitfire, while being more expensive to make. Slower, with lower rate of climb - both categories required for a bomber destroyer. Ability to carry cannons was straight-forward with these two, unlike with Defiant.

 

[Justo Miranda]

When the Defiant was designed, no one expected that German bombers could attack from French bases with fighter escorts. Bombers were supposed to take off from German bases and reach England without escort.

I always find the notion that German bombers are supposed to fly from Germany ... short-sighted from the powers that were. 20+ years before Defiant was mooted, Germans have had air bases in Belgium, for crying out loud.
Defiant was also sporting half the firepower of Hurricane or Spitfire, while being more expensive to make. Slower, with lower rate of climb - both categories required for a bomber destroyer. Ability to carry cannons was straight-forward with these two, unlike with Defiant.

To avoid the defensive fire of the Germans bombers the Defiant designers developed the tactic of shooting against the belly of the bombers using angled upward-firing machine guns. The idea was not new (it has been used by British fighters fighting against the Zeppelins during the World War I) but its advantage was to be able to shoot directly against the engines and wing fuel tanks that in a classical attack from behind were protected by the wing structure.

Firing from below the Defiant's four machine guns were more effective than the eight of a Hurricane firing from behind at a He 111 with 270 kg armour.

 

[tomo pauk]

To avoid the defensive fire of the Germans bombers the Defiant designers developed the tactic of shooting against the belly of the bombers using angled upward-firing machine guns. The idea was not new (it has been used by British fighters fighting against the Zeppelins during the World War I) but its advantage was to be able to shoot directly against the engines and wing fuel tanks that in a classical attack from behind were protected by the wing structure.

Firing from below the Defiant's four machine guns were more effective than the eight of a Hurricane firing from behind at a He 111 with 270 kg armour.

Defiant as-is was incapable of a head-on attack - not the case with Hurricane. Hurricane can also do the angled firing in order to hit vitals of a bomber. Hurricane can also do the 'beam attack' (ie. from the side), or a diving attack either from the front or from rear.

 

[Conspirator]

i see the Defiant being used like the Bidge Busting Jugs of the air force:

art by Stan Stokes.

this could have been a great job for them they were slow enough for precision bombing with rear protection (if it was developed better of course) one 500lb bomb with a good pilot could do a ton of damage and the turret could also act like a gunship. orbiting a target and raining shells/bullets on it for precision battlefield attacks

 

[Archibald]

Archibald, what you are describing is pretty much what BP did with their P.96 project.

https://www.secretprojects.co.uk/threads/boulton-paul-p-96-single-engine-fighter-project.20993/

And a Centaurus on top of the whole thing. What's not to like ?

 

[robunos]

Unfortunately for the idea the bombers were being escorted by fighters which soon broke up the Defiant formations. Then the heavy weight of the turret and air gunner reduced the Defiants performance compared to non-turret fighters so they were at a major disadvantage. Especially after the attacking fighter learnt to stay out of the turret’s field of fire.

To my mind they should have added four wing-mounted forward firing guns to the standard Defiant. While this would have further increased weight and reduced performance,
it would in effect be re-inventing the WWI Bristol Fighter.
These would then be used exclusively as bomber destroyers, the pilot attacking the bombers with his forward firing guns, while the gunner used his turret to deal with the enemy escort fighters, aided by the defending fixed gun fighters.


cheers,
Robin.

P.S. My grandfather worked at Boulton Paul during the war, building Defiants......

Replying to my own post . . .
Reading 'Boulton Paul 1917-1961', by Les Whitehouse, on page 149, I came across this . . .

"A meeting with Boulton Paul Aircraft took place in 1935 in the office of E.D. Davies at A&AEE Martlesham Heath, at which a turreted fighter was considered with a four gun package. While favourable, [designer John Dudley] North's team was told by [later to be AVM] Davies that if they included forward firing weapons for the pilot the proposal could be rejected without consideration. Davies believed that the Bristol Fighter was a failure in the First World War because the pilot used it as a fighter and left the gunner to defence."
(My Bold)

cheers,
Robin.

 

[Conspirator]

Unfortunately for the idea the bombers were being escorted by fighters which soon broke up the Defiant formations. Then the heavy weight of the turret and air gunner reduced the Defiants performance compared to non-turret fighters so they were at a major disadvantage. Especially after the attacking fighter learnt to stay out of the turret’s field of fire.

To my mind they should have added four wing-mounted forward firing guns to the standard Defiant. While this would have further increased weight and reduced performance,
it would in effect be re-inventing the WWI Bristol Fighter.
These would then be used exclusively as bomber destroyers, the pilot attacking the bombers with his forward firing guns, while the gunner used his turret to deal with the enemy escort fighters, aided by the defending fixed gun fighters.


cheers,
Robin.

P.S. My grandfather worked at Boulton Paul during the war, building Defiants......

Replying to my own post . . .
Reading 'Boulton Paul 1917-1961', by Les Whitehouse, on page 149, I came across this . . .

"A meeting with Boulton Paul Aircraft took place in 1935 in the office of E.D. Davies at A&AEE Martlesham Heath, at which a turreted fighter was considered with a four gun package. While favourable, [designer John Dudley] North's team was told by [later to be AVM] Davies that if they included forward firing weapons for the pilot the proposal could be rejected without consideration. Davies believed that the Bristol Fighter was a failure in the First World War because the pilot used it as a fighter and left the gunner to defence."
(My Bold)

cheers,
Robin.

Ahhh of course that makes sense, great find! I feel like they were developed of course for bomber protection and then they had to make do with them as fighters because of how outnumbered they were and current battle situations. It was the right plane. Wrong slap-together design. At the wrong time.

 

[T. A. Gardner]

The turret fighter was flawed thinking right from the start.

Think of it this way. Even unescorted bombers could have turrets. They'd certainly have guns that could be used for defense against an attacking plane. Those guns could, and most likely would, be of equal size, damage, and range to the attacking plane's guns, if not in the same quantity.

The Defiant was supposed to be able to attack such bomber formations much like some old sailing warship using its turret. It could fly alongside the formation, spraying it with gunfire. At least that was the thinking.

Well, the bombers could and would shoot back. The use of a two-seat plane hauling a heavy turret meant if there was single-seat fighter opposition, the Defiant was in serious trouble.

The Defiant also had virtually no room for improvement. You certainly couldn't cram a turret with say 4 x .50 machineguns on it, let alone say 2 x 20mm. The wing really wasn't designed or stressed to take a battery of forward firing guns either. Turning it into a single-seat fighter would result in an inferior aircraft.

If anything, the Defiant is the product of bureaucrats that would never have to fly it.

 

[Foo Fighter]

^ in spades. Far too many vested interests without the requisite knowledge. Lethal.

 

[Hood]

The F.2B was a success because it was flown like a fighter and could punch from both ends. A gunner on an F.2B could build up a respectable tally - simply because he could live long enough to amass a score. Bumbling about in a 2-seater was suicide.
I feel had Davies been an F.2B pilot he would have had a different view and stuck guns in the wings, but I can see his reasoning, the turret-equipped fighter would be heavier and slower and most felt the day of the dogfight was over anyway but encouraging a pilot to dogfight in a heavy slower fighter probably wasn't a good idea.

The use of a two-seat plane hauling a heavy turret meant if there was single-seat fighter opposition, the Defiant was in serious trouble.

True but in 1935 that didn't look likely. Yes it possible a French bombing raid might just have the range for single-engine fighters to accompany it - but even in 1940 the Bf 109 had very limited time over South East England from bases just over the Channel. The idea of a single-engine fighter flying over the North Sea from Germany was highly unlikely, and it took external drops tanks and a lot of effort to get a Spitfire or P-47 past the Low Countries in 1943. The concept of something like the P-51D that could get down to Austria would be fantastic in 1935, nearly as fantastic as those new ideas some officer called Whittle claimed he could squirt hot air out the back to achieve 500mph...

 

[T. A. Gardner]

The F.2B was a success because it was flown like a fighter and could punch from both ends. A gunner on an F.2B could build up a respectable tally - simply because he could live long enough to amass a score. Bumbling about in a 2-seater was suicide.
I feel had Davies been an F.2B pilot he would have had a different view and stuck guns in the wings, but I can see his reasoning, the turret-equipped fighter would be heavier and slower and most felt the day of the dogfight was over anyway but encouraging a pilot to dogfight in a heavy slower fighter probably wasn't a good idea.

The use of a two-seat plane hauling a heavy turret meant if there was single-seat fighter opposition, the Defiant was in serious trouble.

True but in 1935 that didn't look likely. Yes it possible a French bombing raid might just have the range for single-engine fighters to accompany it - but even in 1940 the Bf 109 had very limited time over South East England from bases just over the Channel. The idea of a single-engine fighter flying over the North Sea from Germany was highly unlikely, and it took external drops tanks and a lot of effort to get a Spitfire or P-47 past the Low Countries in 1943. The concept of something like the P-51D that could get down to Austria would be fantastic in 1935, nearly as fantastic as those new ideas some officer called Whittle claimed he could squirt hot air out the back to achieve 500mph...

On the other hand, a 'fighter' with a turret exchanging broadsides with a formation of bombers--possibly similarly armed--doesn't exactly instill a picture of success in the venture.

 

[kaiserd]

The Defiant was intended to be superseded reasonably quickly by a (somewhat multi-role if I remember correctly) higher performance design (twin engined, I think) with an “aerodynamic” four 20mm canon turret which was intended as the evolution of the turret fighter concept (multiple designs from different manufacturers submitted for the associated design competition). For further details I’d need to consult (or direct the reader to their own copy of) Tony Butlers excellent British secret projects books on this era.

As such the Defiant wasn’t really intended to be tackling German bombers with equivalent powered turrets and I’d also query when the first German bomber with such a turret actually entered service (Do 217 or He 177 in 1942 at the earliest, I think?). The concept is clearly flawed but innovations such a the German Scrage Musik cannon installations show that others were thinking along not un-similar lines.

 

[T. A. Gardner]

The Defiant was intended to be superseded reasonably quickly by a (somewhat multi-role if I remember correctly) higher performance design (twin engined, I think) with an “aerodynamic” four 20mm canon turret which was intended as the evolution of the turret fighter concept (multiple designs from different manufacturers submitted for the associated design competition). For further details I’d need to consult (or direct the reader to their own copy of) Tony Butlers excellent British secret projects books on this era.

As such the Defiant wasn’t really intended to be tackling German bombers with equivalent powered turrets and I’d also query when the first German bomber with such a turret actually entered service (Do 217 or He 177 in 1942 at the earliest, I think?). The concept is clearly flawed but innovations such a the German Scrage Musik cannon installations show that others were thinking along not un-similar lines.

All that does is change the numbers in the equation. The results remain the same. The bombers get 20mm cannon as defensive weapons (or something that's effective to the same range) and the bombers exchange broadsides with the turret fighter, likely to the demise of the smaller fighter at a rate equal to or higher than the bombers.

 

[Hood]

A stern attack against a bomber with a tail turret was hazardous. The ventral gun on the Gotha in 1918 proved to make ventral attacks hazardous. Even by 1943 B-17s were packing four 50-cal MGs in the nose, a better battery than some fighters. Attacks from above could be countered by nose, dorsal and tail turrets (early ring gun positions were less limited in elevation and arcs than enclosed powered turrets).
In fact it could be argued a broadside limited the danger from the arcs of fire, i.e. the nose turret cannot aim too far aft due to the engine/wings and the tail turret cannot aim too far forward due to the tailplane - that just leaves the dorsal mount and beam guns and nearly all beam guns were single hand-held MGs. Which against a quad-gun turret seems a no-win situation.

The bombers get 20mm cannon as defensive weapons (or something that's effective to the same range)

The 'Ideal Bomber' of course was designed for the same quad 20mm turrets to stay equal with any enemy developments akin to the P.92. It must be said the RAF hoped its powered turrets as bomber defensive weapons would put them ahead of enemy fighter threats, but it is an open question whether they proved any more effective than hand-held guns in Heinkels, Dorniers, Junkers, FIATs, Savoias or B-17s and early B-24s. They certainly took bomber defence seriously and kept in step-change with fighter technology (turret fighters = turret bombers, 20mm turret fighters = 20mm turret bombers) to make sure they kept one step ahead.
Sadly they didn't persevere with ventral turrets when the similar Schräge Musik concept came along.

 

[T. A. Gardner]

A stern attack against a bomber with a tail turret was hazardous. The ventral gun on the Gotha in 1918 proved to make ventral attacks hazardous. Even by 1943 B-17s were packing four 50-cal MGs in the nose, a better battery than some fighters. Attacks from above could be countered by nose, dorsal and tail turrets (early ring gun positions were less limited in elevation and arcs than enclosed powered turrets).
In fact it could be argued a broadside limited the danger from the arcs of fire, i.e. the nose turret cannot aim too far aft due to the engine/wings and the tail turret cannot aim too far forward due to the tailplane - that just leaves the dorsal mount and beam guns and nearly all beam guns were single hand-held MGs. Which against a quad-gun turret seems a no-win situation.

The best way devised during that period (1930 -40) to attack a bomber formation was the high-side pass. In this, the fighter(s) would approach the formation from ahead and above somewhat off to one side of it. As the two drew even, the fighter would wing over and make a diving turn towards the bombers picking out one as its target.
This required the pilot to have pretty good flying skills and be skilled in deflection shooting. If the pilot was, then this sort of attack was not only very effective and likely to result in the bomber being shot down, but defensive fire was likely to be ineffective against it. The defending gunners had a target that was changing speed and direction constantly and would require deflection shooting to hit.

This is a high-side pass from behind. This is a variant of the head on version I described. It isn't as effective at avoiding return fire as the head-on version is.

 

[T. A. Gardner]

The Defiant has always been one of my favorite WW2 misfits aircraft. it was an incredible idea that (possibly) didnt get the right company to develop it. if you look at the pictures the edges around the turret were almost air scoops. the fuselage was just slashed open to make it fit. the drag was horrible. if possibly it was like an (correct me if im wrong) F4F Wildcat? the dual LMGs back there? they folded down to make room and were in a more aerodynamic cabin. could it be possible to do something like that and still have the same quad .303 system?

If you think the Defiant is bad just look at what Bolton Paul did to the Skua when they turned it into the Roc for Blackburn.

Blackburn Roc - Wikipedia

en.m.wikipedia.org

Biggest problem for both to overcome is the weight of that turret.

Hey, the ROC made a good antiaircraft gun position at the airfield it was sited on... Didn't even have to take off to do that!

 

[Nik]

I thought you were joking, but... Wiki (YMMV):

Blackburn Roc - Wikipedia

en.m.wikipedia.org

"The last four Rocs stationed at HMS Daedalus in Gosport survived until late 1944, all unairworthy, with their turrets still being used for anti-aircraft defence"

 

[ChrisP]

To my mind they should have added four wing-mounted forward firing guns to the standard Defiant. While this would have further increased weight and reduced performance,
it would in effect be re-inventing the WWI Bristol Fighter.
These would then be used exclusively as bomber destroyers, the pilot attacking the bombers with his forward firing guns, while the gunner used his turret to deal with the enemy escort fighters, aided by the defending fixed gun fighters.


cheers,
Robin.

P.S. My grandfather worked at Boulton Paul during the war, building Defiants......

Your grandfather may have met my mother-in-law. She was the dentist's assistant in the factory!

 

[ChrisP]

Your grandfather may have met my mother-in-law. She was the dentist's assistant in the factory!

My mistake. My mother-in-law was a dentist's assistant before she joined Boulton & Paul where she was the Night Nurse.

 

[riggerrob]

…. The Defiant also had virtually no room for improvement. You certainly couldn't cram a turret with say 4 x .50 machineguns on it, let alone say 2 x 20mm. The wing really wasn't designed or stressed to take a battery of forward firing guns either. Turning it into a single-seat fighter would result in an inferior aircraft.

If anything, the Defiant is the product of bureaucrats that would never have to fly it.

Defiant’s cramped turret forced innovations that still benefit civilian parachutists to this day.
Most WW2, RAF aerial gunners only wore parachute harnesses inside their turrets. In the event of a shoot-down, gunners were supposed to exit their turrets, crawl inside the fuselage to an exit hatch, clip on a chest-mounted emergency parachute, dive out and pull the ripcord. A great plan if the pilot remains at the controls and holds the bomber level (see RCAF Pilot Officer Darrell Page’s DFC citation). Unfortunately, damaged bombers rarely co-operated long enough for this exit plan and Bomber Coomand suffered heavy casualties rivalling those of WW1 trench-fighters.
Since it was impossible for Defiant gunners to enter the fuselage, they were forced to wear parachutes full-time while flying in the turret.
George Quilter (of G. Q. Security/Defense now Airborne Systems) invented a solution that was much thinner than previous pilot emergency parachutes. Quilter’s Para-Jerkin distributed the bulk of the parachute canopy under the pilot’s thighs and into his lumbar curve.
The Para-Jerkin was essentially a vest with short legs that ended short of the wearer’s knees.
G. Q. later developed the Para-Suit that was a full-length set of coveralls that incorporated a parachute, flotation and some insulation to serve as an immersion suit for Sunderland crews forced to ditch in the cold North Atlantic Ocean.
Then Quilter invented a new type of pilot-chute spring and mounted it in the gunner’s lumbar curve. The innovative spiral spring was held compressed by a pair of cloth loops (perhaps silk suspension line) that passed completely through the container. The innovative soft through-loops replaced brass cones and a dozen other wood or metal stiffeners. Fewer metal stiffeners made parachute containers lighter with fewer lumps to bruise pilot’s delicate backsides. IOW Quilter’s innovations converted PEPs into passably comfortable seat cushions.
This concept was copied on the USAF’s 1950s vintage BA-22 PEP.
When West Germans started building fibreglass sailplanes with steeply reclined/supine pilot seats in their cramped cockpits, GQ responded by introducing their 150/250/350 Safety-chutes which could be stuffed into almost any cockpit because they were so thin. Part of the secret was making containers 40”/1 meter long to distribute parachute canopy bulk over a wider area. G.Q. Safety-Chutes were barely 2 inches thick and eliminated the “step” where the seat-back met the seat-bottom.
When civilian skydivers started to diverge from just modifying military-surplus parachutes during the 1970s, they adopted Quilter’s soft through-loops and the US Army’s MA-1 pilot-chute with a spiral spring.

All modern PEPs, civilian skydivers and military freefallers benefit from George Quilter’s innovations (through loops and spiral springs) that were originally conceived to compensate for cramped turrets on Defiants.

Master Corporal (retired) Rob Warner, CD, BA, etc.
FAA Master Parachute Rigger
Strong Tandem Instructor Examiner
CSPA Coach 2 and Instructor for static-line, IAD and PFF
Private Pilot