Boulton Paul Defiant

Figures for the Defiant 1 on file at Boscombe Down
were

5,000ft 1,515 ft./min and 294 mph
10,000ft 1,610 ft/min and 312 mph
15,000ft 1,240 ft/min and 305.5 mph
20,000ft 805 ft/min and 295 mph
26,000ft 285 ft/min and 266.5 mph

Sorry for reviving an old thread, but there seems to be a lot of Defiant knowledge amongst you.

I’m trying to find more info on the speeds and climb ratings at the below altitudes and I’m not having much success. If anyone has a sources for these stats, it would be greatly appreciated!

5000ft
10000ft
15000ft – I’ve found a climb rate of 1765ft/min for this altitude
20000ft
25000ft

Thank in advance for any help you can give,

Keith

That’s a cracking image, Bazy, large formations of Heinkels or Dorniers diving down to tree-top height when attacked by Defiants, weaving in and out of balloon cables and frightening the anti-aircraft gunners to death as they roared over the roof tops, and on nights like this, keeping a good watch out for low-flying reindeer.

Have a good Christmas

Agreed Wulfie but if the Defiant had continued on daylight ops then the opposition would have changed tactics,that was the way of things…a new a/c scored well and then the other side counters with new tactics and/or new equipment.
Once the formations were broken up then they would have gone low level !Forward firing guns were (generally) much better !

rgds baz

The Defiant did not normally need depression on the guns, because attacks were usually made from underneath, or in crossover passes. At no time during the daylight battles over Holland, Dunkirk and during the Battle of Britain did bombers dive to low altitude to protect themselves, they maintained their formation. On 29th May 1940 in its second sortie over Dunkirk No.264 Squadron saw a large number of Ju.87s making diving attacks on the beaches. Sqd Ldr Hunter wisely did not try to attack the dive bombers in the dive, but flew to low altitude and waited for them to pull out. The Stukas were then shot from the skies as the Defiants drew alongside and poured fire into each one in turn. A total of 18 Stukas were claimed, though it has since been proved that this number was greatly exaggerated, probably as more than one Defiant was attacking each target without necessarily realising it.

Whenever No.264 Squadron attacked unescorted bombers they shot them down with alacrity, that was what they were designed for. When they were themselves attacked by Bf.109s they could protect themselves very effectively. They achieved what they were supposed to do, its just that single seat fighters were just as effective against bombers, contradicting the theory which had spawned the turret fighter in the first place.

Underside defence on bombers was supposed to be undertaken by retractable turrets (eg. BP Type K) but these turrets were cancelled just as they were being put in production. There was then a Spec. for low-drag underside turrets with periscope sighting (eg. BP Type R) but these were cancelled just as the prototypes had been proven. Underside defence was thus reliant on the other turrets and when the Type B (The redesigned Defiant turret with 25 degrees of depression) was cancelled the Halifax was going into service with no underside defence worth speaking about. Thousands of Bomber crew paid for this Air Ministry muddle with their lives.

Thanks mate. And you.!

Pleasure…and a very merry xmas to you and family 🙂

rgds baz

The original links to Sqn Ldr Clarke’s RAF Flying Review articles that I previously posted are dead so her is an extract from a book about the Defiant and the Roc called ‘The Turret Fighters’ by Alec Brew, published by Crowood.

“A well known engagement involved a 2 AACU (Anti-Aircraft Co-operation Unit) ROC, L3085, and Plt Off D. H. Clarke, who had painted a red ‘Saint’ (the Leslie Charteris character) in a red-framed yellow diamond on each side of the rear fuselage of his ‘own’ Roc. On 26 September 1940 he was sent out to search for survivors in the water 15 miles (24 km) south-west of St Catherines Point. With Sergeant Hunt in the gun turret – which, unusually for 2 AACU Rocs, was fully armed – he took off in the late afternoon. As he instituted a square search in the area indicated, he noticed what he thought was a Swordfish also searching about 3 miles (5 km) away.

After about 45 minutes of fruitless search in the gathering gloom, he suddenly noticed that the Swordfish, now only half a mile away, was in fact a twin engined floatplane. Out of curiosity, wondering what it was, he flew towards it: and then suddenly realised it was a Heinkel He 59, a German aircraft probably on the same air-sea rescue task as himself. Unsure as to whether he should open fire on an aircraft on such a humanitarian mission, he flew across its nose with Hunt training his turret at it.

As he did so the German nose gunner opened fire with his 7.9mm machine gun, and Hunt returned fire, his tracer pouring into the Heinkel’s fuselage. After the pandemonium and shock of his first action, Clarke swung on to a parallel course, and re-established communication with Hunt , whose intercom lead had been pulled out. The Heinkel turned for France, skimming the waves. Happily the twin engined bi-plane was even slower than the Roc, with a top speed at sea level of only 137 mph (220 kph), and Clarke was able to gain on his adversary; although he was still faced with the prospect of having to drop a wing to enable Hunt to open fire, even though his propeller was skimming the wave tops.

At 300 yards range he dropped a wing, and Hunt opened fire with another broadside. The Heinkel replied from all three gun positions, nose, dorsal and ventral, a single machine gun in each, but Clarke had to lift the wing after only a few seconds to avoid side-slipping into the sea, causing the last few rounds of Hunt’s burst to shoot harmlessly up into the air. The two aircraft continued these brief exchanges of fire for about 25 minutes, until the coast of France was looming up. Both aircraft were hit, and one of the Heinkel’s gunners stopped firing; but just as Clarke was about to turn away, the Roc was hit in the engine.

It faltered, and Clarke switched to the reserve 17 gal (77 ltr) tank, pulling up and away. Just as he thought he might have to ditch, the Perseus picked up, and he nursed the damaged aircraft back to Gosport. But before he could taxi in the engine stopped, out of fuel. Clarke claimed the Heinkel as ‘Damaged’.

On his return his groundcrew found two incendiary bullets in the main fuel tank, above which he sat. They had entered low down in the petrol, which had extinguished them; slightly higher, in the explosive fuel/air mixture above, and the Roc would have been ‘missing in action’. This action was almost certainly the nearest the Blackburn Roc ever came to destroying a German aircraft in combat”.

Cheers for posting that Baz. Fascinating account of the Roc’s actions.!

Yes it was so easy for the gunner to bail out of that turret !!!

Anyway here is a video link with some nice defiant footage including turret assembly etc at approx 1.10 and some flying footage inc from the rear cockpit.

Seasons greeting also 😀
http://www.google.co.uk/url?sa=t&rct=j&q=boulton%20paul%20defiant%20&source=web&cd=6&ved=0CFMQtwIwBQ&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dce9My4IKydo&ei=XM71TrmZGM_t8QPm_Y2iAQ&usg=AFQjCNHqT-AwB86e_18Y1nBCpmnTJtuh4g

I did not actually say ‘laying on the turret base’ James and I did cover the higher seating requirement for the gunner anyway,

‘Very well, ‘Almost’, and it’s not ‘almost’ either – please note how I described the structure of the turret.

Secondly, I was not suggesting that the gunner would need to be raised – that’s another assumption you’ve made. For a 10 degree lowering of the guns azimuth, I would expect a replacement of an opaque panel below at chest level perhaps and re-arrangement of some of the auxiliary equipment in that area.

it was an extremely tight (i believe called ‘clean’) turret installation…

I know, I sat in it! However it was a viable working space for a gunner, and although suffering from the heavy frames of the time, was a highly rated turret – with a long wartime service in bombers.

…and I absolutely agree it is a moot point,there would have been no possible reason to spend money on a redesign !

Just to clarify, my thinking was simply that a different choice could have been made for the Roc’s azimuth abilities in the 1930s which would’ve got Clarke a kill.

Even with 10 degrees of depression it would have been a deathtrap anyway!

Back to the start, that’s a generalisation, and hardly a meaningful assessment of the turrent (not true) or the Defiant (more to be considered). Much of the failure of the Defiant was down to the fall of France and 141 Squadron’s CO’s tragic rejection of 264 Squadron’s development of tactics, as has been outlined here by others.

As a night fighter, the Defiant was by far the best Britain had in late 1940 – thankfully. Deathtrap? I’d not wish to go to war in one, but it was far from the only scary hole in wartime.

Anyway, I have other time-of-the-year things to do, so I’m done for the moment. 😉 Season’s greetings,

Regards,

I did not actually say ‘laying on the turret base’ James and I did cover the higher seating requirement for the gunner anyway,it was an extremely tight (i believe called ‘clean’) turret installation and I absolutely agree it is a moot point,there would have been no possible reason to spend money on a redesign !
Even with 10 degrees of depression it would have been a deathtrap anyway!

rgds baz

Baz, on your own account, you’re not familiar with the turret – the guns are not ‘laying on the turret base’ at all! The main issue with adding depression to the guns was the limited sighting of the gunner; something that could be managed, IMHO. The axis of the guns mounting allowed depression before hitting the turret ring, the apparent ‘barrier’ you’ve got is the lower, metal part of the cupola, the mounting ring is lower again.

All that was predicated on the Defiant (and Roc) not needing depression in the turret’s arming, not that the design as it stood couldn’t achieve that – again, ref Wulfie’s post, and the AP on the Defiant turret, British Aircraft Armament Vol.1 R Wallace Clark and the Brew and Ansell books on it mentioned earlier, and not broad remarks on aircraft design in general. (And on design, BTW, as I mentioned earlier, the Hawker and Supermarine designers could’ve learned from J D North’s structure of the Defiant’s airframe. The Defiant’s failure was a good out to avoid other lessons the Defiant may have offered.)

I agree it’s a moot point, regarding the Defiant’s failure in combat it wasn’t designed for, but generalisations about technology based on non-specific data will rebound; as your experience, I’m sure, will have found on occasion! 😉 I suggest a review of the actual turret’s structure as in any of the above refs would prove interesting.

Thanks for the link to my pics posted earlier – hope they’re of interest to another generation on the forum.

Regards,

Surely elavation can be partly cured by the Defiant pilot banking and even doing a cuvred pass of the bomber as the gunner maintains the bomber in his sight?
.

Not at extreme low level James,the pilot would only be able to fly cross controlled for a limited period before the wing tip would dig in,and they would be sitting ducks for the enemy gunners anyway (high or low level)

rgds baz

I have not missed your point James,but as an aircraft engineer of 40 years experience,I am doubting the ability to add even 10 degrees of depression to the turret without redesigning it.
Why did the type A turret not depress below horizontal ?
The answer in my opinion is that it was limited by the design constraints/compromises inherent in all aircraft designs.
There is an image on the internet which shows the guns layed horizontally and to the rear of the a/c…the gun barrels are almost resting on the turret base !!
The answer would of course have been to mount the guns higher and thereby allowing depression,but of course then you would also have to sit the gunner higher to allow for sighting/aiming…result – a very draggy turret and an a/c so slow it wouldnt catch the blasted huns 😉
In my opinion the RAF made the absolutely correct decision with the defiant – it was an extremely flawed concept and we were correct in binning it as a day ‘fighter’

BTW some nice pics here from your excellent 1988 ‘walkround’ of the Hendon Defiant (apologies if you have already linked to it)

http://forum.keypublishing.co.uk/showthread.php?t=31021

rgds baz

Think you’ve missed my point Baz. We like to think that what happened was inevitable; but there are often other options* that we can see might (or would) have been successful, but were not available.

I have to stand by my opinion …

I’ll take Wulfie’s 10 degree depression option on the turret over anyone’s ‘opinion’. 😉 And 10 degrees depression in a Type A would’ve been the *best option to dispatch a low flying aircraft. Certainly the lack of that was the problem in Clarke’s case, not the turret itself.

Regards,

Surely elavation can be partly cured by the Defiant pilot banking and even doing a cuvred pass of the bomber as the gunner maintains the bomber in his sight?

Getting back to the Fleet Air Arm what if, as a carrier based turret fighter in its first and well known form, I would think that it could have been quite a handy fleet defender against the slower and larger threat that the Navy was up against, ie long range land planes (FW Condor) and the various flying boats that the Luftwaffe were using?
I agree that the hook on weight (compares well with existing Fulmar) wouldn’t have been an issue, and with slats and possibly a different flap arrangement (if required?) approach speed could be reduced.
Improved variants could have kept it handy through to the early Firefly period.
I can’t see that a Griffon powered variant could have been a contender for the same role as the Sea Fury though, the latter was a different generation airframe, with all the improvements embodied in it.

It also protects the always vulnerable belly from upward firing from either the fixed or angled or movable guns of an attacker.

Which is exactly why I said the ‘inevitable’ descent to extreme low altitude ;).

I have to stand by my opinion that the defiant turret could not have been successfully modified for any meaningful depression,I think that the turrets were so ‘cosy’ that any increase in depression would have needed an increase in turret height,which would have slowed the a/c even more and possibly led to longitudinal stability problems.

rgds baz

Yes Wulfie…exactly the point – I doubt they could have modified the Defiant turret for depression without fairly severe drag/handling penalties anyway.

Not true, As Wulfie’s said, possible, just a sacrifice to elevation:

The Defiant turret (BP Type A) could be modified to have 10 degrees of depression, but only by losing 10 degrees of elevation. This is why the Halifax nose turret (Type C) was modified as a dorsal turret for the Hudson and the Halifax, because that had 38 degrees of depression on the guns, and therefore provided a measure of under-side defence. This required a high cupola to give the gunner headroom, to sight the guns when they were pointed down, which caused high drag.

Hmmm. I’ve been lucky enough to sit in the Defiant turret when in the Defiant, and there was an adequate view to the beam and if enough depression to the guns dialled in as suggested above, that would cover beam firing. I’ve also been lucky enough to fly in the only airworthy Hudson and it is equipped with the Type C; I’ve also been following the restoration of the AWM’s Type C for their Hudson, being restored fully accurately. I’ll defer to those with greater technical knowledge, but the Type C as an upper turret has a magnificent view, but is oversized, over-complex (structurally) and as for a 38 degrees of depression to the beam, that seems wrong somewhere – clearly it was not adequate given that beam guns were often fitted to Hudsons. The view in the Type A is very cluttered and it’s a much tighter turret, but the C seems a hard way of getting a marginal, arguable improvement over the A. In combat on a bomber I’d expect the turret was mainly used above level and aft firing for the most part. However numerous Hudson gunners gave a good account of themselves, so maybe the turret deserves some credit for being an adequate tool. Frankly how anyone ever hit anything enough to knock it down amazes me.

The Blackburn Roc had the same turret I believe..

Same turret type, yes.

Sqn Ldr D H Clarke DFC AFC Whilst flying a Roc from Gosport on sept 26th 1940 could not knock down a He59 floatplane because the enemy pilot flew at extreme low level and with the turret guns not being able to depress below horizontal…Clarke found it very difficult to keep the He59 in a favourable position for the gunner to hit it…that is without putting either his prop or wingtip into the sea 😉
Not unusual for an evading bomber to go low level 😉

Interesting how easy it is to draw the wrong, or partial, conclusions from data. Why, one should wonder, do ‘evading bombers go to low level’? Because it gives the defending gunners a better chance of hitting the attacking fighters that struggle to manage an effective firing pass even with forward firing guns… It also protects the always vulnerable belly from upward firing from either the fixed or angled or movable guns of an attacker.

A full account of Clarke’s combat and the other written out of history accounts of Skua and Roc successes in our book by Matt Willis as well as Alec Brew’s excellent work.

http://mmpbooks.biz/mmp/books.php?book_id=103

As to the issues of the ventral vulnerabilities of the British bomber, the vulnerability and neglect of the risk is agreed. But we should note most of the turret designs offered were awful or useless; whose fault (designer or specification) I don’t know. Best wartime ventral turret; and IMHO the only real contender for a good job in the hemisphere would be the Sperry ball turret, until the advent of remote-controlled armament. But that’s another tale…

Lots of good points by others again, thanks!

Regards,

The original links to Sqn Ldr Clarke’s RAF Flying Review articles that I previously posted are dead so her is an extract from a book about the Defiant and the Roc called ‘The Turret Fighters’ by Alec Brew, published by Crowood.

“A well known engagement involved a 2 AACU (Anti-Aircraft Co-operation Unit) ROC, L3085, and Plt Off D. H. Clarke, who had painted a red ‘Saint’ (the Leslie Charteris character) in a red-framed yellow diamond on each side of the rear fuselage of his ‘own’ Roc. On 26 September 1940 he was sent out to search for survivors in the water 15 miles (24 km) south-west of St Catherines Point. With Sergeant Hunt in the gun turret – which, unusually for 2 AACU Rocs, was fully armed – he took off in the late afternoon. As he instituted a square search in the area indicated, he noticed what he thought was a Swordfish also searching about 3 miles (5 km) away.

After about 45 minutes of fruitless search in the gathering gloom, he suddenly noticed that the Swordfish, now only half a mile away, was in fact a twin engined floatplane. Out of curiosity, wondering what it was, he flew towards it: and then suddenly realised it was a Heinkel He 59, a German aircraft probably on the same air-sea rescue task as himself. Unsure as to whether he should open fire on an aircraft on such a humanitarian mission, he flew across its nose with Hunt training his turret at it.

As he did so the German nose gunner opened fire with his 7.9mm machine gun, and Hunt returned fire, his tracer pouring into the Heinkel’s fuselage. After the pandemonium and shock of his first action, Clarke swung on to a parallel course, and re-established communication with Hunt , whose intercom lead had been pulled out. The Heinkel turned for France, skimming the waves. Happily the twin engined bi-plane was even slower than the Roc, with a top speed at sea level of only 137 mph (220 kph), and Clarke was able to gain on his adversary; although he was still faced with the prospect of having to drop a wing to enable Hunt to open fire, even though his propeller was skimming the wave tops.

At 300 yards range he dropped a wing, and Hunt opened fire with another broadside. The Heinkel replied from all three gun positions, nose, dorsal and ventral, a single machine gun in each, but Clarke had to lift the wing after only a few seconds to avoid side-slipping into the sea, causing the last few rounds of Hunt’s burst to shoot harmlessly up into the air. The two aircraft continued these brief exchanges of fire for about 25 minutes, until the coast of France was looming up. Both aircraft were hit, and one of the Heinkel’s gunners stopped firing; but just as Clarke was about to turn away, the Roc was hit in the engine.

It faltered, and Clarke switched to the reserve 17 gal (77 ltr) tank, pulling up and away. Just as he thought he might have to ditch, the Perseus picked up, and he nursed the damaged aircraft back to Gosport. But before he could taxi in the engine stopped, out of fuel. Clarke claimed the Heinkel as ‘Damaged’.

On his return his groundcrew found two incendiary bullets in the main fuel tank, above which he sat. They had entered low down in the petrol, which had extinguished them; slightly higher, in the explosive fuel/air mixture above, and the Roc would have been ‘missing in action’. This action was almost certainly the nearest the Blackburn Roc ever came to destroying a German aircraft in combat”.

I found the earlier defiant thread,but as stated above my old links to Clarkes articles are dead…
http://www.google.co.uk/url?sa=t&rct=j&q=blackburn%20roc%20l3085%20he59&source=web&cd=1&ved=0CB0QFjAA&url=http%3A%2F%2Fforum.keypublishing.co.uk%2Farchive%2Findex.php%3Ft-102722.html&ei=YaD1TunqJZPd8QPjzMWbAQ&usg=AFQjCNEHNk9Osvi46PhLagvKGnQV_yuF6g

Yes Wulfie…exactly the point – I doubt they could have modified the Defiant turret for depression without fairly severe drag/handling penalties anyway.
Also the point I was trying to make is that while a turret was ok for Defence – it was not much use for offence – no daylight enemy bomber pilot was ever going to fly straight and level at a safe altitude whilst the defiant gunner blazed away at them – in the ensuing manoevers and inevitable descent to extreme low level then the defiant was actually probably at a slight disadvantage against 2 or 3 enemy gunners !
As JDK has said about many aircraft…the fault lay not with the a/c but more with the specification,I like the defiant,it was a well designed and built a/c and could well have been the basis of a useful naval a/c.

rgds baz