Boulton Paul Defiant

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pinehilljoe

Senior Airman
670
471
May 1, 2016
Why was the Defiant put in production and why did last as long as it did? When it rolled out it was slower than the Hurricane and Spitfire. CinC Fighter Command did not like it. Any thoughts?
 
This question has been covered a number of times in this forum, but here's a brief response; first you have to examine why it was designed and built in the first place, then take a look at the changed circumstances behind its actual use. What it wasn't designed to do was mix it with single seat fighters, so that then leads you to what it was designed to do.

It was a bomber destroyer and in 1935/36 when the idea was produced, no one thought that Germany would invade France and be able to use single seat fighters to escort bombers into British airspace. Also, the gun turret at that time was a new innovation and only the British had workable ones they could put on aircraft, and they put them on everything. It was seen as the most effective means of bringing gun fire to bear on a moving target. Defiants were to dive down upon unescorted bomber formations, splitting them up and stragglers were to be taken out by single seat fighters; that was the idea.

The reality was that when the war started the low speed and acceleration of the type was well known, but FC needed useable aircraft, so the two squadrons (yep, only two) of Defiants over France and the BoB had to be counted among available fighters, even though they were used in scenarios they were unsuited for, like offensive sweeps over the continent. They would have been better used in the north of England and Scotland in their intended role as interceptors, where the threat of single seat fighters was lessened because of the distance the bombers had to fly to reach these areas.

When Defiants intercepted unescorted bombers, they proved their worth, but the appearance of large numbers of single seat fighters meant that they were always out numbered and so, by comparison to the numbers deployed, only around three, six or nine at any one time, losses were high. Bear in mind that three aircraft shot down out of six is not a lot of aircraft lost, but comparatively, it's fifty percent of forces deployed!

The thing about the Defiant that almost all critics of the type overlooks is that it was a very good night fighter, within the limitations of the technology of the day. Between the end of August 1940 and late 1942, when they were retired, Defiants shot down more enemy night bombers than any other type and they equipped some thirteen (a source I have quotes 15/16) night fighter units. Its unique characteristics (two sets of eyes fore and aft, a 360 deg traversable gun turret, good endurance, faster than the Blenheim) meant that it was ideal for the role, and along with the Blenheim pioneered the service use of air interception radar, although it only made one successful intercept using it.

As a night fighter, Defiant pilots and gunners suffered high losses in training, although this was the same among Blenheim and Beaufighter squadrons as pilots flew into unseen obstacles at night, getting used to the different circumstances of night flying.

So, to sum up, of a front line fighter career of some three years, seven/eight months was served as an indifferent day fighter, whereas two years was served as a successful night fighter. Also, besides the fact that the concept had its flaws from the start, the Defiant was a very well engineered and well designed aeroplane and the perception that is held about it today was not shared universally at the time.

This is just a brief overview and I'm sure others here will go into greater detail, as opinion is (naturally) split about it here.
 
I think that the initial response has answered the question admirably.
I have little to add, except to clarify that the use of turret armament on British fighters dates back to Ludlow-Hewitt (after he was appointed Deputy Chief of the Air Staff (DCAS)) in 1933/34. There was a real concern at the demonstrable lack of fire power of British fighters in WW1, and concerns that they would not be able to bring sufficient weight of fire to bear on enemy bombers, in order to shoot them down.
Ludlow-Hewitt envisaged to methods of attack, sporadic 'close in' attack and sustained 'lie off' attack. To carry thes out he postulated four different fighter types and the Defiant most closely resembles what he designated a 'Type W', that is 'the two seater with improved stern armament'. At this time the Air Member for Supply and Research was a certain Hugh Dowding, and he broadly accepted Ludlow-Hewitt's findings.
It was Dowding, now the Deputy Director of Operations and Intelligence (DDOI) who suggested a single engine two seat turret fighter in October 1934. In June 1935 Courtney (now the DCAS) asked Ellington (ex-AOC-in-C Air Defence Great Britain, now Chief of the Air Staff) to cancel the various twin turret and 'no allowance' fighters in favour of the single engine turret fighter.
I'm sorry about all the strange positions that existed in the Air Staf/Air Ministry, but it is pertinent that a relatively small group of senior officers were making many of the decisions, the results of which would be rigorously tested a few years later.
The Operational Requirements Committee discussed a draft 'Air Staff Requirement for a Single Engine Two-seater Day and Night Fighter' on 3rd April 1935. The results of the meeting, and the eventual production of the Defiant, reflect the desire to have a multi seat fighter, whilst no viable tactics for its use had been agreed.
The Air Staff Requirement called for a fighter which
"can bring fire to bear from a moveable battery of at least four machine guns over the upper hemisphere...; thus conferring on it the ability to attack from below and behind, below an in front, or on the flank of an enemy formation, at the same time enabling the batteries of all fighters to be trained on the target simultaneously while in formation."
The lack of forward armament was due to the belief that it was
"Undesirable to split the armament"
even though earlier turret aircraft, like those of the 'Novel Fighter Competition', did have fixed forward armament, indeed two were rejected because their turrets could not be fixed forward to reinforce this!
Cheers
Steve
 
Timing was also aginst the Defiant. In 1938 it was a pretty awesome aircraft not many were faster or had a heavier armament. 109s in 1938 were going to be the B/C/D models with a top speed iirc of 290mph and either 2, 3 or 4 light machine guns. By the time it had got into service in 1940 it flew too slow and climb was very poor also armament had raced ahead.

It just goes to show building a specialist aircraft can catch you out if the enemy hasnt read the script.
 
It just goes to show building a specialist aircraft can catch you out if the enemy hasnt read the script.

The RAF wasn't planning to meet escorted bombers at all, and certainly not escorted by single engine fighters. It is hard to overestimate today the shock of the fall of France then.

The very suggestion in the Operational Requirements Committee of attacks from 'below and in front' shows that the presumed targets were unescorted bombers with minimal forward firing armament. Only a mad man would attempt to attack a fighter with forward firing armament in this manner, by putting himself in just about the most disadvantageous tactical position imaginable :)

Cheers

Steve
 
It was a 'no allowance' fighter with the guns locked forwards and inclined. The turret had special provision for this and the pilot had a firing button. Sadly the sight and training for this vanished as staff changed and the wartime crews knew nothing of how this would work.

In the night fighting role ground RDF would ideally place the Defiant within a couple of miles of the target and the RDF set let the pilot close in until one of the two of them had visual contact and then the Defiant would be placed in a relatively blind spot and roughly matching speed to the target. Giving the gunner a stable position to give it sustained fire even as the target began to react. The pilot RDF was less than ideal (though clearly workable) but by the end of 1941 the Defiant was being replaced by night fighters with a faster closing speed in a stern chase, greater endurance, room for a better RDF for a dedicated operator and cannon firepower to deal with bomber's armour. Even then it went on to meet the great need for a high speed target tug for AA and fighter and gunner training. Even briefly serving with the USAAF in that role.

Had it been given the proper pilot's sight, a worked out tactical system and appropriate crew training it would have done far better in the fighter on fighter role. For which it was never designed. The only mystery left in the Defiant story for me is why it was not deployed in the North in it's intended role to deal with unescorted bombers instead of the escort rich skies of the South. Often missed is it's successes over France and (OT) the sterling dive bomber work of it's inferior Blackburn counterpart the Roc in the defence of Dunkirk. Without the dive bombing of the FAA Albacores and Rocs the ground defences of Dunkirk could have given way earlier.
 
It's a good job the RAF overcame its infatuation with no allowance shooting in time, so that no such fighters were 'on the books' at the start of the war.
In parallel with the quest for firepower, in which the Defiant had it origins, was a quest for speed, in which the Spitfire and Hurricane had their origins. In the quest for firepower manoeuverability was not considered important (the 'Type W' being a case in point) as this was not required for the anticipated tactics to be used by turret and no allowance fighters. They were to formate on enemy formations and bring their firepower to bear. This is just about the only way no allowance shooting can work, the optimal no allowance position being astern and below the target.
With hindsight we now know that this was not the way air warfare developed and it was in fact the fast, manoeuverable, fixed guns fighters that would dominate on all sides. These had been envisaged earlier, but to employ, in Ludlow-Hewitt's description of a 'Type Z' fighter, 'fire shock action'.
Cheers
Steve
 
It is striking how the Brits were ever so enamored of the naval style action, in the formative decades of aviation.

Not just the British, though they certainly did. We tend to forget that the Wright brothers' first flight had occurred in the life times of the decision makers of the mid 1930s, just thirty years earlier, some were already serving in one of the Services at the time the Flyer staggered into the air. They were far closer to that milestone than we are to them, or than we are to another milestone, the moon landing.
It is evident in the terms of the period. Everybody referred to bomber fleets, the Germans called some higher formations 'Luftflotten' which is self explanatory, and came up with a class of aircraft called 'zerstorer'.
Cheers
Steve
 
You have to remember a lot of the RAF senior officers had been in the Royal Naval Air Service before the RAF was formed from the Army and Navy air services in april 1918.

Also the Royal Navy was the Senior Service it had been around in one form or other since King Alfred the Great in 890. The RN had a massive presence in British life it was for a long time the biggest employer in the world outside of the Chinese Civil Service and from about the early 1700s till 1945 the biggest Navy in the world.
 
It wasn't just aircraft. Some of the writings about tanks mention fleets of tanks and formations. It took a while for the firing on the move nonsense to die down and and firing from cover/concealment and quick moves from one firing position to another to take-over.
Firing on the move required either really low speeds or technology that didn't exist at the time.
 
Several times between,say, the early 1700s and the end of the Napoleonic wars a century or so later, Britain's defence spending peaked at over 20% of GDP. A very large percentage of this would have been spent on the Royal Navy.

For perspective, nowadays, few NATO members actually spend the target of 2% of GDP on defence. Last year just Greece, Estonia, Poland and of course the USA and UK surpassed that figure. The average for European NATO members was just 1.43%, still better than Canada's 1.00%, talk about relying on big brother (USA 3.62%) :)

Cheers

Steve
 
...
It is evident in the terms of the period. Everybody referred to bomber fleets, the Germans called some higher formations 'Luftflotten' which is self explanatory, and came up with a class of aircraft called 'zerstorer'.
Cheers
Steve

Plenty of aircraft were referred as 'ships' in the USAAF manuals...
 
Everyone borrows words when something is new "pilot" and "squadron" were naval terms before aviation started.
 
This question has been covered a number of times in this forum, but here's a brief response; first you have to examine why it was designed and built in the first place, then take a look at the changed circumstances behind its actual use. What it wasn't designed to do was mix it with single seat fighters, so that then leads you to what it was designed to do.

It was a bomber destroyer and in 1935/36 when the idea was produced, no one thought that Germany would invade France and be able to use single seat fighters to escort bombers into British airspace. Also, the gun turret at that time was a new innovation and only the British had workable ones they could put on aircraft, and they put them on everything. It was seen as the most effective means of bringing gun fire to bear on a moving target. Defiants were to dive down upon unescorted bomber formations, splitting them up and stragglers were to be taken out by single seat fighters; that was the idea.

The reality was that when the war started the low speed and acceleration of the type was well known, but FC needed useable aircraft, so the two squadrons (yep, only two) of Defiants over France and the BoB had to be counted among available fighters, even though they were used in scenarios they were unsuited for, like offensive sweeps over the continent. They would have been better used in the north of England and Scotland in their intended role as interceptors, where the threat of single seat fighters was lessened because of the distance the bombers had to fly to reach these areas.

When Defiants intercepted unescorted bombers, they proved their worth, but the appearance of large numbers of single seat fighters meant that they were always out numbered and so, by comparison to the numbers deployed, only around three, six or nine at any one time, losses were high. Bear in mind that three aircraft shot down out of six is not a lot of aircraft lost, but comparatively, it's fifty percent of forces deployed!

The thing about the Defiant that almost all critics of the type overlooks is that it was a very good night fighter, within the limitations of the technology of the day. Between the end of August 1940 and late 1942, when they were retired, Defiants shot down more enemy night bombers than any other type and they equipped some thirteen (a source I have quotes 15/16) night fighter units. Its unique characteristics (two sets of eyes fore and aft, a 360 deg traversable gun turret, good endurance, faster than the Blenheim) meant that it was ideal for the role, and along with the Blenheim pioneered the service use of air interception radar, although it only made one successful intercept using it.

As a night fighter, Defiant pilots and gunners suffered high losses in training, although this was the same among Blenheim and Beaufighter squadrons as pilots flew into unseen obstacles at night, getting used to the different circumstances of night flying.

So, to sum up, of a front line fighter career of some three years, seven/eight months was served as an indifferent day fighter, whereas two years was served as a successful night fighter. Also, besides the fact that the concept had its flaws from the start, the Defiant was a very well engineered and well designed aeroplane and the perception that is held about it today was not shared universally at the time.

This is just a brief overview and I'm sure others here will go into greater detail, as opinion is (naturally) split about it here.


The main problem here is, that it was used in situations when mixed with enemy single and twin engine fighters and by crews it was claimed that with huge succes :D Of course, it was disaster all the way with low number of real kills and high number of destroyed and damaged Defiants by enemy fire.
 

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