Boulton Paul Defiant Rationale

[MIflyer]

I started reading Dr, Alfred Price's latest book on the Battle of Britain. He explains the idea behind the Defiant.

It was assumed that enemy bombers would not have fighter escort, presumably because they would have to fly too far to reach the British Isles. The idea behind the Defiant is that it would position itself in front of and slightly below and perhaps to one side of the bomber formation where it would be virtually immune from defensive fire from the bombers. Bombers generally did not have much in the way of firepower for that direction.

From such a position the turret fighters could hose down the bombers with fire while not taking much in the way of hits themselves. More than being a Bomber Destroyer, the Defiant was designed to be a Bomber Formation Destroyer. Coming under withering and relentless fire from the turret fighters, the formation would break up, making the individual bombers easy meat for the RAF single seat fighters.

While not mentioned in any history I have seen, I have seen two references from that time period that claim the Defiant also had very heavy forward firepower. One said it was armed with 14 machine guns and three 20MM cannon. This obviously was disinformation designed to make the Defiant appear to be to formidable to engage head on.

 

[pbehn]

The whole premise was that enemy aircraft would fly straight and level and allow themselves to be "hosed" by machine gun fire.

 

[Greyman]

The whole premise was that enemy aircraft would fly straight and level and allow themselves to be "hosed" by machine gun fire.

Which was a sound premise I think. Big Heinkel formations (the target the Defiant was designed for) weren't dodging about very much.

Essentially:

• the effectiveness of bomber defensive firepower was over-estimated by all
• it was assumed there would be no Bf-109s operating out of Calais

 

[Shortround6]

There was a strange disconnect going on at the time as British "light" bombers (Wellesley, Battle, Blenheim and even the Hampden) were expected to defend the front arc of the aircraft with a single fixed gun which certainly requires some flexibility of formation flying to bring the gun to bear with any hope of success.
Perhaps they "assumed" that other countries could not build bombers that could match the maneuverability of British bombers?

 

[fubar57]

This is from another site...
"The original concept was for the pilot also to be able to use the turret guns, pointed forwards above propellor arc, with a no deflection gunsight whereby the pilot dialled in the expected range of fire and the sight predicted the bullet drop at that range so all he had to do was plant the sight onto the target. That is why he had a button to fire the turret guns. The concept was lost in changes of personnel etc. between design and operations so the crews were unaware of the concept and did not have these sights. So it did have forward firing guns had they but known it. Albeit x4 .303" not x8."
.....was this ever tried in training or combat? I mean someone must have thought about trying it at least once

 

[nuuumannn]

The Daffy's armament was four .303 inch Browning machine guns in its turret and this didn't change in three years of service. Daffy pilots never had gunsights, although I have read that there was that intention. The turret had a switch that gave the pilot command of firing the guns, but the problem was that facing forward, the guns were elevated 19 deg to the horizontal. To my knowledge those that practiced tactics using the Daffy, i.e. initially 264 Sqn's C/O Sqn Ldr Hunter (appropriately named), an advocate for the type concentrated on employing its strengths of a moving turret. These were formation attacks in numbers against bomber formations. Using them for fighter sweeps over Dunkirk etc was asking for trouble, but necessary as Fighter Command's fighter numbers fell short of expectations, so Daffys, Gladiators and Blenheims were expected to pull their weight, regardless of their shortcomings. I have maintained that in hindsight, FC should have placed the Daffy squadrons up north where no fighter escort would be encountered and moved those single-seat squadrons to more dangerous ground would have made sense.

Using formation tactics, the Lufbery Circle of flying nose to tail in a large circular formation when things got out of hand for them was the best form of defence against fighters, but bearing in mind, the design was conceived without foreknowledge the Germans would invade France again. Britain was the only power in the world to have fitted power operated turrets to aircraft in service by 1939 and they were viewed as a necessary advance in precision gunnery. This was proven, of course in bomber defence, if not in use on fighters.

The problem with employing the Daffy in the Battle of Britain and France was manifold, not least because 1. it was too slow, 2. there weren't very many of them at any given combat situation where their strengths could be put to use - there were only two squadrons equipped with the type during the Battle of Britain and only one of those was regularly deployed in combat, 3. combat tactics were taught at squadron level, so whilst 264 Sqn felt it was ready for action, 141 Sqn's CO despised the type and did not put in place the same tactics that Hunter had shared with his squadron, even after Hunter had given him advice. This was before 141 Sqn's terrible day, where six were shot down in less than a minute by some 30 Bf 109s. This action gave the type its bad reputation, which wasn't entirely justified given the circumstances (how well did nine green - 141 Sqn's pilots were inexperienced in combat - Spitfire or Hurricane pilots fare against 30 Bf 109s?) and it meant that there was effectively only 264 Sqn using the type until the end of August 1940, when it was stood down as a day fighter.

Where the Daffy shone was as a night fighter, for its strengths and design conception served the role adequately. It is often overlooked that the Defiant remained front line equipment until mid/late 1942, when 264 relinquished its final Defiants for night fighter Mosquitoes. By then it was obsolete as a fighter. We do tend to examine its flaws more critically through its use as a day fighter, but that was around a third of its time in service and only two squadrons operated it. Two thirds of its service time saw the number of squadrons rise to 16 (13 in some sources) and it become the most successful British night fighter between the end of 1940 and mid 1942, during the Blitz essentially, when Defiants accounted for more enemy bombers destroyed over Britain than any other type. Of course, this came about through the shortcomings of the Beaughter night fighter, particularly the use of AI radar, which took time to get into its stride. Daffy gunners learned tactics that placed them underneath the bombers, where their guns could be angled upwards to fire into their bellies. 'Schrage Musik' before the Germans employed it. This meant, as it was over Germany against Bomber Command, that when this was employed the bomber's crew did not realise they were under attack until it was too late.

 

[The Basket]

The main fear of RAF was invasion so putting all resources within range of bombers or invasion forces meant risk so putting Spitfires in Scotland makes sense in that their airfields are safer and the Ju-88 was fast enough to avoid interception by Defiants plus their was strategic targets in the North that needed air defence.
If all Spitfires were in Kent then a few good bombing raids or Fallschirmjäger landings could end that quick.

 

[MIflyer]

Note that while the Defiant (maybe we should call it The Duck?) seems absurd referenced to both the US concepts of the time and actual RAF experience it was not greatly different from the Bell Airacuda's basic idea. In addition the US was virtually the only major power who did not think that 2 seat fighters were a good idea. The Grumman FF-1 was about the only 2 seater procured and put into US service, and even with it they almost immediately realized that paring it down to a single seater made a lot more sense.

I always wondered why they did not slap forward firing guns on the Defiant; it could hardly have been that difficult, and even the British of that time could move awful fast with the prospect of being hanged on the morrow.. But given the airplane's concept the US was more likely to install a battery of fixed firing forward guns in B-17's and B-24's than the RAF was to put some in Defiants. Tradition and training often equate to inertia and have a huge impact.

Besides that, what was the BF-110's rear gunner really supposed to do? Capt Brown recalled flying a Hawker Hart in training over GB and having a BF-110 pull up alongside and blow away his wingman. But in fighter type air to air combat the rear gunner probably was only useful for checking six.

When SBD's were sent out to intercept IJN torpedo bombers at Coral Sea, only one pilot flew his dive bomber like a fighter; and his rear gunner seems to have not fired a shot . The rest of the SBD's just formed up and tried to cover each other's tails, no doubt like they had been trained. If you are not flying the airplane doing acro your main job is not throwing up.

It seems that the Defiant was a "success" at night fighting only because there was nothing else around.

 

[Shortround6]

Note that while the Defiant (maybe we should call it The Duck?) seems absurd referenced to both the US concepts of the time and actual RAF experience it was not greatly different from the Bell Airacuda's basic idea. In addition the US was virtually the only major power who did not think that 2 seat fighters were a good idea. The Grumman FF-1 was about the only 2 seater procured and put into US service, and even with it they almost immediately realized that paring it down to a single seater made a lot more sense.

See the P-30, also first service use of a turbo charger.

Besides that, what was the BF-110's rear gunner really supposed to do? Capt Brown recalled flying a Hawker Hart in training over GB and having a BF-110 pull up alongside and blow away his wingman. But in fighter type air to air combat the rear gunner probably was only useful for checking six.

He was actually the radio operator, since he was already there they gave him a gun to play with
Bf-110 used the same radio as a He 111. much longer ranged than the radio in a 109 as befitted it's long range role.

It seems that the Defiant was a "success" at night fighting only because there was nothing else around.

Pretty much sums it up.
Much is made of the Blenheims deficiencies but then they never tried to do more than minimal conversion or series of conversions.
Take day bomber and slap a gun pack underneath it that was designed and built by a railroad shop, It functioned just fine but was only slightly more aerodynamic than a brick (or railroad box car) and you have a long range day fighter. Need a night fighter? take the converted bomber, stick drag producing aerials on it, cover it with high drag flat black paint and then complain about the speed.
The Photo recon people under Cotton had modified a Blenheim to hit 290mph. Some of the modifications were not applicable to production aircraft (sealing all gaps and multiple coats of paint sanded between coats takes too many man hours) but others were, sheet metal fairings around the nose (they converted one of the flat nosed MK Is), getting rid if the turret ( they plated it over, smaller observation dome for fighter?) They clipped the wings slightly ( gun pack didn't what the bombs did) and perhaps most important, they fitted the plane with those super special science fiction devices (sarcasm) called constant speed propellers and ran the engines on 100 octane fuel.
Given the 30mph difference (or more?) between the standard Night fighter and Cotton's "prototype" it would seem there was room for 10-15 mph worth of improvement without too much trouble.

Of course since the Air Ministry had rejected the constant speed propeller as just so much gimmickry and had to be dragged, kicking and screaming, into fitting even two position props on bombers to get them out of tiny airfields there wasn't enough production capacity to go around to fit constant speed props to all the planes that would have benefited from them.

Fitting some sort of armor and/or BP glass for the pilot might have done wonders for the survival rate of Blenheim night fighters as the crew in the cockpit was totally unprotected from fire coming in the front of the aircraft.

I would note that the Defiant II only became operational in Sept of 1941 and at that point it's utility should have been called into question. Nothing better was available in part due to several squadrons worth of Douglas Hovacs flying around with radar but no guns, just a giant searchlight in the nose to try illuminate German aircraft for non radar equipet Hurricanes.

 

[nuuumannn]

I always wondered why they did not slap forward firing guns on the Defiant

The obvious reason; nowhere for fuel. Look at the concept; it was a bomber destroyer whose rationale was based on the gun turret being a superior weapon to aiming hand held guns against bombers. It was a tactical aberation in hindsight, but bless the Air Ministry, they didn't have that hindsight which you and we all demonstrate on a regular basis here. No one at the time could have predicted that it wasn't the best idea. No other country had power operated turrets fitted to service aircraft and they provided superior aiming and in a four gun installation gave good hitting power. Remember that in 1939/1940, frontline fighters round the world nominally had four guns, with the exception of the Spitfire and Hurricane, with 8 each. Even the much vaunted Bf 109E only had four guns, granted that two of those were cannon.

In the late 1930s the monoplane fighter was a new idea that was slowly being introduced into service and the biggest threat to Britain from the air was thought to be long range bombers. A turret armed fighter made sense from the point of view of sophistication and accuracy. Hand aimed guns - remember the turret fighter concept was already trialled in the Hawker Demon biplane, were just not as accurate and insufficient as a means of bringing down a bomber. Bearing the turret rationale in mind, the Defiant concept bears little resemblance to that of the Airacuda, since it didn't have a turret. That's the key to the Defiant, rightly or wrongly as a concept.

Yes, the Daffy proved its worth at night because there wasn't anything else available in numbers, but why be so dismissive of this? It was there and it did it well. The USAAC didn't have a dedicated night fighter in service actually combatting enemy aircraft at night in a hostile environment in 1940-1942 - apart from the British, no one did. I'm pretty certain the experience those night fighter pilots Britain fielded in their less than adequate aircraft built up the most formidable and most experienced night fighter team in the world by the end of 1941 early 1942. No other country had such a force with as much experience in the art, not even Germany, which really didn't begin its night fighter force until the same year. Britain's air defence system was the most sophisticated network in the world.

Night fighting was very different and the Defiant proved that it wasn't as simple as putting flame suppressors on a day fighter. The Spitfire was not a great night fighter because of its cockpit ergonomics.

 

[Shortround6]

I can easily agree with some of the above and also easily disagree with some.

The "Daffy" was designed to a 1935 requirement and first flew in Aug 1937, at which point there were only a few (?) 109s that even had DB 601 engines let alone had cannon and those had only appeared in public a few weeks before at the Zurich air meet. Despite how adequate the "Daffy" may have appeared in 1937/38
development of aircraft did not stand still and as usual for this time period, the British took too long to get prototypes into production and into squadron service.
Production aircraft were built to requirement F.5/37 and only began to be issued to No 264 Squadron in Dec of 1939. At this time the majority of 109s had 601 engines and four guns (although not all "E"s had cannon). The 110 had also not only been revealed to the public but featured in propaganda from the Polish campaign. The rest of the World was using 2-4 gun fighters in 1939. What they were planning (in response to the British 8 gun fighters) was something else (Bloch 152 with two 20mm Hispanos and two mgs)
For the British the Beaufighter prototype had first flown in July of 1939 and 300 were already on order when it flew.

Somehow the idea that pilots could not cope with high speed flight/gunnery and needed a turret in order to fire accurately seems to have been put on the back burner and left to simmer rather than being thrown in the trash. Several large twin engine planes being planned that were virtual flying AA batteries.
Single 40mm cannon in turrets and four 20mm cannon in a turret. So the Defiant (and the Roc) continued. In part because too much "stuff" was already in the pipeline. 513 Defiants being on order when the First ones were issued to the service squadron. This was a big part of the 'problem'. All kinds of parts (like landing gear ) was ordered from outside contractors at the same time the aircraft orders are placed (or very shortly there after) and scores, if not hundreds of sets parts sets are the process of being manufactured before the first few production planes come off the line. Canceling hundreds of Defiants does not turn into hundreds more Hurricanes being available in the same months. You have to scrap all the special components of the Defiants and order new components for the Hurricanes (or whatever plane you choose) which would delay completion by months.

The MK II with the Merlin XX engine and radar didn't go into use until Sept of 1941 at which point the whole turret fighter concept should have been seen to be nonsense. A year after the BOB (and two years after the start of the war) they had plenty of experience with high speed intercepts and dog fights.

 

[The Basket]

A few points.
It was certainly unlikely that a German single seater fighter would fly over the UK so planning for that in the 1930s timeframe is not sound and a bomber formation loaded with bombs is going to be a static target.
You don't have to shoot down an aircraft to show effect. If a bomber formation scatters or drops it's bombs early then that's a win. The Bf 110 rear gunner may scare off a fighter or make a fighter shoot from a greater distance and miss. I remember reading that RAF fighter pilots were advised to shoot at distance to keep out of effective gunner range.
If the Defiant only met bombers then I certainly believe it would have done ok and flying from UK airfields then by the rationale of the day it would have been fine. Remember the RAF was brought into existence to fight Zeppelins and Gothas over home soil so I have no issue with the concept by the rules of the 1930s. It was wrong but it was right at the time.

 

[Shortround6]

A couple of points

1. The concept, as whole, only works as long as your expected enemy FAILS to develop power turrets of their own and/or fails to develop larger than rifle caliber machine guns. Had the Germans, for instance, developed a power turret in this time period then you would have had your hypothetical squadron/formation of Defiants flying a parallel course and similar speed to a squadron/formation of He 111s with power turrets of their own. Kill to loss ratio would not have been good.

2. The Defiant's actual contribution may not have been that great. The number 65 kills has been put out.
Nightfighter claims for the night Blitz are put as 8 for the first two months,worse for the next 3 months, 22 in March 1941, 48 in April, and in the first 2 weeks of May 96 claims, at which point the bulk of the Luftwaffe heads to Russia. I would note this is well before the Defiant II shows up at all. While useful the Defiant was hardly critical to defeating the German night bombers if these numbers are accurate.

 

[The Basket]

But the Germans didn't. The Spanish civil war had German bombers that were fast enough to avoid interception so a power turret wasn't needed and every kilogramme of turret is a kilo less of bombs. So instead of been a bomber you become a turret transportation.

 

[Shortround6]

True, but depending on your enemies not to do what you yourself are doing at some point several year in the future is poor planning. The French were fitting power turrets/mountings on some bombers in 1939/40.
Power turrets were not secret technology. Yes the Germans screwed up by trying to jump to remote control barbecues instead of using manned turrets but planning your air defense strategy/tactics in 1937/38 on the assumption that the Germans WILL NOT develop and fit power turrets in 1940/41 seems to be wishful thinking.

 

[Greyman]

The Germans developing powered turrets was seen as another plus of the Defiant.

With careful tactics, the Defiant gunner's shooting problem was reduced to near zero ("no allowance shooting") while the defending bomber's was doubled. This was contrasted against what the enemy's massed, powered, multi-gun turrets would do to normal Spitfire and Hurricane stern attacks.

It was also thought fully plausible that the Germans would armour their bombers to be resistant to attacks from astern, rendering normal fighters impotent. However, armouring bombers to be resistant to all angles from which the Defiant was capable of attacking was definitely prohibitive.

 

[The Basket]

In 1937 the main of fighter of the Luftwaffe was the He 51 and in 1941 it was the Fw 190! So I wouldn't say planning is truly possibility. If you said in 1939 that France would fall and Bf 109 would fly from French fields in 1940 then you be locked up for crazy.
Since the main fighters were Hurricanes and Spitfire arguing over the Defiant is moot as the British gave up on it well before first shot was fired.

Remote controlled barbecues? Those Germans were very advanced when it came to outdoor cooking!!!!!! They should have stuck to jets!

 

[Shortround6]

Trying to use a Kindle and auto correct is bitch.
Barbettes

 

[The Basket]

Remote controlled barbecues get my vote. That a million dollar idea right there.

When taking about the bits and bobs of war it's easy to suggest in hindsight to be ready by May 1940 for the big push. But war is a case of run wot ur brung so easy to dismiss the Defiant but they were available so get the game on.

When the Blenheim first came out if was a winner. In tests Hurricanes and Spitfires were eating them alive. So war comes and by the by here is you Blenheim. So good luck with that. War came too late for some aircraft.

 

[MIflyer]

Well, as explained , the Defiant was not supposed to fly parallel with the German bomber formations but just in front of and below them, firing upwards. With few exceptions the Luftwaffe bombers had very limited armament firing forward and down, and the crews generally were concentrated in a small area in the nose, behind a considerable expanse of Plexiglas. The Defiants were supposed to knock out the German formations by firing into the crew compartment of the bombers, destroying the formations' cohesion by wiping out the leaders, one after the other. Of course, firing .303 from the Defiants you'd have to be relatively close, but the 305 mph top speed of the Defiants would be fast enough to get in front of the German formations and "park." .

I just read were some DO17's were equipped with 20MM flexible guns firing forward and down but the Germans pretty much did not have much in the way of guns able to fire forward and down. For that matter, neither did the B-17 until the G model. I don't know if the nose turrets of B-24J's and Lancasters could fire low enough to handle that kind of a threat. The gun-nosed Ju88's could have been a nasty shock to the Defiants - just sprinkle some in with the lead bombers, but they were not around until some time later.