Best Allied bomber destroyer.

pattle · Sep 5, 2013

I don't think it was all about gun calibre size, they could of armed a fighter with a gun the size of Mons Meg but if it had not of been able to survive it's own attack then it would have been part of the problem and not part of the solution. The Spitfire XIV had the speed and agility to evade the escort fighters, a big part of the problem that the Germans had was that their fighters were being lost along with their aircrew in unsustainable numbers due their inability to fight or flee from the escorts, had the Germans possessed a fighter that could attack and clear off without being shot down then this would have allowed their pilot strength to grow. I think Dowding and Park had it the right way around with regards avoiding contact with fighters. The Spitfire XIV could have been a poor mans ME262.

Shortround6 · Sep 5, 2013

stona said:
Not really. The addition of gun pods, rockets, mortars and the experimentation with ever larger calibre weapons on Luftwaffe fighters simply reflected a realisation that the standard armament was not sufficient for bomber killing operations.
That standard armament on Luftwaffe single engine fighters was not particularly lighter than most allied types. That's why I am arguing that the allies, had the tables been turned, would have had to up gun one or more of their fighters to make a good bomber killer.
Cheers
Steve

The "standard" armament of the 109 was considerably lighter than most allied types. At least until the Mk 108 was fitted. And with the MK 108 the 109 had a rather limited firing time. The "gun boats" and FW 190 had decent armament ( but not heavier than some allied types had standard) but were a bit lacking in performance at altitudes higher than bombers flew (where escorts could bounce the attackers from).

wuzak · Sep 5, 2013

What about the allied rockets? Usually used for ground attack or anti-shipping, but if salvoed into a bomber box may cause soem damage despite their poor accuracy.

And if you could fire them from front and above, you give yourself more area at which to aim.

Of course, what happens to the ones that miss when you are over home soil may be of concern.

wuzak · Sep 5, 2013

wuzak said:
I like the Vampire for this role. Mount a 40mm cannon under each inner wing or under the fuselage, That si if the 4 20mm is judged to be not enough.

Forget putting them under the wings - stick them in the booms!

fastmongrel · Sep 5, 2013

Proximity fused 3 inch rockets sounds good, launch them in pairs and follow up with 4 x 20mm Hispanos. Even if the rockets dont do any damage they are going to be a good physchological weapon. Not many pilots could see the rockets coming and stay level and straight.

Piper106 · Sep 5, 2013

I recall the Tempest, Spitfire, etc. carried 125 rounds per gun when carrying the 4 x 20mm armament, or 500 rounds total on board. Data indicates a 5% hit rate under combat conditions or about 25 hits if the whole ammo load is fired. If you believe the data that says it takes 20 hits from a 20mm cannon to down a heavy bomber, the 4 x 20mm cannon armament is just adequate, and by no means overkill.

The other concern is that it takes 12 to 20 secs to fire those 500 rounds from 4 x 20mm. That implies a minimal deflection stern attack or multiple attack passes, either way a long time within the defensive fire of the bombers.

By contrast if we look at the American M4 37mm cannon, it fired at 120 to 150 rpm, 2 to 2.5 rounds per second. Five seconds of fire equals 10 to 12 shells. If we can get 5% hits with this gun, 5 seconds of fire is around a 50% chance of a hit. One hit from this size shell is destructive enough to have a chance of being decisive.

Once again I am thinking of a P-63 armed with a reverse Lend Lease Soviet NS-45 cannon (the Soviet NS-37 cannon modified to fire a 45mm shell). More than one pilot reports the P-63 being more manuverable than the P-51, and although not as fast as P-51, the speed difference was small enough to make interception difficult. The bigger 45 mm shell pushes further toward a 'one hit kill' potential. This gun fires 240 rpm, significantly faster than the US M4. Since the Soviets were able to fit this gun into the Yak-9, it should be possible to fit this cannon into a P-63.

That is all I think i know.

nuuumannn · Sep 5, 2013

This is beginning to sound strangely familiar...

you'd use your Spits against the bombers' escorts and something else, with heavy armament, for the bombers. If there were no escorts then the Spits could go for the stragglers.

This is very similar to the pre-war RAF's tactic for the use of the turrent fighter to which F.9/35 was written, which produced the much maligned BP Defiant. In 1937 the Air Staff released F.11/37 which called for a twin engined fighter equipped with four 20 mm Hispano cannon in a turret. Nothing was completed except a small scale flying test bed by Boulton Paul. Even after the Daffy was retired from day fighter duties the concept of a cannon armed turret bomber interceptor did not die completely, although the focus was on the night fighter role. In July 1940 F.18/40, before the Daffy became a night fighter, was released, but research and concepts continued to be released until April 1941. A couple of contenders, including Boulton Paul's P.97b resembled the P-61; the also released a big Defiant with either a Sabre or Centaurus with forward firing guns in the wings as well as the turret.

Conslaw · Sep 6, 2013

If climb rate isn't an issue, then the P-61 Black Widow would be a good candidate. Four 20mm cannon and 4 .50 cal. It had a turret so that it had flexibility in how to approach the bomber. If the F7F would have served during the war, it would rank right up there.

Jabberwocky · Sep 6, 2013

Shortround6 said:
Four 20mm Hispano may not be ideal but it is better than the gunboat 109s and is arguably as good or better than a 190 with four MG 151/20s.

Without inventing a new gun the 20mm Hispano is as good as it is going to get. The 37mm M4 cannon has a miserable rate of fire, 1/4 that of a "normal" Hispano gun, each shell is very powerful but the hit chance is very low. The velocity and time of flight also require getting closer than the 20mm Hispano. The gun also weighs about double what Hispano does. The Vickers S gun is even bigger and slower firing (about 2/3 the 37mm or 1/6 the rate of fire of the 20mm Hispano). It also has velocity and time of flight problems which argue against long range gunfire.
Please note that these rates of fire are for the standard British MK II or American M-2 guns. The British introduced the short barreled MK V gun with a higher rate of fire before the war ended and the Americans were working an a faster firing Hispano and adapted it after the end of the war. Rates of fire went up 20-25%. The British Molins company had built prototype guns firing at up to 1000rpm during the war.

Australian Beaufighter crews got their Hispano Mk IIs cranked up past 1,000 rpm for ground straffing missions. Apparently there was a contest between ground crews as to who could get the RoF of their guns the fastest. There were also similar competitions amoung armourers in the UK, with similar results.

The original French Hispanos fired at around 700-750 rpm. This resulted in deformed cases and ejection jams, so the British slowed the RoF down in the Mk I to 600-650 rpm so that the guns would be more reliable. The French Hispano was designed around a rigid mouting - with an equally rigid feed system - and kept nice and warm and dry by the engine. When it transitioned to a wing mounting in the Spitfire and Hurricane, it had none of these and some changes were needed to get the guns to work acceptably. There were quite a few design alterations between the French metric version, various iterations of the Mk I Hispano and the Mk II, which eventually became the standard gun.

I don't know if the Hispano, even the Mk V, is as good as it gets for WW2 20 mm cannon. I think the B-20, which was much lighter and a litte faster firing, probably just shades it. Its let down by the lighter round, worse ballistics coefficient and slightly lower M/V, by the Russians really knew how to build a good gun. Even then though, its a matter of a few % either way in terms of firepower and efficiency.

OldSkeptic · Sep 6, 2013

JtD said:
Well, neither had the Germans when the 8th AF started operating. Or are you saying that the gondola equipped 109 was a better bomber destroyer than any aircraft the Allies were fielding at the time?

No, because you need a good escort destroyer along with a good bomber destroyer. The trouble is that, because of the 190A's poor high altitude performance and it's lower production levels (plus its demand all over the place for low level stuff) they really only had the 109 which, even if you were very optimistic, it was barely competitive with the P-51s (if you were not optimistic it was markedly inferior).

But it's armament was too small and if you hung gondolas off of it was its performance dropped terribly. Basically think of a Hurricane II with the 40mm vs a Me-109F. Which was about (at that time) about the difference between a 'bulge' with gondolas and a P-51B or D.

Plus the lack of a fast twin, which can carry much bigger armament with lower impact on performance which can get in, hit, avoid and break away from the escorts.. They had nothing like a Mossie (2 stage Merlin ones) which were in the 420mph class, even with bigger guns (though if the Ta-154 had come into play they would have).

Remember, in this scenario you are facing Mustangs (Bs and Ds) as escorts .. tough ships to handle along with very good pilots and (though it took a bit of time) very good tactics.

So taking a SE plane, loading it up, unless you have very good escort 'killers' to keep them away they are going to suffer. As did the German 109 and 190 equivalents.

But the Allies, in this scenario, have a major advantage they have several good high(ish) altitude SE fighters and twins.

If we had a mixed US/British equipment I'd use (assuming that for some reason there are no P-51s for the defence) P-47s very high for bounces (very early in that attrition and start the 'peeling off' off of the escorts), Spit XIVs for the 'get in and get dirty' stuff, taking the fight right to the escorts. Mossies (upgunned and with rockets) for the initial hits on the bombers to break them up. Tempests and (if available) Corsairs for the hammering of both of the escorts and the bombers as they leave. Quite possibly upgunned P-47s (maybe P-4Us) to add to the mayhem after the escorts are stripped off/engaged. Both have the raw power to carry more with less of an impact in performance (though I lean towards the P-47s in this).

With all the others coming in as available (they have to land and refuel, etc and get up again).

Basically the invading forces are under attack from all quarters and altitudes all the time, but under a strict tactical control. First peel off the escorts (1st staring with reducing their range by bounces as early as possible), then hammer the bombers.

Hit the escorts early with bounces (and the P-47s would be great for this) to make them drop their tanks. Be a brave Mustang pilot that would hold onto their tanks, when on their way to a rendezvous (using the layered escort system) they get bounced by a squadron of P-47s. Might only be one pass ... but still ugly ... and there go all the drop tanks. Then as the Spit XIVs come up to play, 'they' are the ones looking nervously at their fuel gauges.

stona · Sep 6, 2013

drgondog said:
nothing

How do you know? Did anyone ever try it?

I'm not saying it can't be done. I'm saying there is a tendency for people to write down things like "stick 4 xyz weapons in fighter abc" without reflecting just what that might involve. History shows that altering the armament of most WW2 fighter aircraft was easier said than done. Most needed considerable testing and development before they worked properly. Some needed considerable modification of the airframe to which they were fitted.
The P-47 was a large and rugged aeroplane but that doesn't mean you can just unbolt 4 machine guns and "stick" 2 cannon in each wing. Who knows what other structures or systems the larger weapons might impinge upon?

Cheers

Steve

stona · Sep 6, 2013

Shortround6 said:
The "standard" armament of the 109 was considerably lighter than most allied types.

By one cannon compared with its contemporary Spitfire (in 43/44). At least it's cannon was a centreline weapon which had much debated advantages.

I'd say the standard Fw 190 armament (which does include the outer wing guns on almost all versions) was heavier than average, not many allied single seat fighters toted four cannon and two machine guns. The inboard cannon had 250 rounds, the outboard 125. The MG 131s had 400 rounds each. It was still not enough.

Cheers

Steve

wuzak · Sep 6, 2013

OldSkeptic said:
No, because you need a good escort destroyer along with a good bomber destroyer. The trouble is that, because of the 190A's poor high altitude performance and it's lower production levels (plus its demand all over the place for low level stuff) they really only had the 109 which, even if you were very optimistic, it was barely competitive with the P-51s (if you were not optimistic it was markedly inferior).

But it's armament was too small and if you hung gondolas off of it was its performance dropped terribly. Basically think of a Hurricane II with the 40mm vs a Me-109F. Which was about (at that time) about the difference between a 'bulge' with gondolas and a P-51B or D.

Plus the lack of a fast twin, which can carry much bigger armament with lower impact on performance which can get in, hit, avoid and break away from the escorts.. They had nothing like a Mossie (2 stage Merlin ones) which were in the 420mph class, even with bigger guns (though if the Ta-154 had come into play they would have).

Remember, in this scenario you are facing Mustangs (Bs and Ds) as escorts .. tough ships to handle along with very good pilots and (though it took a bit of time) very good tactics.

So taking a SE plane, loading it up, unless you have very good escort 'killers' to keep them away they are going to suffer. As did the German 109 and 190 equivalents.

But the Allies, in this scenario, have a major advantage they have several good high(ish) altitude SE fighters and twins.

If we had a mixed US/British equipment I'd use (assuming that for some reason there are no P-51s for the defence) P-47s very high for bounces (very early in that attrition and start the 'peeling off' off of the escorts), Spit XIVs for the 'get in and get dirty' stuff, taking the fight right to the escorts. Mossies (upgunned and with rockets) for the initial hits on the bombers to break them up. Tempests and (if available) Corsairs for the hammering of both of the escorts and the bombers as they leave. Quite possibly upgunned P-47s (maybe P-4Us) to add to the mayhem after the escorts are stripped off/engaged. Both have the raw power to carry more with less of an impact in performance (though I lean towards the P-47s in this).

With all the others coming in as available (they have to land and refuel, etc and get up again).

Basically the invading forces are under attack from all quarters and altitudes all the time, but under a strict tactical control. First peel off the escorts (1st staring with reducing their range by bounces as early as possible), then hammer the bombers.

Hit the escorts early with bounces (and the P-47s would be great for this) to make them drop their tanks. Be a brave Mustang pilot that would hold onto their tanks, when on their way to a rendezvous (using the layered escort system) they get bounced by a squadron of P-47s. Might only be one pass ... but still ugly ... and there go all the drop tanks. Then as the Spit XIVs come up to play, 'they' are the ones looking nervously at their fuel gauges.

I assume the P-47swill be mounting standing patrols, to negate their lack of climb?

And P-4U?

Tante Ju · Sep 6, 2013

Shortround6 said:
Germans need to follow that route because they didn't have the engines needed for a single engine bomber interceptor.

The Allies don't.

That silly weight theory again creeps up...

Four 20mm Hispano guns are a decent anti-bomber armament. Not the greatest but well above most single engine fighters. Roughly equal to a FW 190 with two 13mm and four 20mm Mg 151s ( not all 20mm cannon are equal).

Indeed they aren't. For bomber killing purposes, I'd rate the Mauser cannon above the Hispano. Faster rate of fire, better HE shells and also weighting about 3/4 of the Hispano. Bombers dont manouver much.

Better than 109 'gun-boats'

3 x MG 151/20 on 109 gunboat: 3 x 750 rounds per minute = 2250 rounds per minute. 200 + 2 x 145 rounds = 490 rounds.
2 x MG 131 on 109 gunboat: 2 x 900 rounds per minute = 1800 rounds per minute. 2 x 300 rounds = 600 rounds.
4 x Hispano Mk II. 4 x 600 rounds per minute = 2400 rounds per minute.
4 x 120 rounds = 480 rounds, 4 x 150 = 600 rounds on Typhoon/Tempest IIRC.

Not counting for the better HE shells, which very heavily boosts the Mauser setup, the 3 x 151 vs 4 x Hispano setup comes out at about equal in firepower. The plus side is that the triple Mauser setup weights only about half that of the quad Hispano setup.

Things get funnier when the explosive contents of the M-Geschoss is taken into account. 1 M-Geschoss : 18 gram of explosives, 1 Hisso HE = 10 gram of HE. So the above expressed in HE content/total capacity.

Triple MG 151 setup on 109 gunboat. 2250 x .018 kg per minute = 40 kg of HE / min, total rounds: 490 = 8.82 kg HE
Quad Hisso setup. 2400 x 0.010 = 24 kg of HE / min, 480 rounds carried = 4.8 kg, 600 rounds carried: 6 kg of HE

In summary, the triple Mauser gunboat 109 had a potential of delivering about TWICE the HE (40 kg vs 24 kg / min) to a bomber in any given lenght of time, and almost again 1.5x as much in total (4.8-6 kg vs 8.82 kg), at HALF the gun weight.

Oh yes and it still runs circles around a P-47.. Soviet trials showed the P-47D10 had turning time of about 27-28 seconds, the gunboat 109 a turn time of 22 seconds.. I am not sure about the Typhoon/Tempest, but they were not quite as good as the Fw 190, which the Soviets measured at about 22-24 seconds IIRC.

OldSkeptic · Sep 6, 2013

Radar helps too.... The Germans were picking up the formation build ups hours before they came into German territory.

Even the BoB radar levels (much inferior) could pick up fighter sweeps vs bombers. Lots of time to get the P-47s up (have breakfast, lunch, a chat and so on, climb in, take off, climb up to the right place and 'Tally ho').

In that sense they had it much easier than in the BoB, where coming across from France the RAF (11 group especially) had little time. Another mark of Park's genius, that despite that he never got caught out.
The Luftwaffe had wet dreams about catching (as they did to the Polish, Russians, etc) FC on the ground ... never happened .. again thank to Park.

Leigh Mallory, after his great political stuff and got 11 Group, did an exercise, replicating the BoB (obviously again another political ploy to make him look good) in 41 . In that he lost all his planes on the ground.
His response "oh I will do better next time", then never, (ever) did something like that again.

Usual military idiot who can play politics and deliver nothing except lots of losses of their own people.

"There are those who can do .. and then the wankers .. and the second group always get to the top .. except when times are dire ... and after that moment the W group always get to the top, because nothing uniites the W group than opposition against 'those who can do'.
A W type would rather (Catch 22 describes that perfectly) unite with the other side's W's against the doers, than have to submit to them. Common cause and all that.

So when you are out there, fighting, dying ... your enemies are all around you ... and the worst ones are well (really well) behind you.

Shortround6 · Sep 6, 2013

stona said:
By one cannon compared with its contemporary Spitfire (in 43/44). At least it's cannon was a centreline weapon which had much debated advantages.

Was the Spitfire "most allied types"?

the center line thing? You are shooting at B-17s or B-24s and you are worried that your canon shells are hitting 8 feet apart?

stona said:
I'd say the standard Fw 190 armament (which does include the outer wing guns on almost all versions) was heavier than average, not many allied single seat fighters toted four cannon and two machine guns. The inboard cannon had 250 rounds, the outboard 125. The MG 131s had 400 rounds each. It was still not enough.

Yes, the 190 had a heavier than average armament. Which is one reason the Germans were trying to use as the bomber destroyer when they could and use 109s against the escorts. Plans and reality don't match up well at times.

The MK 108 was just being introduced in the fall of 1943 which means the vast majority of losses from fighters in the Schweinfurt raids were due to 20mm cannon. It may not have been optimal but it was far from being ineffective.

swampyankee · Sep 6, 2013

imho, it's probably a bad idea to have a "bomber destroyer" and an "escort destroyer": put the two roles into an aircraft that can do both. The Allies had them: certainly the P-51, the P-47, the P-38, various marks of Spitfire, various versions of the Corsair (F4U; in the USN "P" was for a patrol aircraft), potentially the Tigercat, P-80, Meteor, Vampire, Bearcat, Hornet, Fireball (FR-1), and [Sea] Fury.

JtD · Sep 6, 2013

OldSkeptic said:
Remember, in this scenario you are facing Mustangs (Bs and Ds) as escorts ...

In this scenario you get to chose _one_ Allied type to fly for the Luftwaffe. I don't know how a variety of single engined fighters and a couple of twins qualify as _one_ type. That said, if you want to pick a type only in early 1944, you'll be facing Mustangs. If you pick one to support the defence of Germany from 1943 on, at first you're not. Of course you can also pick a type for late 1945, then again you won't be facing Mustangs, because you've already lost the war.

Glider · Sep 6, 2013

The problem with the 109 Gunboat isn't the firepower but the impact on the aircrafts performance and handleing. Fine against unescorted bombers but not when the escorts arrive.

The 109 wasn't designed to carry that weight on the wings and the impact in handleing was significant. The Tempest/Typhoon were designed with this in mind and it wasn't an issue. Even the Spit with 4 x 20mm retained its good handleing but as you would expect the climb and acceleration were impacted.

I admit to not knowing the impact on the 109 on its climb, acceleration and role rate.

stona · Sep 6, 2013

I'd say typical allied cannon armed fighter armament in 1943/4 was two machine guns and two 20mm cannon, rarely four cannon. For non-cannon armed aircraft, six to eight .50 calibre machine guns.
That puts the Bf 109 slightly below average and the Fw 190 well above average. Even the Fw 190 was modified to carry other weapons in the Luftwaffe's efforts to destroy bombers.
Cheers
Steve

Best Allied bomber destroyer.

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