RAF daylight strategic bombing campaign results

[Shortround6]

A problem when trying to compare P-40s is that they change a lot in the early ones.

IF you could get a P-40 to go 730 miles on internal fuel it was an early one without self-sealing tanks or tanks with a crude sealing applied outside, capacity 160 US gallons. Getting one to go 1270 miles if throttled back requires a real leap of faith. 3 times the range of a Spitfire or 109 on 60% more fuel? Those P-40Bs must have been one slick ship
P-40D/E was rated for 700 miles on 120 US gallons (100imp) remaining with 28 US (23imp) used for warm up and take-off at 173-188mph indicated depending on altitude, sea level to 15,000ft. I am not sure you want to throttle back any more than that. Max endurance is often NOT max range.
At a more useful 229mph indicated at 15,000ft range for the 120 US gallons was 425 miles. Fuel burn was in the 70-80 gallon an hour range depending on altitude.

Some the early performance numbers are a little suspect. this test report has some very good numbers. Trouble is it gives the gross weight of the plane at 6835lbs which is either a misprint or there is a whole lot of "stuff" not in the airplane.

A P-40B with full internal tanks, full ammo and NO external tank could go 7624lbs. A P-40C with external tank could go just over 8000lbs.

http://www.wwiiaircraftperformance.org/P-40/P-40B_41-5205_PHQ-M-19-1227-A.pdf

Some of the P-40s 'success' in North Africa and with the AVG came from over-boosting the engines in service. This only worked at low altitudes and could not be used at the altitudes the bombers were flying (the supercharger simply would NOT supply the higher pressure at those altitudes.)

P-40s climb, unless being over boosted (or running light, ie little ammo or fuel) at low altitudes is best described as mediocre and falling to dismal at higher (in this case 15,000ft and above) altitudes.

A lot is made of speed and while I don't subscribe to the view that is as unimportant as some do it, others focus on it to exclusion of rate of climb. Rate of climb, while not linear, is an indication of acceleration and/or the excess power available to to sustain speed through maneuvers. The Bf 109 gun boats lost very little speed it is true, but they lost rate of climb (and losses in rate of climb tend to carry through to the higher altitudes. a 10% loss in rate of climb at sea level is often a 15-20% loss in rate of climb in the 20-30,000ft range) and turning ability.

An equipped, loaded P-40B at 15-20,000ft is no match for a 109. And you can't escort bombers flying at 12-15,000ft by flying at 6-9,000ft.


and as always, drop tanks are for getting you in, internal fuel is for getting you out. adding drop tanks but not adding internal fuel doesn't do a lot for radius past a certain point.

 

[Glider]

Just what an up-engined P-40 could be is a bit nebulous. And, with enough fuel to get home, so is performance. But the P-40 could well be superior in the vertical in that it maintained rather good roll rate ate high speeds while ME-109 had high roll control forces and suspect structural integrity at speed. Thus the P-40 might well be able to reach more favorable altitudes for escape or combat.

The P40 had a very poor climb and would never win in a vertical combat. It was also poor at altitude.

Overall, the P-40 had been bypassed regarding performance. But, with select tactics taking advantage of the LW fixation on the bombers, the P-40 would have been better than no help at all during the early days.

Overall the P40 had been bypassed in performance and would have been at a serious disadvantage, remember the defenders have the fixation with the bombers, to protect them

 

[stona]

The P40 had a very poor climb and would never win in a vertical combat. It was also poor at altitude.
Overall the P40 had been bypassed in performance and would have been at a serious disadvantage,

It certainly would. It was seriously out classed in North Africa, and the Luftwaffe rarely had more than 30-40 serviceable Bf 109s in the entire theatre at any given time. It also had serious limitations on fuel and an inability to complete the training of new pilots arriving from the schools. Despite this it wreaked havoc on the Hurricanes and P 40s of the RAF whenever they were encountered. Flying a defensive circle is not an option for escorts protecting bombers. The situation in NW Europe would have been rather different and much the worse.

The real answer to the question is that without some serious alteration in thinking before the war the RAF simply didn't have, nor could it acquire, a suitable aircraft to act as an escort to daylight bombers in 1941. It must have been something considered at the time with the resultant switch to night time operations.

I certainly wouldn't fancy flying a 1941 P-40 against the Bf 109 F, I'd just about consider myself having a chance in a Spitfire V. The arrival of the Fw 190 late in 1941/early 1942 only makes things a lot worse.

Cheers

Steve

 

[gjs238]

So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)

Were MTO pilots also slow to adapt?

 

[Glider]

So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)

Were MTO pilots also slow to adapt?

I admit to not understanding this

 

[pbehn]

An escort fighter that has good dive performance but poor climb is in a poor situation doing what it is supposed to do. In my opinion the advantage lies with the escorts, they dont have to win inm a dogfight just stop the enemy getting to the bombers however hard to do if you have a speed and performance at altitude disadvantage.

 

[Shortround6]

You are correct. The escorts don't have to be superior to the defenders but they have to be good enough to stop the majority of the attackers from reaching the bombers (gaining good firing positions). They also have to be good enough not to loose too many of the escorts per mission. This is a campaign and not a single raid or series of a few raids. Loose too many escort fighters too quickly and the campaign will be stopped or suspended.

Defenders, if they have superior (enough superior) climb/altitude performance, can use altitude and trade it for speed on the attack runs, They don't have to do steep dives, just trade altitude for speed. A poor climbing escort is going to be in trouble trying to counter it.

 

[pbehn]

You are correct. The escorts don't have to be superior to the defenders but they have to be good enough to stop the majority of the attackers from reaching the bombers (gaining good firing positions). They also have to be good enough not to loose too many of the escorts per mission. This is a campaign and not a single raid or series of a few raids. Loose too many escort fighters too quickly and the campaign will be stopped or suspended.

Defenders, if they have superior (enough superior) climb/altitude performance, can use altitude and trade it for speed on the attack runs, They don't have to do steep dives, just trade altitude for speed. A poor climbing escort is going to be in trouble trying to counter it.

As I see it the escorts just have to stay in the fight, almost regardless of the A/C involved it is impossible to shoot down a bomber with a fighter on your tail, I believe that eventually was the main philosophy on US missions. The defensive fire of the formation coupled with escorts made the Germans job difficult to almost impossible.

 

[gjs238]

So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)

Were MTO pilots also slow to adapt?

Don't get into a turning fight.
Use boom and zoom - energy fighting tactics.

 

[stona]

Don't get into a turning fight.
Use boom and zoom - energy fighting tactics.

How is a P-40B/Tomahawk II going to do that against a Bf 109 (F would be the 1941 model) which has much superior altitude performance. The Germans could decide whether or not to initiate combat and need only do so on favourable terms. They could also disengage vertically whenever they chose. The P-40 has little chance of preventing the bombers being attacked and should the Luftwaffe fighters turn on it, little chance of doing anything to survive that they didn't try historically. In North Africa this was usually a defensive circle, just as another unsuccessful escort, the Bf 110, had done a year previously during the BoB.

I've read first hand accounts of the frustration of Merlin powered Hurricane pilots watching Bf 109 Es (not Fs) leaving contrails several thousand feet above them, completely safe with their altitude advantage.

Cheers

Steve

 

[gjs238]

How is a P-40B/Tomahawk II going to do that against a Bf 109 (F would be the 1941 model) which has much superior altitude performance. The Germans could decide whether or not to initiate combat and need only do so on favourable terms. They could also disengage vertically whenever they chose. The P-40 has little chance of preventing the bombers being attacked and should the Luftwaffe fighters turn on it, little chance of doing anything to survive that they didn't try historically. In North Africa this was usually a defensive circle, just as another unsuccessful escort, the Bf 110, had done a year previously during the BoB.

I've read first hand accounts of the frustration of Merlin powered Hurricane pilots watching Bf 109 Es (not Fs) leaving contrails several thousand feet above them, completely safe with their altitude advantage.

Cheers

Steve

???
I never said it could.
I was asking if MTO allied fighter pilots were getting hammered due in any way to dated tactics?

So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)

Were MTO pilots also slow to adapt?

I admit to not understanding this

Don't get into a turning fight.
Use boom and zoom - energy fighting tactics.

 

[Shortround6]

As I see it the escorts just have to stay in the fight, almost regardless of the A/C involved it is impossible to shoot down a bomber with a fighter on your tail, I believe that eventually was the main philosophy on US missions. The defensive fire of the formation coupled with escorts made the Germans job difficult to almost impossible.

Yes, it is hard to shoot down a bomber with a fighter on you tail but if the interceptor starts several thousand feet above the escort fighter and can use the height advantage as a speed advantage. It is hard to stay on a fighters tail if it is doing 30-60mph faster than than the plane chasing it. If attacking from above the attackers can also use a modified boom and zoom. After going through the fighters (don't stop and get in a turning fight with them) hit the bombers (one pass) and then do a curved climb back to a higher altitude. The plane with a good climb rate can both turn (not sharp but enough to make a pursuer face a defection shot) and climb. A poor climber can do one or other.
The escort fighter has to be close in performance to the interceptors, just showing up is not enough.

 

[stona]

???
I never said it could.
I was asking if MTO allied fighter pilots were getting hammered due in any way to dated tactics?

The allied pilots tried to fight to the advantages of their aircraft. In the MTO neither the P-40 nor the Hurricane could compete with the 'Friederich' using so called boom and zoom tactics. A slow, horizontal, turning fight was their best bet, if the German pilots would oblige, hence the defensive circle.

The escort fighters shouldn't find themselves in the position of the 'fighter on the tail' of an aircraft attacking the bombers. Their job was to prevent the interceptors getting into a position from which they could launch an attack, ideally by breaking up the intercepting formation with their own attack(s). The idea that P-40s could do this in the face of a determined effort by Bf 109 Fs doesn't wash with me. I believe losses would have been prohibitive.
The close escort implied in the 'fighter on the tail' scenario was repeatedly shown not to work. I wouldn't fancy being the US fighter on the tail of a Luftwaffe fighter attacking a formation of Boeings and exposing myself to their defensive fire in the same way as the German aircraft. Typically air gunners fire at anything that appears a threat, certainly anything that points its nose in their direction, friend or foe, and there are numerous accounts of precisely this from 8th AF fighter pilots. Escorting fighters stayed well out of the range of their bomber formation. Even formatting on a straggler, to offer it protection, could be dangerous

Cheers

Steve

 

[pbehn]

Yes, it is hard to shoot down a bomber with a fighter on you tail but if the interceptor starts several thousand feet above the escort fighter and can use the height advantage as a speed advantage. It is hard to stay on a fighters tail if it is doing 30-60mph faster than than the plane chasing it. If attacking from above the attackers can also use a modified boom and zoom. After going through the fighters (don't stop and get in a turning fight with them) hit the bombers (one pass) and then do a curved climb back to a higher altitude. The plane with a good climb rate can both turn (not sharp but enough to make a pursuer face a defection shot) and climb. A poor climber can do one or other.
The escort fighter has to be close in performance to the interceptors, just showing up is not enough.

Agreed, just keeping the attacking planes up near maximum speed is a help, it took an average of 25 hits to take down a US bomber IIRC not so easy to do at maximum speed with someone following you.

 

[stona]

Agreed, just keeping the attacking planes up near maximum speed is a help, it took an average of 25 hits to take down a US bomber IIRC not so easy to do at maximum speed with someone following you.

Can anyone provide a single instance in which an intercepting fighter was shot down, by an escort, off the tail of a bomber formation? I can't recall one. These battles (Luftwaffe/USAAF which is the only concerted daylight campaign we have for reference) took place over miles of air space, not hundreds of yards. There seems to be a misunderstanding about how escort fighters operated successfully.
Once and if the interceptors could evade or break through the defending escorts they only had to worry about the bombers defensive fire. I'd recommend Boiten and Bowman's 'Battles with the Luftwaffe' which tells the story of the US strategic bombing offensive in Europe from both sides.

Cheers

Steve

 

[kool kitty89]

The problem is NOT getting in. It is getting out. A few 109 recon planes carried a tank under each wing (usually without wing guns?) Spit might carry a 90 gallon drop tank (might go larger, 170 gallon ferry tank is out), both planes may/would need larger oil tanks.
For a mission profile on the way in you have engine warm up and take off taking up fuel plus climb to altitude and forming up. SPits could top off fuselage tanks I think. Pump and piping would solve problem for 109 if not already fitted.
That solves getting IN. Getting OUT has the combat allowance (how many minutes at combat power, how many minutes at max continuous or max climb or? ) and a high enough cruise speed back to the coast to help keep from being bounced. For a Spit V using 16lbs of boost in combat every minute was worth 5 minutes at most economical cruise.
Us planners figured how much fuel was needed to get back after dropping tanks, that was the practical radius and then they figured how to get enough external fuel on the planes to get to the radius distance. Plane limitaions sometimes got in the way on early planes. Please note that the external 52 gallon tank on the P-40 (and the under fuselage tank on the P-39) were to restore fuel capacity after fitting self sealing tanks.

This is all what I intended to imply before. Internal fuel capacity is critical, and if the Spitfire couldn't be expanded to have competitive (clean) range to the P-40 (or P-39 for that matter), there's no way it could have been a competent penetration/escort fighter.

On the allied end of things, especially in a 1941 scenario, things are pretty damn limited. 1942 somewhat less so, but still pretty tight.

Even if you include prototypes on the scene early enough to be considered for the role, it's still fairly limited. (and the Miles M.20 managed longer range than the Spit/Hurricane but was closer to the contemporary P-40 in weight class on top of lower speed)
British twin-engine fighter development might have had more promise had it gone in the long-range direction, but neither Gloster nor Westland's early war designs progressed in that direction ... or even entered production.

Had the export lightning not been botched/crippled (not just the turbo issue, but general mediocre conversion/optimization for non-turbo engines) they might have been compelling early-war options, especially for the somewhat lower alts RAF bombers were operating at.

Prior to the P-51 becoming available in numbers (with any engine), there's not too many options. And service ready P-47s or F4Us (hypothetically) wouldn't really be there much/any earlier either. (get into 1942/43 and you've got a lot more potential hypotheticals we've already been over -from Merlin XX powered mustangs to F4Us to P47s with earlier access to larger drop tanks, etc)

If the RAF wants to run precision daylight raids into Germany proper it needs an escort fighter. The only aircraft that is available that can do the Job is the Curtiss P-40B (Tomahawk IIA) and it most certainly can do the job being the first P-40 with acceptable armour and protection. The P-40B is available from May 1941.

It has a range of 730 miles on internal fuel, 1270 if throttled back. That is 75% more than the Me 109F or Spitfire III or V. With a 75 gallon drop tank it has even more range.

The P-40C/Tomahawk IIB's performance degraded due to the protection on the P-40B being felt to be inadequate (at least by american planners). More advanced (and limited capacity) self-sealing tanks were introduced along with increased armor (including armor glass for the windshield) along with the belly shackle.

So climb/turn performance dropped significantly, speed dropped more modestly.

The P-40's problem is that its larger airframe and relatively weak Allison V-1710 engine gave it an inferior power to weight ratio to the Spitfire and Me 109F2 which was worsened by the relatively low full throttle height of the Allison.

The V-1710's good specific fuel consumption at cruise was part of the key to the longer range on US aircraft (on top of aerodynamics and -mostly- fuel capacity) So some of the range advantage would be lost by using a merlin ... even in a hypothetical 1940/41 export model using British built engines. (or some other hypothetical like the UK licensing the hawk airframe several years earlier and developing it independently around the Merlin ... or just an indepdently developed British design for a similar goal -focus on escort isn't necessary, just some sort of long range duties from intruder to fighter bomber ... I suppose an argument for Hawker focusing on a more advanced faster/longer range Merlin-powered direct successor to the Hurricane -opposed to the Typhoon- could be relevant too)

The higher fuel capacity is still going to be a major advantage, though.

Having said that I believe that Allison engine P-40/Tomahawk IIA would have been effective in substantially protecting the bombers by diverting the Luftwaffe's interceptors. It has to be remembered the Luftwaffe is stretched then as well.

For 1941 I'd still have to agree that ... inadequate or not, of existing aircraft available to the British, the Tomahawk IIA and IIB were the closest things to esxort fighters they had on hand. But inadequate escort fighters are not going to cut it either. (marginally adequate could manage though ... and it's unclear whether modified Spit Vs might have crammed in enough internal fuel to fit the bill there in the interim -let alone hypothetical long-range Spit IX's in 1942)

Or ... maybe ... maybe the Typhoon could have been converted into the medium alt escort role if it had enough internal fuel and drop tanks capacity added.

That or, again, better luck with the P-38 export model development. (and showing enough promise to make procurement over more export P-40s and P-39s more attractive ... particularly to the point of meriting second-sourcing the P-38)

We know that a pair of suspended canon "gondola guns" on the Me 109G impacted speed less than 1%. (See Kurfurst.org) and so I argue that the impact on spitfire speed would have been negligible since the guns were being moved (not added as in the German case).

Such a Spitfire would substantially out range even the P-51D with tail tank.

Hmm ... that's a more interestion suggestion, but do remember the Hispano was a larger/heavier weapon than the MG-151. (the underwing pods on the P-39Q would probably be more comparable than hispano gun pods)

Did the recon spits even use self sealing tanks for the extended range? (that'd be a major issue to consider)

Yes, it is hard to shoot down a bomber with a fighter on you tail but if the interceptor starts several thousand feet above the escort fighter and can use the height advantage as a speed advantage. It is hard to stay on a fighters tail if it is doing 30-60mph faster than than the plane chasing it. If attacking from above the attackers can also use a modified boom and zoom. After going through the fighters (don't stop and get in a turning fight with them) hit the bombers (one pass) and then do a curved climb back to a higher altitude. The plane with a good climb rate can both turn (not sharp but enough to make a pursuer face a defection shot) and climb. A poor climber can do one or other.
The escort fighter has to be close in performance to the interceptors, just showing up is not enough.

With similar technology, you're going to pretty consistently have superior 1 to 1 performance for short range interceptors over long range escort fighters.

So you NEED a technological edge to manage competent escort fighters (or long range roaming intruders/penetration fighters) that are relatively close to even terms with enemy interceptors.


Short range escort is another matter entirely and doesn't skew performance requirements nearly as much.

 

[Vincenzo]

HoHun calculations sustained turn rate
109F-4
S.L. 21.5°/sec, 3 km 17.5°/sec, 6 km 13°/sec, 9 km 7.5°/sec
P-40C (44" Hg)
19°/sec, 15.5°/sec, 11.5°/sec, 6°/sec
P-40E (44" Hg)
17°/sec, 12.5°/sec, 7°/sec, too high
Hurricane IIB (+12/9 lbs)
22°/sec, 18°/sec, 13°/sec, 8°/sec
Spit VC (+16 lbs)
21.5°/sec, 18°/sec, 12.5°/sec, 7°/sec

 

[pbehn]

Can anyone provide a single instance in which an intercepting fighter was shot down, by an escort, off the tail of a bomber formation? I can't recall one. These battles (Luftwaffe/USAAF which is the only concerted daylight campaign we have for reference) took place over miles of air space, not hundreds of yards. There seems to be a misunderstanding about how escort fighters operated successfully.
Once and if the interceptors could evade or break through the defending escorts they only had to worry about the bombers defensive fire. I'd recommend Boiten and Bowman's 'Battles with the Luftwaffe' which tells the story of the US strategic bombing offensive in Europe from both sides.

Cheers

Steve

During the Battle of Britain a hurricane pilot was about to shoot at a bomber when the bomber took cannon hits from a 109 trying to down the Hurricane. Even during the BoB which was a short distance in comparison the object of Park was to strip away the escorts, just the presence of an escort formation makes foring up for the attack difficult.

 

[stona]

During the Battle of Britain a hurricane pilot was about to shoot at a bomber when the bomber took cannon hits from a 109 trying to down the Hurricane.

The Luftwaffe escorts in the BoB, unlike their 8th AF counterparts in the strategic offensive against Germany were 'tied' to the bombers in a tactically limiting (some would later say idiotic) close escort role. Galland later said that it was this denial of freedom to manoeuvre to which he was referring with his famous 'give me a squadron of Spitfires' quip. Rather than being allowed to range ahead of the bombers, attacking and breaking up RAF formations they were forced to fly close to, usually above, the bombers and attempt to protect them at relatively close quarters.

Apart from that this example illustrates my point. Not only did the escort fighter manage to inflict damage on the bomber it was supposed to be protecting, it could have been the victim of the defensive fire of the 'friendly' bomber too.

Luftwaffe interceptors later had only to evade or defeat the escorts to get a run at the bombers. Easier said than done. Earlier I said they then needed only to worry about the bombers defensive fire, but they also braved 'friendly' flak.

Cheers

Steve

 

[Glider]

Don't get into a turning fight.
Use boom and zoom - energy fighting tactics.

Thanks for the clarification. If the main advantage of your aircraft is in its general agility then play to your strengths. If your aircraft has the advantage in dive and climb, then again play to your strengths. The trick is not getting confused when considering who your fighting.

In Europe the RAF normally had the advantage in agility over the Luftwaffe but when they tried it against the IJAAF they came seriously unstuck. In the Far East the RAF normally had the advantage in boom and zoom, in Europe the Luftwaffe had that advantage