Bf-109 vs P-40

Hello Cromwell
You must remember that UK was at war at that time, Bristol helped Napier to solve Sabre's sleeve valve problems, so it was 2-way road.

Juha

Merlin Obsession
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Firstly, I do think that Whitehall was 'Merlin Obsessed' to the point that it actually partly-sabotaged the development of other engines like the Napier Sabre.
For example, Napier were forced, by the MOD, to give copies of their engineering drawings to Rolls-Royce - imagine that ! No wonder they struggled.

The progress of the Sabre was far from sabotaged, I'd go as far as to say it was kept on life-support until it could (almost) stand on its own two feet; 'almost' because even in-service it was plagued with reliability issues.
It was propped up to the point that it borrowed sleeves from Bristol Aircraft Co Ltd to assist in solving the warping problem that was preventing the Sabre from passing even the most basic of run tests, Bristol quite obviously weren't happy about this in light of their 2,000hp Centaurus that they were trying to sell to the Government.
The Government's 'Merlin obsession' could be more correctly applied to the fate of the Westland Whirlwind that was running the Rolls-Royce Peregrine. The latter engine's program was axed in favour of the Merlin, which doubtlessly had more potential (as shown by history) but at the time, the Merlin was really no further along the development line than the Peregrine which could have spelled trouble if the Merlin ran into any problems further down the program.



Merlin P40 - Why ?
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Taking note of your comments - why did they make a Merlin version of the P40 ? (Warhawk, Kittyhawk etc) ?
If the Allison was satisfactory, why produce a Merlin powered variant, especially with Packard at full stretch producing Merlins for the P51 Mustang

Why not? It it worked, they'd just got a new lease of life out of a venerable old fighter and in terms of developmental costs, the work was already done on both the airframe and the powerplant - a bargain. As regards the Allison being 'satisfactory' you are only asking half of the right question; the V-1710 was satisfactory within its requiremented specification ie it was a good low-altitude engine. The Merlin was comparable at the same altitude but far better than the V-1710 at higher altitude.

The P-40F and L revealed little in the way of performance gains for the type utilising a Merlin powerplant, even with the attempts at shedding weight employed by the L.



Defiant - Naval Version ?
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I agree that the Defiant was totally mis-used and abandoned too easily IMHO. After all, it was actually a *good* plane to fly - well balanced and quite powerful.
With its wide 'cart and robust construction I have often thought that a Naval version of the Defiant could have worked with the following adjustments

1. Replace the top-heavy dustbin turret with a twin gun mount (twin Lewis or Vickers)
2. Give the pilot 2 or 4 forward firing Brownings or even some 20mm Cannon
3. Fit racks for Bombs / Depth Charges or 3" Rockets on Zero-zero launchers (as also fired by the venerable if vulnerable Swordfish).
4. Hook - obviously

I'm glad you got rid of the turret, the shear on the fuselage as the 'plane bounces down hard on the deck would have been enormous - repeat until broken in half (I'd imagine). If things got really out of control eg the plane missing everything and disappearing over the side could have proved fateful for the turret operator, who may not be able to get out in time.
I'm not sure the twin mount m/c would have solved the firepower problem.
I think the wide cart would have lended to its unprepared landing strip capability, rather than any Naval application but the idea of underwing ordnance is a good one, supporting a pretty versatile battlefield close support role.

Hi Colin

Yes I think we agree that the Dustbin was a Bad Idea - I am all for recycling. They could have taken them and fitted them to Lancs or anything else suitable !

Close support ? Why not - I only mention Naval application as a wide-track is better than a narrow one vis a vis the Seafire etc etc

Twin Gun for 2nd crew member is not supposed to be a full solution or perfect answer - but something to fill the gap at the back left by the absent Dustbin !

I am just trying to give some back-facing defence and also good for strafing Subs perhaps after making a bombing run ?

Flak suppression ?

Colin1 said:

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I'm glad you got rid of the turret, the shear on the fuselage as the 'plane bounces down hard on the deck would have been enormous - repeat until broken in half (I'd imagine). If things got really out of control eg the plane missing everything and disappearing over the side could have proved fateful for the turret operator, who may not be able to get out in time.

I'm not sure the twin mount m/c would have solved the firepower problem.

I think the wide cart would have lended to its unprepared landing strip capability, rather than any Naval application but the idea of underwing ordnance is a good one, supporting a pretty versatile battlefield close support role.

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Juha said:

Hello
According to Soviet tests time to make 360deg turn at 1000m: Bf 109F-4 20,5 sec, Bf 109G-2/R6 (with 20mm underwing gun gondols) 23sec, Bf 109G-2 21sec.
Curtiss P-40C 18sec, P-40E 19,2 sec.

Juha

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I can buy that at 1000m, but what would it be at other altitudes. That is the problem with stuff like that. I am sure the Bf 109 could turn faster at other altitudes.

Hello Adler
Finnish tests were in line with the Soviet ones. Bf 109G-2 at 1.000m 360deg turn, speed at beginning 450km/h, at the end 330km/h, time 18sec, but if speed was kept constant 360km/h from the beginning to the end, 360deg turn took 22 sec. Most probably Soviet times were times for turns without speed or altitude loss.

Juha

POSTSCRIPT: Forgotto mention that the Soviet flown Gs seemed to have been in excellent condition if one looks the max speed and climb but the F-4 was on slow side and maybe a bit lazy in climb.

ok say a p-40 can't shake a 109 how much damage could it take?

I think that if a 109 got a cannon shot in, then most ww2 planes would be severely compromised inc the p40

The Brit 20mm Cannon would shred most enemy planes in double-quick time (as used in Beaufighters) so I should imagine that the German large calibre machine-cannon would be equally effective.

Juha said:

Hello Flyboyj
easest way probably still is Table of ftrs 1943
but I have seen the same figures also in Soviet/Russian literature.

Juha

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Hmmmm, that link isn't working for me. edit [OK, IT'S WORKING NOW.]

EDIT: Just wanted to add some stuff without making another post.
I don't think it's quite fair to say that putting the Merlin in the P40 didn't provide much of a performance increase. Usually the comparison is made to the more dramatic increase achieved in the P51, but the P51 was given the V1650-3 (2 speed 2 stage), while the P40 only had the V1650-1 (2 speed single stage).
Neverthe less, when comparing P40E to P40F, climb time to 20,000 feet was reduced from 13 minutes to 10.9. Range was increased by 145 miles, and endurance from 2.72 hours to 4 hours (on main tanks alone). Power loading went from 7.5lb/hp (at mean weight) for the P40E to 7.2lb/hp for the P40F. Max speed went from 340 mph to 354 mph. Keep in mind the P40F max speed is at 20,400 ft and the P40E is at 12,500 ft and the F pretty much matches the E's speeds at low altitudes. All this was done with a slight weight gain.

Here is some info on roll rates of P40 from Perils P40 site:

http://www.raafwarbirds.org.au/targetvraaf/p40_archive/pdfs/Allied AC rollrate.pdf

Note the difference between P36 and P40 ailerons and control system.

Juha said:

Hello Flyboyj
easest way probably still is Table of ftrs 1943
but I have seen the same figures also in Soviet/Russian literature.

Juha

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Thanks

fly boy said:

ok say a p-40 can't shake a 109 how much damage could it take?

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That is probabley the big question. I believe the P-40 to be way more tolerant of damage than the Messerschmitt. Now for sure the 20mm cannon is more devestating than the .50s of the later P-40's, but I still believe the Curtiss pilot would survive a couple of hits from the 20mm as long as it wasn't in the cocpit, fuel system, or coolant section, but that works the other way as well for if the 109 is hit in any of those areas by the .50 he too is in a bad way.

I have seen alot of gun-camera footage of 109's losing wings (or large portions of them) after being struck by blast from .50 cals.

Your question leaves me with another couple of questions. In a bounce scenario, where the other pilot is caught unaware and takes some good strikes, which is more likely to survive that first punch? And the second is which aircraft, once it has the other on its tail, is more likely to be able to shake its opponent? My guess at those two are in the first scenario, I think the P-40 has a higher probablility of survival. But in the second, I think the Me 109 would be more difficult to shake off of your tail. ( in any plane for that matter! , P-40 included )

Mike:
Judging from the 90 degree/sec roll rate of the P40, the Soviet tests of turn times, and historical accounts, I think the P40 has a very good chance of shaking off a 109 on it's tail. It's gonna roll into a turning bank quicker than the 109 can follow (without taking into consideration the reaction time of the 109 pilot), it's going to pull into a slightly tighter turn, and in a bounce situation the attacker is usually at a higher speed so he can't turn as tightly or as quickly.
This fits with what WC James 'Stocky' Edwards and other North Africa RAF pilots have related and with the tactics of the 325th FG which waited till the last second to break when attacked by 109s.

claidemore said:

I don't think it's quite fair to say that putting the Merlin in the P-40 didn't provide much of a performance increase. Usually the comparison is made to the more dramatic increase achieved in the P-51, but the P-51 was given the V-1650-3 (2 speed 2 stage), while the P-40 only had the V-1650-1 (2 speed single stage).
Nevertheless, when comparing P-40E to P-40F, climb time to 20,000 feet was reduced from 13 minutes to 10.9. Range was increased by 145 miles, and endurance from 2.72 hours to 4 hours (on main tanks alone). Power loading went from 7.5lb/hp (at mean weight) for the P40E to 7.2lb/hp for the P-40F. Max speed went from 340 mph to 354 mph. Keep in mind the P-40F max speed is at 20,400 ft and the P-40E is at 12,500 ft and the F pretty much matches the E's speeds at low altitudes. All this was done with a slight weight gain.

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Hi Claide
I believe it was 364mph
introduced in 1942, the P-40F did provide significant gains in performance over preceding versions.
When compared to other fighters in 1942 however, the P-40F was still falling short, the Bf109F, the Fw109A, later that year the Spitfire Mk IX turned up to redress the balance for the RAF and of course, the one you mentioned - in 1942 the P-51 was fitted with a Merlin; the P-40F wasn't comparing favourably with any of these, its contemporaries, for level-flight speed or rate of climb.
Whether the P-40 would have benefitted further from the installation of the V-1650-3 is, I believe, unquestionable but once again only in terms of performance comparison with earlier incarnations of the P-40; a more powerful engine would undoubtedly get more speed, higher, out of the airframe but the parasitic drag of that same (and pretty dirty) airframe would be a significant limiting factor.

Colin, I think you hit it right on the head. The P-40 was getting long in the tooth as a fighter but found a good life as a fighter-bomber like the Hurricane by 1942.

Quite right, imho,

I would put the P40, with the Hurricane and also the Martlet as 2nd string planes that could still put in a good show for ground attack or shooting up submarines from Jeep carriers

- well the P40 was never used by the Navy - although perhaps it should have been

Maybe P40 Cam Fighters !!

I mean they used clapped out Hurris and even Stringbags after all

Marshall_Stack said:

Colin, I think you hit it right on the head. The P-40 was getting long in the tooth as a fighter but found a good life as a fighter-bomber like the Hurricane by 1942.

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Hi Colin,

Yup I agree with you 100%. The P40 airframe just wasn't competitive against other 'cleaner' designs (and it was heavier).
The P51 on the other hand, was alreay doing around 400 mph with the Allison engine, so the installation of the Merlin gave it both altitude performance, long range, and a big speed increase. The Mustang was after all the product of North Americans claim that it could design and build a better plane than the P40 for the RAF (rather than tooling up to produce P40s), and that is exactly what they did.

It is strange (but true) that with some planes or tanks or cars you reach a point where no amount of 'improvements' or tweaking can change the basic fact


The Design has just Run out of Steam - End of the Line !


I actually think that the P40 would need to be totally re-designed especially on the weight front to have gone anywhere i.e. New Plane

claidemore said:

Hi Colin,

Yup I agree with you 100%. The P40 airframe just wasn't competitive against other 'cleaner' designs (and it was heavier).
The P51 on the other hand, was alreay doing around 400 mph with the Allison engine, so the installation of the Merlin gave it both altitude performance, long range, and a big speed increase. The Mustang was after all the product of North Americans claim that it could design and build a better plane than the P40 for the RAF (rather than tooling up to produce P40s), and that is exactly what they did.

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who are the 12 who said the P 40 OMG....

Tiger!

claidemore said:

Mike:
Judging from the 90 degree/sec roll rate of the P40, the Soviet tests of turn times, and historical accounts, I think the P40 has a very good chance of shaking off a 109 on it's tail. It's gonna roll into a turning bank quicker than the 109 can follow (without taking into consideration the reaction time of the 109 pilot), it's going to pull into a slightly tighter turn, and in a bounce situation the attacker is usually at a higher speed so he can't turn as tightly or as quickly.

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Heartily agreed.

Consider- US Army trials of the P-51 Mustang found that it could turn nearly as good as a P-40, with the P-40 having, perhaps, a slight advantage at low altitudes. (This is from the P-51 technical trials on wwiiaircraft.net.) Now, the opening anecdote to Bud Anderson's autobiography, "To Fly and Fight," relates a battle between P-51Bs and Bf-109s in which the P-51s demonstrate slightly superior turning ability.

I do know that the simplest, rough indicator of turn performance is "wing loading," i.e. weight of the aircraft divided by lift area. Lower is better. The P-40E had a wing loading of 35lbs/ft, the Bf-109G-6, 40lbs/ft. There are other factors to consider as well- a cleaner ship will make a faster turn, but a slower ship will make a tighter one, etc. The factors are varied enough that I personally put more faith in period test data then my own half-baked attempts at complex aerodynamic equations, and the information from both the Russians and the Americans puts the P-40 as turning slightly better then the Messerschmitt.. Heck, look at Wikipedia's P-40 article:

] An anecdote concerning the 325th FG, indicates what could happen if Bf 109 pilots made the mistake of trying to out-turn the P-40. According to 325th FG historian Carol Cathcart: "on 30 July, 20 P-40s of the 317th [Fighter Squadron] ... took off on a fighter sweep ... over Sardinia. As they turned to fly south over the west part of the island, they were attacked near Sassari... The attacking force consisted of 25 to 30 Bf 109s and Macchi C.202s... In the brief, intense battle that occurred ... [the 317th claimed] 21 enemy aircraft."

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As for the P-40s ability to survive damage:

Wikipedia said:

For example, on one occasion in August 1941, Caldwell was attacked by two Bf 109s, one of them piloted by German Ace Werner Schröer. Although Caldwell was wounded three times, and his Tomahawk was hit by more than 100 7.92 mm bullets and five 20 mm cannon shells, during this combat Caldwell shot down Schröer's wingman and returned to base.

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When I skimmed the first several pages of this thread I got quite a chuckle out of those theorizing that a P-40 would disintegrate from one or two cannon hits.

The incredible strength of the P-40 is simply beyond doubt:

The strength of its 5-longeron wing became legendary after an aerial engagement on 8 April 1942 [19]. On this day, flight commander Lieutenant Aleksey Khlobystov rammed German aircraft two times in a single engagement. He cut off the tail assembly of one Messerschmitt in an overtaking maneuver and severed a portion of the wing of a second Messerschmitt. Both times he struck the enemy aircraft with the same right wing panel. Both Messerschmitts went down and the Tomahawk landed safely at its airfield, where it was repaired without any particular difficulty.

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One more comment from a few pages back that I think applies to many of these kinds of threads:

Waynos said:

Why do some people put so much effort into trying to put some planes, whether reasonable (P-40) average (P-39) or poor (F2A) higher up the pecking order than they belong?

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Because they really were higher up in the pecking order then the slot history has aligned them. To me, the study of the under-appreciated fighters is a fascinating study in how history is so warped and distorted by false perceptions introduced years after the fact. Most of the tanks did not sink during D-Day, over 50 of them made it to the beaches and played an invaluable role in opening the passes. The assault of the 82nd Rangers up the cliff face of Point Du Hoc was NOT in vain; they located the artillery cannons some miles inland where they'd been relocated and destroyed them. Horrible misconceptions about these events dominate in the popular conciousness, to the point that the F2A Brewster Buffalo, the fighter with the best power-to-weight ratio of any fighter in the American inventory, an excellent climb, roll and turn rate, and the heaviest firepower- has been featured in TWO "worst fighter of all time" books!

This is the fascinating part of websites like this- unearthing facts that "common knowledge" is clueless of.

Demetrious said:

One more comment from a few pages back that I think applies to many of these kinds of threads:



Because they really were higher up in the pecking order then the slot history has aligned them. To me, the study of the under-appreciated fighters is a fascinating study in how history is so warped and distorted by false perceptions introduced years after the fact. Most of the tanks did not sink during D-Day, over 50 of them made it to the beaches and played an invaluable role in opening the passes. The assault of the 82nd Rangers up the cliff face of Point Du Hoc was NOT in vain; they located the artillery cannons some miles inland where they'd been relocated and destroyed them. Horrible misconceptions about these events dominate in the popular conciousness, to the point that the F2A Brewster Buffalo, the fighter with the best power-to-weight ratio of any fighter in the American inventory, an excellent climb, roll and turn rate, and the heaviest firepower- has been featured in TWO "worst fighter of all time" books!

This is the fascinating part of websites like this- unearthing facts that "common knowledge" is clueless of.

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Well said.