Bf-109 vs P-40

[DerAdlerIstGelandet]

Does he think we are stupid?

 

[billswagger]

I'm asking no better to trust you, Bill. But it should take curvature vs speed tables or abaccus for both planes to convince everyone.

Indeed it should, but in my experience with researching hard data, in order to make direct comparisons it would assume similar instrumentation which as you know rarely is ever exactly the same for two different aircraft.
German instrumentation has at times been found to be optimistic particularly at high speeds.
More to comment of differences in speed later.

Actually it seems that Messerschmitt airframe was stressed to withstand about 7.3 g in positive. It's 1.5 g more than its pilots. Anyway concerning human limits (loose of conscience) it's useless to stress the aircraft more than +6, -3G. Of course if you have some docs proving that Herr Professor Willy totally missed in fulfilling that technical request, it would be with pleasure...

Good point, but G load on the airframe is an important consideration beyond what's exerted on the pilot because its well documented that humans can withstand upwards of 9-12 (vertical) Gs if for only brief moments.
It is sustained G loads that can black out the pilot at much lower Gs.

Messerschmitt airframe was stressed to withstand about 7.3 g in positive

I was looking for figures on the 109 as well as the spitfire many months ago.
What i found for the P-40 was with a full load it had a limit of 7.5 Gs, and up 8.5Gs with out a drop tank. No combat limits were listed.
In other reading its been mentioned that the P-40 could exceed 9 Gs in hard sudden turn with no adverse affects to the airframe, but these are estimates gained on G meters in the early 1940s.

The other consideration for turn is stick force which is often what i've found where the bigger difference in high speed turn is. Every plane experiences stick force at high speeds, but the difference is the duration and consistency of the stick force through the turn or pull out.
An example of a P-40 in a steep pull out @ 400mph was met with about 80lbs force at 4-5Gs of pull out. 80lbs sounds like a lot until you see that its actually the peak weight in a spike that occurs for about a tenth of a second.
So deflection with a brief moment of stick force as the plane changes its trajectory.
The actual study was about a tail plane design used to lighten stick force (XP-42 vs P-40), however it was also commented that stick force was a better indicator for G loads and that an absence of stick force made it difficult to gauge acceleration limits of the plane.

Well Bill. Honesltly considering both 109 G-2 parameters 3023 kg and 1250 hp, it makes 187 kg/m² and 2.42 hp/kg . Taking now the soviet P-40 E, 1150 hp and 3840 kg it makes 175 kg/m² and deplorable weight to power ratio 3.34 hp/kg, there is absolutly no reason for the P-40E to outurn the 109G-2.

Its a matter of speed and altitude, as i said. The sustained turn performance of the 109 would prove to be superior from a strictly mathematical perspective, but the P-40 had a better instantaneous turn at higher speeds.
It rolled and dove better which allowed for the Thatch weave tactic to be utilized in air battles.
The superior maneuverability of the P-40 over the 109 is reiterated in articles in MTO, as well as in Russian accounts.
Even to the extent where Germans used Emils in an attempt to gain a turn advantage against their Russian adversaries but they were found to be much to slow for a turn advantage to matter.

I also have a problem comparing simple horsepower to weight when propeller efficiency and reduction gearing can also be significant to actual thrust efficiency. The horsepower is a better indicator for performance at altitude where its well known the 109 was favored because of its lighter weight and better supercharging.

Furthermore, its well documented that the figure of 1150hp is lower than the actual power achieved by the F3R engines in the field. The main issue was altitude performance where the critical height at 60" was a mere 12,000ft, however it was capable of producing above 1500hp up to those heights.
The Allison was also capable of producing 1800+ HP at 3200RPM under 3000ft.
There is much more to the comparison than what the 1150hp suggests.

But there is a limit , the plane was oversized and so overweighted for it's engine. During turns and immelmans it was loosing speed, with no way to recover it.

Disagree, for the reason described above. Your assessment might be more agreeable above critical heights for the P-40. Note: The P-40 engine still shoveled out 1000hp at 20,000ft.

Moreover i take the advantage of posting to kill another urban legend. Neither P-40, nor P-39 were unfortunately low atitude fighters.

The P-40 was better suited for lower altitudes, thats where its peak performance was found to be. Afterall, when surveyed, the Japanese said the P-40 was their most difficult adversary of WW2 at lower altitudes.

Its not so one sided when comparing 109s and P-40s although some squadrons had significant success against the 109s using P-40s.
I can't completely discount the 109, however German tactics would suggest its strengths against the P-40 were more in the vertical than in the horizontal.
P-40 pilots said Germans rarely engaged with them from an even altitude and usually climbed away only to come back a few minutes later with thousands more feet in height advantage. It was then easier for the 109 to use vertical dives into zoom climbs where the P-40 had no chance of competeing with out dragging the 109 to lower heights.
With out the height advantage to dive from, the speed margin between these two aircraft was probably much closer, though above critical heights, as mentioned, the P-40 would not compete as well as the 109.


my two cents, anyways.

Bill

 

[davparlr]

I read a few of those Aussie logs, which are interesting, some with photos, and it seems they quite liked the P-40. Some liked the Tomahawk over the Kittyhawk. They did not seem to hesitate attacking Bf-109Fs although they considered it a formidable adversary. They also were successful in combat with them, at least a far as I could tell.

 

[drgondog]

Was reading recently about the P-40 compared to other allied fighters and what a couple of US aces said about the P-40, I think it was Bob Dehaven(14 kills) and Joal B Paris (9 kills) who said the P-40N was more manuverable than the P-38 (both flew the P-38 after P-40's), had a faster roll rate than even the P-51 and the 5 spare wing ment it had no G limit and was almost indestructable (no wonder the Russians liked them) and was there choice of fighter below 10'000 ft

Why did it 'have no load limit'?? It seems difficult to believe that the N was even superior to the D/E as it weighed more.

Redesign wing to make it stronger is a 'good' be a thing structurally speaking - but unless you perform a detailed study of the Rest of the airframe to determine if those components can withstand greater than the original design loads at the original gross weight - then you may lose your tail to a high speed slow roll long before you rip it off in a corner speed pull out..

 

[wwii:)aircraft]

This post has mostly focus itself with the comparison between the Bf 109f vs P-40E. But what about the comparison of later variants such as the Bf 109G-6 vs the P-40N seeing that in some ways the Bf 109G has become worse than the F and the P-40N being argued as the best overall P-40 variant. Not only that but both of these variants were the most produced of each aircraft.

Even though the G-6 introduces a stronger armament, is more versatile, and is installed with the much more powerful DB 605A-1 engine, the G-6 has also become much heavier and much less aerodynamic decreasing its climbing performance, agility, and handling.

As the P-40N its almost the opposite case. The N introduces a new lightweight structure as well as several other modifications resulting in a decrease in weight therefore, improving its climb and maneuverability. On top of that the N uses the same engine as the M, the V-1710-81 making it the fastest P-40 variant (the Q not being included).

Based off of this I think the P-40N is overall more superior to the G-6 in the one vs. one situation, but barely. The only true advantage the P-40 would have would be that it is more agile than the G-6 at high speeds (the Bf 109 becoming increasingly stiff at high speeds).

Things such as fighter-bomber capabilities and armaments being very subjective (except for when the G-6 carries a 30mm cannon).

If I were to choose it would be the G-6. Even though the N has better features such as a better canopy, more aerodynamic, better takeoffs and landings etc..., the G-6's armament is one of my favorites (2 13mm and a single 20mm all firing from and around the nose; some cases even a 30mm), I really like how well the G-6 can accelerate, and I like how the G-6 is more of a stable gun platform than previous variants especially when carrying the 2 20mm in the wings. Plus its versatility doesn't hurt either.

 

[Shortround6]

This post has mostly focus itself with the comparison between the Bf 109f vs P-40E. But what about the comparison of later variants such as the Bf 109G-6 vs the P-40N seeing that in some ways the Bf 109G has become worse than the F and the P-40N being argued as the best overall P-40 variant. Not only that but both of these variants were the most produced of each aircraft.

True they were the mot produced but that also introduces the problem of which P40N or which 109G

Even though the G-6 introduces a stronger armament, is more versatile, and is installed with the much more powerful DB 605A-1 engine, the G-6 has also become much heavier and much less aerodynamic decreasing its climbing performance, agility, and handling.

I think if you leave off the wing guns the G-6 didn't deteriorate that badly. A bit over the earlier "G"s but they were a bit down hill from the "F"s

As the P-40N its almost the opposite case. The N introduces a new lightweight structure as well as several other modifications resulting in a decrease in weight therefore, improving its climb and maneuverability. On top of that the N uses the same engine as the M, the V-1710-81 making it the fastest P-40 variant (the Q not being included).

Here is the real problem, there wasn't much lightweight structure in a P-40N, aside from aluminum radiators, oil coolers and lighter landing gear(?) most of the weight reduction was in reduced capabilities. Like going from 6 guns to 4 and limiting the ammo to the remaining guns. Removal of one of the interior fuel tanks. Removal of the battery and electric starter on the engine. Removal of the wing bomb racks helped a bit with streamlining. Later versions of the P-40N added everything back in over several production blocks and late P-40Ns were allowed to carry 500lb under each wing in addition to under the fuselage. Once everything was put back in a P40N was only about 200lbs lighter than an M.
there are a few discrepancies about speed also. The 378mph of the N-1 was done using combat or WER and while there is nothing wrong with that (most planes were measured that way) the later P-40Ns were the slowest P-40s ever built using military power ratings. The 378mph was achieved at 10,500ft with the speed falling off both above and below that altitude. WER power only is available at altitudes below the critical height of the engine and the closer to the critical height the closer the WER and military ratings become. once you are above 15,000ft or so the P-40 has 1150hp or less (diminishing with altitude) and with it's weight it is just not competitive with the 109. It is a much better bomber though

 

[billswagger]

I read a pilot interview who had flown all the P-40s, E,F,K,M,and Ns.

He thought that the N was too light, in the sense that the parts sacrificed for weight actually made flying a little more tedious and in some ways less useful as a front line fighter. For example, the removal of the starter meant the aircraft had to be hand started, which prolonged take off procedure.
It was said an E could already have taken off and flown to 10,000ft by the time the N was getting off the ground.
He also favored the K and the F saying there was little difference in performance from what he could tell. He thought they were a good balance for power and weight and at that time, he'd rather be in a P-40 than flying in the heavier P-47s.

As for G-6 comparisons to the P-40, you can find one on Kurfurst's site.
I think its inflated the actual difference in weight between the 109F and G, but perhaps its more about weight distribution which can make a fighter "feel" heavier. The idea the G was a less capable climber is refuted by flight tests that show it took only about five minutes for it to climb to 20k ft.
The P-40 had no chance in that capacity, but the comparison does show the P-40 had better dive and zoom characteristics than the G-6 tested.
I doubt the P-40 matched the actual 109 in zoom climb but if it was able to gain more speed in the dive then the subsequent zoom climb could be higher.
I just have a hard time believing the P-40 out zoom climbed the 109 when there is such a difference in weight and climb performance. It might be true at lower heights.

 

[drgondog]

Given a higher (nominal) wing loading and inferior power to weight ratio, the P-40 could only outzoom a 109 (briefly) with a higher diving speed and pull up. There are circumstances in which a light P-40 vs a max gross weight Me 109 would out perform the 109 in turn and zoom from a dive.

I would not believe that any version of a P-40 could out zoom a 109G (or F) for any reason except (briefly) the rare circumstance that the P-40 entered the engagement with greater energy.

 

[Glider]

This may be of interest.

This excerpt from the book "Black 6":

Squadron Leader Bobby Gibbs, RAAF, at Gambut, Cyrenaica, test flew it: "He had taken to flying mock combat sorties against his unit's P-40 fighters and soon found that the obvious superiority of the German fighter was in danger of demoralizing his men!" In his diary, 14 November 1942, he wrote: "The 109 is a hell of a nice kite with terrific performance. On the lowest permissible boost and revs was clocking 220-230 mph." At Lydda, it under went flight testing by Group Captain Buxton, who said after a second flight, 30 December 1942: "Very good performer," and from Don Batger, 452 Squadron on Buxton's fight: "He turned the 109 inside out and came back and said that it was better than anything we had at the time." (Spitfire Mk V variant).

 

[FLYBOYJ]

Given a higher (nominal) wing loading and inferior power to weight ratio, the P-40 could only outzoom a 109 (briefly) with a higher diving speed and pull up. There are circumstances in which a light P-40 vs a max gross weight Me 109 would out perform the 109 in turn and zoom from a dive.

I would not believe that any version of a P-40 could out zoom a 109G (or F) for any reason except (briefly) the rare circumstance that the P-40 entered the engagement with greater energy.

I think this totally sums up this debate and those pilots who flew the P-40 successfully aganinst the -109 used this situaltion to their advantage.

 

[Kryten]

I have read this thread with interest, and one thought keeps cropping up when combat reports stating who turned tighter than whom are quoted.

If your attacking an enemy aircraft you must be faster than it otherwise you dont get in range, surely the real issue here is if a 109 attacks a P40 it is travelling faster , therefore its turn radius will be greater and the P40 could evade by breaking left or right, but this scenario would then be true if the P40 was the attacker?

the only realistic way to compare the two would be side by side on the same day and same conditions at varying speeds and altitudes?

another quote which made me raise an eyebrow was the "with experienced pilots real maneuvering only started when the slats deployed"
as i understand it the leading edge slat deployed as a function of airspeed to increase the lift of the wing a low speed, if your slats are deployed surely this means your down to zero energy and are in a world of trouble unless the old fighter pilot axim of "speed is life" turns out to be untrue?
or is it just ego trampling on reality?

 

[drgondog]

I have read this thread with interest, and one thought keeps cropping up when combat reports stating who turned tighter than whom are quoted.

If your attacking an enemy aircraft you must be faster than it otherwise you dont get in range, surely the real issue here is if a 109 attacks a P40 it is travelling faster , therefore its turn radius will be greater and the P40 could evade by breaking left or right, but this scenario would then be true if the P40 was the attacker?

Same principle - if either attacker wished to shed energy to stay engaged, then following a deflection shot (that missed) one pursuer in a turn will shed energy with high G/high bank angle turn. If the manuever is continued - it will break down to pilots skill and ability of one airframe over the other.

the only realistic way to compare the two would be side by side on the same day and same conditions at varying speeds and altitudes?

Yes - but to a degree also somewhat subjective unless several pilots of equal skill and familiarity with the aircraft are taking turns - and careful attention to condition of engines, fuel, rigging, etc before flights.

another quote which made me raise an eyebrow was the "with experienced pilots real maneuvering only started when the slats deployed"
as i understand it the leading edge slat deployed as a function of airspeed to increase the lift of the wing a low speed, if your slats are deployed surely this means your down to zero energy and are in a world of trouble unless the old fighter pilot axim of "speed is life" turns out to be untrue?
or is it just ego trampling on reality?

Slats are automatically deployed based on adverse pressure gradients (low speed or high speed 'near stall' conditions)..

 

[Jerry W. Loper]

True they were the mot produced but that also introduces the problem of which P40N or which 109G


I think if you leave off the wing guns the G-6 didn't deteriorate that badly. A bit over the earlier "G"s but they were a bit down hill from the "F"s



Here is the real problem, there wasn't much lightweight structure in a P-40N, aside from aluminum radiators, oil coolers and lighter landing gear(?) most of the weight reduction was in reduced capabilities. Like going from 6 guns to 4 and limiting the ammo to the remaining guns. Removal of one of the interior fuel tanks. Removal of the battery and electric starter on the engine. Removal of the wing bomb racks helped a bit with streamlining. Later versions of the P-40N added everything back in over several production blocks and late P-40Ns were allowed to carry 500lb under each wing in addition to under the fuselage. Once everything was put back in a P40N was only about 200lbs lighter than an M.
there are a few discrepancies about speed also. The 378mph of the N-1 was done using combat or WER and while there is nothing wrong with that (most planes were measured that way) the later P-40Ns were the slowest P-40s ever built using military power ratings. The 378mph was achieved at 10,500ft with the speed falling off both above and below that altitude. WER power only is available at altitudes below the critical height of the engine and the closer to the critical height the closer the WER and military ratings become. once you are above 15,000ft or so the P-40 has 1150hp or less (diminishing with altitude) and with it's weight it is just not competitive with the 109. It is a much better bomber though

I was under the impression that only the earliest production blocks of the P-40N which had the most weight removed had the 378 m.p.h. speed, and that the speed was 35 m.p.h. slower with later blocks that, for one thing, restored the armament from just four .50-caliber guns to six.

 

[billswagger]

I don't think Ns ever competed with 109s did they?
I know many were sent to the USSR on lend lease when they were found to be obsolete to the newer planes.
They appear to have been relegated to mostly bomber/fighter rolls in the Pacific and more commonly used as training aircraft.
There is also info that they were used in escort rolls in the bombing campaigns done in the Aleutians adding to the Ms, Ks and Es.

There apparent advantage was there ability to take off and land on less than ideal surfaces. An example given was that the P-39's tricycle gear was not strong enough to deal with rough landing surfaces and as a consequence only one squadron in the Aleutians was fitted with P-39s.
This advantage of the P-40 also presents itself in the MTO allowing the aircraft to use make-shift airstrips or poorly maintained or battered runways.
Its also been discussed in other articles that the significant weight of the P-40 was due to its landing gear struts and mechanism. Possibly differing as much as a 1000lbs of weight compared to the Zeros (P-40C vs A6M2) landing mechanism.
I've never thought of that particular advantage before because usually comparisons present air to air data, and perhaps the P-40 in some combat zones was more common because of its ability to be flown from less restrictive locations.
The 109 was probably a comparable fighter in that regard given its popularity in almost every front the Luftwaffe fought from.
I wonder if there were any particularities that would limit the 109 in the way of take off or landing surfaces. I would suspect it would be similar to the Spitfire, but then again, it is more of a question about weight distribution.

 

[Shortround6]

I was under the impression that only the earliest production blocks of the P-40N which had the most weight removed had the 378 m.p.h. speed, and that the speed was 35 m.p.h. slower with later blocks that, for one thing, restored the armament from just four .50-caliber guns to six.

You may be quite right, But I believe there were only about 200 of that initial production block built which makes it one of the rarer P-40s. Some of them were also re-equipped when in squadron service with the electric starters, batteries and extra fuselage tank which would leave them somewhere in between in performance. Maybe only a few MPH of the top speed but acceleration and climb would suffer a bit more than speed.
Another explanation of the speed discrepancy is the altitudes involved. Just as many authors claim that the Merlin powered versions showed only a slight improvement over the Allison powered "E"s the truth is a bit different. The "E" maxed out at 15,000ft while the "F" maxed out at 20,000ft. The two maximum speeds were only 5mph apart or so but if the "E" tried to run at 20,000ft it's speed had fallen to a point were it was 30mph slower than the "F".
With supercharger gear ratio used in the engines on the "N" aircraft a WER rating of 1410hp was available at 9,500ft (without ram?) which gives the aircraft it's speed of 378mph at 10,000 or 10,500ft? but as the plane climbs above that hight the supercharger looses the ability to supply the extra air and power falls until there is only 1125hp available at 15,500ft. It is at 15,000ft that the "N"s were rated at 343-348mph. This is about 15mph slower than an "E" at the same hight and "E" had even less power at 15,000ft. It's engine maxed out at 11,700ft at 1150hp and lost power above that hight. (it was good for 1490 hp down at 4,900ft though).
There seems to be very little documentation on the speeds P-40s could reach using WER settings (or their climb rates) which makes comparing action reports using such settings difficult to compare to aircraft which have known speeds, climbs. This may help explain the P-40s advantages at low altitudes though. The P-40K was the most extreme with 1580hp available at just 2,500ft compared to it's take-0ff or military ratings of 1325hp at sea level and 1150hp at 12,000ft. An extra 20% of power in hand that doesn't show up in most performance specifications might make a big difference in what the P-40 K could do under 5,000ft in combat.

 

[cimmee]

I think the P-40 (USAAF) in the MTO, had well over 500 aerial kills. Sure the Bf 109 has the advantage on paper. But it would not be dessert.

Correct...

It depends on the mission.

That is my favorite airplane. The Allison was OK and the Warhawk was a fine a/c.

It was manufactured until the end of the war... I wonder why......

 

[FLYBOYJ]

Correct...

It depends on the mission.

That is my favorite airplane. The Allison was OK and the Warhawk was a fine a/c.

It was manufactured until the end of the war... I wonder why......

Actually it wasn't, production ceased in NOV 44.

 

[billswagger]

Actual combat use probably ended well before Nov 44.

It may still have been used as a bomber in the PTO in outlying islands.
The P-40 made its mark earlier in the war between 41-42 and was somewhat more competitive by 43 with the F and M but it was still well behind the 109 in the altitude regime.
I would only place the P-40 on par or slightly superior to the 109 other the climb and slow turns at lower altitudes.

Bill

 

[claidemore]

After consulting the 'be all and end all' of online resources:
Production of P40s stopped in Nov 44, but the type continued in service (limited) in MTO with USAAF until end of hostilities.
It also served with RAAF in PTO till end of hostilities (Borneo and New Guinea) and was not taken out of service with RAAF till 1947. (eg. 82 Squadron was doing ground attack in March 45 with P40s, converted to P51s in Sept.)
The Netherland East Indies Air Force (attached to RAAF) also operated the P40 till the end of the war and beyond.

 

[JoeB]

After consulting the 'be all and end all' of online resources:
Production of P40s stopped in Nov 44, but the type continued in service (limited) in MTO with USAAF until end of hostilities.

P-40's were phased out of US 12th AF in MTO by 1944 (nor operated by 15h AF in that theater). They (Kittyhawks) however did serve in Italy in Commowealth units (eg. RAAF) until the end of the war. The idea they served in 12th AF in 'be all' sources of web might originate from an error in a table in Kenn Rust's "12th AF Story", which shows 57th FG operating them through end of war, but actually they completed converting to P-47's by early 1944.

P-40's were used by regular USAAF 14th AF units into early 1945 (51st FG), and by Chinese American Composite Wing through the end of the war, and beyond in Chinese Nationalist AF proper, though mainly replaced by P-51's. China is probably the most relevant theater for late P-40 ops because they sometimes met serious fighter opposition which late P-40 ops rarely did elsewhere. As discussed on a thread some time ago, USAAF/CACW P-40 units held their own, at least, in combat with Japanese Army Type 4 (Frank) fighters in 1944-45 when comparing the loss accounts of both sides, in marked contrast to high ratio's early model Zeroes racked up against P-40's in PI, DEI and early New Guinea through mid '42; as always such outcomes are only partly and not mainly about the performance of airplanes.
http://www.ww2aircraft.net/forum/aviation/p-40-vs-late-war-japanese-fighters-10144.html

Joe