Bf-109 vs P-40
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Sorry but he's completely incorrect as usual.
The Bf-109F through to the K series featured these wing specifications: Root = NACA 2R1 14.2% Tip = NACA 2R1 11.35%.
The Emil: Root = NACA 2R1 14.8 Tip = NACA 2R1 11%.
These figures are even listed in Original MTT documents.
And as for the slats, the La-5 has them only to offset the nasty tip stalls that the high taper ratio causes. The high taper ratio was chosen to reduce drag in level flight, but it meant a decrease in turn performance, the slats were then added to solve the issue, bringing the overall Clmax of the wing back to the normal range. The bf-109 on the other hand didn't need the slats, but they were added anyway as they significantly increased the overall Clmax of the wing and therefore the turn performance with it, and as a bonus the landing speed was drastically lowered as-well. The Bf-109F has a landing speed of 135 km/h, which is a good deal lower than the 150 km/h landing speed of the P-40C.
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claidemore
Senior Airman
Hi Soren:
I tend to think of the addition of LE slats the other way round, they lowered landing speed, with a bonus benifit of some improvement in turn at speeds close to the stall. The LE slats on more modern fighters, ie jets, are proven to be very useful, but I feel that Willy Messerschmitt was a little ahead of his time and that on a prop driven fighter, they aren't quite as useful.
Nice to finally see that entire F4 report. My German isn't good, but it seems to me the 1.7 figure is for Camax at a certain bank angle, 15.9 degrees? Not sure how that translates to Clmax in level flight.
I tend to think of the addition of LE slats the other way round, they lowered landing speed, with a bonus benifit of some improvement in turn at speeds close to the stall. The LE slats on more modern fighters, ie jets, are proven to be very useful, but I feel that Willy Messerschmitt was a little ahead of his time and that on a prop driven fighter, they aren't quite as useful.
Nice to finally see that entire F4 report. My German isn't good, but it seems to me the 1.7 figure is for Camax at a certain bank angle, 15.9 degrees? Not sure how that translates to Clmax in level flight.
The Clmax is reached just before the critical AoA at the stall claidemore, which was a good deal higher than 15.9 degrees clean for the Bf-109 
The 15.9 degrees is the stall angle with the flaps gear fully down I assume.
And you don't have to be flying at low speeds for the slats to work Claidemore. Auomatic LE slats work by means of local airpressure, extending at certain AoA's nomatter the speed (Hence why they are so effective on both prop jobs fighter jets alike), and since you can pull hard enough to enter a stall at virtually any speed the slats will always function and increase the lift when needed. In short they increase the critical AoA and lift in the covered areas by ~25%.
On the 109 the slats were primarily added to further improve the turn performance of the a/c. Also you can see on the document that the slats gives the wing an overall increase in lift of 12.3%.
The 15.9 degrees is the stall angle with the flaps gear fully down I assume.And you don't have to be flying at low speeds for the slats to work Claidemore. Auomatic LE slats work by means of local airpressure, extending at certain AoA's nomatter the speed (Hence why they are so effective on both prop jobs fighter jets alike), and since you can pull hard enough to enter a stall at virtually any speed the slats will always function and increase the lift when needed. In short they increase the critical AoA and lift in the covered areas by ~25%.
On the 109 the slats were primarily added to further improve the turn performance of the a/c. Also you can see on the document that the slats gives the wing an overall increase in lift of 12.3%.
"Chuckle"
I would say that completely incorrect, my info was from French and Finnish documents and IMHO French and Finnish expert had fairly good understanding on NACA profiles but as always it's best to check manufactures docus as you did.
BTW Bf 109 F1/F2 Kennblat p. 6 says on landing speed at 2700kg 140km/h IAS, 150 km/h TAS. Bf 109F-4 Datenblatt gives landing speed at 2560kg 135km/h. As always weight has important effect on landing speed.
On LaGG-3, slats were introduced only in serie 35 to combat tip stall but also to minimizes the effect of high wing loading. One clear indication of that is that they were deleted from the lightest development project, Gorboonov I-105 prototypes, Gorboonov was one of the Gs in LaGG, which was lightened and aerodynamically cleaned version of LaGG-3.
Juha
I would say that completely incorrect, my info was from French and Finnish documents and IMHO French and Finnish expert had fairly good understanding on NACA profiles but as always it's best to check manufactures docus as you did.
BTW Bf 109 F1/F2 Kennblat p. 6 says on landing speed at 2700kg 140km/h IAS, 150 km/h TAS. Bf 109F-4 Datenblatt gives landing speed at 2560kg 135km/h. As always weight has important effect on landing speed.
On LaGG-3, slats were introduced only in serie 35 to combat tip stall but also to minimizes the effect of high wing loading. One clear indication of that is that they were deleted from the lightest development project, Gorboonov I-105 prototypes, Gorboonov was one of the Gs in LaGG, which was lightened and aerodynamically cleaned version of LaGG-3.
Juha
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Is it your own extrapolation or data from a MTT either windtunnel report?
Well, I trust your knowledge about Me-109 history, but as a matter of fact j'm looking for Charlais-Meudon report, not Bf 109 pictures. Can you help me on that?
drgondog
Major
Joe - that about sums it up.
Furthermore, dealing with 'historical data' in these forums often draws 'assumptions' not entered into any evidence, and then multiple assumptions ('e', prop activity factors, parasite drag entering a turn, 'Meredith effect', slat behavior in turns, etc - and worst of all no evidence that parasite drag remains the same (it doesn't) as the a/c increase angle of attack) - then plots appear and "aha's" are proclaimed.
Turn performance was not an analytical discipline performed for serious prediction, at least not in US Aviation Design circles. It is far easier to predict level speeds, and extrapolate some variations in angle of attack as the single variable (i.e. no spanwise flow, asymmetric loads, etc) in climb performance.
'Thing's" like manuevering flaps, dive brakes, etc were to a degree trial and error from drawing board to wind tunnel.
Tham
Recruit
The Allison, basically. No other suitable inline
engine available in quantity at that time,
including the Merlin, which was "out of bounds"
to the P-40, until the "F" model.
The alternative wasgoing back to the R1820 as
used in the P-36, or the R2600/2800 which were
probably too big for the P-40's airframe.
Weren't all versions of the P-38's Allisons turbocharged ?
True, ducting or plumbing would be complex, as
in the P-38 and P-47, not to mention the weight,
complexity and reliabilty of the whole works,
including freezing problems in the European
theater as experienced by the P-38s.
" .... from its inception, the Allison V-1710 was
designed to accept a turbo-supercharger. "
Dispatch Archive
The Allison was quite a versatile engine, far more
so than the Merlin which in my opinion was overrated.
" A turbocharged V-1710-F17L/-F17R engine
equipped with ADI produced a WER of 2,300 bhp ... "
Allison V1710 Engine
The F-17R/L engines were the -89/91.
Lockheed P-38H Lightning
33rd Photo Reconnaissance Squadron Online
Interesting threads.
http://www.ww2aircraft.net/forum/aviation/supercharger-vs-turbocharger-2355.html
http://warbirdsforum.com/showthread.php?t=1282
Hello
Argument over turning ability has reigned for a while, so I'll sum my opinion on 109 vs P-40 question.
IMHO P-40 had a few excellent features, early P-40s had excellent roll rate and P-40 was rugged (downsize was that it was heavy with all the penalties which followed that)
Later P-40s (from D / Kittyhawk Mk I onwards) had good rollrate, not so good than the early versions but still clearly better than that of 109s.
P-40 turned slightly better than 109 at low level, higher situation reversed.
But on the other hand Bf 109 was clearly faster, climbed much better and IMHO must have had clearly better acceleration. All these features allowed 109 pilot dominate the combat if he played it right. And IMHO vertical tactic (dive and zoom) was clearly more effective combat method than horizontal (turning fight) so Bf 109 which was better suited to vertical combat but high speed rollrate was IMHO clearly better figher. A bit lightly armed from F onward but MG 151/20 was a good cannon with effective ammo so its armament was adequate to fighter vs fighter combat.
Juha
Argument over turning ability has reigned for a while, so I'll sum my opinion on 109 vs P-40 question.
IMHO P-40 had a few excellent features, early P-40s had excellent roll rate and P-40 was rugged (downsize was that it was heavy with all the penalties which followed that)
Later P-40s (from D / Kittyhawk Mk I onwards) had good rollrate, not so good than the early versions but still clearly better than that of 109s.
P-40 turned slightly better than 109 at low level, higher situation reversed.
But on the other hand Bf 109 was clearly faster, climbed much better and IMHO must have had clearly better acceleration. All these features allowed 109 pilot dominate the combat if he played it right. And IMHO vertical tactic (dive and zoom) was clearly more effective combat method than horizontal (turning fight) so Bf 109 which was better suited to vertical combat but high speed rollrate was IMHO clearly better figher. A bit lightly armed from F onward but MG 151/20 was a good cannon with effective ammo so its armament was adequate to fighter vs fighter combat.
Juha
Colin1
Senior Master Sergeant
All of them except the batch that was supplied to order to the RAF.
It wasn't the complexity of the ducting that I was implyling would be problematic, it was the volume of the ducting - where would it all go in a P-40? They got a turbocharger on board the P-47 and look how big a fighter that turned out to be.
Well, that's not how I understand the history of the V-1710, Allison had attempted to homogenise their manufacturing operation by producing all V-1710 power units in a standard form, this would allow all marks of engine to be produced on one line. If a two-stage supercharger was required it would need to be fitted as a separate unit, external to the engine.
That was for superchargers, I have found no mention of turbochargers.
From what I can gather, Allison and Curtiss joined forces to persuade the USAAC to accept the V-1710's integral mechanical supercharger, this arrangement satisfied existing service requirements.
So, designed from the outset with an integral mechanical supercharger, not a turbocharger.
The Allison went on, somewhat belatedly, to become a very competent high-altitude engine eg in its -143/145 mark but I think describing wartime operational marks as 'versatile vs contemporary Merlins which were overrated' is contentious and you'll be pushed to corroborate your argument with any factual data.
For example, the Merlin addressed the needs of the P-51 in turning it into a high-altitude fighter which proved to be a stepping-stone to long-range escort. In 1942, when Allison produced a two-stage supercharged version of the V-1710, it proved too long to fit in the P-51. Versatile?
The V-1710 was never developed along the lines of the Merlin, it had become too straight-jacketed by Allison management's decision to base their production on a standardised power section.
Yes, and didn't the -89/91 V-1710s suffer from overheating issues?
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J addict in order to support your opinion some BNT (New technology Bureau) NKAP (Ministry of aircraft industry) N°193 and 256 test reports from 1944, 1945
Maксимальные скорости и коэффициенты маневренности
Самолеты Спитфайр F.Mk.IX Кертисс Р-40Е Мустанг Р-51 Эркобра Р-39 Bf 109G-2* Bf 109G-2** FW 190A-4
Max скорость на Н=5000м, км/час 618 574 584 577 610 593 588
Приемистость самолета, м
/с Н=5000м за 60 сек/ 8600 7700 7550 7900 8720 8400 8750
Время виража, сек 17,5 19,4 23,0 19,0 20,0 22,6 22,5
Ускор в гориз плоск. м/сек 30,5 25,9 21,5 27,6 26,4 24,2 26,4
Радиус виража, м 235 242 290 253 290 315 340
So
at 5km altitude P 40E is slower 574 km/h against 610 and 593 for Me 109G2 3guns, 5 guns respectivly
at 5km P40E has worst acceleration 7700m/s in 60s against 8720, 8400.
Time to turn at 1 km high 19,4 vs 20.5 , 22.6 is better for the P-40
Turn radius 242 vs 290, 315 is far better for the P-40
It's radial acceleration is 25.9 m/s , is lower than 109G2 one but higher than 109G2 (26,4) with underwing pods (24,2)
Regards
VG-33
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Thanks a lot VG-33!
And You gave as extras info on Spitfire F.Mk IX, Mustang Mk I?, not sure on that but I know they got at least 4 of those in 1942, P-39, do you know the subtype D-2, N or Q?, and Fw 190A-4. Excellent.
Very much appreciated.
Thankfully
Juha
And You gave as extras info on Spitfire F.Mk IX, Mustang Mk I?, not sure on that but I know they got at least 4 of those in 1942, P-39, do you know the subtype D-2, N or Q?, and Fw 190A-4. Excellent.
Very much appreciated.
Thankfully
Juha
Performance curves? Yes but you have to wait a little, i don't have them with me...
And some P-51D tests from Mark Gallaî memories during Shuttle raids.
19s: Probably a P-39D, with Allison V-1710-35 engine, or some P-39Q with soviet fuel. The D-2 used a more powerfull 1325/1520 WEP HP V-1710-63 wich in turn explain it's very good turning results. The Q a 1200/1420 HP V-1710-83 one. First P-39Q (5-10) were lighter than the latter ones (20-25).
Read Golodnikov at airforce.ru. It's very good since he's very representative for the great majority of the soviet fighter pilots.
Best Regards
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Hello VG-33
Quote:" Performance curves? Yes but you have to wait a little, i don't have them with me..."
I only thanked You for the extra info, gave is past tense, I'm very glad for the extra info, because while I don't speak Russia I know some of Cyril alphabets, so I recognised the a/c types. So I only tried clarify the exact subtypes of some of the types mentioned in the Russian part of Your message. Not that I would say no to the performance curves, extra info is always welcomed.
Yes, airforce.ru is very interesting site, thanks for reminding me on it, it was a year ago when I visited it last time.
Juha
Quote:" Performance curves? Yes but you have to wait a little, i don't have them with me..."
I only thanked You for the extra info, gave is past tense, I'm very glad for the extra info, because while I don't speak Russia I know some of Cyril alphabets, so I recognised the a/c types. So I only tried clarify the exact subtypes of some of the types mentioned in the Russian part of Your message. Not that I would say no to the performance curves, extra info is always welcomed.
Yes, airforce.ru is very interesting site, thanks for reminding me on it, it was a year ago when I visited it last time.
Juha
true i've loss the 5 km but german test give 622 km/h (original tailwheel), and in '44 you can use 1.42 ata.
i read something some trouble on finnish test they haven't the "state of art" (at time) instrumentations
In matter of fact we had state of the art instrumentation developed here, we sold them after the war to Sweden and to Switzerland. But MT-215 didn't has it installed because FAF couldn't spare one for purely tests, So it belonged to a frontline unit during the tests and stayed at Malmi airport and flew combat sorties between the tests.
But the speed test should be OK, there was a bit more doubt on climb tests, at least that is what is written in testreport.
Juha
But the speed test should be OK, there was a bit more doubt on climb tests, at least that is what is written in testreport.
Juha
claidemore
Senior Airman
Juha, VG-33, you guys bring up some of the most interesting information. Thanks a bunch guys.
Claidemore
Claidemore
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Thank you, but i have maid a mistake, max speed for the P-40E was 574 km/h. 577 is the value for the P-39D, so the 360°/19s turn rate.
Link:
http://base13.glasnet.ru/text/p39bakur/p39.htm
Regards
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