# Best Messerschmitt Bf109 subtype



## claidemore (Apr 1, 2008)

This poll thread area has been kinda slow lately. 
I'm curious, what in your opinion was the best Bf109? There are a lot of choices, but I'll go with eight general subtypes that should encourage some discussion, Bf109 A/B/C/D, E3-7, F2/F4, G2, G6, G10,G14, K4. 

Claidemore


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## DerAdlerIstGelandet (Apr 1, 2008)

I personally like the G-6 the best. I think it was a good all around varient. It combined good speed with decent handling. Was it the best fighter of the war? By no means but it was a competitor.


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## Juha (Apr 1, 2008)

To me definitely 109F-4, IMHO the best fighter around when it began its front-line service, maybe a bit lightly armed but anyway MG 151/20 was an effective cannon with very good ammo.
E-3/-4/-7 were also top class at their time but IMHO not so outstanding as F series in its haydays.
IMHO early Gs lost the relative supremacy of Fs, mostly because problems with DB 605A. In itself for example the thicker skin of the wings was necessary improvement but because the use of 1,42 ata in DB 605A was forbidden rather long time the extra weight had negative effect. IMHO during the reign of early Gs other fighters catch up and some even overtook 109.

IMHO with G-10 109 again reached at least near parity with the best enemy fighters.

Juha


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## kool kitty89 (Apr 1, 2008)

*Erich* has posted that the G-10 was the fastest (even more than the K-4 at 460 mph iirc) on several threads, but this doesn't seem to match up with figures I've seen.

Most sources show it was still quite fast though with most figures giving ~440 mph as max speed.


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## drgondog (Apr 1, 2008)

Juha said:


> To me definitely 109F-4, IMHO the best fighter around when it began its front-line service, maybe a bit lightly armed but anyway MG 151/20 was an effective cannon with very good ammo.
> E-3/-4/-7 were also top class at their time but IMHO not so outstanding as F series in its haydays.
> IMHO early Gs lost the relative supremacy of Fs, mostly because problems with DB 605A. In itself for example the thicker skin of the wings was necessary improvement but because the use of 1,42 ata in DB 605A was forbidden rather long time the extra weight had negative effect. IMHO during the reign of early Gs other fighters catch up and some even overtook 109.
> 
> ...



I am torn based on 'the mission' - I would favor the F in the east where high altitude performance was not as critical as bomber defense in West.

Then the question of G-10 versus G-6 is another of those questions about 'what are we trying to fight?

The A/S certainly had good performance where they needed to fight US Escorts - so did the -10 and the -10 had better mid altitude/low altitude performance than the G-6 if I recall correctly?


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## pbfoot (Apr 1, 2008)

this is my reason
look you guys in California and Australia green grass


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## claidemore (Apr 1, 2008)

My pick of this litter is the 109 G1/G2. The G2 was in IMO, the ultimate 109, because it was the model flown at the zenith of Luftwaffe power. 1942 saw the furthest expansion of the Reich in the east, and the G2 was a big part of that. Earlier models didn't have the performance superiority the G2 enjoyed over it's enemies, and later models were faced with fighting a retreating battle against better and better planes in ever increasing numbers. 

I feel the G2 was the last improvement of the 109 (except 109 K4) where it didn't lose substantially in one capability or performance area to gain in another. I think from a design standpoint, the G2 was a highpoint before they started moving away from Messerschmitts original concept of building the lightest plane possible with the most powerful engine available. The K4 was a return to that philosophy, but a day late and a dollar short.


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## Fokker D21 (Apr 1, 2008)

The 109 F is praised by Luftwaffe pilots as the best flying one. The 109 K4 had superb climbing capabilities and a high speed. I choose the K4.


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## Konigstiger205 (Apr 2, 2008)

I'll go with the G6, highly versatile with lots of mounts, it could be adapted to fighter, bomber and ground attack plane.I also like the K version but that appeared late in the war and the materials used were not so good.


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## rochie (Apr 2, 2008)

i voted for the G6 it seems to be the best allrounder but the emil looks to me to be the classic bf109


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## Zarathos (Apr 2, 2008)

F2/F4 - it was the plane, that kicked RAF during Kanalkampf and, in my personal opinion, _the_ final stage of Bf 109 developement. G and K were just an attemt to make use of outdated airframe by placing stronger engine in it.


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## Juha (Apr 2, 2008)

Drgondog
I admit that G was a logical response to changing requirements of air war but
my reasoning went like this, 109E was better than other fighters but Spitfire in 1939-40 and E and Spit Mk I/II were more or less equal.
109F was better than any other fighter in 41-mid 42. Especially F-4 from mid41 to mid-42.
109G-2 superiority lasted only a couple months before Spit Mk IX arrived, after that IMHO Spit IX was a better fighter than G-2/-4/-6. And anyway Spit Mk IX , LaGG-3 Series 66 , La-5F or La-5FN were more dangerous enemies to 109G-6 than Spit V, LaGG-3 series 3, MiG-3 (very high altitude excluded), I-16 or P-40 had been to 109F-4. So I have looked the question from a bit different viewpoint.

Juha


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## Fokker D21 (Apr 2, 2008)

Was an early Spitfire MK9 really better than a Me 109 G2?

Topspeed of the 109 G2 at combat rating (30 minutes) is 649 km/h.
Topspeed of the Spitfire Mk9 F at emergency rating (5 minutes) is 656 km/h.

That makes the 109 relative the much faster plane.


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## drgondog (Apr 2, 2008)

Fokker D21 said:


> Was an early Spitfire MK9 really better than a Me 109 G2?
> 
> Topspeed of the 109 G2 at combat rating (30 minutes) is 649 km/h.
> Topspeed of the Spitfire Mk9 F at emergency rating (5 minutes) is 656 km/h.
> ...



Not for the five minutes that may count the most? how is 7km/hr slower 'much faster'..

If the 109 was chasing a Spit on a long run he would have an edge. Most fights didn't last more than 5 minutes at WEP..

But the argument is best 109. I have said for me that its tough to say. I agree with Juha that for its time the F2/F4 may have been the best relative to its opponents. I would have a far harder time making the statement that any Me 109 variant was better than say a Spit XIV or a P-51B or an Fw190D-9 or Tempest V. Pilot skill and numbers dictated fortunes in 1944 and 1945.

I ended up picking the -10 based on observations Rall and several others made even though the K-4 had better performance.. for some reason more than a few of the 'old hands' felt more secure in the G-10 than the K-4.. all that I have ever talked to liked the F2/F4 but the competition the F2/4 faced was not the same as the G and K series in a much more hostile environment.

Regards,

Bill


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## Hunter368 (Apr 2, 2008)

Agreed Bill,

I like your comment "Pilot skill and numbers dictated fortunes in 1944 and 1945", thats so very true.


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## claidemore (Apr 2, 2008)

Fokker D21 said:


> Was an early Spitfire MK9 really better than a Me 109 G2?
> 
> Topspeed of the 109 G2 at combat rating (30 minutes) is 649 km/h.
> Topspeed of the Spitfire Mk9 F at emergency rating (5 minutes) is 656 km/h.
> ...



Those are top speed figures for one altitude, and not the same altitude at that. At 33,000 feet the Mk IX is 45 mph/72 kmh faster, at 15/16000 feet they are exactly the same speed. Thats at 15lb boost combat rating for the Spit IX Merlin 61. 

Better performing Merlin 66 and 70 Mk IXs in early 1943 would have squared off against G4's, which had exact same performance as G2. 

Of course top speed doesn't make a plane better, we have to look at all of its capabilites. Mk IX had twice the firepower of the 'clean' G2, had higher ceiling, smaller turn radius and shorter turn times (by about 2 seconds, which ain't much). Climb rate was very similar, and the 109G2 had quicker initial dive. MkIX had better visibility form the cockpit and lighter controls during high speed pullouts. 

I think the G2 was as close a match for the Mk IX as the 109E was for the Mk1, but to say it was better would be ignoring too many factors.


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## Fokker D21 (Apr 2, 2008)

I didn't say the 109 G2 is better, merely that the Spit might not have been so superior as often assumed. Most Spitfire Mk9's were Low Flying variants though. (4010 LF, 1255 F and only 400 HF = 5665 Spit MK9).

The three Spit versions have very different top speeds at different altitudes. For an honest comparison the Spit Mk9 HF (Merlin 70) should be compared with a 109 G1 with GM 1 installation (not a 109 G2).

On paper the Spit has twice the firepower, the central placed guns on the 109 compensate this at least partially. The ammo load for the 109 is not that far behind, 200 versus 240 cannon rounds and 1000 versus 1400 machine gun rounds. And if the cannons were depleted you better consider going home.

At 33000 feet the speed of a 109 G2 at combat rating is 398 mph. Add 45 mph and you get a Spit Mk9's top speed to be 443 mph. No Spit Mk 9 version was that fast. With Merlin 66 at 25 lbs boost the top speed at 25000 feet is 394 mph, any higher altitude results in a lower top speed.

At around 15000 feet the 109 G2 does 386 mph at combat rating, the merlin 66 engined Spit does 373 mph at 18 lbs boost. Only the later use of 25 lbs boost brought the Spit up to 397 mph in 1943.


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## Glider (Apr 2, 2008)

Persoanlly I went for the Emil. The reason being it dominated the opposition in the first year of the war and ruled the skies over France. 
Only over the UK in the BOB did it meet a plane that was its equal and even here it had two priceless advantages
1) Its cannons.
2) The Fuel injected engine

The first gave it a punch that totally outclassed the 8 x LMG, which in itself, was at least as good if not better than any other non German fighter in the air.
The second gave it an evasion tactic that was both effective and very simple to use by any German pilot, of almost any level of experience.

We can (and have) debated the later versions against the opposition but in its time the Emil was the one to beat.


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## kool kitty89 (Apr 2, 2008)

Twice the number of guns doesn't mean twice as good an armament, especially in a Fighter vs Fighter sense. The 'clean' 109G-2 had all its armament nose mounted making it much more accurate with no convergence zone and simpler aiming. That said the Spit still had a slight edge with better spread and more round out there making a hit more likely at least near the convergence zone. And the single MG 151/20 was certainly better than the 2x MG FF of the 109E, particularly in a dogfight. (due to the poor velocity and RoF of the FF gun, and the wing mounting)

That changed once the 109 got the 13mm guns though. (I'd say it had the edge, even with the Spit's 2x 20mm 2x .50 cal armament)



But we're getting off topic. The best true "dogfighter" 109 would probably be the F-2/4 with the best agility. The Armament was better than the Emil's, except maybe the (relatively) weak 15mm gun, though in a dogfight it would probably be superior and it had excellent velocity and decent RoF and ballistics as well.

I'm still wondering about the performance of the G-10 though...


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## claidemore (Apr 2, 2008)

I guess I should clarify my argument about the Spitfire weapon advantage. 

The Spitfire with 2 x 20mm Hispano II and 4 x .303 Brownings was putting out 133.2 lbs of projectiles per second. 

The 109G2, with 1 x 20mm Mg151 and 2 x 7.92 Mg17, put out 64.4 lbs of projectile/second. 

Thats better than double the weight of projectiles per second. Add to that a 2 x 25% greater explosive charge of the twin 130 gram Hispano cannon shells vs the 105 gram Mg151 shell, and the 880mps velocity of the 20x110 Hispano vs the 725 mps of the Mg 151 20x 82 and you see quite a marked advantage to the Spitfire. All those numbers from this website:

The WWII Fighter Gun Debate: Gun Tables


But, KK makes a good point about the 13mm armed G6 onwards, that gave the plane 94lbs/second, with the E wing Spit at 130.8lbs/sec and B wing at 133.2lbs/sec. 
Better, but still not equal. (the l/s figures for the.50 mg on that site are incorrect)
The .50 is 880m/s, (130m/s faster than Mg131) same as the Hispano, so that would make aiming simple for the first couple hundred meters. 

Stick two wing cannon gondolas on the 109 and you get 124 lb/s for G2 and 154 lb/s for G6> with subsequent loss in other performance areas.

Nobody is voting for the ABCD 109, those models were the absolute best monoplane fighters in the world during their time weren't they?


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## Fokker D21 (Apr 2, 2008)

The Hispano II HE round has 8% HEI * 130 gram projectile = 10,4 grams of high explosive.

The MG 151/20 HEM round has 21,7% HEI * 92 gram projectile = 19,964 grams of high explosive.

That gives the MG 151/20 the advantage in HE of almost 2 to 1 (the numbers come from Tony Williams website who wrote a book about the subject together with the writer of the gun debate website).

Muzzle velocity for HE rounds is not very important (according to the same website).

Also see my website below about this subject. The Hispano wins the kinetic contest but the MG 151/20 wins the chemical (HE) contest.

I agree that the MG 151/20 API and HET rounds are not very strong but the HEM round more than compensates for this. The Hispano SAPI and HE round are more equally matched. Add to that a higher rate of fire (700 versus 600 rpm) for the Mg 151/20 and both guns turn out to be pretty equal in power.


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## Fokker D21 (Apr 2, 2008)

The strongest opponent for the 109 B, C, D variants was the Polikarpov I-16. It had about the same speed but was more agile and had a much better armament with 4 ShKas fast firing machine guns (2 x 1800 rpm unsynchronized and 2 x 1400 rpm synchronized).

The 109 was however at the beginning of its development stage, the I-16 at its end.


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## Juha (Apr 2, 2008)

And French AF Curtiss Hawk 75As seemed to have been more than match to 109Ds in early 1940.

Juha


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## HoHun (Apr 2, 2008)

Hi Claidemore,

>The Spitfire with 2 x 20mm Hispano II and 4 x .303 Brownings was putting out 133.2 lbs of projectiles per second. 

>The 109G2, with 1 x 20mm Mg151 and 2 x 7.92 Mg17, put out 64.4 lbs of projectile/second. 

Hm, let's have a look at the actual firepower instead of mere projectile mass (using international decimal separators):

Spitfire: 

2x Hispano II: 2x 1,06 MW
4x Browning ,303: 4x 0,09 MW

Total 2,48 MW

Me 109G-2: 

1x MG 151/20: 1,27 MW
2x MG 17: 2x 0,09 MW

Total 1,45 MW or 58% of the Spitfires.

However, with the centreline position of the Messerschmitt's armament and the extreme outboard position of the Spitfire's machine guns, I'd still consider both weapons systems as about equal.

The Me 109's hub cannon has about half the dispersion (four times the fire concentration) of the Spitfire's wing cannon, and there no problems with wing flex shifting the aim point during turns. Besides, there is no need to compensate for convergence/divergence of wing guns in relation to range, so aiming is considerably simpler for the Me 109 pilot.

Regards,

Henning (HoHun)


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## Fokker D21 (Apr 2, 2008)

The French Hawks were delivered first in December 1938. The first Me 109 E were also completed at the end of 1938. Providing that it took the same time to get the aircraft into service the rival of the Hawk is the 109 E (not the D).

My country also ordered these aircraft, unfortunately they arrived too late.


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## HoHun (Apr 2, 2008)

Hi Fokker,

>Providing that it took the same time to get the aircraft into service the rival of the Hawk is the 109 E (not the D).

It seems that the Bf 109D met the Hawk 75 in combat, as Osprey's "Bf 109 D/E Aces of the Blitzkrieg" mentions an engagement between 27 Doras of JGr 102 and 9 Hawks guarding a Potez 63 reconnaissance aircraft. 

The score was 4 Me 109s shot down and another 5 crash-landed against just 1 Hawk shot down. (It appears that the Messerschmitts tried to bounce the Hawks, so it's not like they were caught unaware.)

The Me 109E certainly was a tough opponent for the Hawk, but I'd say the Me 109D was outperformed due to its much less powerful engine.

Regards,

Henning (HoHun)


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## claidemore (Apr 2, 2008)

Bookmarked your site Fokker, will read it as I get time, theres a lot there. Good info in your post too!

Questions,(which i might answer myself as I read further) 
-Why did the 130 gram Hispano HEI (that's High Explosive Incendiary? right?) round have so much less explosive material? 
-Did the Hispano rounds have heavier jackets, thereby making them less frangible?
-Did they use a different explosive material than the Germans? 
-Did that 130 gram round have more incendiary material if it had less explosive stuff (I'm using the technical form of the word "stuff") ? 

BTW, the longer heavier Hispano round would have a much higher ballistic coeffficient, making it more accurate. 

Post war investigation of downed planes showed that it was incendiary rounds that contributed the most, so agree that AP was not as important.


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## lesofprimus (Apr 2, 2008)

I voted for the F series... I think it was the most superior vs. its opponent than any other version... The 4-5 Vets I talked to concerning the 109 all said the same thing....

Thats good enough for me...


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## claidemore (Apr 2, 2008)

Hi Fokker;

After a bit of perusal of your website, which is excellent BTW:

Mg 151 HEM (thin walled shell) had 19 grams of explosive, while the HET had only 3.68 grams. 
The Hispano had 10.4 grams in the HEI round. 

I think that answered some of my questions! 

Anybody know the usual mix of API, HET and HEM in the 109? and the mix of API and HEI in the Spitfire?


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## HoHun (Apr 3, 2008)

Hi Claidemore,

>Anybody know the usual mix of API, HET and HEM in the 109? 

According to the Schießfibel manual, 13 was found to be the best combination against fighters.

>and the mix of API and HEI in the Spitfire?

As they have virtually the same total energy, it doesn't really matter. I think Tony once pointed out that early on, there were actually ordinary steel "ball" rounds were used in the mix, substituting for one of the shell types, but I'm not certain that he was able to pin down the exact time ball was abandoned.

(My above calculations are based on an even API/HEI mix without ball. If it's used, Hispano II firepower drops below the figure I gave.)

Regards,

Henning (HoHun)


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## kool kitty89 (Apr 3, 2008)

And a 25% heavier projectile doesn't mean 25% more filler.
The MG 151/20 used the Mine Round ammo with a much higher % filler than normal, this also resulted in a lighter, less dense round. (due to less metal content)

I don't have figures for the Hispan ammo but for the MG 151/20:

AP - round weight of 117 g. 
HE - round weight of 115 g. HE filler: 3.6 g 
HE(M) - Minengeschoß ("mine shell") - round weight of 92 g. HE filler: 18 g 
HE(XM) - round weight of 104g. HE filler: 25 g 


Though the Hispao gun did have a somewhat higher muzzel velocity and muzel power (and a higher recoil force), it was a bit heavier as well and had a lower max ammo load. (150 rounds with belt feed iirc, opposed to well over 200 rounds for the 151/20; though in later developments this did change)


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## SpitfireKing (Apr 3, 2008)

Unfortunatley, I prove my ignorance on aircraft. I chose the variants as a guess, brand me as a heretic if you must, I say what I say, and I did because I just felt like it.


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## kool kitty89 (Apr 3, 2008)

I missed Fokker's earlier comment that already explained the HE difference:


> The Hispano II HE round has 8% HEI * 130 gram projectile = 10.4 grams of high explosive.
> 
> The MG 151/20 HEM round has 21,7% HEI * 92 gram projectile = 19.964 grams of high explosive.



And as I posted the HE(XM) - round weight of 104g. HE filler: 25 g 

Widened this gap even further; but it should also be noted that while actual kinetic energy of the round doesn't matter too much for a HE shell, muzzle velocity (and balitic shape) always matter for trajectory/range reasons.


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## lesofprimus (Apr 3, 2008)

SpitfireKing said:


> Unfortunatley, I prove my ignorance on aircraft. I chose the variants as a guess, brand me as a hertic if you must, I say what I say, and I did because I just felt like it.


This is a perfect example of why these Polls are usually bogus...

And for the record, we dont need ur stupid ignorant comments as to why... And what the fu*k is a hertic??


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## Fokker D21 (Apr 3, 2008)

The Hispano was used with a 1 to 1 ratio (SAPI to HE).

The MG 151/20 was used in the ratio's 1 to 1 to 1 and 1 to 2 to 2 and 1 to 1 to 3 (HET to API to HEM).

It depended on the type of target. Against bombers the ammo make up was 1 to 1 to 3, against heavily armored Il-2 the make up was 1 to 2 to 2 or perhaps even 1 to 2 to 1

Local commanders had the freedom to make their own choices in ammo make up.

The Germans found out that HE rounds were more effective in air combat (except against heavily armored planes). So they came up with the idea of an extreme thin walled round (Minengeschoss) , with more HE capacity.

Both 20mm and 30 mm guns got a HEM round. The 30mm is even much more powerful.


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## Fokker D21 (Apr 3, 2008)

> It seems that the Bf 109D met the Hawk 75 in combat, as Osprey's "Bf 109 D/E Aces of the Blitzkrieg" mentions an engagement between 27 Doras of JGr 102 and 9 Hawks guarding a Potez 63 reconnaissance aircraft.
> 
> The score was 4 Me 109s shot down and another 5 crash-landed against just 1 Hawk shot down. (It appears that the Messerschmitts tried to bounce the Hawks, so it's not like they were caught unaware.)




It proves that the 109 D was quickly becoming obsolete. Probably why it doesn't get many votes.


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## kool kitty89 (Apr 3, 2008)

> It proves that the 109 D was quickly becoming obsolete. Probably why it doesn't get many votes.



??? What was that in response to?

And the 
HE(M) - Minengeschoß ("mine shell") - round weight of 92 g. HE filler: 18 g 
should later have been upgraded to the
HE(XM) - round weight of 104g. HE filler: 25 g 
which had the HE filler much more compressed along with a slightly different shell casing.


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## Kurfürst (Apr 4, 2008)

I would tend to go with the G-1/G-2. These were matured designs, with multirole capabilty, excellent performance at all altitudes easily converted to special tasks; they also made quite an impression on evaluation teams, particularly in Russia and in North Africa, where they were most heavily faced; they can be argued to be the best fighters in the World when they appeared, but certainly in top 5, with a good degree of superiority over the _most common_ (which were not neccesarily the latest) enemy types they faced.

Overall, the things that make me consider them the best of the 109 lineage is their maturity as a design, their availability (a bit connected to the last point as they required little changes, and thus could be produced quickly) and their relative performance compared to the opposition they faced; as Bill pointed out, the later, more 'ultimate' variants may be a tempting choice, but the late war enviroment was a much more challanging one, both in terms of opposing aircraft quality and the overall situation in the air..


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## claidemore (Apr 4, 2008)

Agree with you 100% Kurfurst. 

Claidemore


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## Fokker D21 (Apr 8, 2008)

> I would tend to go with the G-1/G-2



Kurfürst, at what time did the 109 G6 finallly get approval for emergency rating (notleistung)? And was combat rating (kampfleistung) as a maximum for the 109 G2 a disadvantage in air combat?


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## Kurfürst (Apr 9, 2008)

1,42ata was finally cleared in October 1943. There`s clear indication that it was cleared before, in November 1942, and June 1943, but was probably recalled in those two earlier instances.

As for 1.3ata for the G-2 (and G-6) until the automn of 1943, I wouldn`t say it was that much of a disadvantage - especially the G-2 had excellent performance anyway..


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## Soren (Apr 10, 2008)

The K-4 because it was more aerodynamically clean than the previous versions and boasted an unrivalled climb rate of some 5,000 + ft/min and turned better than the latest Spitfire. 

Pretty awesome with a 645 km/h cruising speed as-well.


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## flojo (Apr 17, 2008)

Soren said:


> The K-4 because it was more aerodynamically clean than the previous versions and boasted an unrivalled climb rate of some 5,000 + ft/min and turned better than the latest Spitfire.
> 
> Pretty awesome with a 645 km/h cruising speed as-well.



What is the source of the information that the K4 turned better than the latest Spitfires. Was any K4 tested against Mk14 or MK21 at the end or after the war?


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## Soren (Apr 22, 2008)

The source is aerodynamics flojo. 

When it comes to turn performance there are a number of very important factors to consider:

1.) The weight size of the aircraft 
2.) The Clmax of the wing 
3.) The Aspect ratio of the wing (The e-factor needs to be taking into consideration for better accuracy)
4.) The power available
5.) The Cd value of the a/c ( Cd = Cd0 + Cdi)


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## Hunter368 (Apr 22, 2008)

Soren said:


> The K-4 because it was more aerodynamically clean than the previous versions and boasted an unrivalled climb rate of some 5,000 + ft/min and turned better than the latest Spitfire.
> 
> Pretty awesome with a 645 km/h cruising speed as-well.



At what speed could it out turn a Spitfire ? At what height is that at?


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## drgondog (Apr 22, 2008)

Soren said:


> The source is aerodynamics flojo.
> 
> When it comes to turn performance there are a number of very important factors to consider:
> 
> ...



You didn't present 'sources', Soren. 

You present several calculation factors, but you don't present all the ones desirable to ATTEMPT to model relative turn performance.

There are 'opinions' based on standard aircraft 'rules' of thumb to predict a rough estimate of performance.

You are expressing an opinion not based on an unimpeachable model, not tested, not tested under controlled conditions and not verified.

You have left out several 'model' factors that are also important such as the more efficient load distribution of the elliptical wing, the stiffness of the wing, the static stick free margins with respect to stability, the effectiveness of the rudder, the relative aerodynamics - particulary at near separation angles of attack - for flow over rudder and elevator, the control forces required to sustain a high speed/High G turn..., the relative stability in pitch and yaw for large asymetric loads, 

The relative Drag comparisons to help estimate the energy 'bleed' at different flight envelopes.

etc, etc.

Do you have all those factors at hand and could you actually use them to prove your thesis?

You are entitled to your opinion, but he asked you a polite question about sources and you blew it off with your standard Aerodynamics mantra.

I am pretty sure you can not... anymore than I could disprove your statement. I don't have all the data necessary to attempt a sophisticated model for either aircraft. The primary difference is that I know what I don't know.

It is a lot tougher to a.) model asymetric flight conditions, and b.) have them match closely with controlled tests.

Why don't you answer a question like that with some opinions based on fact, acknowledge facts you don't know which could alter your opinion - and leave it as an Opinion?


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## DerAdlerIstGelandet (Apr 22, 2008)

Soren said:


> The source is aerodynamics flojo.
> 
> When it comes to turn performance there are a number of very important factors to consider:
> 
> ...



Then let us see it by a reputable source.


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## claidemore (Apr 22, 2008)

Would love to see the figures that 'prove' that turn superiority. 


Climb rate was definately not unrivalled, we proved conclusively that the Mk IX and Mk XIV outclimbed 109K4's in another thread. Only one existing test performance chart shows climb rate of just under 25m/s (4900 ft/min) with 1.98ata and MW50 (which 'may' have seen limited operational service with a combat trial unit), and Mk XIV charts show regular 'operational' planes exceeding that rate. There was also at least two squadron of operational Mk IXs with 25lb boost that had climb rates in the neighborhood of +5700 ft/min in May of 1944.

The K4 was definately the best climbing 109, and also the fastest climbing axis fighter, but it was not unrivalled by its opponents.


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## Lucky13 (Apr 22, 2008)

I don't know squat about the Bf 109 and its sub variants as such. But, I have always had a soft spot for the F and G variants...so I'm gonna read more of the discussion before voting....
Best sub variant of the Bf 109? Wouldn't each variant of the 109 be the best one in its respective period of time?


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## Soren (Apr 22, 2008)

drgondog said:


> You didn't present 'sources', Soren.
> 
> You present several calculation factors, but you don't present all the ones desirable to ATTEMPT to model relative turn performance.
> 
> ...



Errr, Bill this isn't just some "rule of thumb" presentation, we can quite easily calculate the capability of these fighters in the horizontal if we have the following figures from windtunnel data: Cd0, Clmax and thrust by prop at specific engine output. We know the weight and dimensions so the rest is easy.

Remember we're not trying to predict stability, stall angle or anything in that spectrum. 

We're not designing a new a/c here Bill, we have the data we need from windtunnel tests. Don't make it harder than it is


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## Soren (Apr 22, 2008)

claidemore said:


> Climb rate was definately not unrivalled, we proved conclusively that the Mk IX and Mk XIV outclimbed 109K4's in another thread. Only one existing test performance chart shows climb rate of just under 25m/s (4900 ft/min) with 1.98ata and MW50 (which 'may' have seen limited operational service with a combat trial unit),



Claidemore that performance chart was an estimate with a thinner prop which increased speed but also decreased climb rate, plus rads were assumed open. Climb rate with rads closed and with the std. prop were no doubt in the 5,000 + ft/min area.


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## claidemore (Apr 22, 2008)

Soren:

Maybe, but the K4 @1.8 ata (with the production prop?) climbs at 4035 ft/min, so boosting it to 1.98 is unlikely to jump it past 5000 ft/min, IMO. 

Spitfire tests were done with open rads as well, they had automatic rad flaps without manual override so the comparison is a fair one. 

Climb rates for Mk XIV at 21 lbs or 25 lbs boost would also be MUCH higher than 5000 ft/min. It's just no contest in the climbing department against the late marks of Spitfire. 

I can offer a couple simple figures in the turn debate. Assuming the oft quoted clmax of 1.7 for the 109, stall speed @ sea level would be 100mph. The MkXIV stall speed according to the pilot notes is 85 mph. An obvious turn advantage at max turn rate hovering just above the stall.

In a higher speed sustained turn, the Mk XIV with 25lbs boost producing better than 2400 hp at low alt, with a much lower wingloading than the K4, would again have a significant advantage.


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## kool kitty89 (Apr 22, 2008)

Wingloading isn't lift loading... You need to consider CL, and the CL of the 109's airfoil is a bit higher than the Spit's and the LE slats add another ~25% to CLmax. Sot the Spit would have to have well over 25% lower wing loading to have an advantage. (closer to 35% lower)

But the Spit's eliptical wing did offer a good lift to drag ratio.


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## drgondog (Apr 22, 2008)

Soren said:


> Errr, Bill this isn't just some "rule of thumb" presentation, we can quite easily calculate the capability of these fighters in the horizontal if we have the following figures from windtunnel data: Cd0, Clmax and thrust by prop at specific engine output. We know the weight and dimensions so the rest is easy.
> 
> *Soren, 'easy'for you often translates into 'wrong'. Aircraft have different stability characteristics in high G loading... e.g. Nobody predicted viloent snap roll stall conditions in low speed high G turn for an Fw 190 because aerolasticity was not a well understood science. At stall in a high G turn the predictions of boundary layer separation within several degrees may become an exercise in Chaos Theory.. CL degradation in a statistical context can be huge if a 3 degree window.*
> 
> ...



Don't make it easier than it is. Start producing facts and sources.


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## drgondog (Apr 22, 2008)

kool kitty89 said:


> Wingloading isn't lift loading... You need to consider CL, and the CL of the 109's airfoil is a bit higher than the Spit's and the LE slats add another ~25% to CLmax. Sot the Spit would have to have well over 25% lower wing loading to have an advantage. (closer to 35% lower)
> 
> But the Spit's eliptical wing did offer a good lift to drag ratio.



The lift distribution for the Spit/P-47 eliptical wing planform was superior to the Mustang/Fw 190 and Me 109 trapezoidal plan form..

This (theoretically and realistically) gave the Spit an imprecise advantage over a similar CL in either a 51 or 190 or a 109 for same aspect ratio and CLmax. The real question is 'how much' - also more efficient in induced drag - but nobody on this forum can answer that question - at least he/she has not made him/her self known.


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## claidemore (Apr 22, 2008)

kool kitty89 said:


> Wingloading isn't lift loading... You need to consider CL, and the CL of the 109's airfoil is a bit higher than the Spit's and the LE slats add another ~25% to CLmax. Sot the Spit would have to have well over 25% lower wing loading to have an advantage. (closer to 35% lower)
> 
> But the Spit's eliptical wing did offer a good lift to drag ratio.



Like I said, I can only offer simple figures. Wingloading is considered a good general indicator of turn performance, generally speaking lower wingloading = better turn performance, all other factors being equal. 

Simple don't always mean wrong. 

*Wingloading *of the MkXIV was 35.1 lbs/sq ft, 30.7 for the Mk IX and 43.4 lbs/sq ft for the 109K4. That's a 21% advantage for Mk XIV and 29% advantage for Mk IX. 

As I mentioned, the 109 wing is often quoted as having a clmax of 1.7 *with slats deployed* and possibly *with combat flaps deployed*. (The RAE tests seem to indicate that their clmax calculations were with both slats and combat flaps.) Without slats, it is assumed to be 1.4. The slats therefore only give an 18% increase in cl. 

The Spitfire MK IX is generally given a clmax of 1.6, a figure which my calculations support. In my calculations for the Mk XIV with stall speed of 85 mph (as indicated in the pilots notes) and weight of 8500 lbs I get a clmax of 1.9.


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## kool kitty89 (Apr 23, 2008)

Okay, I don't remember the Spit's CL being anywhere near that high (in the 1.34 region is what I remember) that would change things alot. This isn't with flaps is it? And did the Spit ever even get a combat/maneuvering setting for the flaps?


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## DerAdlerIstGelandet (Apr 23, 2008)

Still waiting on a reputable source...


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## Kurfürst (Apr 23, 2008)

claidemore said:


> Would love to see the figures that 'prove' that turn superiority.



I think an educated guess can be made using assumed values of drag, Oswald effiency etc. Then these can be applied to different altitudes.



claidemore said:


> Climb rate was definately not unrivalled, we proved conclusively that the Mk IX and Mk XIV outclimbed 109K4's in another thread.



I don`t think so.



> Only one existing test performance chart shows climb rate of just under 25m/s (4900 ft/min) with 1.98ata and MW50 (which 'may' have seen limited operational service with a combat trial unit), and Mk XIV charts show regular 'operational' planes exceeding that rate.



I would like to see that Mk XIV climb chart. I doubt it even exists.



> There was also at least two squadron of operational Mk IXs with 25lb boost that had climb rates in the neighborhood of +5700 ft/min in May of 1944.



The figures you are using are referring to climb test done with a Mk IX missing ca. 300 lbs takeoff weight. Of course it climbs faster.

Remove 300 lbs from any plane, and it will climb faster, too.



> The K4 was definately the best climbing 109, and also the fastest climbing axis fighter, but it was not unrivalled by its opponents.



I`d say the fastest climbing 109 was the G-10 at 1.98ata. 
The fastest climbing Axis fighter would be the Me 163, though, I don`t think there`s much comparison with... what, _160_ m/sec IIRC? 



> Climb rates for Mk XIV at 21 lbs or 25 lbs boost would also be MUCH higher than 5000 ft/min. It's just no contest in the climbing department against the late marks of Spitfire.
> ...
> In a higher speed sustained turn, the Mk XIV with 25lbs boost producing better than 2400 hp at low alt, with a much lower wingloading than the K4, would again have a significant advantage.



It is a pity that +25 lbs was never cleared or used by the Griffon engined XIV operationally. I think it was tested once, and the engine immidiately failed. I haven`t seen conclusive evidence to the use +21 lbs operationally either, apart from anti-diver missions, though it was proposed for the 2nd TAF in late 1944, obviously for anti fighter use.

Of course in the real world these comparisons meant little, given how rare the XIVs were.


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## parsifal (Apr 23, 2008)

I am no expert in this, but I am surprised someone is claiming the 109 to have better turn characteristics over a spitfire.

I will admit i dont understand the science, but isnt the wing area going to alter the the force vector from one direction to another, more quickly if you have a large wing. One would think that a large wing results in a larger moment of force, and hence a quicker effect on the current force vector. 109 and spitfire are similar weighted aircraft, but the spit , I believe, has a much greater wing area than the 109 (doesnt it???). Isnt it sort of like a sail, a big sail, set in a diffferent direction, is going to move you off in that direction more quickly, than say a smaller sail for a vessel of similar weight.

I am genuinely confused. Would any of you gentleman please like to try and explain. And i dont want to be browbeaten please, just wanting the basic theory, and results of that theory


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## Glider (Apr 23, 2008)

Take care, they will also try to make you believe that there is a tooth fairy and the moon is made of cheese.


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## Lucky13 (Apr 23, 2008)

The 109 Lair- The Online Source for Messerschmitt 109 information

virtualpilots.fi: 109myths


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## claidemore (Apr 23, 2008)

Kurfürst said:


> I think an educated guess can be made using assumed values of drag, Oswald effiency etc. Then these can be applied to different altitudes.
> 
> *A guess based on assumed values? I'd rather see some numbers. *
> 
> ...



Two famous quotes by Galland, one about Mk XIV rarity, one about his desire for a squadron of Spitfires. Do we believe..... both, neither, or pick one? 
Over 900 Mk XIVs produced, compared to 856 K4's in 1944 and how many in 1945? Don't forget, the XIV wasn't the only fighter opposing the K4's, there were Mustangs, P47s, Tempests, Mk IXs, Mk VIIIs, La5s, Yak 9s, Yak 3's, La7s, P38s, and Typhoons. Still, we are comparing performance, not production.

A comparison of climb rates for "operational" 1.8 ata K4 and 18lb boost XIV and Mk IX with Merlin 66 18lbs boost. (based on historical data from Mike Williams site and Kurfurst site) 

*Mk XIV*, *4700*ft/min @sea level, *3650* @20,000 ft, *2100* @ 32,800 ft. 
*Mk IX*, *4640* @ 2000ft (best climb is 4700) *3560* @20,000 ft , *1830* @32,000
*109 K4*, *4429*ft/min @ 500m, *3543* @ 20,000 ft, *1467* @ 32,800 ft. 

1.8 ata was only approved in January 45, so during 1944, the K4 had much lower performance. 

*Even so, Mk IX and Mk XIV with normal 18lb boost engines are outclimbing the 1945 1.8 ata 109K4s. Do we need more proof than that?*


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## DerAdlerIstGelandet (Apr 23, 2008)

Do not let this thread turn into a flame fest. This is a good informative thread and it does not need to be ruined.

That goes to all parties in this thread.


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## claidemore (Apr 23, 2008)

Rgr that Adler. 

Gotta admit, I was feeling a mite testy when I made my last post, other things in my life affecting my mood. 

Claidemore


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## Hunter368 (Apr 23, 2008)

It will be interesting to see what the response is from Kurfurst, he does seem to know the Bf-109 very well. Lets wait and see.


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## Soren (Apr 23, 2008)

> you didn't even understand the Lednicer report Soren but you are trying to BS your way into being 'acknowledged' as someone who understands Aero.



And that rude remark amongst many other automatically puts you on my ignore list.


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## Soren (Apr 23, 2008)

> Simple don't always mean wrong.



Very true, however Bill doesn't understand this as he now sees himself as an expert over everybody else because he feels he won the argument over Lednicer's article.



> *Wingloading *of the MkXIV was 35.1 lbs/sq ft, 30.7 for the Mk IX and 43.4 lbs/sq ft for the 109K4. That's a 21% advantage for Mk XIV and 29% advantage for Mk IX.



Which *simply* means it takes a 21% advantage in Clmax to gain the lost ground. Bill wants to slither his way around this by emplying that all these WW2 fighters were so different from each other in terms of aerolasticity and load symmetry that this means nothing, it's ridiculous. 

As Bill claims: _Nobody predicted viloent snap roll stall conditions in low speed high G turn for an Fw 190 because aerolasticity was not a well understood science._

Where are the facts and sources to back this up ??? Fact is that even TsAGl were very well into this area in the early 30's!!!

Fact is the FW-190 didn't have a violent stall purely because of aerolasticity, and it was infact predicted by Focke Wulf. The airfoil choice, the NACA 23000 series is in great part responsible for the violent stall. And the fact that wash out was applied to such a degree that much of the wing stalled at the same time was no disadvantage as Bill wants to make it sound like, it was purposely designed like that and Focke Wulf ofcourse performed tests to perfect the washout to permit maximum efficiency in maneuvers. 



> As I mentioned, the 109 wing is often quoted as having a clmax of 1.7 *with slats deployed* and possibly *with combat flaps deployed*.



Often qouted ? Claidemore it was established in multiple windtunnel tests conducted by Messerschmitt and is listed on every MTT aerodynamics chart on the 109. And it's NOT with flaps deployed, that would've raised the Clmax to well above 2.00. The Clmax of the Bf-109 F series and onwards is 1.7 with slats deployed clean, flaps and gear up.



> (The RAE tests seem to indicate that their clmax calculations were with both slats and combat flaps.) Without slats, it is assumed to be 1.4. The slats therefore only give an 18% increase in cl.



Claidemore the slats give atleast a 25% increase Clmax and critical AoA in the covered areas, but only 48% of the 109's wing is covered by the slats, so the increase in Clmax by virture of the slats was somewhere in the area of 12.5 - 13%. The Clmax of the wing without the slats was already high, around 1.50 - 1.55, by virtue of the high thickness ratio.



> The Spitfire MK IX is generally given a clmax of 1.6,



It is never given such a high Clmax figure Claidemore, that would be above the FW-190's Clmax of 1.58 which was above all others without high lift devices and much higher than the Spitfire's. 

The Spitfire's wing's Clmax is 1.36 as established in windtunnel tests, which is only logical considering the very thin wing with a thickness ratio of 12% at the root to 9% at the tip. The 190's was 15% at root and 9% at tip and ion top of this with a higher lift airfoil. The 109's wing TR was 14.2% at root and 11.35% at tip, and again with a higher lift airfoil to start with.



> a figure which my calculations support.



??? Could you show us these calculations ?



> In my calculations for the Mk XIV with stall speed of 85 mph (as indicated in the pilots notes) and weight of 8500 lbs I get a clmax of 1.9.



A Clmax of 1.9 ?? Do realize how ridiculously high that is ? Btw, thrust increases Clmax (Or it really doesn't but it has the same effect as it accelerates air over the wings, creating more lift)

Btw, be careful about relying on IAS figures at landing, the high AoA of the wing will affect the pressure in the pitot tube.


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## kool kitty89 (Apr 23, 2008)

Careful guys, don't get this thread closed...


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## Marcel (Apr 23, 2008)

DerAdlerIstGelandet said:


> Do not let this thread turn into a flame fest. This is a good informative thread and it does not need to be ruined.
> 
> That goes to all parties in this thread.



Ah... what a job you have here, Chris. Being the referee, keeping the fighters in their corners


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## Soren (Apr 23, 2008)

Oh and about elliptical planform wings:

If truly elliptical they offer a high Oswald Efficiency factor, that's it.

However, the Spitfire's wing doesn't offer elliptical lift distribution because of washout, and neither does the P-47's. The Fw-190's DOES however, and this is because of washout, AGAIN done totally on purpose by Focke Wulf.


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## kool kitty89 (Apr 23, 2008)

But the full elliptical lift distribution of the Fw 190 will only take place when encountering the aeroelastic changes in high G maneuvers, correct? (hence why low speed/ low G stalls were not violent)


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## Soren (Apr 23, 2008)

Yup, very correct KK.

And that the FW190 on top of this used the NACA 23000 airfoil only made the stalls even more violent, luckily control was quickly regained emmidiately after the stall as G dropped.

Fully ellipitical wings with elliptical lift distribution all suffer violents stalling characteristics, it's an inherent characteristic of this type wing.


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## claidemore (Apr 23, 2008)

Soren said:


> Very true, however Bill doesn't understand this as he now sees himself as an expert over everybody else because he feels he won the argument over Lednicer's article.
> 
> 
> 
> ...



Soren, you know how to calculate clmax as well as I (probably better). If you would bother to plug in a weight of 8400 lbs, stall speed of 85mph IAS (figure out TAS if you wish), and wing area of 242 sq ft (or use the extended wing area) you will get clmax of 1.88. I used 8500 lbs and got 1.9, my bad.


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## DerAdlerIstGelandet (Apr 23, 2008)

Marcel said:


> Ah... what a job you have here, Chris. Being the referee, keeping the fighters in their corners



Yeap but some of the people here do not realize (you know who you are) that my patience is running thin...

If they dont quit the BS they might find themselves on an extended vacation.


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## Soren (Apr 23, 2008)

Claidemore,

It's the thickness ratio which matters, thickness of the wing in comparison to the wing chord, as the higher the TR is the higher the Clmax is. A higher thickness ratio means a higher critical AoA and Clmax.


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## Soren (Apr 23, 2008)

I'm not trying to confuse you Claidemore, what I'm trying to tell you however is that the stall speed is lowered by the thrust of the propeller accelerating air over the wings faster than freestream - in effect increasing the Clmax. You do understand that lift is a byproduct of speed right ?

But lets see:

Weight: 3,855 kg
Wing area: 22.48 m^2
Stall speed: 136.7 km/h

1 * 22.48 * .5 * 37.9984^2 = 16,229.1932 N (1,654.91 kgf)

3,855 / 1,654.91 = 2.32

Thus the Clmax is 2.32 in that condition... But again this isn't freestream, it's with the engine prop producing a lot of thrust and pushing air faster over the wings, affecting the calculated Cl value.

Thus the Clmax of the wings can't be calculated by using such stalling speeds, you need freestream windtunnel tests to establish the Clmax.


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## Soren (Apr 23, 2008)

By comparison the Bf-109E has a stalling speed of 74 mph with flaps and gear up, and 61 mph with gear and flaps down.

Stalling speed of the Bf-109 K-4 was around 83 mph with flaps and gear up.


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## claidemore (Apr 24, 2008)

Hawker Typhoon had a very high TR, but it did not turn as well as the Spitfire. The Tempest employed a thinner wing, with similar turn performance compared to the Typhoon. 

IF the 109E stalled in level flight, engine off, at 74mph, the Cl would be 2.32, which is ridiculously high. At 84mph for the 109K4 the CL would be 2.4, an even higher number! Sorry, but those numbers just don't fly. (pardon the pun)

Plug in the cl of 1.7 into the equation, and you get 86 mph stall speed. In the RAE Spit1/109E comparison charts they indicate a stall speed for the Spit 1 around 75mph and the 109E at around 90mph *TAS*. Those charts also show the 109 stalling at higher speeds at equivalent G factors, at a contstant rate. We can argue about the accuracy or bias of those charts, but since there are no other charts offering different results, if we discount them we are left with only speculation and opinion. 

The only thing that changed from the time of the RAE test and 1944/45 was the power loading and a clean up of the airframe on the 109. K4 had a very high power loading for the 1.98 ata engines, but very few of them made or used, so we have to look at 1.8 ata or less. Even with a small advantage in power loading for the K4 over Mk IX or XIV, keep in mind that the Emil had a power loading advantage over the Spit I, and all trials indicate better turn performance for the Spit I. 

Spitfires are given a turn superiority throughout its developmental history against 109s by, 1)tests and trials by RAF and Luftwaffe, 2)anecdotal evidence from _majority _of RAF/USAAF and Luftwaffe pilots, 3)mathmatics. The changes in the K4 would give it a better turn performance than G6 models, but are certainly not improvements in a scale that can enable it to outperform the Spitfire. 

To state that the 109K4 had better turn performance than the latest Spitfire Marks is simply wishful thinking, relying on the faulty logic that if it's better than it used to be, it must have made a quantum leap and be able to turn better than the Spitfire. That is just too big a stretch. 

No one has offered any conclusive evidence to back the statement up while there is considerable evidence to the contrary. 
Claidemore


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## Soren (Apr 24, 2008)

Claidemore you're completely wrong.

As for he calculation in my post, that was for the Spitfire Mk.XIV, not the 109E, and if the stalling speed was 137 km/h then the Clmax is calculated as 2.32in that condition. (With engine running ofcourse)

The stalling speeds of the 109E are as stated 74 mph flaps and gear up, and 61 mph gear flaps down, and this is from the Dash 1 (POH).

As for the Typhoon vs the Tempest, well the Typhoon does turn better, and this is despite having less wing area and weighing more, and you can thank the higher thickness ratio wing for that.


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## Soren (Apr 24, 2008)

> IF the 109E stalled in level flight, engine off, at 74mph, the Cl would be 2.32, which is ridiculously high. At 84mph for the 109K4 the CL would be 2.4, an even higher number! Sorry, but those numbers just don't fly. (pardon the pun)



Ha! They certainly fly better than the 2.32 Clmax for the Spitfire !!

PS: As already explained a Clmax of 2+ isn't unormal at landing speeds as the prop accelerated air much faster over the wing than freestream leading the Cl estimation to be higher. 

Therefore, I repeat, we can't use stalling speeds as a reference here as it depends on two factors, 1) the Clmax freestream 2) the thrust provided by the prop. Thus you need the freestream figures for comparisons, and as explained the Clmax for the different a/c are as follows:

Bf-109F/G K: 1.70
Ta-152H: 1.62 
FW-190: 1.58 
P-51: 1.35 (According to NACA)
Spitfire: 1.36


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## Udet (Apr 24, 2008)

Whatever the turn rate of any Spitfire version might have been, German fighter pilots feasted with the almighty Spit.

Ask RAF for Spitfire losses for 1941, 1942 and the first of months of 1943 [pre-8th Air Force assembly era], when a gross slaughter of British pilots took place.


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## claidemore (Apr 24, 2008)

I can 'prove' your CL figure for the 190 as being correct, but the same formula does not 'prove' the 1.36 for the Spitfire. Sorry, but that number is incorrect. 

Even the clipped wing Spitfire IX/XVI had a CL of 1.5. 

I've seen that 1.36 number on a gaming forum, tested the formula that was supposedly used to get it and it didn't work. 

As for stall speed, it is arguably the most important factor in max turn rate, particularly in combat situations. We have to use it as a reference. It is also one of the numbers we must have to calculate CL, and one of the numbers we can calculate if we already have CL. Thus, knowing the CL of the 109 as being 1.7, we can calculate stall speeds that are in all cases higher than those you have indicated for 109s, in the case of the 3400 kg 109K4 the stall speed is 100 mph.


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## Soren (Apr 24, 2008)

> I can 'prove' your CL figure for the 190 as being correct



You can ? please do then cause I know the true stall of the Fw190 and it aint the one in the RAE report, that bird as already noted suffered from ill adjusted ailerons.


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## Soren (Apr 24, 2008)

claidemore said:


> I can 'prove' your CL figure for the 190 as being correct, but the same formula does not 'prove' the 1.36 for the Spitfire. Sorry, but that number is incorrect.
> 
> Even the clipped wing Spitfire IX/XVI had a CL of 1.5.
> 
> ...




Wrong wrong wrong and wrong.

The Bf-109 K-4 has a landing speed (Which is always a good deal higher than stall speed for obvious reasons) of 150 km/h for crying out loud!! 10 km/h below the speed you're wanting it to be stalling at !!

Do you want NACA's own papers on the Spitfire to show the Clmax of the Spitfire's wing ?? Ok, attached below it is.. The Clmax was establised as 1.18 to 1.15. There you go. So shall we use these figures or the British results of 1.36 ??

In short the only one suffering from wishful thinking is you Claidemore.


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## kool kitty89 (Apr 24, 2008)

If you use the true CL directly to determine stall speed, you'll get the stall speed in engine off condition (dead stick/ gliding) but as Soren said the prop wash adds considerable lift due to the higher speed of airflow. Engine at idle should give similar figures, though still very slightly skewed. (some added airflow will still be present, but not very significant; basicly negligable)

This is also why twin engine a/c ("twin slipstream) tend to turn better than single engine craft of similar configuration. Also why jets (and pusher props) stall a bit differently and why the taildragger configuration didn't work on the Me 262.


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## Hunter368 (Apr 24, 2008)

Good information KK


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## claidemore (Apr 24, 2008)

The American test used an unreliable method of measuring stall speeds, hence the low CL figures they recorded. RAE used a trailing static head (very difficult in a single seat fighter and seldom done) to get much more accurate results on both the Spitfire and the 109. This alone gives the RAE tests of the 109 considerable value as far as stall and CL go. 

RAE did record 1.36 CL in a glide, but 1.89 power on. This corresponds to the 1.95 they got for the 109 power on. Only a 4% difference. Basically, the slats on the small 109 wing only increased it's CL to slightly ahead of the Spitfires broad elliptical wing, not enough to overcome the 109s initial inferior wingloading, consequently the Spit *always *had a tighter turn, as recorded in tactical trials by both sides. 

This did not change with the K4. It was an improved plane, not a completely redesigned one. 

When I say 'prove', i mean using an equation to prove a number mathmatically, ie doing a calculation in reverse to make sure you get the number you started out with, I'm not using the word in a "I'll show you' context. Stall speed for FW 190 at 1.58 CL is 110 mph (P51B is 100 I believe?). Some sources give stall speeds as high as 127 mph for the 190, so 110 is pretty generous, though being generous in these discussions seems unpopular and possibly unwise. But then I'm not trying to change history, just trying to prove what has always been held to be true. 

All the landing speed minimums I've seen for 109s are 180 kmh, thats gear and flaps down. Might hit 150 just as the pilot pulls the plane into a 3 pt attitude and touches down but doing approach speed at 150? Cripes, thats the approach speed of a Hurricane! You're not going to tell me the 109K4 could turn with a Hurricane are you?

On the Mk XIV, landing speed is 100 mph, clean stall speed is 85, 15 mph less. (incidently, they recomended landing 20mph faster for safety)

Knock 20 kmh off the 180kmh for 109 approach speed, and you get 160kmh for clean stall, a similar ratio as in the Mk XIV Spit example above. So I don't see anything wrong with my calculated stall of the K4 at 100mph. If there is an historical document that says otherwise, I'd love to stand corrected. 

Other factors not included in a simple CL/stall calculation might put me out by a few kmh for that stall speed, but definately not in the 134 kmh area that you maintain. 

Once again, that is the stall speed of a Hurricane! The Hurri and Spit were very close in turn rate, so if the 109 was turning circles around the Spit, was it kickin the Hurris butt too? I haven't seen anybody trying to prove that one...yet. 

At the end of the day, despite haggling over CL and stall speeds, we still don't have any historical test or trial that gives any 109 model a better turn performance than any Spitfire. We do have trials that show the Spitfire turning better than FW, 109, Mustang, Tempest, Typhoon etc, in fact it was used as the standard by which to measure all the others.


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## kool kitty89 (Apr 24, 2008)

The 127 mph stall figure for the 190 was of ther early prototype with much smaller wing area and different wing plan form, and with the original BMW 139 engine. (albeit it was lighter a/c as well)



> The first prototype, the Fw 190 V1 powered by a 1,550 hp BMW 139 two-row 14-cylinder radial engine, with civil registration D-OPZE, was flown on 1 June 1939 and soon showed exceptional qualities for such a comparatively small aircraft, with excellent handling, good visibility and speed (initially around 610 km/h (380 mph)).[8] The roll rate was 162 degrees at 410 km/h (255 mph) but the aircraft had a high stall speed of 205 km/h (127 mph). According to the pilots who flew the first prototypes, its wide landing gear made takeoff and landing easier, resulting in a more versatile and safer aircraft on the ground than the Bf 109. The wings spanned 9.5 meters (31 ft 2 in) and had an area of 15 m² (161.46 ft²).



This became excessive on the heavier V5 with similar configuration to production 190A's (but not the pre-production A-0's) but initially retaining the original wing:


> At first the V5 used the same wings as the first two prototypes although, to make room for the bigger undercarriage, the wheel arches were enlarged by moving forward part of the leading edge of the wing root (in this form this prototype was called the V5k for kleine fläche/small wing). The V5 first flew in the early spring of 1940.
> 
> However, the weight increase was substantial, 635 kg (1,400 pounds), leading to higher wing loading and a deterioration in handling. As a result, following a collision with a ground vehicle in August 1940 that sent the V5 back to the factory for major repairs, it was rebuilt with a new wing, with a larger area, 18.30 m² (197 ft²) and span of 10.506 m (34 ft 5in) and which was less tapered in plan than the original design (the aircraft was now called the V5g for grosse fläche/large wing). This new wing platform was to be used for all major production versions of the Fw 190.


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## claidemore (Apr 24, 2008)

Footnote: the RAE tests with trailing static head to measure stall and CLmax, gave a figure of 1.36 in a glide for the Spit 1, and 1.4 in a glide for the 109E. Static head indicated a speed at the stall for the 109 of 95.5 mph, cockpit instrument IAS was 75. This was with slats open, and they noted that both slats opened up simultaneously.

So comparing a cl of 1.7 for the 109 to 1.36 of the Spit, is comparing apples to oranges, the actual comparison derived using the same equipment under the same test conditions, is 1.36 to 1.4. 

Or full throttle, 1.87 to 1.95.


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## Soren (Apr 24, 2008)

Claidemore are you seriously trying to suggest that the Clmax of the 109's wing without slats was below the Spitfire's ?? This is as far out as your claim that the Clmax for the Spitfire's wing is 1.50! 

Don't you understand that the Spitfire's wing Clmax was as low as proven because it was thin and used a rather low Clmax airfoil ??? (NACA 2200 series)The Bf-109's wing is thicker and uses a higher lift airfoil (NACA 2R1)!

Moving on..

The Emil the RAE tested was first of all not using proper fuel, so power wasn't high enough, and secondly the stalling figures are completely off so something wasn't done right, go read the 109E's POH and you'll see that right away.

Furthermore the V24, a 109F with a reduced wing span and wing area of 15.1m^2 because of removed wing tips achieved a Clmax of 1.48 (Freestream) in windtunnel tests, and this was WITHOUT slats and with a lower AR wing. So the Clmax WITHOUT slats for a full span wing was somewhere in the area of 1.55.

Here's the effect slats flaps have on the Clmax of a std. 12% Clark Y airfoil (Note: The NACA 2R1 is a modified Clark Y airfoil with a higher Clmax and lower drag)







So are you still under the illusion that the slats only helped a few percent ?

As for landing speeds, here are the landing speeds for the Bf-109F-4 and K-4:

Bf-109F-4 V-lande: 135 km/h
Bf-109K-4 V-lande: 150 km/h

These are the official landing speeds, in TAS! Not IAS!

And the Clmax and Cd0 of the 109F gear and flaps up:





By Comparison the Ta-152H-1 has a landing speed of 155 km/h and the Fw-190 D-9 one of 167 km/h and the P-51D one of 170 km/h.

Do you need further proof ??

Oh and guess what the Bf-109 also has a much shorter take off roll than the Spitfire. Do you see the pattern emerging ??


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## claidemore (Apr 24, 2008)

I am seriously suggesting that clMax in a power off glide (slats OUT)for a 109E is 1.4 and clMax for a Spitfire Mk 1 is 1.36. This is straight from the RAE test chart. I don't see how we can get a more accurate comparison than two tests done by the same organization at the same time. Other data may indicate different results, but for purposes of comparison, the RAE test is ideal. 

As usual, those who find that those numbers do not support what they want to believe, will claim that the British didn't know what they were doing, so the test must be wrong or biased or something. Sometimes the grapes are sour. 

I fail to see how the type of fuel can affect a 'power off' glide? 

Actually the 109 wing resembles the NACA 2315 and 2310. The slats helped the 173 sq ft 109 wing, by a factor of about 12-13% as you alluded earlier, HOWEVER they only increase it's cl compared to the 242 sq ft Spit wing, by 3%. That is not hard to understand. 

20 degree flap setting and 150 more horsepower, 500 lbs less weight, the 109 should have a shorter take off roll, particularly if the Spit does not have a constant speed prop. With constant speed prop the Spit roll off was only 150 yards (for the heavier Mk II!). 

We still have trials done by Rechlin and RAE and AFDU that show the Spitfire outturning the 109. Can all those trials be wrong?


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## kool kitty89 (Apr 25, 2008)

Soren, something I noticed from the Drag Estimation chart, the automatic "slot" increases the CLmax by ~42.6% not 25%, so using that figure for the 109's ~48% span LE slats the CLmax should increase by ~20.4%.

And if you work backwards (using all figures according to claidmore's post) with 1.4 CLmax with slats adding 13%, w/out slats the wing's CL would be ~1.24 (which is worse than the standard Clark Y airfoil), which is decidedly low. And if we use other figures it's even lower.

Even if we assume the wing is a standard (less efficient) Clark Y airfoil from that chart with 48% span slats, the CLmax with slats should be in the area of 1.67. (using data from the Drag Estimation chart) possibly a little less since the inner wing may be past critical AoA. (not sure on that)


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## claidemore (Apr 25, 2008)

> The stalling speeds of the 109E are as stated 74 mph flaps and gear up, and 61 mph gear flaps down, and this is from the Dash 1 (POH).



This is in very close agreement with the RAE tests of the 109E, which got a stall speed reading of 75 mph for flaps and gear up (ASI air speed indicated, which we usually refer to as IAS nowadays) on the regular airspeed indicator in the cockpit, and 61mph for flaps and gear down. Of course the real speed, (TAS) as measured by the 60 ft trailing static head, was _95.5 mph_ for flaps and gear up, _with slats deployed_. 

That gives us a clmax of 1.4 but more importantly, it gives us an accurate stall speed, which is _11.5 mph_ higher then the stall speed of the Spitfire measured using the exact same method. And there lies the turn advantage for the Spitfire, the 109 stalls first, and the Spit is still turning. 

The guys who flew these planes have been telling us this for nearly 70 years, but we're just too smart and arrogant to believe them.


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## Soren (Apr 25, 2008)

> The guys who flew these planes have been telling us this for nearly 70 years, but we're just too smart and arrogant to believe them.



I beg your pardon ?? Are you forgetting that just as many has said otherwise and most notably so the experts flying the a/c such a LW chief test pilot Heinrich Beauvais ??

I think it is arrogance to refuse to want to learn the truth and desperately cling to old claims myths, refusing to use ones logic,

Claidemore,

You're Cl estimations are to put it simply very inaccurate, heck take a peak at the normal Clmax of a std. 12% Clark Y airfoil and then remember that the Bf-109's wing used an improved higher lift Clark Y airfoil designated NACA 2R1 which Clmax range is close to that of the 23000 series. And with a TR which ranged 14.2% at the roots to 11.35% at the tips, the 109's wing is alos thicker. By now use of pure logic will tell you that the Clmax can only then be significantly higher, esp. when adding the approx. increase in Cl offered by the slats, which is atleast in the 25% range in the covered areas.

As for the RAE tests, no they can't have been very accurate for the very reason that everyone, including the French, Finnish Germans got completely different results from actual windtunnel tests which mind you are allot more accurate than those RAE field tests. Remember that in a windtunnel you are in complete control of the inviroment, while out in nature a large magnitude of things could effect the way the tests come out.

KK,

The Handley page auto slots represented on that chart are of a different design than the ones on the 109, as they drop down to increase camber. The fixed slot is of the same design as the 109's auto slats when they're fully deployed and this is therefore the one to be looking at. The increase is in this case from 1.29 to 1.77, a 37% increase in Clmax, but this is only in the covered area, so we can cut that down to 17% and then down to around 13% when we factor in that the 109's wing was thicker to begin with.


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## claidemore (Apr 25, 2008)

Soren;
Rechlin test: Spitfire outturns 109 in *every *situation.
RAE tests, Spitfire has smaller turn radius, Spitfire stalls at a higher G load, Spitfire stalls at a lower air speed, measured TAS stall speeds of 95.5/109 and 84/Spit I. 
AFDU tactical trials: Spitfire out turns 109, 190, and every thing else. 

Would this be the source of the myth? 

Logic somehow ignores all these tests and all the data contained in them, and assumes that the 109 wing which has "_improved higher lift_" has cl that is "_significantly higher_" and has an "_approx. increase in Cl_" with cl range " _close to that of the 23000 series_" and 2%? higher TR has somehow overcome a 30% deficiency in wing area, and a 21% deficiency in wingloading. 
So we take some assumptions, a handful of generalizations, and use logic to come up with what? 

The Hawker Typhoon had a nice thick wing,(NACA 23 series) and it didn't turn as well as the Spitfire either. Interesting that it has a similar trapezoidal profile to the 109 and 190 which caused it to get shot down by over-enthusiastic Mustang pilots. Could that trapezoidal shape be the source of its poor turn performance? 

Quote from Mike Williams site:


> The Tempest arose from Hawker’s desire to apply a new, thin wing to the Typhoon in order to enhance performance. The Tempest V combined the new semi-elliptical wing with the Typhoon airframe and Sabre II engine. The new wing was five inches thinner at the root with the maximum depth of the new section occurring farther back, at 37.5% of the chord, while the thickness/chord ratio was reduced, 14.5% at the root tapering to 10% at the tip.



Hmmm, those numbers are pretty close to the 109 numbers, how did the Tempest fair in a turn fight against a Spitfire? Not well. Mustang outturned it too, and it was just slightly better than the 109G2. Since I think the G2 used in those trials was not up to snuff, I'll allow that it might have matched or even outturned the Tempest slightly if it was in 100% condition. (i know that will come back to haunt me!) 
In any case, we know that the Spitfire easily outturned the Tempest, and the Tempest turned about the same as a 109, so logic tells us?


As for my cl calculations, they are completely accurate. 
Stall speed of 95mph TAS, weight of 5600 lbs, wing area of 173 sq ft and you get cl of 1.4020.


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## Soren (Apr 25, 2008)

Claidemore,

We've already discussed why the tests with the Emil aren't worth anything many times before so I wont even go there.

As for the stalling speeds of the Bf-109E that I listed, these are TRUE airspeeds, NOT indicated stall speeds. The indicated stalling speed was 10 km/h lower in all cases. 

As for the Clmax of the wing, it is 1.70 as established in multiple windtunnel tests clean with gear flaps up. With no slats the Clmax would've been around 1.50+. 

The Spitfire's wing's Clmax was 1.36.

And here the Clmax of the NACA 23000 series airfoil from 9 to 18% in thickness ratio. As you can see there's a limit to how thick the wing can be before Clmax start to drop instead of increasing:





The average Clmax for a airfoil from 15 to 09% is 1.58 to 1.59, much higher than normal, which can also been seen when compared to the Clmax ofthe std. Clark Y airfoil.

Btw, the Clark Y airfoil was used by all Yak, La LaGG fighters, while the 109 featured a modified type with a higher Clmax and lower drag.

And as for the Typhoon, like I said it outturned the Tempest despite being heavier, having less wing area and having less power available, and this was thanks to its higher TR AR wing.

PS: The Tempest also used a airfoil which was bad for turn performance but good for speed.


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## kool kitty89 (Apr 25, 2008)

He's saying that the combination of the higher lift airfoil, the higher TR, and LE slats, overcome the high wing loading.

The Typhoon should have had a fairly high CL, but it had high wing loading and no additional high lift devices.

The Tempest's wing should have had a much lower CL, due to being much thinner and using a low drag airfoil with the max thickness at 37.5% chord. (similar to the P-51's psudo-laminar-flow wing;low-lift and low drag= good speed but not for turn)


Technically the 109F and later models had a tapered wing with rounded tips, and thus would no longer be considered trapizoidal. And anyway there were other a/c with similar plan for that had decent maneuverability as well.


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## Soren (Apr 25, 2008)

Very correct KK.


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## claidemore (Apr 26, 2008)

RAE had people who devoted their entire lives to aircraft research, they had experienced test pilots, aeronautical engineers and designers, skilled technicians, research scientists, the best aviation people in Britain, with an enviable reputation. (they had Beatrice Shillling too!) They had access to some of the best equipment in the world, and cooperated extensively with American test facilities and personnel. Hitler wanted their research so much that he would not allow the Luftwaffe to bomb it, assuming that eventually he could capture it. 

You seriously think we should completely dismiss their findings and results? All these highly qualified experts were wrong, and you are right? 

Persoanlly, I think they knew a hell of a lot more about this stuff than your or I, and this chart illustrates it pretty well.


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## Glider (Apr 26, 2008)

Soren said:


> The Emil the RAE tested was first of all not using proper fuel, so power wasn't high enough,



I admit I thought that I had heard all your arguments but this is a new one on me.
Can I ask what fuel was used in the test and what fuel should they have used plus how do you know?

I say this as the standard front line fuel in the RAF was 100 octane, which was higher than the normal fuel available to the Luftwaffe. So at worst it was likely that they gave it a higher than normal octane fuel, at best the correct level.


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## parsifal (Apr 26, 2008)

This was a quote relating to the Emil, concerning manouverability

We in J52 were very inexperienced, in just two months, our strength fell from thirty-six pilots to four. We really wasted our fighters. We didn't have enough to begin with, and we used them in the wrong way, for direct close escort. We were tied to the bombers, flying slowly - sometimes with flaps down - over England. We couldn't use our altitude advantage nor our superiority in a dive. Of course, the Spitfire had a marvelous rate of turn, and when we were tied to the bombers and had to dogfight them, that turn was very important". 
Gunther Ball of 8/JG52

It was also thought that unbeknown to the pilots the British Air Ministry instructed that Hurricanes and Spitfires use 100% high octane fuel instead of the 87% octane that both the RAF and the Luftwaffe were using at the outbreak of the war. Richard Hough and Denis Richard's mention in their book that in September 1939 the U.S Congress invoked the Neutrality Act that prohibited the use of 100% octane fuel, but after some anxious moments, the British Government and the Roosevelt Administration had reached a compromise where the supply of this fuel could be used on a 'dollar on the barrel-head' basis [1].

This is an Link to an article I found by John Dell on this very issue. Dell argues that it is actually unclear as to which aircraft was the more manouverable, but in the end, in his opinion, ther was a slight advantage to the Spitfire. Dell attributes these advantages to the small cockpit size, and heavier controls for the 109 at high speed, coupled with an apparently peculiar and less efficient stick design. He seems to think that these peripheral handicaps added up to the german pilots having a lesser physical ability to match the spit in a high g turn.

Anyway, have a look an see what you think

The Supermarine Spifire in combat - an essay.


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## kool kitty89 (Apr 26, 2008)

Kfurst should have more info on the fuel. nd iirc the normal liste "octane" number for the LW fuel didn't always corespond to to the same number as in standard fuel. (particularly the blended fuel iirc)



Claidmore, the turn testing is interesting, but where are the Cl figures you were talkin about. (which operating condition should have litte effect on, as testing would be done in a power off glide)


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## Glider (Apr 26, 2008)

kool kitty89 said:


> Kfurst should have more info on the fuel. nd iirc the normal liste "octane" number for the LW fuel didn't always corespond to to the same number as in standard fuel. (particularly the blended fuel iirc)



I await it with interest. Its a major claim and its one that I have never heard before. I have read the reports as I am sure you have and can find no mention of fuel issues impacting the performance of the 109.


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## parsifal (Apr 26, 2008)

A very quick comment about different fuels (I have to go to a lunch). Higher octane rating fuels essentially have a slower burn rate than the lower rated fuels. This is achieved by putting burn inhibitors into the fuel. Typically lead (although banned in many countries now). The longer fuel burn time means that the fuel air mixture is burning down a greater portion of the cylinder, whilst on the power stroke. A much greater proportion of the fuel can be burnt in this way, and a sustained power stroke is more efficient than if the fuel "explodes", rather than "burns".

However, if you put higher octane fuel into an engine tuned for a lower rating fuel, you will downgrade the power output of that engine markedly. This is because the fuel air mixture will continue its burn cycle into the exhaust stroke.

Every old car engine I have ever worked on can be retuned to accommodate 100 octane fuel. This was certainly also true for the Hurricane and Spit 9note i have never worked on any aero engines). They ran on both types of fuel. Dont know about the DB 601. One of you more technically minded guys will have to answer that. But one would assume that it could be re-tuned.

Even if it was not re-tuned, the guys undertaking the tests would immediately have known that. The engine would simply not run correctly if it was fuelled up incorrectly. Running an engine in that state would be very obvious due to all the backfiring and noise that would be going on. moreover, it would be quite unsafe to fly. To even a first year engine mechanic, it would have been obvious what the problem was, and since the RAF was still using the lower rated fuel at the same time as the 100 octane fuel, the solution easily at hand. 

So Sorens claim about using the wrong fuel is possible, in a theoretical sense, but the practicalities make it a highly unlikley scenario


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## Soren (Apr 27, 2008)

Guys the Germans used low octane synthetic fuel, the Allies used high octane natural fuel, and that is why the engine didn't perform well. It's the same with Fabers A-3 which got captured, the engine ran extremely poorly and the problem was only corrected well after all the tests by the RAE AFDU.


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## Kurfürst (Apr 27, 2008)

claidemore said:


> Persoanlly, I think they knew a hell of a lot more about this stuff than your or I, and this chart illustrates it pretty well.



... this chart illustrates calculated turn radiuses based on estimated Cl etc. values obtained with unreliable methods on a captured plane the French tested after it made an emergency landing...

It shows that and nothing more. And while the RAE paper you quote draws the - to me at least, reasonable, given the basic technical characteristics, ie. wingloading, power loading, drag etc. - conclusion that the Spitfire can, technically, turn better, it also mentions that 'in a surprisingly large number of cases', the 109E had no trouble turning with the Spitfire; this was entirely down to the Emils better control&stall characteristics is pitch and near the stall. Simply to put, less experienced pilots found it more difficult to push the Spitfire to the edge than the 109. The Spitfire was oversensitive in pitch (something that Rechlin, RAE, and NACA agrees on), it took very delicate movements on the coloum to ride the stall - which was very violent on the Spit - when at the same time the control harmony was poor, and the handling ailerons were like arm-wresting match.

Not much of a conclusion can be drawn based on these 109E vs Spit I results though, their design did not remain constant through the war. Basically the Spitfire gained more weight in both absolute and relative (%) terms than the 109 during its development life; also the 109 was gradually cleaned up aerodynamically, whereas the Spitfire only detoriated from the drag`s point of view after the Spitfire Mk I.

In brief, whatever the relative merits of the 109E and Spitfire I were in the turning department, with the later variants the balance is increasingly in favour of the lighter, cleaner 109 version.

My 2 fillérs, but I dont want to get any deeper than that, you guys are having the same conversation for the 100th time here...


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## Soren (Apr 27, 2008)

> you guys are having the same conversation for the 100th time here...




Exactly, and its getting real tiring..

As stated by German, British and modern pilots, the two a/c were very close in all aspects of flight, esp. turn performance, and it was a matter of pilot experience in the end. 

We have Mark Hanna, Skip Holm, Dave Chairwood, Walter Wolfrum, Erwin Leykauf, Heinrich Beauvais etc etc and aerodynamics confirming this.

Both a/c were excellent fighters IMO.


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## Kurfürst (Apr 27, 2008)

kool kitty89 said:


> Kfurst should have more info on the fuel. nd iirc the normal liste "octane" number for the LW fuel didn't always corespond to to the same number as in standard fuel. (particularly the blended fuel iirc)



A quickie.

The LW used two kinds of fuel. B-4, nominally 87 octane, and C-3, nominally 96 octane.

By Allied standards, C-3 was actually 130 grade fuel; in late 1942, its mixture was changed and it was an equivalent of 150 grade fuel. I am not sure about B-4.

Some reports though indicate that the fuel found in cases the downed fighters tanks was some kind of mixture of B-4 and C-3, something like 92 octane IIRC.

In any case, its worth to consider the fuel requirements from the technical sides; the main Allied inline engines, the Merlin and Allison, were relatively low displacements at 27 liters compared to the DB etc. engines. So the only way they could match the larger engine`s output was using highly manifold pressures, and/or higher RPMs. Higher manifold pressures absolutely required higher grade fuels to prevent knocking; also, to make best use of these fuels for power, comparatively low CRs were used; combined with the high supercharging needs required for high manifold pressure, this lead to high fuel consumption, and much more need for high octane fuels; the Germans, French (and thus Russians, who copied French inlines) with their high capacity engines simply didn`t require such fuels for high output.


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## parsifal (Apr 27, 2008)

But soren, using incorrect fuel in an engine (whether it be synthetic, or natural) is an obvious and easily corrected problem. A simple engine timing test would reveal the problem. I dont know anything about these "RAE" tests, not even when they were carried out, but putting the wrong fuel into an engine can only be something you would do deliberately. To a trained mechanic, the engine knock is something detected immediately, and an ignition timing test would pinpoint the problem with complete accuracy. Even small differences in the type of fuel could be detected very easily. 


It just seems very implausible that tests such as these "RAE" tests would be compromised by such a silly error. What is entirely plausible is that the wrong fuel is put into the tank initially ( and recorded, I guess), and then the problem being corrected, either by putting the correctly rated fuel in, and/or adjusting the ignition timing.

Kurfurst also mentioned that the 109 could use either 87 rated fuel, or 150 octane rating fuel, or some mixture in between. in each case, the engine would need to be re-tuned to take the new fuel.


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## parsifal (Apr 27, 2008)

I found this posted in Wikidapedia.

Seems that the 87 octane rating given to German "standard fuels" was the same as the 100 octane rated fuels in allied circles. 

The quote from wikidapedia should be taken with the usual caveats as to accuracy

During World War II, Germany received much of its oil from Romania. From 2.8 million barrels (450,000 m³) in 1938, Romania’s exports to Germany increased to 13 million barrels (2,100,000 m³) by 1941, a level that was essentially maintained through 1942 and 1943, before dropping by half, due to Allied bombing and mining of the Danube. Although these exports were almost half of Romania’s total production, they were considerably less than what the Germans expected. Even with the addition of the Romanian deliveries, overland oil imports after 1939 could not make up for the loss of overseas shipments. In order to become less dependent on outside sources, the Germans undertook a sizable expansion program of their own meager domestic oil pumping. After 1938, the Austrian oil fields were made available, and the expansion of Nazi crude oil output was chiefly concentrated there. Primarily as a result of this expansion, the Reich's domestic output of crude oil increased from approximately 3.8 million barrels (600,000 m³) in 1938 to almost 12 million barrels (1,900,000 m³) in 1944. Even this was not enough.

Instead, Germany had developed a synthetic fuel capacity that was intended to replace imported or captured oil. Fuels were generated from coal, using either the Bergius process or the Fischer-Tropsch process. Between 1938 and 1943, synthetic fuel output underwent a respectable growth from 10 million barrels (1,600,000 m³) to 36 million. The percentage of synthetic fuels compared with the yield from all sources grew from 22 percent to more than 50 percent by 1943. The total oil supplies available from all sources for the same period rose from 45 million barrels (7,200,000 m³) in 1938 to 71 million barrels (11,300,000 m³) in 1943.

By the early 1930s, automobile gasoline had an octane reading of 40 and aviation gasoline of 75-80. Aviation gasoline with such high octane numbers could only be refined through a process of distillation of high-grade petroleum. Germany’s domestic oil was not of this quality. Only the additive tetra-ethyl lead could raise the octane to a maximum of 87. The license for the production of this additive was acquired in 1935 from the American holder of the patents, but without high-grade Romanian oil even this additive was not very effective. 100 octane fuel, designated either 'C-2' (natural) or 'C-3' (synthethic) was introduced in late 1939 with the Daimler-Benz DB 601N engine, used in certain of the Luftwaffe`s Bf 109E and Bf 109F single-engined fighters, Bf 110C twin-engined fighters, and several bomber types. Some later combat types, most notably the BMW 801D-powered Fw 190A, F and G series, and later war Bf 109G and K models, used C-3 as well. The nominally 87 octane aviation fuel, designated 'B-4' was produced in parallel during the war.

In the US the oil was not "as good," and the oil industry had to invest heavily in various expensive boosting systems. This turned out to have benefits: the US industry started delivering fuels of increasing octane ratings by adding more of the boosting agents, and the infrastructure was in place for a post-war octane-agents additive industry. Good crude oil was no longer a factor during wartime, and by war's end, American aviation fuel was commonly 130 octane, and 150 octane was available in limited quantities for fighters from the summer of 1944. This high octane could easily be used in existing engines to deliver much more power by increasing the pressure delivered by the superchargers.

In late 1942, the Germans increased to octane rating of their high-grade 'C-3' aviation fuel to 150 octane. The relative volumes of production of the two grades B-4 and C-3 cannot be accurately given, but in the last war years perhaps two-thirds of the total was C-3. Every effort was being made toward the end of the war to increase isoparaffin production; more isoparaffin meant more C-3 available for fighter plane use.

A common misapprehension exists concerning wartime fuel octane numbers. There are two octane numbers for each fuel, one for lean mix and one for rich mix, rich being greater. The misunderstanding that German fuels had a lower octane number (and thus a poorer quality) arose because the Germans quoted the lean mix octane number for their fuels while the Allies quoted the rich mix number. Standard German high-grade 'C-3' aviation fuel used in the later part of the war had lean/rich octane numbers of 100/130. The Germans would list this as a 100 octane fuel while the Allies would list it as 130 octane.

After the war the US Navy sent a Technical Mission to Germany to interview German petrochemists and examine German fuel quality. Their report entitled “Technical Report 145-45 Manufacture of Aviation Gasoline in Germany” chemically analyzed the different fuels, and concluded that “Toward the end of the war the quality of fuel being used by the German fighter planes was quite similar to that being used by the Allies.”


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## Glider (Apr 27, 2008)

Kurfürst said:


> ... this chart illustrates calculated turn radiuses based on estimated Cl etc. values obtained with unreliable methods on a captured plane the French tested after it made an emergency landing...
> 
> It shows that and nothing more. And while the RAE paper you quote draws the - to me at least, reasonable, given the basic technical characteristics, ie. wingloading, power loading, drag etc. - conclusion that the Spitfire can, technically, turn better, it also mentions that 'in a surprisingly large number of cases', the 109E had no trouble turning with the Spitfire; this was entirely down to the Emils better control&stall characteristics is pitch and near the stall. Simply to put, less experienced pilots found it more difficult to push the Spitfire to the edge than the 109. The Spitfire was oversensitive in pitch (something that Rechlin, RAE, and NACA agrees on), it took very delicate movements on the coloum to ride the stall - which was very violent on the Spit - when at the same time the control harmony was poor, and the handling ailerons were like arm-wresting match.
> 
> ...



Section 5.4 of the paper summerises the 109's Good and Bad points

*Good*
a) High top speed and excellent climb
b) Good control at low speeds
c) Gentle Stall even under G
d) Engine doesn't cut out under negative G

*Bad*
a) Controls, Particularly the ailerons, far to heavy at high speeds
b) Owing to the high wing loading, the aeroplane stalls readily under G and has a poor turning circle
c) Aileron snatching occurs as the slots open
d) Quick manoeuvers are difficult, at high speed because of (a) above, at low speed because of (b) and (c) above.
e) Absence of the rudder trimmer, curtailing the ability to bank to the left at high speed.
f) Cockpit to cramped for comfort in combat.

Re the ability of the 109 to turn with the Spit it strikes me as being the age old point that an experienced pilot will get that bit more out of an aircraft than a 'normal' pilot. If the Spit went to the edge it would turn better, if it didn't and the 109 went to the edge then the 109 could hang on.
If both pilots were the of similar skill then the Spit would have the edge in the turn.

What I suggest and am sure that Kurfurst would agree with, is to encourage everyone to read the entire report and draw your own conclusions.

For those who don't know the link its as follows: -
http://www.ww2aircraft.net/forum/flight-test-data/bf-109-performance-threads-8132.html


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## kool kitty89 (Apr 27, 2008)

The 109F and later models cured or improved most of those faults.


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## Glider (Apr 28, 2008)

Of course the 109 improved as did the Spitfire, but that wasn't the point. 

The point was that emphasising small parts of what is a very detailed paper can be very misleading. That applies to any paper of any topic.

All I am trying to do is to print out all the summary (time permitting) which covers both the positive and negative sides of the report and encourage anyone interested to read the entire thing and draw their own conclusions. Nothing more and nothing less.


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## kool kitty89 (Apr 28, 2008)

Yes, but the Spitfire had fewer faults to cure and did so more slowly. (this is with changes in engines/weapons aside).

The Major problem with the Spit's airframe was with aileron control at high speeds, then wing tip warping causing control reversal. Other than that there weren't many things they corrected. Low drag radiator was added, that's about it. The aerodynamics stayed about the same. (sometimes got worse for certain applications or to trade off one performance category for another: ie CW spitfires, or long range versions) Also the Spit had a considerable weight increase throughout development while the 109 generally did not. (sometimes getting lighter)

And the 109 consistently got cleaner.


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## Soren (Apr 28, 2008)

Also noteworthy ofcourse is the change in slats design from the Emil series to the F series and beyond. The Emil's slats were very unreliable, jamming all the time or deploying incorrectly according to each other, causing premature stalls in turns and vicious spins.


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## kool kitty89 (Apr 28, 2008)

And there was the jolt from the rapid deployment of the Emil's slats while the later design introduced in the 109F line opened smoothly, same as the Me 262's.


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## Soren (Apr 28, 2008)

Yes.


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## pbfoot (Apr 28, 2008)

i believe the slats issue is a maintainence problem , it has nothing to do with the slats themselves its the maintainers


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## Soren (Apr 28, 2008)

Wrong, design flaw, way to sensitive to dirt and very unreliable in action under G's. This problem was first fixed with the F series.


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## pbfoot (Apr 28, 2008)

Soren said:


> Wrong, design flaw, way to sensitive to dirt and very unreliable in action under G's. This problem was first fixed with the F series.


Dirt is a maintainence problem


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## Soren (Apr 28, 2008)

Yeah but unreliable operation during G loads is a design flaw.


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## kool kitty89 (Apr 28, 2008)

And design that is too sensitive to dirt: ie requires excessive maintemence to operate correctly is also flawed as it doen't work in a practical manner in real world conditions.

This apears to be the case here.

And according to Kfurst, the slats wre fixed twice on the 109F, the initial models using an improved mechanism of the same type as the Emil, and later a new mechenism using rollers was introduced which stayed for the rest of th design and was used on the Me 262.



Kurfürst said:


> 109E and early F had the slats operated by wing arms, the late F and all G series had it deployed by bearings, probably hence the much smoother operation noted by Southwood on the G-2. Changes in the K also had the slats made out of steel.





Kurfürst said:


> I am not sure if they still present with the early F model - the mechanism was similiar, but the slat design was already different, as was the wing, ailerons were now of the Friese type etc.
> 
> Unfortunately, there are no 109F trials to shed light on the issue.


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## pbfoot (Apr 28, 2008)

kool kitty89 said:


> And design that is too sensitive to dirt: ie requires excessive maintemence to operate correctly is also flawed as it doen't work in a practical manner in real world conditions.
> 
> This apears to be the case here.
> 
> And according to Kfurst, the slats wre fixed twice on the 109F, the initial models using an improved mechanism of the same type as the Emil, and later a new mechenism using rollers was introduced which stayed for the rest of th design and was used on the Me 262.


compressed air should be enough to clean them out,


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## Soren (Apr 28, 2008)

No pbfoot, the dirt can lodge itself in many places within the mechanism which probably needs to be lubricated to function as smoothly as possible, allowing dirt to stick very well. In Africa the Emil had VERY serious problems, and the LW took great care to cover up the slats while the a/c were on the ground, the dirt litterally came in everywhere.


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## drgondog (Apr 30, 2008)

Soren said:


> Exactly, and its getting real tiring..
> 
> As stated by German, British and modern pilots, the two a/c were very close in all aspects of flight, esp. turn performance, and it was a matter of pilot experience in the end.
> 
> ...



Er, your 'notion of aerodynamics' does not quite meet the standard of 'aerodynamics' knowledge. I suspect you are a fairly rapid learner of empirical and rudimentary knowledge with a technical background that I haven't quite figured out yet. When a guy (you) boldy states and re-states that a lift distribution in a model is Drag 'equivalent to boat tail or spitzer wake drag' it should raise flags to most people.

What say you post your degree (s) on-line and I'll post mine to compare at least the academic standards for comparison? If you have a BS (or equivalent) degree even in ME with a minor in Fluid Mechanics I'll apologise publically for thinking you are a bonehead. If you don't I would ask you to state your opinions of aerodynamic or 'physics' by starting every sentence with 'in my opinion...'??

Would that work for you?


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## parsifal (May 1, 2008)

and the silence is deafening


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## Soren (May 1, 2008)

I won't reply to pissing match posts, it's ridiculous.

What Bill seems unable to understand is that if you haven't used a computer pressure distribution program before then you can't expect to undertsand it right away. 

Furthermore the only reason he keeps bringing this up is because he knows all I've said in this thread is 100% correct.


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## kool kitty89 (May 1, 2008)

And that thing about the Bubble canopy is sometimes correct, depending on the layout of the a/c and the overall change to the canopy and fusalage. Like with the 109, it was found that addition of a bubble canopy to that airframe would result in a performance drop. And in the case of the P-47, not only did the fusalage streamlining change, but the windshiels was blunt (flat sheet) opposed to the angled fram of the razorback. 

And Soren, not to get into this, but you mentioned before that your areodynamic knoledge is self-taught right?


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## Soren (May 1, 2008)

kool kitty89 said:


> And Soren, not to get into this, but you mentioned before that your areodynamic knoledge is self-taught right?



Besides what you are taught at flight school, yes. I'm an educated engineer with a passion for aerodynamics, having studied it allot over the past decade.


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## DerAdlerIstGelandet (May 2, 2008)

Yet Bill is a school educated Aeronautical Engineer, and you claim he does not know what he is talking about?

Yeah okay...


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## kool kitty89 (May 2, 2008)

...

I think the first problem was the argument over the term "suction" soren used, which dodn't match the terminology Bill was using. (Soren reffering to lower pressure, as in the same context to the vacuum in the bullet anology -translating to a net drag-, Bill referring to the qualty airfow over wetted surfaces I think)


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## Kurfürst (May 2, 2008)

Part I still can`t get is that why all this stuff about P-51 windshields is being discussed in the thread titled 'Best Bf 109 subtype'...

This board needs a bit of discipline when it comes to off topic arguements, I mean it is not bad to steer off a bit sometimes from the subject, but when it becomes a regular issue of hijacking threads, I must ask myself, that if some of us are so thrilled with the same subjects that we feel the unconquerable pressure to discuss it over and over again between ourselves, then, why not do it in its own dedicated thread, say in:

P-51 vs. Luftwaffa Thread MMII.
Spitfire vs. Messerschmitt in turns thread MMMDDCILV.
Soren vs. drgondog Thread XIII.
Hartmann didn`t even flew in combat, his claims are bogus CXXII.
I`m getting pissed off with off topic post and thread hijacking II.


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## Soren (May 2, 2008)

DerAdlerIstGelandet said:


> Yet Bill is a school educated Aeronautical Engineer, and you claim he does not know what he is talking about?
> 
> Yeah okay...



I don't claim he doesn't always know what he's talking about, but he rightly keeps his mouth shut when he knows I'm 100% correct, like in this thread. Then ofcourse he has to post something, so to divert from the topic he begins the now so popular canopy suction debate..

Oh and about being a school educated Aeronautical engineer, well they have to read similar or the very same books I have Adler. The only advantage is they get to fool around with computer fluid programs, something I have to pay hundreds of dollars to do.


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## kool kitty89 (May 2, 2008)

The canopy discussion was interesting (the original discussions a couple threads ago) but even for the context of a 109 with bubble canopy it doesn't belong here. Maybe a dedicated thread. (for canopy design and effects, not exclusively for the Mustang)



So how does the G-10 compare to the K-4, Erich mentioned a couple times that the G-10 was a little faster (460 mph), but that doesn't seem to match up with most data.

Another interesting comparison would be range of the 109's. (particularly with 300L drop tank, accurate figures for which seem to be hard to find)

This site has some good range figures, but with drop tank. www.adlertag.de - Messerschmitt BF109 - Sprachenwahl


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## kool kitty89 (May 2, 2008)

Here: I started a new thread: http://www.ww2aircraft.net/forum/aviation/canopy-design-13084.html

Now let's get back to the topic at hand.


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## DerAdlerIstGelandet (May 2, 2008)

Kurfürst said:


> Part I still can`t get is that why all this stuff about P-51 windshields is being discussed in the thread titled 'Best Bf 109 subtype'...
> 
> This board needs a bit of discipline when it comes to off topic arguements, I mean it is not bad to steer off a bit sometimes from the subject, but when it becomes a regular issue of hijacking threads, I must ask myself, that if some of us are so thrilled with the same subjects that we feel the unconquerable pressure to discuss it over and over again between ourselves, then, why not do it in its own dedicated thread, say in:
> 
> ...



Ditto

I completly agree. It almost allways seems to involve the same people as well.


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## DerAdlerIstGelandet (May 2, 2008)

Soren said:


> Oh and about being a school educated Aeronautical engineer, well they have to read similar or the very same books I have Adler. The only advantage is they get to fool around with computer fluid programs, something I have to pay hundreds of dollars to do.




Soren it goes way more in depth than just reading books. Come on now, you know that experience is worth a lot more. Dont even go there!


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## drgondog (May 2, 2008)

Soren said:


> I won't reply to pissing match posts, it's ridiculous.
> 
> What Bill seems unable to understand is that if you haven't used a computer pressure distribution program before then you can't expect to undertsand it right away.
> 
> Furthermore the only reason he keeps bringing this up is because he knows all I've said in this thread is 100% correct.



Ah, no. I do not and have repeatedly indicated to you why your 'math and physics' with respect to manueverability can't stand the scrutiny of rigorous modelling..

You can state your opinion Soren, but browbeating people with simple contempt beccause they aren't 'convinced' of your credentials can be insulting - particularly when you declare victory be stating that "anyone can see.." 

Perhaps when you can demonstrate industry practices and/or academic grounding in your assumptions and the equations you wish to bring to the table, your opinion will be held in higher regard.

It simply isn't as 'simple' as you think trying to model with accuracy any manuever results - 

Even today with very sophisticated models, there IS a reason to go from prototype to flight test, then to production.


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## drgondog (May 2, 2008)

Kurfürst said:


> Part I still can`t get is that why all this stuff about P-51 windshields is being discussed in the thread titled 'Best Bf 109 subtype'...
> 
> This board needs a bit of discipline when it comes to off topic arguements, I mean it is not bad to steer off a bit sometimes from the subject, but when it becomes a regular issue of hijacking threads, I must ask myself, that if some of us are so thrilled with the same subjects that we feel the unconquerable pressure to discuss it over and over again between ourselves, then, why not do it in its own dedicated thread, say in:
> 
> ...



You are right Kurfust. 

In a manner of speaking the hijacking between Soren and myself is all about Soren dismissing any opionion opposing his own regarding a/c performance as unfounded. 

Frequently, he then proceeds to use aero theory and coefficients to suit his own argument and proceeds to present them as 'irrefutable fact' - which has led me from a debate on facts to a debate on theory.

So, I apologize to you and others that are similarly irritated and will try to NOT wander when I engage.. but I will pound Soren everytime he 'theorizes in a no-theory zone' about stuff he really doesn't fully understand. I also will restrain myself from the same territory.

Regards,

Bill


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## drgondog (May 2, 2008)

kool kitty89 said:


> ...
> 
> I think the first problem was the argument over the term "suction" soren used, which dodn't match the terminology Bill was using. (Soren reffering to lower pressure, as in the same context to the vacuum in the bullet anology -translating to a net drag-, Bill referring to the qualty airfow over wetted surfaces I think)



Actually KK, Lednicer used the term "Suction" when referencing the P-51D canopy model results. What Soren did not understand is that Lednicer been redundant he would have described the flow over wing as "Suction" also - as they are pressure 'forces' in a vertical plane to the free stream.

Anybody that had a rough clue of Fluid Mechanics or the enxt extension, Aerodynamics, would have recognized this immediately whether he had ever seen a computer model like this before, or not.

When he kept up the argument, he never stopped and recognized his limits in understanding what he saw, did not acknowledge that he didn't understand the context and further went on to make the anology of pressure (or wake) Drag which is In Line with the free stream flow but a force retarding the bullet's sustained flight.

I only pushed him on this because he missed the theory behind slats, he kept claiming that it was 'obvious' that a 109 out turned a Spitfire (model for model) and always out turned a Mustang despite flight tests and many combat experiences to the contrary (note: I did not say "Always").

Then, ignoring experiences and opinions to the contrary he trotted out his 'vast aero knowledge' to prove his point. He does not really fully understand the limitations of his knowledge.

Once again, I apologize for hijacking the thread with this relentless pursuit of Soren's lack of 'bona fides' in this field - and wish to stress that my 5-6 years in industry practice, combined with my BS and MS Aero degrees, does NOT make Me a Practicing Expert.


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## parsifal (May 2, 2008)

Bill, remind me never to doubt your credentials in any debate concerning aero engineering. I am impressed.

For the record, i have no formal experience in aero engineering, or any flight experience. I have experience in tactical handling, and some grounding in military theory, but nothing like this.

Very impressive. I know which horse i am backing in this horse race at this point. This is an intersting (but hard to follow) thread guys


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## drgondog (May 2, 2008)

parsifal said:


> Bill, remind me never to doubt your credentials in any debate concerning aero engineering. I am impressed.
> 
> For the record, i have no formal experience in aero engineering, or any flight experience. I have experience in tactical handling, and some grounding in military theory, but nothing like this.
> 
> Very impressive. I know which horse i am backing in this horse race at this point. This is an intersting (but hard to follow) thread guys



Parsifal - I make mistakes, no doubt about it. more often than not I know what I don't know and have learned over time when to NOT open my fat mouth..


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## kool kitty89 (May 2, 2008)

Bill I agree, but if you wan't to discuss that more in the canopy poll I opened.

And granted, test data will be different from calculated data, and an advantage of an a/c on paper may not hold up in reality. (although a huge deviation would seem odd)

But in the case of this discussion the airframe almost the same, so a change or advantage over another model would apply much more closely than figures from an entirely different a/c. The only major changes was going from the E to F with resulting in the F and later models being much cleaner. The K changed this again, though not as drastically.


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## Soren (May 3, 2008)

Bill,

I'm getting real tired of your ridiculous rants. You know I've said nothing wrong in this thread and so you had to bring up that stupid suction debate you have come to love so much!

But if you're the expert you claim to be then tell me please, is there anywhere in this thread that I've said anything whch isn't 100% correct ???? 

So if you can't find anything in this thread which is incorrect then in the future, for everyones sake, keep your mouth shut, otherwise it's clear that you could care less about sidetracking any thread and care more about your own personal agenda!


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## kool kitty89 (May 3, 2008)

Okay lets get on topic though, and leave that for PM's. 

Lets get back to comparing 109's and other 109's 8)


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## Juha (May 3, 2008)

Hello
how much aerodynamically cleaner K-4 was?
G-2 650kmh @ ? with 1310hp engine (1,3 ata)
K-4 727kmh @ ? with 2000hp engine (2,0 ata)

Juha


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## DerAdlerIstGelandet (May 3, 2008)

Nobody seems to listen...


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