Bf109G-6 Question!

Koopernic · May 22, 2014

Garyt said:
If you mean turn radius, you are probably right. The mustang was certainly not the quickest turner. Would not surprise me either if the Me climbed better, all the Me109's seemd to be great climbers, the P-51 was not the best at climbing.

Not sure how it would effect roll rates though.

It all depends on speed and altitude of the engagement and which engine the Me 109 had. At speed the Mustang was clearly superior. Roll rate of the Mustang was unbeatable by any aircraft except for the P-63 King-cobra. This is because the NAA/NACA laminar flow wings were resistant to compressibility/mach effects, because they were thick enough to contain the internal pressure balancing mechanisms for the ailerons which reduced pilot force required to deflect the ailerons. Also the NAA/NACA profile was so thick it made the wing stiff, aeroelasticity meant that thin wings twisted opposite to the wing thereby even rolling the aircraft in the opposite direction, well known limitation of spitfires untill a new wing came in from the F.22 onwards. The P-51 had about the same maneuverability in terms of turning circle as the Tempest V, the Tempest was faster at low altitude but the tempest had absolutely no warning of an oncoming stall.

Milosh · May 22, 2014

I think someone has forgotten about the Fw190.

Garyt · May 22, 2014

It all depends on speed and altitude of the engagement and which engine the Me 109 had. At speed the Mustang was clearly superior. Roll rate of the Mustang was unbeatable by any aircraft except for the P-63 King-cobra

THe mustang rolled well indeed, but it's turn radius was not good. Combination of roll and turn radius puts it at best average IMO for the ability to turn.

Unless of course it's at low speeds, then it's just pretty bad at turning overall.

Juha · May 23, 2014

Koopernic said:
It all depends on speed and altitude of the engagement and which engine the Me 109 had. At speed the Mustang was clearly superior. Roll rate of the Mustang was unbeatable by any aircraft except for the P-63 King-cobra. This is because the NAA/NACA laminar flow wings were resistant to compressibility/mach effects, because they were thick enough to contain the internal pressure balancing mechanisms for the ailerons which reduced pilot force required to deflect the ailerons. Also the NAA/NACA profile was so thick it made the wing stiff, aeroelasticity meant that thin wings twisted opposite to the wing thereby even rolling the aircraft in the opposite direction, well known limitation of spitfires untill a new wing came in from the F.22 onwards. The P-51 had about the same maneuverability in terms of turning circle as the Tempest V, the Tempest was faster at low altitude but the tempest had absolutely no warning of an oncoming stall.

I wonder from where you got the claim "thin wings twisted opposite to the wing thereby even rolling the aircraft in the opposite direction, well known limitation of spitfires untill a new wing came in from the F.22 onwards."? Spit suffered from wing twisting in high speed rolls and that reduced its rate of roll at high speeds but it didn't suffere aileron reverse.

Spit aileron reverse speed according to April 1941 test report was 477mph IAS that means 477mph TAS at SL, 555mph at 10000ft TAS and 654mph TAS at 20000ft. That was calculated from test data, earlier based on conventional theory was appr. 550mph IAS

The RAE 1231 (DSIR 23/12865) gives reversal speed 580 mph EAS for the Spitfire V with standard wings and that value is calculated from flight test results.

Juha · May 23, 2014

Koopernic said:
...The problem with this 'production approach' was that more Me 109 were being produced than mature pilots to fly them. Vast numbers of Me 109 were lost during delivery, with their delivery pilots who were incapable of air combat maneuvering. There is an argument that quality should have been emphasized before quantity.

Very good message K
I would only add that the urgent need of max. production affected also others, e.g. most Spitfires produced were so called "interim types", V, IX and XIV because of that. E.g. there were many more IXs than VIIIs, which was the designed unpressured Merlin 60 series type with stronger airframe and retractable tailwheel and extra range.

Koopernic · May 23, 2014

Juha, seems to me however that the German compromises actually effected performance in terms of speed at a time Pilots with 1300hp Me 109G6 were up against Spitfires with 1700hp, an almost unbelievable difference in power. The compromises the Spitfire IX made over the Spitfire VIII were
the IX lacked internal fuel in the wings
the IX lacked a retractable tail
the IX lacked the enlarged tail

nevertheless the repeated wing standardization cycles of the Spitfire wing must have been very expensive. And of course the P-51, Fw 190 and P-47 all had fully retractable tails.

for the Me 109G6
The G6 lacked the retractable tail of the Me 109F and Me 109G1/G2 (speed penalty at sea level was 12kmh or 7mph)
The G6 due to the gun bulges lost 9kmh(5.6mph) in speed of which 6kmh could be regained by streamlining these so that the loss was only 3km/2mph)
The failure to streamline the gun bulges seems unbelievable given this was non structural metal.

In other words a total of 18kmh was lost, 11mph. We had a situation of 408mph Spitfire Mk IX's flying against 386mph Me 109 (latter 397mph when boost was raised to 1.42 ata). The corresponding speeds would have been 398mph and 408mph, which is far less difficult.

The 11mph gain would drive the Me 109G6AM and Me 109G14A to 363mph at sea level which is only 3mph short of a Tempest V running 100/130 fuel.

This 'cleaned up' version, known as the Me 109K1 was ready in late 1943.

Juha · May 23, 2014

Hello K
remember that cannon armed Spits also had gun bulges, not in fuselage but on their wings. After all Spit and 109 had much in common, they were in essence short range interceptors with very good rocs

stona · May 23, 2014

Juha said:
I wonder from where you got the claim "thin wings twisted opposite to the wing thereby even rolling the aircraft in the opposite direction, well known limitation of spitfires untill a new wing came in from the F.22 onwards."

It's an internet 'factoid' which grows more insidious by repetition. Like deep rooted weeds, you can cut the tops off but the damned things keep coming back.

Cheers

Steve

Aozora · May 23, 2014

Juha said:
During the long production run of 109G-6, all with DB 605A engines but the 1.42ata boost was at last allowed, for very short period (1 or 3 mins), in late 1943, was that in Oct. Before that the max allowed boost was 1.3ata but short periods when 1.42ata was at first allowed then again barred due to engine failures. Then there were subtypes like G-6/U3 with DB 605AM engine. 109G-14 was in practice G-6 with MW50 system installed ie like G-6/U3. G-6/AS (DB 605AS engine) had the max speed of 410mph, IMHO it was the most dangerous G-6 for the Mustang

The 109G suffered from performance limitations because of the DB 605A's problems from about June 1942 to early 1944 - roughly 19-20 months (eg; from February 1944 109G-6/R3 handbook - 1.42 ata was blocked, again http://www.wwiiaircraftperformance.org/me109/Bf109_G4-R3_G6-R3_Bedienungsvorshrift-Fl_Feb_1944.jpg ). It must have been frustrating for ground crews and pilots alike to have to cope with the continual chopping and changing of the boost limits while Daimler-Benz tried to sort the problems out.

Denniss · May 23, 2014

There was not 1.42 ata ban on the 605A in 1944 unless it was an old aircraft with non-modified engine. The recons were probably not high on the list.
Is this really a 2/44 manual or just released in 2/44 with data updates from later 43?

DonL · May 23, 2014

This is why I'm skeptical to Tony Williams and wwii aircraftperformance.
Also to my knowledge the clearence for 1.42 ata was late autumn 1943

Aozora · May 23, 2014

Denniss said:
There was not 1.42 ata ban on the 605A in 1944 unless it was an old aircraft with non-modified engine. The recons were probably not high on the list.

Mike is a member of this forum so you can ask him directly. Do you have any documents confirming that this page might be exceptional?

DonL said:
This is why I'm skeptical to Tony Williams and wwii aircraftperformance.
Also to my knowledge the clearence for 1.42 ata was late autumn 1943

At least Mike is generous enough to buy and compile the information and put it up on an expensive to run website: if you have problems with the information on his site send a personal message to Mike instead of trying to denigrate the guy.

DonL · May 23, 2014

Kurfurst - Your resource on Messerschmitt Bf 109 performance

KurfÃ¼rst - Transcript of Generalluftzeugmeister meeting on 7th September, 1943.
http://kurfurst.org/Engine/Boostclearances/DB605A_clearance_Aug-Oct43_G2FzgHB-T0-Full.JPG
http://kurfurst.org/Engine/Boostclearances/DB605A_clearance_Aug-29sept43_G3FzgHB-T0_full.jpg
http://kurfurst.org/Engine/Boostclearances/DB605A_clearance_Aug-29sept43_G4FzgHB-T0-Full.jpg

Edit:

instead of:

http://kurfurst.org/Engine/Boostclearances/DB605A_ban_Jun-10Nov42_G2FzgHB-T6-Full.JPG

DonL · May 23, 2014

@ Aozora,

if you write me a PM, but block any answer, it is impossible to arguement or answer!

Milosh · May 23, 2014

There was a period around the time of the Battle of Stalingrad when the max boost was returned to 1.30ata. Don't know if this was also on the other Fronts.

Kurfurst is not known for being honest and truthful.

DonL · May 23, 2014

Kurfurst is not known for being honest and truthful.

Where he has ever posted a wrong source on his webpage of the Bf 109?
Tell me one source and this are all german primary sources and germans built the Bf 109!

I have every book from Dietmar Hermann and to my knowledge he is the only Author in the whole world, who has direct access to the FW archive. His sources and performance charts of the different FW 190 a/c's are quiet different, then the sources and charts of wwii aircraftperformance.
Also the US test of the FW 190 A5 compare to the F6F-3 and the F4U-1D, where the Fw 190 A5 reached the same performance as shown from german primary sources, contradict to performance charts of wwii aircraft performance.

From here comes my skeptic!

nuuumannn · May 23, 2014

Oh Lordy. DonL's back from exile and he's brought Kurfurst with him. There goes the neighborhood...

DonL · May 23, 2014

Do you have any argumentation or sources instead of insults? Show me proves and we can discuss!
Also I was only one week away, what a large timeline!

If you mean for a week vacation, you could offend or intimidate me, you're wound wrong

kettbo · May 24, 2014

c'mon guys, let's talk planes and not people.
Post up facts, some sources, discuss, and learn

nuuumannn · May 24, 2014

If you mean for a week vacation, you could offend or intimidate me, you're wound wrong

Easy Tiger; no offence or intimidation implied or necessary, just a joke. Stop and smile every once and awhile, Don; you come across very confrontational is all I mean.

Bf109G-6 Question!

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