MW-50 Bf 109s Vs Fw 190 A

[GregP]

Gaston, first paragraph or so: how do you figure the Spirfire wing is bent at 6g in a 3g turn? How do you figure the Fw 190 wing is bent at 4 g in a 3 g turn?

The aircraft is pulling 3 g and the downward-tending wing may have less stall margin, but is still pulling 3g. The entire airframe is pulling the same g force, including the pilot. If he starts to feel a nibble on the stick (impending stall warning from air separating from the airfoil), he knows not to pull any harder or he will stall. Perhaps in certain circumstances, the stall might be preferable to the alternative course of action, but not close to the ground! That is certain death and most pilots would not pull to a stall deliberately at low altitude.

The wing isn't being "bent" by full power application; the structure can handle the engine torque and the wing doesn't experience any bending force from engine torque at all. The engine mount, longerons, firewall, bulkheads, and fuselage structure does, but it is designed to do that.

Gaston, aerodynamics is well known and the books explain it. You cannot reinvent a science that works according to the already-established rules. CL doesn't "collapse."

Propellers don't have resistance to being forced below their potential speed. ALL propellers fly at speeds below their potential because there must be some angle of attack for lift to be developed from most propeller airfoils. I don't know of any symmetrtic propellers. Do you?

Coefficient of Lift is a number, not a force. It cannot be ahead of or behind the CG. There is a CG and center of pressure or center of lift, if you prefer the term. In a stable aircraft (and all WWII fighrter were stable) the center of lift is behind the center of gravity and the horizontal tail must "lift" downward to keep the aircraft in stable flight. If you lose the horizontal tail in a conventional wing-first and tail-behind aircaft, it will nose down very quickly. If you lose speed the tail loses lift faster than the wing ansd the nose drops. If you gain speed the tail gains lift faster than the wing and you nose up. Both tendencies return the aircraft to trimmed speed ... and it is called a "stable" aircrtaft. Lack of these characteristics makes for an unstable aircraft. Some unstable aircrtaft can fly for a short time, but not many, and the pilot must apply reverse stick force to make things work out ... so it sometimes happens that an aircraft that is unstable (loaded too far aft CG) can make it around the pattern and land. Most crash in a heap.

I'm afraid you need to read an aerodynamics text before you continue with theories that, while being inventive, are incorrect. But you have heard this before in another forum and obviously haven't yet bought an aerodynamics text. You also said in the other forum you'd post the math behind your theories within a month and that was more than 2 years ago with no math post to date. I am not trying to put you down, but aerodynamics is pretty well known, especially in here, and you are trying to say it is wrong while a century of real, live aircraft say that you may be mistaken since they mostly perform as designed.

Seriously, go take a course in aerodynamics. You'll like it.

 

[Siegfried]

Lightweight Me 109G? Please!

The Me 109F, widely regarded as the best of the breed by the Aces, weighed in at 6,054 pounds.

The Me 109G weighed in at about 6,942 pounds (normal, not max). Max was 7,053 pounds!

The Me 109K weighed in at about 6,832 pounds normal and 7,493 pounds max.

The Me 109G could outweigh the F model by a whopping 1,000 pounds, all without an increase in wing area. In truth, it was the heavyweight of Me 109's and had the heaviest wing loading.
.

I think you will find that the weight given for the Me 109G is with the twin Gondala weapons mounted. These added considerable weight. Unfortunatly this retrofit variants keeps cropping up as representative of its speed, climb etc.

 

[Siegfried]

The actual strain gauge is a single axis device - but for most purposes using just a single axis isn't very useful. Often they will use two devices mounted at 90° (as you said), or 3 at 0°, 45° and 90°

As you can see from this picture, you need a channel for each strain gauge axis used.

btw, it's gauge pretty much everywhere except the USA.

This particular kind of strain gauge in which the resistor is an etched device on a plastic film that is glued to the surface whose strain is to be measured was not available during WW2. Strain guages did however exist: they used taught wires, somewhat like a piano string, to act as the resistor.

 

[GregP]

That may or may not be the case Siegfried, and I won't argue the point, but in many interviews with German pilots after the war, the weight gain in the Me 109G was remarked upon negatively. The people who did not like the G included Erich Harttmann. He stated that the F was the best Me 109 and the G was not nearly so good. It has been said the G model was heavy enough that it required almost full power in the landing configuration around the pattern. I have seen that said in books by William Green and in interviews of former Luftwaffe pilots.

All my references on German aircraft relect the weight gain, too.

Power to weight ratio affects climbing ability, wing loading reflects maneuverability, and span loadiong relects maneuverability at high altitude.

As far as I can tell by reading and talking with people who flew and fly them, the Me 109G was a strong climber that was much less maneuverable than the Spitifre counterparts. The thing is, the Spitifre was one of the best climbing aircrtaft of WWII in several marks. It lacked a bit in roll, but the LF Spits had clipped wings to assist in roll that made them less desirable at altitude. So the Me 109 fought well in the vertical arean. So did the Spitfire, but the Spitifre also was a strong turner.

Alas, everything is a compromise. Help in one area causes degradation in another area.

I will not select a "better" aircraft, I will jst say that the Me 109G was past the prime of the Me 109 series, at least in my book.

Last, in my time as an engineering manager, we used strain gages that were already laid out in two and three axes. The only time we used single axis units was when size dictated it. In those cases, we simply used multiple strain gages aligned to whatever axis was required. We used piezoelectric presure transducers for pressure in a closed explosive device and strain gages for stress and strain measurements on the structure.

Semiconductor strain gages weresd not available in WWII, but a kind of Wheatstome bridge arrangement with wire resistors was. What they mostly did was to static load the wings to the design load factor and then to the design safety factor. If the wing survived and returned to shape, it was assumed to be strong enough ... and it was.

 

[Tante Ju]

I doubt Hartmann fly the 109F. It was not in service perhaps when Hartmann joined his unit.. Data show JG 52 completed switch to G-2 model by August 1942, a month or two after this plane appear, and no longer had any 109F. Hartman joined JG 52 in October, but intially flew transfer of Stukas.

IMHO G-2 was better than F in every respect. Probably best fighter 1942.

 

[tomo pauk]

Probably best fighter 1942.

As much as I like the Fs and early Gs, why would that be so? We can continue the discussion in the '1942: the best fighter thread', so this thread does not go off-topic

 

[GregP]

Tante Ju, My remarks about Hartmann come from interviews WITH Hartmann. I make no claim he flew anything, but HE does. You may believe it or not, and you might be right wither way you choose.

I am not a fan of the Me 109G, but liked the E and F models. I am not a fan of the K models either, but late models of almost all piston fighters had poorer flying characteristics than earlier models, so the Me 109 is not singled out in this regard by any means. The Girffon-powered Spitfires don;t fly nearly as nicely as their lighter, Merlin-powered coutnerparts, either.

The exception is the late model P-47M, which was meavier and yet performed better in all aspects than earlier P-47's. Go figure, huh.

 

[Gaston]

I am not sure why we have to throw out all the data that was collected with static testing.

I mean those engineers/designers knew how much wing bend/deflection they were getting at certain given loading's. Any major discrepancies (like being off by 50%) would probably have been noticed.

As far as "Did you ever achieve 6 G in horizontal turns at full power below 300 mph? At normal power? Remember you cannot unload the prop by spiralling down: It has to be a true level turn."

I don't think ANY WW II fighter was going to pull 6 "G"s in a horizontal turn for very long ( a couple of seconds?) without spiraling down.

If you haven't seen them try these charts for starters.

http://www.spitfireperformance.com/spit109turn.gif

Please note the Spitfire has to be doing 250mph in a 6 G turn or it stalls. also please note how far the Spitfire is from being able to maintain a 6 G turn. It has descend at rate equal to 27.5-28 degree descent in level flight in order to maintain the 6 G turn.
Later Spitfires with more powerful engines will do better but then later Spitfires also weigh more and will have a a higher stalling speed limit which will affect the tightest turn radius.
Please also note that turn radius varies with speed and G's pulled.

Which Spitfire is out turning which?

A. taking 19 seconds at a 1600ft radius at 375mph.
B. taking just under 16 seconds at a 1200ft radius at 325mph.
C. taking 13 seconds at 800ft radius at 265 mph.

All are pulling 6 Gs and all are loosing thousands of ft/min altitude.

The Spitfires "best" turn performance seems to be a 23-23.5 second turn at 225mph at 1200ft radius at 3gs. it may actually hold height at that turn "rate" and speed.

Obviously starting position between two aircraft could be critical to a turning fight. a little altitude advantage helps, the pursuing airplane starting on the outside of the target plane has to pull more Gs ( or turn tighter, momentarily trading speed for turn radius)to get the target in the sights while starting from inside the turn (target turns across the pursuer) makes things easier for the pursuer. initial bank can affect results.

Blacking out in a sustained 6 G turn can really affect the results

All that data is entirely calculated and was not derived from actual flight tests. Think about it: If these calculations had proved of any practical combat value at all, would they not have been repeated for the Mk V, MXII, Mk IX, Mk XIV?

Besides, there is a chart for the Me-109E as well: If the British had access to more than one Me-109E they would have run out of spare parts to fly them long before they were halfway through flying half those innumerable data points... You have to read between the lines on things from that era...

Trust me, we don't have later war examples of those charts (I always see the same two: Spit I and Me-109E) because all that data proved completely useless, just as was useless the Mk I in 1944... That data would have been priceless to have and certainly would have been collected on similar charts for other types if it was of any value... The numbers data proved hard to gather consistently for some reason, and what we have later from the RAE are general recommendations... The same approximate mess is true for all other WWII fighters, as the testing procedures and instruments were simply not up to the task of informing us about these things if only on the most general terms, and sometimes not even that...

Want some further indication of that? The G data on those charts... There were apparently no G meters in 1940...

Gaston

 

[GregP]

Gaston, I don't trust you at all .. but please continue.

You are in need of an aerodynamics course. The aircraft designed to conventional principles fly well. Amateur-designed aircaft sometimes don't. Think of the Christmas Bullet.

You might want to have a good-flying aircraft (if you fly, that is) designed to formulas and principles that work. Then again, you ay be onto something. If so, build it, fly it, and post the results. We already know how Spitrfires, Fw 190's, etc. fly ... quite well. And when they pull 3g, they don't pull 6 g or 4g ... just the 3.

 

[Gaston]

I'll say one thing for you Gaston, you don't go in for short posts, do you? I'll have t read that one awhile ...

By the way, at 8,000 pounds or less, the corner speed of a P-51D is very close to 265 mph and 8g. At 320 mph you can easily break a P-51D. If you exceed these limits, you may get away with it, but you have structurally compromised the aircraft. The desgn safety factor is 1.5, but the flight limits are the flight limits. Exceed them and you are a test pilot..

12G matches the 1.5 safety factor you mention, as it does for most WWII types.

I don't agree these aircrafts are easy to break in horizontal turns: They are easy to break in dive pull-outs, but hardly ever broke in horizontal turns in combat without some prior hits. At 320 mph you cannot break the P-51D in a true horizontal turn because, as the SETP tirelessly tells you through me, the P-51D can hardly even REACH 6G horizontally at that speed without stalling... Note they were allowed to stall the aircrafts for the test, but not to go for 7G...

It is the minimum speed at which it can even barely make 6 G in a horizontal turns under normal maximum continuous power. At this power level or higher, when have you ever heard of a P-51D reaching 8 G at 265 mph in a horizontal turn? According to the SETP, "The P-51D at these speeds will still stall at the slightest provocation, dropping one wing violently"

The Society of Experimental Test pilots does not have the authority to change the manufacturer's pilot manual. If they want to allow a higher speed, they have to do the engineering, the testing and verification, get approval and release the FAA-approved new flight limits. That has not happened and will not. The liability is WAY too high for anyone to be that stupid...

They tested to 6G only so as to not strain the P-51 and the 3 others: They could not even reach that 6G value horizontally below 320 mph without stalling it is what they are saying... I am sure they could reach it in pulling out of a dive at 250 mph, but that is NOT what they tested...

To get the g limit at other than 8,000 pounds, you divide 64,000 by the weight in pounds ... and that is straight from the pilot's manual.

...

But the manual doesn't care if you can't even reach those values in horizontal turns because you are stalling now does it?

Gaston

 

[Gaston]

Gaston, I don't trust you at all .. but please continue.

You are in need of an aerodynamics course. The aircraft designed to conventional principles fly well. Amateur-designed aircaft sometimes don't. Think of the Christmas Bullet.

You might want to have a good-flying aircraft (if you fly, that is) designed to formulas and principles that work. Then again, you ay be onto something. If so, build it, fly it, and post the results. We already know how Spitrfires, Fw 190's, etc. fly ... quite well. And when they pull 3g, they don't pull 6 g or 4g ... just the 3.

But how do you know that since we don't have the wing bending data while in flight?

How would you know if a wing determined to have 3G of lift in the wind tunnel at a certain point is not in fact reacting differently in the actual flight where the aircraft is not just a shape sitting in the wind?

The only way to really know is to know how badly it bends on the real thing.

You forget that aircrafts are not mathematical models: They are concrete objects made of matter, and matter tells the math what it is doing.

Gaston

 

[Gaston]

Gaston, first paragraph or so: how do you figure the Spirfire wing is bent at 6g in a 3g turn? How do you figure the Fw 190 wing is bent at 4 g in a 3 g turn?

The aircraft is pulling 3 g and the downward-tending wing may have less stall margin, but is still pulling 3g. The entire airframe is pulling the same g force, including the pilot. If he starts to feel a nibble on the stick (impending stall warning from air separating from the airfoil), he knows not to pull any harder or he will stall. Perhaps in certain circumstances, the stall might be preferable to the alternative course of action, but not close to the ground! That is certain death and most pilots would not pull to a stall deliberately at low altitude.

The wing isn't being "bent" by full power application; the structure can handle the engine torque and the wing doesn't experience any bending force from engine torque at all. The engine mount, longerons, firewall, bulkheads, and fuselage structure does, but it is designed to do that.

Gaston, aerodynamics is well known and the books explain it. You cannot reinvent a science that works according to the already-established rules. CL doesn't "collapse." .

-How exactly do you know what the CL is doing? Any pictures of it staying put?

-How do you know the wings are not working harder than the rest of the airframe?

-How do you know there is not a greater void than expected over the wings on these types?

-Torque or P factor has nothing to do with anything here...

Propellers don't have resistance to being forced below their potential speed. ALL propellers fly at speeds below their potential because there must be some angle of attack for lift to be developed from most propeller airfoils. I don't know of any symmetrtic propellers. Do you?.

-Are you saying the prop disc surface is not symmetrical?

-How do you know pulling part of the prop disc back slower is not a lot harder than pulling it whole like an exterior mirror's drag does?

Coefficient of Lift is a number, not a force. It cannot be ahead of or behind the CG. There is a CG and center of pressure or center of lift, if you prefer the term. In a stable aircraft (and all WWII fighrter were stable) the center of lift is behind the center of gravity and the horizontal tail must "lift" downward to keep the aircraft in stable flight. If you lose the horizontal tail in a conventional wing-first and tail-behind aircaft, it will nose down very quickly. If you lose speed the tail loses lift faster than the wing ansd the nose drops. If you gain speed the tail gains lift faster than the wing and you nose up. Both tendencies return the aircraft to trimmed speed ... and it is called a "stable" aircrtaft."

-I use CL for Center of Lift.

-I already explained why the CL can move in front of the CG without the aircraft becoming unstable: The resistance of the prop to assymetrical incoming air speed is what caused the CL to move in the first place: That resistance substitutes for the forward position of CG...

I'm afraid you need to read an aerodynamics text before you continue with theories that, while being inventive, are incorrect. But you have heard this before in another forum and obviously haven't yet bought an aerodynamics text. You also said in the other forum you'd post the math behind your theories within a month and that was more than 2 years ago with no math post to date. I am not trying to put you down, but aerodynamics is pretty well known, especially in here, and you are trying to say it is wrong while a century of real, live aircraft say that you may be mistaken since they mostly perform as designed.

Seriously, go take a course in aerodynamics. You'll like it.

-In historical terms a century is little, and instrumentation for testing the aircrafts in question was primitive when it mattered: That the mode of propulsion for combat suddenly changed explains why the error was never corrected, because the new mode flattered the old theoretical errors: You'll never need any of this to fly or even design a Cessna, and you can very well design a perfectly successful aircraft while still having your basic flight physics wrong...

Sorry, but if the flight physics say the P-47D is out-turned by a Me-109G in low-speed sustained turns, then the flight physics are dead wrong, because out of thousands of to-the-death combats I cannot find any indication of this happening or being even close to happening.

Same with the Spitfire vs FW-190A: Past an initial sharper Spitfire turn at the first merge (always from a dive, or high speed, or high altitude), sometimes gaining on up to close to one circle, the Spitfire is then hopeless if it lets speed get too slow: The opposite of what flight physics say...

On these types the basic flight physics is wrong, that's all there is to it: You can deduce most of the math from the bigger post I made on this thread, but in the end only in-flight wing bending measurements will prove me right or wrong...

Gaston

 

[Juha]

Hello Gaston
test flown figures
Soviet tests were flown at 1000m. When time of turn is given xx – yy sec, they are different times for turning in left or right.

Yak-9 (1943)
- 17 or 17 - 18 sec

Spitfire F Mk IX
- 17,5 sec

Spitfire LF Mk IX (Merlin 66)
- 18,5sec

Spitfire Mk VB
- 18,8 sec

La-5FN (1943)
- 18 – 19

Me 109F-4
- 19,6 ( sometimes 19,8 ) -20.5 NII (Soviet max speed for the ac on slow side, so probably the plane had some problems)

P-39Q-15, without gunpods.
- 20-21sec

Me 109G-2
- >20-21,5 middle 21 NII (Finnish tests, also at 1000m, 1,3 ata, sustained 22 sec, speed 360 km/h 3G)

FW 190A-4
- 23-24s LII-NKAP
- 22-23s NII-VVS

Me 109G-2/R6
-22,6 sec

MiG-3 (1942)
- 23

P-47D-10-RE, engine R-2800-63
- 26 sec 30 sec depending on source.

Turn radius

Spitfire IXLF - 235m
Yak 1 - 275m
Yak 9? - 290m
La-5 : 310m
La-5FN : 295m
Me109G-2 : 290m
FW190A : 340m
P-39 : 253-280m


Juha

 

[Shortround6]

All that data is entirely calculated and was not derived from actual flight tests. Think about it: If these calculations had proved of any practical combat value at all, would they not have been repeated for the Mk V, MXII, Mk IX, Mk XIV?............

Want some further indication of that? The G data on those charts... There were apparently no G meters in 1940...

Gaston

So what if they are calculated.

Your contention is that that the engineers and test pilots were off the mark by considerable amounts.

I think that if the actual flight test results were as far off as you seem to think, somebody would have noticed.

"G" meters in the instrument panel may not have existed in 1940. Recording "G" meters with a pencil drawing a graph on a drum of paper certainly did.

The NACA did a number of instrumented "G" tests of various aircraft by the late 30s including a few pylon racers. In fact back in 1922 the NACA had figured out how to Synchronize the following instruments.

1) Single component gyro (N.A.C.A. Report #155).
2) Single component accelerometer (N.A.C.A. Reports #99 130).
3) Three component accelerometer (N.A.C.A. Technical Note 112).
(4) Air speed meter (N.A.C.A. Technical Note #64).
(5) Control force recorder (N.A.C.A. Report #112).
(6) Control position recorder (N.A.C.A. Technical Note #97).
(7) Multiple manometer (N.A.C.A. Report #148 ).

Since accelerometers are "G" meters it would seem that they did exist in 1940 and just perhaps those engineers/designers were not so ignorant of what was really happening as you think.

SO in 1922 the NACA had the capability of recording the data from the above instruments and synchronizing the data to the split second. Something no test pilot could hope to do.

Test report No.163 describes fitting an S.E.-5A with the the Three component accelerometer and gives graphs for the results in 6 different maneuvers. that is to say Instantaneous G load readings in 3 dimensions with the aircraft speed also recorded.

I would think that 18-27 years later they might have some idea if actual flight results differed from calculated values by a large amount and that since these reports were publish and freely available other countries had access to them and also had their own aeronautics research establishments performing similar work and publishing the results, at least until the very late 30s.

 

[Shortround6]

Gaston,

In some cases the wings were put in wind tunnels and the airflow studied at different angles of attack. At times there were strain gauges used to measure the lift or with several strain gauges you can measure the shift in the center of lift at different angles of attack and airspeeds. Many aircraft were flown with those little tufts of wool all over them to study airflow with cameras recording the movement.

Of course your theory seems to be that a wing that will withstand being loaded with 10s of thousands of pounds of sand bags while static and a fuselage/wing joint that will withstand the torque of the engine just fine on the ground will, when flying behave like a slightly under cooked lasagna noodle. And nobody noticed this during the entire time high powered propeller aircraft were being built and flown.

 

[GregP]

Gaston, Re post 70:

No, the manual doesn't care if you cannot reach the g-limit, The graph is the g-limit designed into the aircraft.

The air is not smooth most of the time. There are updrafts and downdrafts. The V-N diagram is the design limit for the weakest part of the aircraft structure, If you are flying in moderate turbulence, as you are many times over European mountains, and if you pull a 4g turn, horizontal ot not, it is entirely possible to see a momentary 5 - 6g depending on the turbulence level, perhaps more. That is usually called "gust loading."

Wartime P-51's most operated at anywhere frpm 9200 to 10500 pounds and were stressed per the formula I quoted at about 5.9 - 6.3g. Today, most Mustangs fly at 7,900 - 8,200 pounds and are stressed at close to 8g. 320 mph is a good speed in a P-51D but is not significant on the V-N diagram or anywhere else in the flight envelope. And Gaston, the limit at 8,000 pounds is 8g, not 8g plus a safety factor. The safety factor is there to get the pilot home after he screws up and over-g's the airframe. In some cases, WWII P-51D's came home with a few more degrees of dihedral than when they left due to over-g. The planes got home but werre scrapped for spare parts of a non-structural nature.

The saftey factor means the the planes can be overstressed and MAY still get you home. It is NOT intended as a safe operating limit.

I don't suppose this is all a big joke, is it?

 

[Shortround6]

The NACA instrumented a few pylon racers in the late 30s and found (using recording accelerometers =G meter) that a pylon racer executing a 10 sec 2 "G" turn could have momentary "G" loadings as high as 6 "G"s and, at times, in the negative "G" range. If you ease off the elevators to open the turn the "G" loading can go negative for a fraction of a second. The readings were taken during practice sessions and the planes were flying by themselves with no other planes around. Ground observers said the turns looked normal and smooth.

A constant "G" turn is often a decreasing radius turn because as the speed bleeds off the "G" forces would lessen if it was a constant radius turn.

 

[davparlr]

I don't even want to exercise the brain molecules!!!!

 

[GregP]

Gaston, Re: Post 72:

You asked how I know some of these things. I took courses in aerodymanics including a wind tunnel! How do you think I knew it? Airplanes react to gust loads, but they perform as designed for the most part. The stresses are as calculated and demonstrated in testing.

For several years you have been advised to take a course in aerodynamics and get an aerodynamics text ... and you still haven't done it. I'm beginning to think maybe you DID try but were thrown out of class for interrupting the Professor in his or her lectures.

From this point forward, I will try not to react to the bait you post; please don't try to tell me it was really the Germans who bombed Pearl Harbor instead of the Japanese due to a "space-time continum collapse" due to the propeller resisting going slower than it t should be going ... if you do, I'll have another beer and laugh about it.

 

[Gaston]

Hello Gaston
test flown figures
Soviet tests were flown at 1000m. When time of turn is given xx – yy sec, they are different times for turning in left or right.

Yak-9 (1943)
- 17 or 17 - 18 sec

Spitfire F Mk IX
- 17,5 sec

Spitfire LF Mk IX (Merlin 66)
- 18,5sec

Spitfire Mk VB
- 18,8 sec

La-5FN (1943)
- 18 – 19

Me 109F-4
- 19,6 ( sometimes 19,8 ) -20.5 NII (Soviet max speed for the ac on slow side, so probably the plane had some problems)

P-39Q-15, without gunpods.
- 20-21sec

Me 109G-2
- >20-21,5 middle 21 NII (Finnish tests, also at 1000m, 1,3 ata, sustained 22 sec, speed 360 km/h 3G)

FW 190A-4
- 23-24s LII-NKAP
- 22-23s NII-VVS

Me 109G-2/R6
-22,6 sec

MiG-3 (1942)
- 23

P-47D-10-RE, engine R-2800-63
- 26 sec 30 sec depending on source.

Turn radius

Spitfire IXLF - 235m
Yak 1 - 275m
Yak 9? - 290m
La-5 : 310m
La-5FN : 295m
Me109G-2 : 290m
FW190A : 340m
P-39 : 253-280m


Juha

Hello Juha,

Yes I know... And these tests led me astray for years as well, but consider their intrinsic value by the following results the German got actually flight-testing their own Me-109G against an underpowered P-47D Razorback with needle-tip prop: "The P-47D out-turns our Me-109G" (Source: "On Special Missions: KG 200"

So according to Soviet tests, German conclusions are that 26-30 sec < 20-22 Soviet/Finnish times?...

See the problem?

Now in order to evaluate who's right it helps to have a "background" of several thousands combat accounts to see where the reality leans to...

Out of 600 P-47D combat accounts at the Mike Williams "WWII Aircraft Performance" site, about 200 show multiple turns turning contests between P-47Ds and Me-109Gs...: P-47 Encounter Reports

Out of those roughly 200, ONE shows some parity with a Me-109G, in a fast steeply descending spiral to the RIGHT, over about 40+ 360s, then later against the same Me-109G, the P-47D slowly gains over the same amount of time in another downward spiral, winning the turning contest, but this time to the LEFT.

This is one of the few turning contests dated to late 1943, the vast majority being 1944. I think the better performance of the Me-109G could be due to it being a sleeker bumpless and retractable-tailwheel G-2 in 1943...

All the 199 or so other turning contests show a crushing P-47D superiority in all circumstances, especially down to 140 MPH, and even sometimes in climbing spirals (against gondola-equipped 109Gs I suppose)...

Usual turn gain success: Reversed tail position, or equal merge opposite-circle side start, in typically 3 X 360s°, about seven out of ten times...

The remaining 3 out of ten times, the P-47D gains into a firing position is LESS than 3 X 360s°... This in all types of flying situations, but better at low altitudes and slow speed for the P-47D, down to 140 mph!...

Number of Me-109Gs exhibiting even fleeting turn superiority: 0... Turn equality? 0.5 times in a high speed right-hand diving spiral.

The FW-190A usually out-turns the P-47D in sustained turns, sometimes very badly so in later 1944, less so in early 1944.

700 P-51D accounts: Two accounts of unsolvable parity with the Me-109G: 2 X 15 minutes or about 45 + consecutive 360s° to one side, on the deck. One other account of 90 + X 360°s: 30 minutes of continuous turning to one side, no victor... The P-51 usually wins turns vs Me-109G, but slowly: 5-10 turns is common.


So you can go with a bunch of numbers... Or the combat reality.

Don't overestimate the smoke screen of pilot skill that is constantly thrown at you for the express purpose of clouding everything, so as to make even the most crystal clear empirical data useless... Unless you want to believe in the pilot's levitation powers...

My guess is that 22 seconds is not far off for the Me-109G-2 as per Finnish numbers, G-6 (and the P-51D) is more like 23-24 or even 26 with gondolas.

Tsagi tests have the Spit Mk V at 18.8 sec, and the Mk IX at 17.5, but note how Greg P has just told us the Mk V is slightly FASTER than the Mk IX in "Planes of Fame" comparisons... I think the real Mk V numbers are about 19-20 seconds and the Mk IX 21-22 seconds. The FW-190A was around 18-19 seconds, which makes it even with many Soviet fighters, just as combat accounts show. The P-47D was around 19-21 seconds, more towards 19 perhaps on the early Razorbacks and maybe slower than 21-22 on later Bubbletops: Similarly, some FW-190As were armored "Rammjagers" which would be slower as well.

Depending on the availability of intermediary flap settings (none on the Spitfire), reducing the throttle to below 200 MPH could shave as much as 2-4 seconds off all those figures, especially for the P-51D, Me-109G and the FW-190A : G-6: 19-20 secs, P-51D: 21 secs, FW-190A: 16-17 secs.

Ultimate turning speed for the Me-109G-6 was an extremely low 160 mph (250 km/h) according to Finnish ace Karhila:

virtualpilots.fi: 109myths

Which is why I give the 109G a "downthrottled" edge over the Merlin P-51, which it did not display at full power...

By the way you can do the math for my theory easily: Spitfires and P-51s may have a 30:1 prop-to-tail ratio: Assume a 900 lbs prop disc slice involved, so +27 000 lbs over the wingload at 3.5 Gs.

It could be as low as just a 20:1 ratio, but then it would be with a 1300 lbs slice of the prop disc, so still a similar +26 000 lbs as well...

FW-190A is probably as little as an 8:1 prop-to-tail ratio, with maybe a 600 lbs slice of the prop disc... So add + 4800 lbs to the wingload at 3.5 Gs...

Now is the math clear?

The ratio of course uses the lever of the "crushed" forward position of the CL compared to the CG, say four inches, over a ten foot nose, hence 30:1...

BTW, I just learned the early "super-long" nosed early P-40 prototypes tended to pull their wings off, so much so a supply of wings had to be "borrowed" from a delivery to replace all those wings buckled by flight testing on those hugely long-nosed aircrafts.... Hmmmm, that couldn't be related to my theory now could it?

Gaston