P-51 Airfoil and Turn Performance

[Viking]

There are such "hard evidence" for other aircraft such as the Spitfire with regard to turning circle with and without flaps. Why not for the Pony?

[Viking]

Messerschmitt Bf 109 G-6/U2 (TP814 c/n 412951) RAF



This Bf109G-6/U2 was used for tactical trials by the Air Fighter Development Squadron until crashing on take-off in November 1944. It is as you might have noticed a Kanonenboot, and its performance fits very nicely with the aforementioned P-51B vs. 109G test results:

http://www.wwiiaircraftperformance.org/mustang/mustang-tactical.html

Maximum Speed
45.            The Mustang III is faster at all heights. Its best heights, by comparison, are below 16,000ft (30mph faster approx) and above 25,000ft (30mph increasing to 50mph at 30,000ft).

Not surprisingly the Pony is faster than the G-6/U2 at all altitudes.

Maximum climb
46.            This is rather similar. The Mustang is very slightly better above 25,000ft but worse below 20,000ft.

The added weight of the extra guns and ammo reduces the 109G-6/U2’s climb rate to about parity with the Pony.

Zoom Climb
47.            Unfortunately the Me. 109G appears to have a very good high-speed climb, making the aircraft very similar in a zoom climb.

The added weight of the extra guns and ammo makes the G-6/U2 similar to the Pony in zoom climb.

Dive
48.            On the other hand in defense the Mustang can still increase the range in a prolonged dive.

The added drag of the extra guns increases the Pony’s high speed advantage in shallow dives.

Turning Circle
49.            The Mustang III is greatly superior.

The added weight of the extra guns and ammo gives the 109 a worse wing loading than the Pony.

Rate of Roll
50.            Not much to choose. In defense (in a tight spot) a rapid change of direction will throw the Me.109G’s sight off. This is because the 109G’s maximum roll is embarrassing (slots keep opening)

This was a bit surprising.  The Pony has always had a better roll rate than the 109 in AH.


This 109G-6/U2 also fits with the earlier comparison with the 109A. A heavy Kanonenboot 109 would turn worse than a light 190A.

[Neil Stirling]

Army Air Force Wright Field report on EB-102 Bf 109G-6/trop Wnr 16416.

http://www.wwiiaircraftperformance.org/me109/matcom109g.html

No underwing cannon on this one either. Visit LEMB for confirmation.

I wonder if the speed used when turning may explain some of the differences?

Neil.

[MiloMorai]

The added drag of the extra guns increases the Pony’s high speed advantage in shallow dives.

Kurfurst says the drag was negligable, something like ~10kph speed loss with the gondies. It should also be mentioned the drop tank mounts of the P-51 had more drag than the 109.

Check his site, for am sure the correct number is there.

This Messerschmitt Bf-109G-6/U2, W.nr.412951, White 16 of I/JG1, landed by mistake at Manston in the early hours of 21 July 1944. It was flown to the RAE and became TP814.

It is doubtful this is the a/c used in the P-51 trials since it is dated Dec 1943. Now in Neil's link, most likely.

[Neil Stirling]

It is doubtful this is the a/c used in the P-51 trials since it is dated Dec 1943. Now in Neil's link, most likely

Milo  is correct the above aircraft is TP 814 the serial number can be seen just fwd of the empenage. The aircraft used in the original test was R.N 228. Note the date of the stamp, 8th May 1944. And as Milo said,TP 814
did not arrive in the UK until the 21st of July 1944.
 





Neil.

[Viking]

Perhaps allied pilots just don't know how to fly a 109 then.

[MiloMorai]

Originally posted by Viking
Perhaps allied pilots just don't know how to fly a 109 then.

At that time how many LW pilots knew how to fly a 109? Allied pilots certainly had more flight time, especially those doing flight testing.

[Viking]

At that time? Only the few Experten still alive.

[Widewing]

Inasmuch as there is much disagreement among posters and somewhat controversial comments in test reports, I figured it was time to talk to probably the best source alive on the P-51 Mustang.

Dudley Henriques is a pal of mine, of sorts. We have known each other for about 11 years. Our discussions are always centered on aircraft. Dudley has about 4,000 hours of flight time in P-51s. He is a long-time air show performer flying aerobatic displays. Dudley is a past President of the International Fighter Pilots Fellowship. He has served as Eastern Region Director, and Director of Special Projects, for the Combat Pilots Association of the United States. He was an active member of the Professional Race Pilots Association, and the P-51 Mustang Pilots Association. For health reasons, Dudley quit competitive flying about 12 years ago. Dudley has flown just about every fighter in the inventory, from Mustangs through the F-14A and the YF-17.

Through Dudley, I was introduced to John Callahan. John flew the P-51B in the ETO and later the P-51K in the PTO. John was asked about flap use in combat.

First, here's what Dudley had to say....

"I always found the best Vc for the 51 was at about 270 indicated. This married to about +8g's gave me a maximum TR and was for me at least the best corner velocity for the Mustang.

Considering a Vc of 270mph with no flaps, and that up to 20 degrees of flap could be used in the bird up to 400 indicated, all other flap speeds are below corner up to 50 degrees at 165 indicated which is fine....BUT!!!! At 270 pulling about +8g on the pole is already giving you best rate.

My guess is that unless you are turning at max rate and radius and need less radius for a tracking solution, I would leave the flaps alone. Using them will decrease your turn radius but at a HUGE payout of bleeding Ps like a stuck pig. Any advantage I would imagine would be temporary at best and downright destructive to your energy state to say the least.

Just my 2 cents on all this from hassling around with Bearcats, Spits, and assorted other play toys for big boys :-)) .. "

John tosses in his thoughts:

"The two combat areas fought the bird differently. In Pacific the Jap birds could out turn us and had a higher perch so we kept the airspeed up and hit and ran, climbing back to a top position in a high speed climb (faster A/S than the Japs) to make another high energy diving attack.

In ETO the 109 and 190 had about the same altitude as the 51 but we had a
few mph on them. Again not bleeding off energy was the best combat tactic.
Some friends of mine told war stories about having a 109 on their tail and
to get away they made full throttle dives. The 109 had bigger troubles in max velocity dives so many German pilots would not follow a high speed dive.

On flaps. A small amount of flaps would reduce your turn radius and increase
your rate but the additional drag caused you to bleed off airspeed faster
than clean. With the loss of energy you could not fight the bird the best.
Also to put flaps down you had to put your head in cockpit and could lose
track of others in fur ball. Suffice to say, I never used flaps in a dog
fight."

So, here we have two guys with solid to world class credentials. Between them they have about 6,000 hours in Mustangs. Neither one has any definitive experience using flaps in combat or simulated combat. It was something they just didn't do...

I asked John if he knew of any P-51 jocks who had used flaps in combat. He will ask around, but tells me that the number of WWII Mustang pilots he knows is getting pretty small.

So, no concrete answers as of yet.... Will keep digging.

My regards,

Widewing

[MiloMorai]

Originally posted by Viking
There are such "hard evidence" for other aircraft such as the Spitfire with regard to turning circle with and without flaps. Why not for the Pony?

Did not the Spit not have 2 position flaps, 'up' and 'down', unlike the 109 and P-51 which had variable flaps?

'Down' is something like 80*, so would act like speed brakes would they not?

[hitech]

I know of 2 pilots who have done fighting in the p51, and both used 1 notch flaps when slow.

Pilots were Bob Shaw, and Me.


Dale

[Tilt]

Originally posted by Widewing

So, no concrete answers as of yet.... Will keep digging.

My regards,

Widewing

Thanks for that Widewing............ P38's and the odd Blooo bird apart it has always seemed to me that flaps were not a "tool of combat" as we use them in game.

I know of anecdotal 109 stories about flap use but these are each told as if the occurance was unusual or uncommon. It has always seems to me that the split/plain flap is primarily an aid to take off and landing (as stated in every pilots manual)........... not a combat turning aid...........and instinctively they just look like damn big air brakes to me.

but then we dont typically exercise our in game air combat as was done historically............

Maybe the drag model on all non fowler (like) flap systems in AH (except the P51) is too light.

[Mike Williams]

Use of flaps by P-51 pilots during combat?

Absolutely:

1st Lt. Louis H. Norley  "I dropped 20 degree flap and easily out turned him."
1st Lt. Paul S. Riley "Letting down 20° of flaps, I could get on the inside of the turn and pull deflection."
2nd Lt. Grover C. Siems  "Observing that I was overtaking too fast, I pulled up over the right e/a and dropped flaps."
2nd Lt. Frank E. Speer  "I had to put down 20° flaps to keep from overrunning him, indicating above 500 m.p.h."
1st Lt. Thomas D. Shank  "I dropped full flaps and placed myself directly astern of the e/a on the extreme right of the formation."
1st Lt. Frank E. Oiler "I got into a Luftberry at 1100 feet with the FW 190, and with the use of flaps I got on his tail in two turns."
1st Lt. Chris J. Hanseman  "I cut my throttle and turned inside of him, dropping 20 degrees of flaps."
2nd Lt. Chris J. Hanseman "…dropped 20 degree flaps…"
Harold W. Scruggs  "I lowered about 10 degrees flaps and made two 360 degree turns in which I gained rapidly on the E/A…"
Capt. Bradford V. Stevens  "…I was able to turn inside the Me 109 after dropping 20° flaps."
2nd Lt. Myer R. Winkelman  "I put down 20° flaps and got on his tail."
2st Lt. S. K. Moats  "I dropped 20 degrees flaps and after 2 more turns I was closing on the tail of the E/A."
Lt. Glennon T. Moran  "We fought for about 20 minutes and it was necessary for me to put down combat flaps three times in order to turn with him."
Major George E. Preddy "He turned into me and I dropped 20 degrees of flaps, out turning him."
1st Lt. Arthur C. Cundy  "With throttle pulled back and full flaps down, I overshot this 190."
1st Lt. William J. Cullerton  "I started to overshoot so I dropped full flaps and gave him another long burst just as he was leveling off to land."
Capt. Walter V. Gresham  "I downed 40 degrees of flaps and got in another burst which hit him hard."
>Capt. Fred R. Haviland  "At 1,000 feet, I dumped 20 degree flaps and made a turn inside him and started to get within firing range, when the E/A made an abrupt turn, snapped over and crashed into the ground, exploding as he hit the ground."
2nd Lt. Esward Moroney "...I put down full flaps and closed on the E/A."
1st Lt. Harold W. Spencer, "I dropped full flaps to keep from overrunning and fired from dead astern at about 100 yards and as I went over him, the Jerry popped his stick forward and crashed."
Capt. Clarence E. Anderson "By using 20°  flaps and full throttle I pulled around on their tails in one turn and started firing…"
Capt. Leonard K. Carson  "I chopped my throttle and dropped flaps."
1st Lt. Leonard K. Carson "I dropped flaps and turned back behind him."
Capt Robert W. Foy "I lowered flaps and gave E/A a short burst."
Capt. Robert W. Foy "He suddenly pulled into a sharp right turn and I put down 20° flaps and followed giving several bursts with about two radii lead."
1st Lt. Gilbert M. O’Brien  "I slid right up beside him with my flaps down.  He bailed out as I was alongside of him, at about 12,000 ft.  His chest was covered with blood and he hit the rudder."
Capt Richard A. Peterson "I realized I was over running him and lowered flaps as I pulled along side of him."
1st Lt. James R. Sloan "In the ensuing combat I was unable to turn inside the E/A until I dropped 10 degrees of flaps."
F/O Boyd N. Adkins "I dropped flaps and slid in trail with him at close range."
1st Lt. George F. Baker "I dropped flaps to stay astern of E/A."
Capt. William C. Forehand "I dropped twenty degrees of flaps and cut my throttle and closed in behind him firing from approximately 100 ft.”
1st Lt. Frank O. Lux "I closed on him, dropped about 10 degrees of flap, and started to fire."
1st Lt. James L. McCubbin "The e/a then dropped his wheels and I dropped 20° flaps to stay behind."
Lt Elmer A. Taylor  "I dropped 20°  Flaps and outturned him."

[Angus]

T.E. Jonsson had to use flaps to turn inside a 190, which he promptly did, forcing the enemy pilot to bale.
He had damaged the 190 so a mechanical failiure made the 190 drop the UC on one side. The 190 took a turn into the drag and turned like the devil. So he needed one notch to turn the table.
With a 109 he said "not to worry, and you could outrun and outdive them anyway in a P51"
vs a Spitfire IX he made a grin, and said that in a knifefight the Spit was better. And a P51 could not expect to turn with it.

But these are anecdotes.......

[Badboy]

Originally posted by hitech
I know of 2 pilots who have done fighting in the p51, and both used 1 notch flaps when slow. Pilots were Bob Shaw, and Me.

Sounds like an interesting story, care to share?

Badboy