P-51 Airfoil and Turn Performance

[Ack-Ack]

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.


Dale

Who won?


ack-ack

[Rebel]

bah.  nevermind

[Tilt]

Originally posted by Mike Williams
Use of flaps by P-51 pilots during combat?

Absolutely:
 

............ seems pretty conclusive

[Kweassa]

............ seems pretty conclusive

 They're the guys that used flaps, and lived to tell about it. The really intersting thing would be what the dead people, rest their souls, have to say about it.

 I don't doubt people did use flaps for combat, and I don't doubt at some point a pilot with enough combat experience, will feel more or less confident enough to try and do something they've not done before - especially if some of their own squadron's veterans would actively teach, and advocate the use of more aggressive dog-fighting tactics, rather than just sticking to the "basics". I also don't doubt some squadrons, with some specific pilots of notable performance records, might have adopted the use of the flaps as a whole.


 ..

 What I do doubt, is how the stories of such "frequent use of flaps" fits in with the world of average pilots.

 Those sometimes with little combat experience, who stumble over their own controls inside the cockpits, and in other times would fiddle with the levers and buttons in the wrong way in midst of the confusion of combat, and would accidentally damage their own engines. Stories of very typical pilots like Lawrence Thompson, who during combat with a German Bf109G-14, engaged flaps at some point and actually forgot to retract them, thus causing a one in a million lucky stall that enabled him to escape from the 109.

 Or, the basic doctrine of keeping things as simple as possible inside the cockpit, where the more a pilot has to fiddle around, the more the danger of a misinput or a slip of concentration.


 None of the above, would fit into those pilots who can be called "skilled", of course. But then again, how many of those pilots are in a typical airforce? Those who would regularly step over the line drawn and set by the HQ, do some things that their superiors tell them not to do, and still emerge victorious, and live long and a happy life after the war?


 
 Just curious.

[Charge]

IMO the deployment of flaps and choice of dumping you E in aircombat is a rather big risk and is done in situations where you can afford to do it i.e. no other imminent threat around. I'm not sure what kind of opposition those P51s in those anecdotes were facing but the choices those pilots were making sound like bold ones. In some cases drop flaps and dump E and get one good shot in and live to tell about it...

-C+

[Wmaker]

Originally posted by Neil Stirling
109 G-2 R N.228 used in the trials was not fitted with under wing cannon.  

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

http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=10048&start=30

Sorry, missed the thread for a while...

Eric Brown describes Air Fighter Development Squadron's trials using TP814 against Spifire LF IX, Spitfire XIV and Mustang III yielding the exact results that are being talked about here. At least he makes it easy to misunderstand the identity of the G-6.

I was commenting to Widewings comment about the Mustand III. There isn't any comparisons with a Mustang III in the US testing report.

In Finnish testing with 109G-2 360 degree turn took 22 seconds with speed through the turn being 360km/h. I can't see a reason why G-6 would be significantly behind that time. I think it is very comparable with other fighter aircraft produced at the time.

EDIT/ Here is the test I was talking about:

http://www.wwiiaircraftperformance.org/me109/me109g6-tactical.html /EDIT

[Knegel]

Hi Wmaker,

d you know the condition of turn of the G2(altitude, power setting, slats in or out)?.
360km/h seems to be a rather soft sustained turn.

btw, iam somewhat suprised about the Tempest vs the G6-R6.

Greetings,

Knegel

[Wmaker]

Hi Knegel!

I understand it sounds soft because it is. He used constant 360km/h speed through the turn. That makes a pretty huge turning radius but because the speed is high the time is probably very similar (maybe a bit longer) compared to tightest possible turn with slats out.

So in the test:

- Slats shut
- Bank angle 70 degrees
- 1000m altitude
- 1.3 ata/ 2600rpm powersetting

Pekka Kokko states that in order to make a tighter turn you needed to throttle back below 350km/h and let the slats come out.

All my speculation, but I think here could be the problem that British test pilots ran into aswell. If they were turning with the Mustang throttle firewalled and weren't really accustomed to the heavy control forces of the 109 they were turning with a huge 350m radius. IF this was the case it could easily seem that the Mustang outturns 109G-2 easily. 109 wasn't the easiest fighter plane out there to fly to its strenghts, that's for sure.

[Knegel]

Hello again,

do you know why they did need to throttle back to turn more tight?? Shouldnt it be possible to pull the stick until the slats open, to turn with full power??
Afaik as faster a plane fly as less thrust a propeller plane have, and so i guess a full power flight with max CL(open slats) should be more tight and with a faster turn rate(with the more constant thrust of a jet engine thats different).
According to all sources i know, the elevator was absolutly not heavy at 350km/h, at 350mph it did start to stiff up.
The 109E4 did turn with just above 200km/h and i once did guess the G2 would do the job with around 260km/k, just like in AH. 100km/h more would add a huge amount of drag, reduce the efffective thrust much and the low AoA would increase the radius much.

Is it possible that the document include a mistake and it should be 260km/h?? Otherwise the best turn rate must be better.

btw. In EAW the 109G2 need almost exact 22sec for 360°, with 360km/h at 1000m, the min turnspeed in this hight, with max power, is 255km/h, the resulting time is 18sec.

[drgondog]

BTW what was the effect of the forward joint extension in D model? IIRC it was deleted in later models.

"The F4U wing leaks air from underside to top side."

The effect of that is also measured in the same document and the effect seems to be quite minimal according to figure on page 610. The low Cl is puzzling. On page 606 the Cl figure is again different.

The left wing was modified with a wing fence to mitigate the early stall of the left wing at landing speeds

It must be noted though that the speeds where measurements were done were quite small as they were below 100mph (60mph). Their loaded performance in higher speed is probably somewhat different.

What ever the profile performance is that is only one variable in the equation although a significant one when trying to figure the performance at the edge of the flight envelope. It seems that although both P51 and FW190 had a twist i.e. washout in wing they both suffer from somewhat sudden loss of control and the twist does not seem to do what it is supposed to which is to provide delay and warn of stall -or maybe the stall actually is less abrupt than it would be without the twist. What 190 wing behaves like that is a mystery to me since it uses a more conventional airfoil.

The FW 190 had zero twist on the outboard 20% of the wing. IMO that contributed to the vicious high speed stall in high G turns. I have heard without proof so far that the wing was less stiff torsionally than say a 51

I think this table gives some idea of the relative behavior of wing sections.
(Image removed from quote.)

Source: Abbott&Doenhoff 1949 "Theory of Wing Sections"

-C+

PS. Bah, it doesn't show....

[drgondog]

i aint no good with numbers or figures like you guys and reading some of these well done graphs etc is great but.....

maybe the P51 of old was wrong and the current one is right?



the P51 wasnt the greatest low-med alt dogfighter, it was a high alt escort plane, it was designed for long runs to berlin and back, nothing more really.According to Rall it was the best of the Allied fighters based on his experience at Rechlin following his wound on May 12, 1944.  That impression was based on the combined maneuverability and range. He didn't state that it was as maneuverable as the Spitfire or better than the 109.

Additionally, it was designed as 'a better fighter than the P-40. It was the Brits, however that instantly realized that it was not only a delight to fly but its performance potential was potentially superb with the Merlin 60 series engine. While the Spit could out climb a turn the Mustang I, the Mustang was 30 mph faster at same power settings up until FTH of the Allison.

P51's only really won dogfights because there was so many of em, plus better training on fighting tactics, something that was starting to lack in German pilots by the end.

P-51s did Not outnumber the LW attacking forces until near the end of the war simply because the LW knew where they would attack and from zero to perhaps two Fighter groups covering say six bomb groups out of 35 and a 70 mile stretch would be available to engage 50 to 250 German day fighters into that small volume.  Read the history of the 8th FC on deep escorts from December 1943 through May, 1944 when the total long range escort force was one to eight Fighter Groups (including P-38s) taking 1000 to 1500 bombers in three BD to three to six separate targets scattered from Berlin to Posnan to Munich.

In other words the LW died because in many cases they didn't have the speed to disengage, and only marginal maneuverability advantage when flown by equal pliots.   If say a 190G6 A/S could outclimb a 51 by 500fpm that is moving away at 6mph/8.8 fps - that doesn't out run a 50 cal starting at 2800 fps.

but in game, everyone (err mostly) knows there planes inside out, so its good pilots getting the most out of there planes, hence the P51 in a 1on1 will not be that great. if it was a 3to5 on 1  (p51 vs 109) then the results would match real life?



i know this a rubbish point to put forward without figures etc but its just the way i see it.

Go find whatever figures make sense to you but consider this set.

During Big Week Feb 20-25 there were Nine P-47D (4, 56, 78, 353, 355, 356, 358, 359, 361) fighter groups, two P-38 (20, 55), and two P-51 (354 and 357).All flying escort, and all the targets were deep, out of range in general from the P-47s. Both 8th and all 9th AF fighter groups flew long range escort until the end of May which is why the effective operational numbers increased for the P-47 data below

Credits for e/a Destroyed 2/20 - 2/25
P-38  10
P-47  78
P-51  64

For 2/20-3/31
P-38 35   (3 P-38 FG's)
P-47 316 (11 P-47 FG's)
P-51 318 (4 P-51FG's)

Source USAF 85 Air Victory Credits WWII

[The Fugitive]

I don't think anyone was waiting around for 7 years for those answers, but thanks.

[BnZs]

A Pony that turned much better would be a liability to Aces High. Its popularity already almost demands perking, yet perking the ONE plane the average new subscribers is most likely to want to get in immediately would be deleterious to retaining new subscribers. Thus the turn performance of the Pony we currently have is what we will continue to have, out of what could reasonably be called necessity.

[Stoney74]

So, after a 5 year absence, imagine my surprise when I stumbled in here tonight to find this still on the 2nd page of the Aircraft and Vehicles forum...  Holy necro!

[Gaston]

  
  Are you really sure want to know how the P-47D and the Merlin P-51 compared in real life?


  Quote, KG 200: (early captured Razorback without full power available, and with needle tip prop) "The P-47D out-turns our Bf-109G"

    Bf-109G vs P-51B: "The P-51 has a dangerous stall which killed two of our pilots"

  Source: On Special Missions: The Luftwaffe's Research and Experimental Squadrons 1923 - 1945 (Air War Classics)

  Sounds like they are not saying the Merlin P-51 out-turned the Me-109G... (Maybe that's why I heard of two 15 minutes continuous turning fights, all to one side without any gain (45 X 360° turns), and even of one that went on for half an hour! (90 X 360° turns)...

  P-47D vs the Me-109G is more like 3X 360° turns and bye bye Gustav, or rather, to mention one memorable Lufbery quote (at 20 000 ft): "They went around with us in a Lufbery for two turns, and then they quicky lost interest and rolled out"

  They lost interest you know...

  

  Let me opine here for a sec: Hanging on to 1940's test flights, a time when the in-flight procedures were not scrutinized correctly, will usually only produce what that particular vintage test was expected to produce...

   What do you know, the 1989 SETP test flight using modern test flights method produced results largely in agreement with the combat record:

======================================

  Quote, 1989 SETP test: "Heading Change Time (180 deg at METO, 220 KIAS at 10,000 ft.)
FG-1--8.5 sec P-47--9.7 sec F6F--9.9 sec P-51--10.0 sec"

====================================================

  So for the P-47D 9.7 sec for a 180° at moderate speed vs 10 seconds P-51D, no matter what the wingloading says...

  The P-47D's superiority would have probably been more evident at a lower speed (unless maybe the P-51 seriously downthrottled, coarsened the prop pitch, and dropped 20° of flaps at around 180 MPH IAS, but that's a whole other thread).


=======================================

  Quote 1989 SETP test: "AIR-TO-AIR TRACKING 210 KIAS at 10,000 ft. (straight & level into a 3g
turn to the left building to 4g followed by a hard reversal into a 4g
right turn.)
FG-1 best, followed by P-47, F6F and, trailing badly, the P-51."

==========================================

  I don't know what more needs to be said when you read a few combat reports, and you see most of what they did in the P-47D was turn, all the way down to the deck at 140 mph...

  One of the few Western European fighters that could more than hold its own in low speed sustained horizontal turns with the the P-47D was of course, you guessed it, the FW-190A! But rather than list all the instances of Spitfires getting out-turned by it at low speed (longuish), how about focussing on the ONE thing the FW-190A Absolutely HATED?

  
======================================

 A translated Russian article from "Red Fleet" describing Russian aerial tactics against the German FW-190, from Tactical and Technical Trends, No. 37, November 4, 1943.

  Quote:

  -Since the FW-190 is so heavy and does not have a high-altitude engine, pilots do not like to fight in vertical maneuvers.

  -Being very stable and having a large range of speeds, the FW-190 will inevitably offer turning battle at a minimum speed.

  -In fighting the FW-190 our La-5 should force the Germans to fight by using the vertical maneuver.

  -Throughout the whole engagement with a FW-190, it is necessary to maintain the highest speed possible. The Lavochkin-5 will then have, when necessary, a good vertical maneuver, and consequently, the possibility of getting away from an enemy attack or on the contrary, of attacking.

==============================================

  Man, I think the Fw-190 doesn't like vertical maneuver, y'know... But it's not done saying it...:

==============================================

   Osprey "Duel" #39 "La-5/7 vs FW-190", Eastern Front 1942-45:

P.69 "Enemy FW-190A pilots never fight on the vertical plane.---The Messerschmitt posessed a greater speed and better maneuverability in a vertical fight"

P.65 Vladimir Orekov: "An experienced Fw-190A pilot practically never fights in the vertical plane"

==========================================================

  Man! I think it is possible the Fw-190A doesn't like the vertical plane...

  But what the heck DOES it like?:

  ================================

  Red Fleet, No. 37, November 4, 1943.:

  -The speed of the FW-190 is slightly higher than that of the Messerschmitt; it also has more powerful armament and is more maneuverable in horizontal flight.

  -A fairly good horizontal maneuver permits the FW-190 to turn at low speed without falling into a tail spin.

 -Being very stable and having a large range of speeds, the FW-190 will inevitably offer turning battle at a minimum speed.

============================================================

  Weirner Steiz: "The 190 was a much better aircraft than the 109: You could curve it"

==============================================================

I could go on, but you know...


  And just in case you really wanted to know how the P-47D and the P-51 actually compared in turning ability (and I mean really!), read this, but just before, allow me a disclaimer: [warning, not for the faint of heart]


========================================

  Osprey, P-47 Thunderbolt units of the 12th Air Force.
 
  P.32: 15th May 1944, 87th Fighter squadron operational report (Paddle-blade propellers only started to be delivered to the group in late May 44, and only with new aircrafts, so all these are needle-tip props, which does explain in part their turning performance).
 
  That afternoon, the 87th FS took off (16 aircrafts) with 32 X 1000 lbs bombs underwing to add to the destruction in Acquapedente. Target Acquapedente bridges.
 
  "A flight of 15 Me-109s and 5 FW-190s was encountered. One section kept the fighters occupied while the remainder attacked the bridges. Three enemy fighters were destroyed for one of ours damaged.
 
  A gratifying result of this engagement was that a P-47, not considered a low-altitude aircraft, can maneuver advantageously with Me-109s almost on the deck, even though under the handicap of being on a bomb run." (2 X 1000 lbs of bombs underwing)

  =====================================================================

  Yes guys, he does mean the P-47D out-dogfighted the Me-109Gs on the deck with 2X 1000 lbs bombs underwing, because otherwise they would not be handicapped and on a bomb run, and dropping the bombs would mean the mission for all these bomb-dropping aircrafts would be a failure, and that's a success for the enemy and thus not gratifying...

  Feel free to hate my totally unreasonable interpretation, you know you want to...

  
 
   So how does the P-51 do against Me-109Gs (but without 2000 lbs of bombs hanging from it?, Chhh!):

======================================================================

   "The P-51 Mustangs of Major George Preddy" EC # 100, Eagles Editions limited.

   P.20: "Preddy spotted two 109s and got into a Lufbery with the first one. Neither was gaining much advantage when all of a sudden another 109 cut in front of him."

===================================================
 
     Osprey, RAF Mustang and Thunderbolt Aces, P.42:
 
   Sq. Lt. Hearner (No 19 Sq) commenting 11 April 1945 battle over Lister airfield (P-51 Mk IV vs late Me-109Gs or Ks):
 
  "The 109s we encountered were obviously an experienced bunch of boys. Their turning circle is decidedly better than ours at low speed. The lowering of 20 degrees of flaps may just enable us to hold them in the turn, although I feel they could outclimb us." (Note: RAF P-51s of this period typically used 80 inches of manifold pressure boost with 150 octane fuel, higher than the 72 inches US Mustangs used in Europe. Similar boost to RAF 80" boost was only used in Iwo Jima by the USAAF.)

=================================================

  

  And how about the Spitfire while we are at it?:

  In "Le Fana de l'Aviation" #496 p. 40: " Les premiers jours furent marqués par des échecs dus à une tactique de combat périmée dans le plan horizontal, alors que le Spitfire était particulièrement adapté au combat dans le plan vertical."

Translation: "The Spitfire failed in horizontal fighting, but was particularly adapted to vertical fighting"

  And of course Johnny Johnson's dogfight with a FW-190A: Quote: "Opposite sides of an ever diminishing circle... I asked the Spitfire for all she had... It was just a matter of time and he would have me in his sights..."

  But you don't think you were getting away from reviving this thread without my pal John Weir did you? :

  ""A Hurricane was built like a truck, it took a hell of a lot to knock it down. It was very manoeuvrable, much more manoeuvrable than a Spit, so you could, we could usually outturn a Messerschmitt. They'd, if they tried to turn with us they'd usually flip, go in, at least dive and they couldn't. A Spit was a higher wing loading..."
"The Hurricane was more manoeuvrable than the Spit and, and the Spit was probably, we (Hurricane pilots) could turn one way tighter than the Germans could on a, on a, on a Messerschmitt, but the Focke Wulf could turn the same as we could and, they kept on catching up, you know."

  Yeah, Y'know...

  Gaston