# WW2 fighter turning performance comparisons



## bryce (Apr 11, 2007)

I am very interested in comparing the different turning performances of different fighters during WW2.

Does anybody know of any sites that would help with this?


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## davparlr (Apr 11, 2007)

bryce said:


> I am very interested in comparing the different turning performances of different fighters during WW2.
> 
> Does anybody know of any sites that would help with this?



Good luck and good hunting. Here is something.

Comparitive Performance of Fighter Aircraft


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## renrich (Apr 11, 2007)

bryce, Good luck with your quest for turning data for WW2 a/c. I will bet you this: if you study on this long enough and go to enough sources, you will end up with so much info, much of it contradictory that you will say there is no definitive authority on turning or for that matter any other performance characteristics of fighters. And remember this, if you post on a forum like this always try not to be too definite or dogmatic about your beliefs or opinions because as soon as you say that such and such was the best turning or best climbing or anything someone else will come up with some data or source which will contradict your statement.


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## JoeB (Apr 11, 2007)

Here's a modern style contour graph of sustained g, turn rate etc. for early Spit and Bf109
Spitfire Mk I Performance Testing
That kind of date is relatively rare for WWII a/c. And what Renrich said is true even for simple parameters like speed. There's lots of interesting info on the web and in books but a lot of it disagrees for the same planes. It seemed to depend significantly on the particular test and standards of quotation when tested by different sides, or even the particular example of the plane type. And even when 'friendly' and 'enemy' planes were tested together, the captured enemy planes might not be in as good shape, or even be "repaired" to better shape and using better fuel, than when actually met in combat. And the friendly test pilots wouldn't be as familiar with, nor perhaps subconsciously inclined to try to prove the superiority of, captured planes.

Back to turn, WWII planes couldn't pull a whole lot of g, sustained at constant altitude. So especially if they started at higher altitudes combats would generally descend using the gravity vector of a slight dive to pull some real g's. And high g's such as for example to make benefit of a g-suit (as some US pilots had late war) were only transient turns while the plane was bleeding away energy slowing to the steady state. And many or most WWII fighter combats consisted of just one or a couple of maneuvers. Somebody generally had the opening positional or energy advantage, and the other guy would either evade the attack or not (or not even see it coming); then on to other opponents in a the furball. It was less often prolonged chess matches of sustained manuevers 1v1 or 2v2. So I think it's really hard to completely represent and correctly weight the key comparative performance stats of real WWII combat on paper (and what you start with on paper is what creates the results of computer simulations).

Joe


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## mad_max (Apr 11, 2007)

JoeB,

I haven't seen such a well put together bunch of words describing exactly my
thoughts about this paper performance vs. real life. I hope you won't mind if I
quote you on another forum.

Best,


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## renrich (Apr 12, 2007)

Joe B you said exactly what I would have said if I had known enough to say it.


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## Soundbreaker Welch? (Apr 12, 2007)

I hadn't realized the Mustang was so good a turning. A lot of the opinions on here often have said it was a poor turner.


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## Civettone (Apr 12, 2007)

JoeB, your post also struck me as very good! 

I personally believe sustained turn rate is the most overrated quality of WW2 fighters. In the beginning of the war aircraft like the Fiats or Zero's relied upon it but soon found themselves on the losing side by high-speed power fighters which could initiate and abort the attack at will. Sustained turning fighting met its end in WW2.

Kris


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## FLYBOYJ (Apr 12, 2007)

JoeB said:


> And many or most WWII fighter combats consisted of just one or a couple of maneuvers.


Well said Joe - the same exists today as well....


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## krieghund (Apr 13, 2007)

One thing which is not usually talked about is Specific Excess Power....
Sustained turn is ok as it is a measure of an aircraft's SEP but one important factor is energy (or speed loss) durning the maximum turn rate.

For example a A6M2 at low level full power at 230 mph pulling a hard break turn for 180 degrees has a turn radius of 1118 feet and ends up with 186 mph remaining.

Now a Spitfire Mk II with the same conditions if pulling the same g's will do the same turn radius....question is what is his remaining airspeed after 180 degrees and how close was he to stalling out?

If the Zero has more SEP he could keep the same radius and use his extra SEP for altitude but ending at the same speed as the Spit II only he is above and has the advantage.

Remember the old addage; "out of airspeed and ideas"

I am writing a computer program to give these answers which of course is how modern jet combat is calculated.

More to come.......


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## Civettone (Apr 13, 2007)

That seems a correct observation Krieghund. 
Also reminds me of all those stories of fighters outturning others though in theory this wouldn't have been possible. Fact is that there's always the question of how much air speed you can or are willing to give up to get that tighter turn. If you drop too much speed and there's a faster bird flying overhead you're dead meat. It's no coincidence that the Germans and Americans always stressed speed in air combat.

Good luck on writing that computer program... 
Kris


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## bryce (Apr 13, 2007)

Thanks guys for all your views and opinions, they are much appreciated.

I realize that most data found on the net must be viewed with skepticism, rather that taken as gospel...and as JoeB said there are many different factors that effect turning performance of aircraft...

but I must say I was very interested in this diagram…

http://www.wwiiaircraftperformance.org/wade-turning.jpg

I have heard many people say at this forum that the P-51 is over rated in a dogfight, so I was surprised to see it rated with a very good turning circle.

I was even more surprised to see how poorly rated the FW-190As turning circle was.
I have always thought that the FW-190A turning circle would be more comparable to the P-51, rather than the P-47 and Bf-109G?

I have also heard a lot of people claim that the FW-190D Dora is one of the Best (or best) dogfighters of WW2.
I am guessing that it would have had a better turning circle than the FW-190A. 
So I am wondering which aircraft FW-190D turning circle might the most comparable too?
Perhaps the P-51, or the later model Spitfires?

I realize that having a good turning circle is the only important thing in a dog fight, but im just interested in horizontal turn performance.


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## FLYBOYJ (Apr 13, 2007)

bryce said:


> I realize that having a good turning circle is the only important thing in a dog fight, but im just interested in horizontal turn performance.


But dogfights are not strictly fought in the vertical...

A good pilot can defeat another aircraft with a superior turning radius by doing a "yo-yo" or going vertical and getting inside the turn for a firing solution. Turing is important, but it's not the only thing....


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## bryce (Apr 13, 2007)

Doh! 

Sorry, that was a typo!

Let me try that again....

I realize that having a good turning circle is NOT the only important thing in a dog fight, but im just interested in horizontal turn performance.


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## FLYBOYJ (Apr 13, 2007)

bryce said:


> Doh!
> 
> Sorry, that was a typo!
> 
> ...


Got-cha!


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## renrich (Apr 13, 2007)

bryce, somewhere in this forum you will find a couple of reports that compare the performance of the P51B with the F4U1 and the F6F3 and also a FW190A4 with the two navy fighters. I believe you might find it interesting.


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## bryce (Apr 13, 2007)

Thanks renrich, would you be referring to this...

http://www.wwiiaircraftperformance.org/fw190/ptr-1107.pdf

I have read many posts at this forum that claim these reports show bias against the Axis aircraft?


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## renrich (Apr 13, 2007)

bryce, you have one of the comparisons but there is another that compares the P51 with the navy planes. They find the P51 unsuitable for carrier operations because of insufficent slow speed controllability among other draw backs. These reports are intriguing to me because, if the reports are accurate they show that first, two navy fighters that supposedly are inferior inherently because they are shipboard fighters, are superior if flown to their strong points to two premier WW2 fighters. If that is true then the designers of those aircraft must have been geniuses. Second, and what is more likely, is that almost any first line fighter of any nation in WW2 if flown by a superior pilot will have at least an even chance against any other first line fighter if he knows his plane's strong points and is able to exploit those strong points against what he knows are his enemy's weaknesses. There was no such thing as an a/c without weaknesses since all a/c are compromises.


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## Mike Williams (Apr 13, 2007)

Hi guys: Here's a US Navy Evaluation and Comparison Trials of the P-51B and F4U-1
I don't know if the F4U ever used 65" Hg MAP operationally. Anyone know? I do know that the P-51 used higher than the 67" Hg MAP limits of this test on operations in the ETO; i.e. 72" 80" Hg (+25 lbs) MAP.


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## Kukuruznik (Aug 8, 2007)

Ok so there is no centralised databank for WW2 aircraft turning circles, and that includes also bombers and other types for whom it is important such as transports. Have you compiled anything of the kind Bryce?

I'd like to ask if there is more then one source of roll rate online? 

Its interesting that these two performance indicators are not usually given in aircraft data although apparently considered very important by the pilots.

Cheers


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## FLYBOYJ (Aug 8, 2007)

Kukuruznik said:


> Its interesting that these two performance indicators are not usually given in aircraft data although apparently considered very important by the pilots.
> 
> Cheers



These are not put in aircraft performance charts because turn rates vary with bank angle and speed, also factor in aircraft loading and weight. Not necessarily finite numbers that would be of interest of pilots during the heat of combat especially when you could manipulate the turn by skidding or slipping.


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## Brain32 (Aug 8, 2007)

bryce said:


> but I must say I was very interested in this diagram…
> 
> http://www.wwiiaircraftperformance.org/wade-turning.jpg
> 
> ...



That diagram is very interesting, but it has some contradicitons with other AFDU material, even the one you can find on the same site.
For example the Mustang3 is highly rated on this diagram while FW190 turns out to be very poor.
However this is what MustangMkIII tactical trial has to say about it and I quote:

"Turning circle
42.Again there is not much to choose. The Mustang is slightly better...."
That was against BMW801 engined FW190, who knows which one and in what condition. Would you say that above diagram says "not much to choose" and "slightly better"?


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## pbfoot (Aug 8, 2007)

I would think a major factor in turning would be the condition of the pilot if he was in superb condition he might be able to turn to the aircrafts potential realizing G suits were not in vogue during this period


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## drgondog (Aug 9, 2007)

krieghund said:


> One thing which is not usually talked about is Specific Excess Power....
> Sustained turn is ok as it is a measure of an aircraft's SEP but one important factor is energy (or speed loss) durning the maximum turn rate.
> 
> For example a A6M2 at low level full power at 230 mph pulling a hard break turn for 180 degrees has a turn radius of 1118 feet and ends up with 186 mph remaining.
> ...



Which is close to the thesis of Energy Manueverability and subsequent generated airframe design performance criteria that Boyd developed at great personal career sacrifice in USAF in the 50s and 60s - leading to the F-16 and F-15s

He`crafted the concepts at USAF Fighter School at Nellis post Korea and demonstrated to everyone's dismay that ALL the multi role fighters we had in ops and on the boards were inferior in fighter to fighter Energy manueverability to the Mig19 and Mig21 - and sure enough proved it in VietNam


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## drgondog (Aug 9, 2007)

Mike Williams said:


> Hi guys: Here's a US Navy Evaluation and Comparison Trials of the P-51B and F4U-1
> I don't know if the F4U ever used 65" Hg MAP operationally. Anyone know? I do know that the P-51 used higher than the 67" Hg MAP limits of this test on operations in the ETO; i.e. 72" 80" Hg (+25 lbs) MAP.



Hey Mike - as a cynic I might have suggested a couple of months back that the prime off line instructions to the Navy pilots conducting the tests "Don't come back with a conclusion that the 51 is superior in any way" - which is why the Patuxent River tests are not accompanied by Turn and acceleration comparisons at various speeds and altitudes - lol - but definitely accompanied by statements that the F4U out turned, accelerated and climbed better -


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## Kukuruznik (Aug 10, 2007)

FLYBOYJ said:


> These are not put in aircraft performance charts because turn rates vary with bank angle and speed, also factor in aircraft loading and weight. Not necessarily finite numbers that would be of interest of pilots during the heat of combat especially when you could manipulate the turn by skidding or slipping.



Yes, ok, but good pilots knew what their aircraft could take (and they could take in terms of Gs), and in most memoirs the words 'turn' and 'roll' are mentioned very frequently. I'm looking for optimum of course, as any pilot of the period would be also. 
The problem with memoirs is that they give descriptions of combats that rarely provide technical data (of course!), and this data is not readily available from other sources I find.
Of course its early days in my research, so I may be able to dig up something eventually. However given all the sites online dedicated to study of WW2 combat aircraft, I am rather surprised of the lack of data on these two aspects of air combat...or even discussion.

Cheers


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## FLYBOYJ (Aug 11, 2007)

Kukuruznik said:


> Yes, ok, but good pilots knew what their aircraft could take (and they could take in terms of Gs), and in most memoirs the words 'turn' and 'roll' are mentioned very frequently. I'm looking for optimum of course, as any pilot of the period would be also.
> The problem with memoirs is that they give descriptions of combats that rarely provide technical data (of course!), and this data is not readily available from other sources I find.
> Of course its early days in my research, so I may be able to dig up something eventually. However given all the sites online dedicated to study of WW2 combat aircraft, I am rather surprised of the lack of data on these two aspects of air combat...or even discussion.
> 
> Cheers


For what you're looking for your going to have to ask the respective engineer. For the most part when you're in an aircraft and turning there is one instrument your going to use, and it comes in two different configurations depending of the size of your aircraft...


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## Crumpp (Aug 11, 2007)

There are a couple of very practical reasons why sustained level turn ability is much more important to today's computer gamer than it is to a fighter designer or pilot in RL.

*Facts are all aircraft at the same velocity and angle of bank will make exactly the same turn.* 

That is a very powerful fact. Sustained turning ability is a function of the fundamental relationship of aircraft performance, power available to power required. However, the most important factor in turn performance is velocity. The slower aircraft will always outturn the faster aircraft. 
In BGS terms:

Radius of turn = Velocity in Knots^2 divided by the product of correction factor of 11.26 because we are using Knots and the tangent of the angle of bank.

r = Vk^2 / (11.26* tan AOB)

The portion of the envelope in which any design contemporary fighter has an advantage over another design is very small. 

This small portion occurs at the popular term of flying at the _edge of the envelope_. 

My experience comes as a pilot, aircraft owner, and someone formally trained in aerodynamics. I throw a big BS flag on any claims of consistent flight at the edge of the envelope. Pilots certainly may come close to "the edge". Many have to change their shorts when they do brush up against it. Many pilots are dead after thier first real brush with the "edge". Facts are flying at any portion of "the edge" is very detrimental to controlled flight and in the majority of cases downright deadly.

Some quick examples:

1. Flying at the "edge" of the cruise envelope all it takes is a gust of wind to damage or destroy the airframe.



> The red line is preceded by a yellow band which is the caution area, which runs from VNO (maximum structural cruise speed) to VNE



Airspeed indicator - Wikipedia, the free encyclopedia

2. Flying at the "edge" of our turn performance envelope, that same gust of wind will induce a stall and chances are it will be an aggravated or uncoordinated stall. Now we are in danger of experiencing a spin. 



> The difference in altitude required to recover from stalls and spins is significant. Most airplanes recover from a "normal" stall in several hundred feet, assuming the pilot recognizes it and takes prompt corrective action. Variables such as weight, aerodynamic design, power setting, load on the wing (Gs), and center of gravity (CG) have an effect, which can be pronounced. In an incipient spin recovery the pilot's operating handbooks (POH) of many aircraft are not very clear about altitude loss. Based on anecdotal observation and the few POHs that do provide data, plan on 1,000 to 1,500 feet as the bare minimum altitude loss, assuming that the pilot was right there with a textbook recovery. Under the best conditions it probably takes at least three to five times as much altitude to recover from an incipient spin as from a stall.



AOPA Online - ASF Article of the Month - Safety Pilot: Spinning In

If it occurs without sufficient altitude to recover we have lost our life.

No matter what "edge" you choose, there is a very real danger of turning our controlled flight into a fight for survival. That is not even factoring in another airplane with a pilot trying to kill us!

It takes a very skilled and experienced pilot to fly the highest performance and most technologically advanced aircraft of the day anywhere close to the edge. The kind of skill and experience only a small percentage of pilots in any given force are capable of exhibiting.

Given the reality of flight and the fact aircraft performance is not an absolute but rather a percentage range over a mean average, only a handful of WWII designs stand out as having a sustained turn performance that would even be noticeable in the air.

If anyone is interested, I have done the calculations for several WWII fighter design sustained turn performance and could post the results as well as the methodology used. 

All the best,

Crumpp


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## FLYBOYJ (Aug 11, 2007)

Crumpp said:


> It takes a very skilled and experienced pilot to fly the highest performance and most technologically advanced aircraft of the day anywhere close to the edge. The kind of skill and experience only a small percentage of pilots in any given force are capable of exhibiting.


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## drgondog (Aug 11, 2007)

Crumpp said:


> There are a couple of very practical reasons why sustained level turn ability is much more important to today's computer gamer than it is to a fighter designer or pilot in RL.
> 
> 
> That is a very powerful fact. Sustained turning ability is a function of the fundamental relationship of aircraft performance, power available to power required. However, the most important factor in turn performance is velocity. The slower aircraft will always outturn the faster aircraft.
> ...



Crumpp - With enormous respect to you, I agree everything you said except the flat statement that 

*Facts are all aircraft at the same velocity and angle of bank will make exactly the same turn.* 

If you mean by the above statement that all exact model aircraft at same weight and configuration (external stores) - then I agree

For dissimilar aircraft entering that turn I would disagree as I think you would also. The "G" forces will be exactly the same as long as the velocity and angle of bank are the same - but aerodynamics (energy bleed) and wing loading and airfoil properties will immediately enter into the equation

Not all a/c could 'maintain' the same angle of bank and airspeed given reasonably close thrust to weight equivalency. I have in mind an F-105 in a turn with a Jap Zero to illustrate the problem with the concept.. or even a very light F105 in a turn with a heavily loaded one.

For every other comment I am in violent agreement


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## Crumpp (Aug 11, 2007)

Hi drgondog,

Thank you for the kind words.

I think you misunderstood what I wrote regarding turn performance. Don't worry it is a difficult concept to grasp but as I said, it is a very powerful fact of aircraft performance. You will begin to see why sustained level turn is just not very important to a fighter designer. 



> Notice in the development of the radius of turn equation that the weight (W) canceled out of the equation. This is a very important observation since it means that the size of the aircraft has no effect on the radius of turn. Thus, two aircraft flying at the same angle of bank and velocity will make the same radius of turn even if one is 1000 times larger than the other.



Radius of Turn

Turn performance is based on the relationship of power available to power required. In a very simplistic form, wing loading is a reflection of this relationship. However aircraft are a system and not one characteristic. The designers in WWII were very competent and I would even venture to say much more competent in high power piston aircraft design than we are today. There simply is not much of a market for 2000hp single engine aircraft.

Not all aircraft can _sustain_ the same angle of bank at the same velocity. The L/D characteristics of the design play a very important role. In fact all aircraft performance depends on the L/D curve.

*For WWII fighter design contemporaries, the differences are a very small portion of the total maneuvering envelope. * 

In your example, the F-105 simply cannot travel as slow as the Zeke, velocity being the key component to turn radius.

Now the Zeke cannot travel as fast as the F-105 either. So at the higher velocities the F-105 is comfortable maneuvering, the Zeke cannot sustain the same turn performance.

Just as excess power extends into the low velocity realm, it also extends into the high velocity realm. At Vmax, an airplane only has enough power to sustain wings level flight.



> In the graph above the red lines represent the radius of turn for any airplane, at 10,20...80 degrees of bank. Keep in mind that the radius of turn equation is universal, therefore this graph is valid for any airplane, from a C-150 to a Boeing 747.





> The blue line in the graph is for an airplane with a stall speed of 60 knots in straight and level flight. This line will be different for every airplane of course.



Minimum Radius of Turn

You can confirm this aerodynamic fact easily with the following program:

Gyles AeroDesign - Freeware Turn Radius Calculator

All the best,

Crumpp


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## drgondog (Aug 11, 2007)

Crumpp said:


> Hi drgondog,
> 
> Thank you for the kind words.
> 
> ...



Crumpp - I wasn't having a problem grasping the concepts - strictly to the statement and question I posed. Like you I have both the education and the experience behind the stick to agree the points you made.

In my example with the Zeke I was perhaps not clear enough. 

The F-105 could in fact fly at 300 kts, and enter a turn with a Zero at three hundred kts, and not be able to keep up in the turn radius no matter how much power is subsequently added by the 105 jock to try to maintain bank angle... 

If he continued to try to maintain the turn and the rule of this engagement is a.) do not add any more throttle, and b.) put the engagement on the deck, the 105 will be severely out turned by the Zero.

I would pose the same outcome for a MiG21 and F-105 entering a turning fight on the deck, each entering at 550 kts and let the 105 be able to increase his power to all available as he is faster on the deck. The 105 would be able to enter with the same bank angle but would not be able to sustain it (or lose bank angle/energy less slowly than the MiG).

This is the end of my only rebuttal to a statement that I think you did not mean in the context I parsed it..

As to 'not very important', at low altitude and very little excess energy available to break combat with a fighter with significantly better turn performance....it might be critical. 

As to the pilot who knows his ship and understands the strengths of his speed and zoom, then he avoids the circumstances above - and makes it 'less important' - 

And to your point a superior pilot (say, in a P-47) on the deck might be able to outfly the inferior pilot in a 109 or 190 in a turn, entering at the same speed and bank angle, and defeat them by being able to skirt closer to the stall - in which case as you pointed out, the turn radius (optimal) was not the critical factor, but the skill of the pilot in the a/c with 'inferior' turn potential performance and his ability to ultimately 'out turn' the better a/c in that manuever.

This is a lot of words for what I thought was a minor point of disagreement for a literal statement I wasn't sure you meant - <smile>

If you meant it, I tip my hat and withdraw from the debate.

Regards,

Bill


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## Glider (Aug 11, 2007)

I admit that I am with Drgondog on his comments about radius of turn. Some aircraft have lift devices that enable them to reduce the turn radius for a given speed. This must be reflected in the final result somewhere along the line.
Weight surely must also play a part. The heavier plane is going to have a harder time in the turn due to the additional forces in play trying to 'throw' the plane out of the turn, plus of course wing design. I cannot see an F104 staying, say with an F86 in a turn at the same speed and bank, due to the different amount of lift generated by the wing.

Also isn't there a significant danger in looking at this in isolation. For example the roll rate has a major impact on how long it takes to get into a bank for the turn to take place. I have some experience in gliders and I am confident nothing powered could keep up with me in a turn, but my roll rate is shocking and to get into a turn takes an appreciable amount of time compared even to a simple Cessna.


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## Crumpp (Aug 11, 2007)

> The F-105 could in fact fly at 300 kts, and enter a turn with a Zero at three hundred kts, *and not be able to keep up in the turn radius no matter how much power is subsequently added by the 105 jock to try to maintain bank angle...*



If we are not considering the effects of power then yes, our F-105 would turn _exactly the same_ as our Zeke at 300KEAS at the same angle of bank. It could keep up and match turn performance exactly. There would be no difference in the two aircraft's turning ability.

However power available to power required is the fundamental relationship of aircraft performance. We have to consider the effects of power.

Lets just use EAS so we can simply things by eliminating density effects.

Actually the Zeke is incapable of turning at 300KEAS. In fact it is incapable of even reaching that speed in KEAS in level flight. It does not have the power available. If the pilot attempted to turn at 300Kts he would have to trade altitude for airspeed if he wanted to maintain 300KEAS.

The F-105 would end up above him.

The Zeke could give up energy in the form of airspeed to maintain alitude. As he travels at a slower velocity he will now turn a smaller radius but will have lost energy.

Here we can see the Zeke 52 maximum sustain load factor using TAIC data:






Here is the excel spreadsheet data from the sheet I designed:






Here we can see the P47D-22 using AHT data at combat weight. Notice the curve is very similar to the Zeke’s. However the Zeke can sustain this at a much lower velocity. The P47D-22 however can sustain a turn at 250KEAS of 2.76G's while the Zeke can only sustain 1.5G's at 250KEAS.






Now which would you rather dogfight in? The aircraft that has to give up a large portion of its energy to maneuver or the aircraft that can remain fast and still maneuver?

Speed is life.

All the best,

Crumpp


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## Crumpp (Aug 11, 2007)

> I have some experience in gliders and I am confident nothing powered could keep up with me in a turn,



Certainly it can outturn most "powered" aircraft for a while at least. Your glider has much more power available than a Cessna as long as it exchanging PE for KE to maintain that altitude. It uses it's lightweight and low drag to gain the advantage in Pa. Great example of how L/D characteristics determine performance.

Typical L/D max for a sailplane is ~60:1. Typical L/D max for a Cessna 150 is ~7:1. Your glider is moving 60 feet forward for every foot of altitude lost. The Cessna 150 is moving 7 feet forward for every foot of altitude lost. It takes a lot less energy to move your glider than it does the Cessna.

Hence your glider has more power available in the turn. You will reach a point where you have exchanged all energy available and can no longer maintain that altitude. The Cessna on the otherhand will reach a point it can sustain performance at that altitude as long as it has fuel to convert to KE.



> due to the different amount of lift generated by the wing.



This statement bothers me and I just want to clarify your meaning here. Airfoils on different aircraft due generate different amounts of lift. However all of them generate only the amount of lift _required_ for a condition of flight.

It does not matter what airfoil or lift devices you place on a 2000lb aircraft for example. It will always generate only 2000lbs of lift in level flight. In climbing flight our wing will generate less lift than in level flight and in a dive it will generate more lift than in level flight.



> For example the roll rate has a major impact on how long it takes to get into a bank



Yes, in fact designers consider roll rate to be much important than level turn ability. All manuvers begin with a roll.

Any aircraft with a significant roll rate advantage can use it to overcome a level turn advantage. Placing the vector of lift below the horizon adds weight directly to thrust based on the angle. Adding thrust to the turn equation directly increases our maximum sustainable load factor.

All the best,

Crumpp


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## Crumpp (Aug 11, 2007)

> Some aircraft have lift devices that enable them to reduce the turn radius



The effects depend on the device in question. Flaps for example, depending on the setting selected will actually reduce turn performance. In the first few degrees the tendancy is too gain more lift benefit than drag penalty. After that first few degrees, the drag penalty increases explosively.

While TE or trainling edge flaps do increase an airfoils usable angle of attack by changing camber, they also increase the angle of incidence. This has the effect of lowering the nose of the aircraft while maintaining the capability to fly at a lower velocity for the same lift production. If we did not have flaps, our body angle at approach velocity would be high enough to obstruct the pilots view of the landing site.

Airfoil lift devices can be divided into two broad catagories. Those that increase camber, and those that energize the boundry layer.

As for the calculations, the effects are acounted for in the forces required.

All the best,

Crumpp


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## Crumpp (Aug 11, 2007)

Just to clarify on the Zeke/P47 comparision.

Any turn that is below the blue line, the two aircraft will make exactly the same turn and the performance is sustainable.

Any turn above the blue line, the two aircraft will make exactly the same turn but the performance is not sustainable.

So if the Zeke is sustaining performance in an area the P47 cannot sustain the same performance, the P47 can exchange energy if available to match performance up to the stall line. This goes both ways for both aircraft.

Hnece the expression all aircraft at the same angle of bank and velocity will make exactly the same turn.

The graphs only show the thrust limited performance. There is a lift or stall line which is not shown. Niether aircraft can achieve controlled flight if they pass the stall line.

Understand now?

All the best,

Crumpp


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## Crumpp (Aug 11, 2007)

> I wasn't having a problem grasping the concepts



Hi Bill,

I know that you do not have any trouble grasping the concepts. It is just a difficult concept to explain on a BBS over the internet.

I hope my explainations above make the concept I was conveying much clearer.

You are correct that there are situations where turn performance can be decisive. In fact turn performance is much more important in the Jet age due to the differences in thrust producers and power producers behavior in the region of reversed command.

It is an interesting line of discussion IMHO.

All the best,

Crumpp


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## Soren (Aug 11, 2007)

I agree completely with Crumpp

The pilot is an extremely important factor, but taking away the pilot factor L/D T/D ratio, lift-loading and power-loading are the most important factors as to how well an a/c turns.

Believe it or not the Me-262 A-1a is actually a very capable turn fighter as long as the speed is kept high, and the extremely low drag of this a/c coupled with its high AR wing LE slats made sure it possesses a high L/D ratio, which means a much lower drag penalty for the amount of lift produced in aturn than normal - as its pilots explained the Me-262 was very slow to loose speed in a turn, which was very good cause if you did go slow you were in trouble as the acceleration of the jet-engines was very low at low speeds, making for a pathetic turn performance at low speed.


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## Soren (Aug 11, 2007)

At 540 km/h at a weight of 6,000 kg the Me-262 A-1a will be capable of a 8 G turn, which is more than what the average pilot can take.

Lift: 1.58*21.7*.5*1.225*150^2 = 472503.938 Newtons (N)

472503.938 N = 48181.99 Kgf

48181.99 kgf / 6000 kg = 8.03033167

G-force at Clmax at 540 km/h: 8.03


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## Mike Williams (Aug 11, 2007)

> Hey Mike - as a cynic I might have suggested a couple of months back that the prime off line instructions to the Navy pilots conducting the tests "Don't come back with a conclusion that the 51 is superior in any way" - which is why the Patuxent River tests are not accompanied by Turn and acceleration comparisons at various speeds and altitudes - lol - but definitely accompanied by statements that the F4U out turned, accelerated and climbed better –



Hello Bill:

It would be natural and understandable to have misgivings about trials where the Navy compared an Army aircraft against their own or vice versa. After reexamining the Evaluation and Comparison Trials of the P-51B and F4U-1 I don’t believe the findings were too terribly politicized if one assumes that the Navy was interested in comparing the P-51 against the best performance possible from standard production operational F4U’s as well as F4U’s that might be coming into service in the not too distant future.

Allow me to explain why I feel that this particular comparison is at least a reasonable interpretation of how the P-51 and F4U compared. The Navy utilized three aircraft in the trials, namely P-51B No. 37050, F4U-1 02390 and F4U-1A No. 17930.

Firstly, let’s check the performance of the P-51 obtained by the Navy and compare it against other sources. 

Level Speeds:

P-51B 37050 (Navy, Patuxent River): 358 mph at SL and 450 mph at 29,200’ using 67” Hg, 3000 RPM.

P-51B No. 43-6883 (Army, Wright Field): 370 mph at SL and 442 mph at 29,400’.

P-51B FX953 (UK, Boscombe Down): 360 mph at SL and 450 mph at 28,000 ft.

See also  P-51 Tactical Planning Characteristics Performance Chart and Aircraft Data Sheet for Mustang III (P-51B)

Thus it can be seen that in this respect at least, the Navy’s findings are in good agreement with other flight trials and data sheets. 

Climb:

P-51B 37050 (Navy, Patuxent River) 9,423/9,100 lbs.: F4U’s are 750 – 1,000 ft/min superior with the P-51B loaded to 9,423 lbs and “superior in climb to 20,000 feet, and the P-51B superior above that altitude” with the P-51B loaded to 9,100 lbs..

P-51B No. 43-6883 (Army, Wright Field) 9,205 lbs.: 3,450 ft/min at 13,800 feet

P-51B FX953 (UK, Boscombe Down) 9,200 lbs.: 3,610 ft/min at 10,600 feet

Unfortunately the Navy didn’t provide actual rate of climb figures for the P-51B, rather just the comparative figures as stated above. 

The Navy tested two F4U’s during the comparison trials. F4U-1A No. 17930 is described as “a standard production raised cabin airplane, with a surface finish in rather poor condition, but with the tail hook removed. It is considered to have been in a drag condition representative of production airplanes after moderate service.” The report also notes that “F4U-1A No. 17930 was flown at the standard war emergency rating of 60” at 2700 RPM, with water injection.” The level speed results obtained, along with those of another F4U-1 tested by the Navy at the same power settings for comparison, are as follows:

Level speeds:

F4U-1 No. 17930: 365 mph at SL, 431 mph at 20,300 feet. 60” MAP, 2700 RPM. 31.5” carburetor impact pressure setting. (without tailhook opening faired.)

F4U-1 No. 50070: 364 mph at SL, 421 mph at 19,850 feet. 60” MAP, 2700 RPM 31.5” carburetor impact pressure setting. (with tailhook)

In contrast the Bureau of Aeronautics-Navy Dept. Airplane Characteristics Performance data sheet lists the level speeds of the F4U-1 as 359 mph at SL and 417 mph at 19,900 feet using water injection.

It can thus be concluded that F4U-1 17930’s condition while not exactly standard, is close to standard and its performance a bit stronger than would be typical of production models. 

The other F4U-1 tested is certainly not typical of those F4U’s entering service at the time of the trials. It’s important to note that the Navy doesn’t try to pass it off as standard either. “F4U No. 02390 was a standard low-cabin production airplane, in a drag condition representative of that to be expected in the _F4U-4_ airplane as a Marine land-based fighter. … The principle changes included sealing and fairing the wing fold hinge line, removal of the tail hook, carefully fitted cowling, and a faired and smoothed, but not polished, skin. The total speed gain, as a result of drag reduction alone, in this airplane is estimated to be 8 mph at the airplane upper critical altitude.” “F4U-1 No. 02390 was flown at a _special war emergency power rating of 65”_ manifold pressure and 2700 RPM, with water injection at an increased water flow rate.” One of the conclusions of the report on F4U-1 No 50030, dated August 2, 1945 was “A combat power rating in excess of 60” manifold pressure is considered to be impractical for general use when atmospheric temperatures are in excess of NACA standard.” 

Climb:
F4U-1A No. 17930 max climb = 3210 ft/min at SL (12,162 lbs.)
F4U-1 No. 50070 max climb = 3460 ft/min at SL (12,162 lbs.)
F4U-1 No. 02390 unknown but stated as superior to the P-51B at various loadings except above 25,000’.

In contrast the F4U-1’s climb rate as shown on the Airplane Characteristics Performance sheet is 2890 ft/min at SL at 12039 lbs and using water injection. It appears that the Navy is on less solid ground with their conclusions regarding climb comparisons of the F4U and P-51B.

Was the Navy trying to mislead their intended readership based on what we know so far? With respect to level speed performance, I don’t think so, but including F4U No. 02390 in the trial does muddy things up for us in this day and age if we are just reading their conclusions, looking at the charts and not examining the details. It does appear to me, however, they were stretching the truth a bit with respect to their conclusions regarding climb. Sure, the report is probably somewhat biased but in the end I believe the F4U served the Navy well and was probably a better choice for them just as the P-51 was the better choice for the Army Air Force. 

Frankly the report only touches on maneuverability and response and apparently is little more than pilot’s impressions. It falls far short of "turn and acceleration comparisons at various speeds and altitudes" (well, to be fair, no one was doing that at the time) or full fledged tactical comparison trials such as those conducted by Eglin or AFDU in the UK. I’d agree with you that the report’s conclusions in this respect were a bit of a stretch. A USAAF report comparing an F4U and an Allison engined P-51 provides an interesting counterpoint.

There must be a good reason why most test centers of the period used comparative, head to head testing, for performance variables such as turn, acceleration, roll, etc. Interestingly the Navy did occasionally test and quantify roll rates such as that found in this report on the F4U and this report on the F6F. Quibbles with the report analyzed here aside, on the whole I find the Navy performance testing, especially that carried out at Patuxent River, to be very thorough, professional and the equal to Wright Field or A&AEE in the UK. 

I suppose this ramble is not terribly on topic to the overall thrust of this thread but it is intended as a reply to Bill’s post and it’s what is interesting to me at this time and hopefully some of you too. What material I’ve found on WWII fighter turning comparisons can be found at the link in my signature, some reports and diagrams of which have already been linked to in this thread.


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## Glider (Aug 12, 2007)

Crumpp said:


> Typical L/D max for a sailplane is ~60:1.



I do wish the ones that I could afford to buy, had been that good


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## Crumpp (Aug 12, 2007)

> I do wish the ones that I could afford to buy, had been that good



I misread the L/D characteristics. 60:1 is a typical _racing_ sailplane. 43:1 is a typical high performance sailplane L/D max. They are not cheap for sure. Especially since the utility of a glider is rather small. "Fun toy" is about as far it gets IMHO when considering Glider ownership. Shame as you really need some decent piloting skills to get the most out of them.

I am considering installing a tow on one of my aircraft to get some of the "cost of flying" back.

The point still stands:



> Certainly it can outturn most "powered" aircraft for a while at least. Your glider has much more power available than a Cessna as long as it exchanging PE for KE to maintain that altitude. It uses it's lightweight and low drag to gain the advantage in Pa. Great example of how L/D characteristics determine performance.
> 
> Typical L/D max for a sailplane is ~60:1. Typical L/D max for a Cessna 150 is ~7:1. Your glider is moving 60 feet forward for every foot of altitude lost. The Cessna 150 is moving 7 feet forward for every foot of altitude lost. It takes a lot less energy to move your glider than it does the Cessna.
> 
> Hence your glider has more power available in the turn. You will reach a point where you have exchanged all energy available and can no longer maintain that altitude. The Cessna on the otherhand will reach a point it can sustain performance at that altitude as long as it has fuel to convert to KE.



All the best,

Crumpp


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## drgondog (Aug 12, 2007)

Mike Williams said:


> Hello Bill:
> 
> It would be natural and understandable to have misgivings about trials where the Navy compared an Army aircraft against their own or vice versa. After reexamining the Evaluation and Comparison Trials of the P-51B and F4U-1 I don’t believe the findings were too terribly politicized if one assumes that the Navy was interested in comparing the P-51 against the best performance possible from standard production operational F4U’s as well as F4U’s that might be coming into service in the not too distant future.
> 
> ...



Mike - thx for the details. 

Actually I am not a Mustang bigot with respect to performance and the F4U is probably the best fighter we put into combat in WWII when you look at every possible role. I wish it had been in Europe in 1943.

PS - I'm waiting for last detail from 357 guys on the 24 April mission - then I will send it your way.


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## drgondog (Aug 12, 2007)

Crumpp said:


> Hi Bill,
> 
> I know that you do not have any trouble grasping the concepts. It is just a difficult concept to explain on a BBS over the internet.
> 
> ...



Crumpp - I thought you explained it well. You actually had me digging up old (very old) performance text books to refresh my thinking. I had some minor points to debate but wasn't worth quibbling over.

Regards,

Bill


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## Glider (Aug 12, 2007)

Crumpp said:


> I Especially since the utility of a glider is rather small. "Fun toy" is about as far it gets IMHO when considering Glider ownership. Shame as you really need some decent piloting skills to get the most out of them.



I must not comment on the average PPL, I must not comment on the average PPL, I must not comment on the average PPL, I must not comment on the average PPL,


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## FLYBOYJ (Aug 12, 2007)

Crumpp - what type of plane do you own? I work at the USAFA on the soaring program.


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## Crumpp (Aug 12, 2007)

Socata MS894A on the East Coast.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/0b315259f82b9463862572ac005464f2/$FILE/7a14.pdf

Airliners.net Photos: Untitled (Fluggruppe Hasenstrick) Socata MS 894A

All the best,

Crumpp


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## drgondog (Aug 12, 2007)

Glider said:


> I must not comment on the average PPL, I must not comment on the average PPL, I must not comment on the average PPL, I must not comment on the average PPL,



Lol! Glider.

I actually had about five or six rides in a glider back in late 50's when my father taught me how to fly. 

His theory was that I would more quickly learn how to a.) perform a co ordinated turn and b.) obtain quick 'power' off judgment and skills for the 'just in case' scenario than just being exposed to powered flight.

I also did my first stalls and landings in a glider before advancing to next stage of my tutorials..

and he was right.


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## Crumpp (Aug 12, 2007)

> I must not comment on the average PPL,



LOL yep. Well being an engineer does not make you a pilot and neither does being a pilot make you an engineer.

I admit to hearing some somewhat ignorant statements about the science of flight coming from the pilot's lounge. Statements like a wing which "generates more lift" and "having excess lift" come to mind.

This has to be caveated with the fact that on a practical level those kind of statements make perfect sense. This naturally comes from operating a vehicle that speed measurement instruments do not tell you how fast you’re going and altitude measuring instruments do not tell you how high the plane is flying! Very little about an airplane operates as it seems too.

IMHO there is also quite a bit about flying that your natural reactions will get you killed that it just becomes easier to simply tell the student pilot, "This is how it works in the air and don't worry about why or what is really going on". Otherwise the FAA would require 4 years of Ground Instruction.

All the best,

Crumpp


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## FLYBOYJ (Aug 12, 2007)

Crumpp said:


> IMHO there is also quite a bit about flying that your natural reactions will get you killed that it just becomes easier to simply tell the student pilot, "This is how it works in the air and don't worry about why or what is really going on". Otherwise the FAA would require 4 years of Ground Instruction.
> 
> All the best,
> 
> Crumpp



Well said - It's funny, I did a flight review this morning for a guy who mainly flew low wing aircraft. After he got the feel for proper C-172 approach speeds (so he isn't floating down the runway all day) I told him "See the bottom of the green on the airspeed indicator? Unless your wheels are on the ground, keep the needle above that!"

BTW nice airplane, don't know how you'll do as a tow plane but if you're at sea level all should be fine....


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## Crumpp (Aug 12, 2007)

> BTW nice airplane, don't know how you'll do as a tow plane but if you're at sea level all should be fine....



Thanks! They are pretty popular tugs in Europe with a few here in the states. The tow hook is a factory option for the design.

All the best,

Crumpp


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## FLYBOYJ (Aug 12, 2007)

Crumpp said:


> Thanks! They are pretty popular tugs in Europe with a few here in the states. The tow hook is a factory option for the design.
> 
> All the best,
> 
> Crumpp


At the academy we use a Toast hook and 180 hp Supercubs. Our TPA is 7000' MSL so we need a lot of pull to be able to tow and it seems the Supercub woks best.


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## Glider (Aug 12, 2007)

The one that I have the most experience of is a Piper Pawnee but the most interesting, was a one off Chipmunk. 
It was a one off, because it was used to teach Prince Charles to fly in. As Prince Charles was going to use it, a number of small modifications were made to it, enough changes so that once he had learnt to fly, the RAF didn't want it any more. 
At RNAS Culdrose we were looking for a tug and got it cheap.


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## Crumpp (Aug 12, 2007)

That's a good story, glider. 

flyboyJ,

My aircraft feeds off Supercubs and Cessna's.....It has a filler port for the parts.

Here it is all dressed up to bag a limit of 172's:


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## FLYBOYJ (Aug 12, 2007)

Crumpp said:


> That's a good story, glider.
> 
> flyboyJ,
> 
> ...


Hehehe - that's funny...

Can it do it at 6000' MSL???


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## Crumpp (Aug 13, 2007)

I don't see why not!



That is an actual picture of the Military version. New Zealand and El Salvador use it in the ground attack role.

It can lift some weight as a design.

All the best,

Crumpp


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## FLYBOYJ (Aug 13, 2007)

Our Cubs are in the air within 200'. We actually looked at Socatas during a study and found they might of been powerful enough for towing here but would present some other problems. Nice plane though....


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