Draining E in turns

[Crumpp]

Actually there is quite a lot of wrong in your calculations.

Not really so don't be a drama queen.  I missed two units.  Psi instead of PSF and MPH instead FPS.

Not bad for the very first time calculating Cl's.

For Drag I used CDwet from David's article and the Wet Area.  Because my "r" was not converted to the correct units then it threw the calculation off.

Aspect ratio is simply:

I know the formula and have posted it.   I have also said SEVERAL times that this comes from Original Documentation!!  The FW-190A4 that was captured by the RAF has an aspect ratio according to them of 5.8.  The Luftwaffe says the FW-190A8 had 6.01.  Only wing change to the FW-190 was in the FW-190A6 in order to make room for the Mg151 outboard cannon.  Additionally the wing was "modified to provide extra lift to off-set weight gain in the design" according to the Luftwaffe. How exactly it was modified, besides the obvious external modifications which have nothing to do with lift, is unknown.

Now those are the facts.  This is one of the things I am digging into to find out what is up.  I am NOT nor am I, about too, start standing up and crowing about it.  Right now I am searching for pre-FW-190A6 Luftwaffe documentation which shows the Aspect Ratio.  And of course Pre V5.

Got a reply back on the Cl increase in a steep bank From an aeronautical engineer:

You asked:

 >> Why doesn't the lift co-efficient go up in a Steep turn?

Maybe it does, maybe it doesn't.

The yoke (and trim) give the pilot powerful control over
the coefficient of lift.

LOL Again it all depends on the control input!!!

Regarding drag in the turn here is a little quick and dirty comparison at different g loads calculated with Lednicer's flat plate values. Speed is 483km/h ie 300mph and e factor is same for all planes (0,8).

Those look pretty good.  I will check them after I recalculate "r" in the correct units. The P51 is way ahead of the FW-190 and the Spit.  The FW-190 is ahead of the Spitfire in parasitic drag.  It is interesting to note that that:

 

According to Gripens Calculations the Spitfire and FW-190 keep about the same ratio of mass to force throughout with the FW-190 pulling out ahead the higher the G's. The clear winner in that line up is the P51! It has less force acting on it and more mass. The Spitfires appears much lower but since it is a much lighter plane it does not need as much force to put the brakes on.

Crumpp

[Charge]

I don't think that an a/c which is good in retaining E can be good in braking its speed. Meaning that a Spit is forced through a tight turn by its wing area whereas aircraft with higher wing loading will "slip through" in a high G turn and thus brake more efficiently.

Of course a larger braking area is better but here the wing profile comes into play. The elliptical design produces lift with less drag as everything that causes most drag in wing design is left off (->maximum wingarea with least drag). This in turn causes that the elliptical design is not very good in high AoA ->thus the washout in the wing to make it conrollable in high AoA. But what does the outer portion of the wing in level flight as its AoI is different from the root? I find it strange if it manages to produce lift the same way the root does.



-C+

[Crumpp]

I don't think that an a/c which is good in retaining E can be good in braking its speed. Meaning that a Spit is forced through a tight turn by its wing area whereas aircraft with higher wing loading will "slip through" in a high G turn and thus brake more efficiently.

I don't beleive the spit was known for retaining E.  It was a great turner and master of the spiral climb.

Just read the numbers.

The point is the Spitfire due to it's higher parasitic drag but lower wingloading produced about the same ratio of breaking forces to mass as the FW-190 which has lower parasitic drag but higher induced drag.  That ratio favours the FW-190 the more G's you pull.

It's numbers appear lower but it is a light plane and doesn't require as much force.

Crumpp

[bozon]

I don't think that an a/c which is good in retaining E can be good in braking its speed.

This is a reasonable generalization to make If you do not allow to pull more than x G, but you must be careful with the details. You should also remember that pulling on the stick is not the only way to bleed energy.

Bozon

[gripen]

Originally posted by Crumpp
Not bad for the very first time calculating Cl's.

So now you announce that screwing up completely a very simple calculation is not bad. Well, maybe in the elementary school.

Originally posted by Crumpp
I have also said SEVERAL times that this comes from Original Documentation!!  The FW-190A4 that was captured by the RAF has an aspect ratio according to them of 5.8.  The Luftwaffe says the FW-190A8 had 6.01.

The RAE paper gives just a quick and dirty wing area. There was no change in the wing area from the Fw 190A-1 to Fw 190A-9 according to original german documentation.

Originally posted by Crumpp
Right now I am searching for pre-FW-190A6 Luftwaffe documentation which shows the Aspect Ratio.  And of course Pre V5.

Well, I have such documentation on my table, not difficult to find.

Originally posted by Crumpp
Got a reply back on the Cl increase in a steep bank From an aeronautical engineer:

"You asked:

>> Why doesn't the lift co-efficient go up in a Steep turn?

Maybe it does, maybe it doesn't.

The yoke (and trim) give the pilot powerful control over
the coefficient of lift."

LOL Again it all depends on the control input!!!

So now you loudly announce that an aeronautical engineer told you that there is a connection between controll input and lift coefficient. That might sound earth shaking but I believe pretty much every one here allready knows that.
 

Originally posted by Crumpp
According to Gripens Calculations the Spitfire and FW-190 keep about the same ratio of mass to force throughout with the FW-190 pulling out ahead the higher the G's. The clear winner in that line up is the P51! It has less force acting on it and more mass. The Spitfires appears much lower but since it is a much lighter plane it does not need as much force to put the brakes on.

You can't draw anykind of conclusions on turning performance based on the total drag only. What we need to know is the relation between thrust and drag (excess power). These can be easily added to the calculation and with the excess power (positive or negative) and the mass of the plane, we can also easily calculate forward acceleration (positive or negative). As an example below are accelerations calculated for couple planes at 483 km/h at sea level. Note that flat plate areas are now calculated same way as in the Lednicer's paper  (Cdwet includes Cdi and Cd=1 for flat plate) and thrust is calculated assuming 85% efficiency and 120 kp exhaust thrust:

Spitfire IX (average), 3400 kg, 1586 hp, flat plate area 6,18 sqft, e factor 0,9
0g 0,74 m/s2
1g 0,66
2g 0,41
2,99g 0
3g -0,01
4g -0,59
5g -1,34
6g -2,26

P-51B 4128 kg, 1480 hp, flat plate area 5,23 sqft, e factor 0,8
0g 0,76 m/s2
1g 0,64
2g 0,30
2,58g 0
3g -0,26
4g -1,05
5g -2,06
6g -3,31

Fw 190 (US Navy) 3940 kg, 1740ps, flat plate area 6,69, e factor 0,8
0g 0,70 m/s2
1g 0,57
2g 0,20
2,38g 0
3g -0,42
4g -1,29
5g -2,41
6g -3,77

So here we can see that the only g load where the P-51 does higher acceleration  than the Spitfire is 0 g. The max continous g load at 483 km/h is that value where the acceleration is zero and at higher g loads deacceleration shows relative decrease of the speed at given g load, the Spitfire being clearly better than other two.

It should be noted that above flat plate areas give same sea level speed values as in the real world tests:

Spitfire IX 539 km/h (A&AEE average)
P-51B 560 km/h (USAAF test)
Fw 190 537 km/h (US Navy test)

Lednicer's values would have resulted over 350 mph sea level speed for all planes.

Originally posted by Crumpp
I don't beleive the spit was known for retaining E. It was a great turner and master of the spiral climb.

Just read the numbers.

Well, actually the point is to understand numbers not just read them.

gripen

[Crumpp]

The RAE paper gives just a quick and dirty wing area. There was no change in the wing area from the Fw 190A-1 to Fw 190A-9 according to original german documentation.

Which ONE Gripen?  There are quite a few reports.  LMAO!

You don't even know what report I am refering too.  One I have offerred to provide you free of charge.  A report which cost almost 200 US dollars to get a copy of from the National Archives.  I would say I have been more than generous.

 

So now you announce that screwing up completely a very simple calculation is not bad. Well, maybe in the elementary school.

It is no more than High School Algebra.  I am sure YOU have never made an error.  So I got 2 units wrong.  Simple conversion and a Simple fix to recalculate.  

However you want to make out like it's huge deal.  

Between fixing my math and you solving your insecurities, I have the far easier task!

Well, I have such documentation on my table, not difficult to find.

Good for you.  Thanks I was hoping it would not be hard to find.

So now you loudly announce

It's a Bulletin Board, you can't loudly announce anything.  I just thought it was funny the vague response.  However, if you were the aeronautical guru you pass yourself off as, you could have saved everyone some time and simply explained it.  Since you did not, then obviously you were just like the rest of us and probably learned something in this thread too.

Ohh, And you can do High School Level Algebra better than I can.

Lednicer's values would have resulted over 350 mph sea level speed for all planes.

Looks to me like all three could do 350 on the deck pretty easily:

Spitfire Mk IX LF - LOOKS like 350 mph to me!  Aren't the Spitfire fans always complaining that this data is too slow??

http://www.fourthfightergroup.com/eagles/jl165speed.gif

http://www.fourthfightergroup.com/eagles/jl165.html

FW-190A8 - LOOKS like 350 to me!

http://www.terra.es/personal2/matias.s/fw190-1.jpg

Do I need to post the P51B speed?  It was 50 - 70 mph faster than both the FW-190 AND the Spitfire....

the Spitfire being clearly better than other two.

Yeah If I was a Spitfire Fan I would probably recalculate those numbers too.

Sorry Gripen.  Looks like fandom to me and an attempt to discredit an actual aeronautical engineer whose analysis is both transparent and public.  Not mention one with lots more resources and knowledge to figure out the deal than you with a 5 dollar calculator.

You can't draw any kind of conclusions on turning performance based on the total drag only.

Nobody is drawing any turn performance conclusions.  The answer was in braking forces which the FW-190 and the Spitfire are proportionally equal.  In the sustained turn the Spitfire ruled supreme between the three.

Note that flat plate areas are now calculated same way as in the Lednicer's paper

Except your values are totally different and not his flat plate areas or CDwet?  So how much access did you have to a detailed engineering computer analysis when you did them?

Your ***-U-ME-ing what values?  Funny I don't remember reading those words in David's Article at all.  In fact, he seems pretty adamant that aeronautical engineers should NOT do that.  It leads to the wrong conclusions!

Here you can read it again and look for the assuming part:

http://www.thetongsweb.net/AH/EAAjanuary1999.pdf

Crumpp

[gripen]

Originally posted by Crumpp
Which ONE Gripen?  There are quite a few reports.  LMAO!

RAE TN No.1231.

Originally posted by Crumpp
Looks to me like all three could do 350 on the deck pretty easily:

Spitfire Mk IX LF - LOOKS like 350 mph to me!  Aren't the Spitfire fans always complaining that this data is too slow??

http://www.fourthfightergroup.com/eagles/jl165speed.gif

http://www.fourthfightergroup.com/eagles/jl165.html

FW-190A8 - LOOKS like 350 to me!

http://www.terra.es/personal2/matias.s/fw190-1.jpg

Do I need to post the P51B speed?  It was 50 - 70 mph faster than both the FW-190 AND the Spitfire....

Now you are playing plain childish, those are all with higher ratings. The ouputs are mentioned above and the ratings are:

Merlin 66: +18 lbs 3000rpm 1586 hp at sealevel with RAM
V-1650-3: 67" 3000rpm 1480 hp at sealevel with RAM
BNW 801D: 1,42 2700rpm 1740 ps at sealevel with RAM

Originally posted by Crumpp
Nobody is drawing any turn performance conclusions.  The answer was in braking forces which the FW-190 and the Spitfire are proportionally equal.

The thrust opposites drag and for one reason or another you don't want to count thrust.

Originally posted by Crumpp
Except your values are totally different and not his flat plate areas or CDwet?  So how much access did you have to a detailed engineering computer analysis when you did them?

The guidelines to do simple drag and thrust analysis are given above. My values are calculated from the real world tested performance. If you are not happy with them, you can do your own analysis as several posters have said above.

Originally posted by Crumpp
Your ***-U-ME-ing what values?  Funny I don't remember reading those words in David's Article at all.  In fact, he seems pretty adamantq1qaz that aeronautical engineers should NOT do that.  It leads to the wrong conclusions!

Lednicer says clearly (page 6) that his Cdwet values are for cruise lift coefficient ie the values contains induced drag. The flat plate Cd used can be easily calculated with the wet area and Cdwet.

gripen

[Crumpp]

The thrust opposites drag and for one reason or another you don't want to count thrust.

And prop efficiency helps determine thrust.  Your's is an AssUme - d VALUE. IN addition to several other key values.  Don't see those words in David's analysis.

If you don't think prop efficiency counts ALOT then I will send you a spread sheet showing the Newtons.

RAE TN No.1231.

It is NOT the one I am refering too.

Now you are playing plain childish

No I am just having to deal with you.

 

ouputs are mentioned above and the ratings are:

I would say David knows the outputs and thrust of the A/C.

you can do your own analysis

I did and I have using Davids numbers.  It is totally different from what your calculations with ASSUMED values say.

Lednicer says clearly (page 6) that his Cdwet values are for cruise lift coefficient ie the values contains induced drag.

You used his method but not his values.
And now your making assumptions and trying to pass them off as fact.

Crumpp

[gripen]

Originally posted by Crumpp
And prop efficiency helps determine thrust.  Your's is an AssUme - d VALUE.

I have checked the propeller efficiency with blade element theory  and 85% efficiency seems to be reasonable. Besides it's same for all three. If you are not happy with 85%, you can do your own analysis and prove that assumption wrong, if you can.

Originally posted by Crumpp
It is NOT the one I am refering too.

So what? That report contain mentioned value but so far I have not seen any German documentation which claim AR 5,8 for the Fw 190.

 

Originally posted by Crumpp
I would say David knows the outputs and thrust of the A/C.

 
Lednicer's analysis is not based on output but on the drag data taken from tests and his wet area calculations.

Originally posted by Crumpp
I did and I have using Davids numbers.  It is totally different from what your calculations with ASSUMED values say.

So far only calculation I have seen from you is just a totally srewed up 1 g drag calculation for 300mph. That proves absolutely nothing about my or Lednicer's numbers.

You must calculate the thrust, the induced drag as well as the Cd0 to check my numbers.

 

Originally posted by Crumpp
You used his method but not his values.
And now your making assumptions and trying to pass them off as fact.

As noted above, please check with the thrust and drag calculation if my numbers are true.

gripen

[Crumpp]

I have checked the propeller efficiency with blade element theory and 85% efficiency seems to be reasonable.

I can read it and throw out a number too.

So what? That report contain mentioned value but so far I have not seen any German documentation which claim AR 5,8 for the Fw 190.

Why do you think I offered to send it too you!!  

 

Lednicer's analysis is not based on output.

Your isn't either.  It's based off several assumptions.

 

So far only calculation I have seen from you

We are not comparing MY calculations to yours, Gripen.  

You keep saying that David Lednicer's values are WRONG.  To do so you are using a bunch of mathmatical assumptions and completely different values.

It does not pass the common sense test.

1.  David Lednicer is a qualified Aeronautical Engineer working in the field.

2.  He has access to AND uses the correct information for his calculations.  He makes NO assumptions.  IN fact he exposes several "assumptions" made about the P51.

3.  He uses engineering tools and programs YOU don't have access too.

Go look up Assumed in the dictionary:

http://www.google.com/search?hl=en&lr=&ie=UTF-8&oi=defmore&q=define:assumed

That means you don't know!  If your making assumptions YOU DON"T KNOW.  It's the details that count NOT guessing.  

Crumpp

[gripen]

Originally posted by Crumpp
I can read it and throw out a number too.

So what's the efficiency according to your calculations?  I found 85% perfectly fine.

Originally posted by Crumpp
Your isn't either.  It's based off several assumptions.

Well, assumptions are mostly same for all compared planes so relative results should be comparable. The only difference is the e factor which according to Lednicer is better in the Spitfire than in other two .
 

Originally posted by Crumpp
We are not comparing MY calculations to yours, Gripen.  

If you want to challenge my calculations on turning performance, the only way is to calculate and point out errors.

Originally posted by Crumpp
You keep saying that David Lednicer's values are WRONG.  To do so you are using a bunch of mathmatical assumptions and completely different values.

I have noted that Lednicer's data seems to at least partially wrong. So far I have not found real world tested data which supports assumption that the Fw 190 had signifigantly lower drag than the Spitfire. Lednicer's admits directly that he has choosed the data  which he believes to be best.

Originally posted by Crumpp
1.  David Lednicer is a qualified Aeronautical Engineer working in the field.

Yes, he seem to be quite professional

Originally posted by Crumpp
2.  He has access to AND uses the correct information for his calculations.

Large part of the data is available from the net and I also have copies of some other documents he uses.
 

Originally posted by Crumpp
He makes NO assumptions.  IN fact he exposes several "assumptions" made about the P51.

Actually he admits directly that he has made assumptions as noted above.

Originally posted by Crumpp
3.  He uses engineering tools and programs YOU don't have access too.

Anyone can do an output based analysis with accurate speed and output data without anykind of engineering tools. As can be seen above, this method appears to be quite accurate and perfectly fine for relative comparisons.

Besides, Lednicer's analysis contains no Cdi nor energy comparisons  which are actually subject of this thread and which I have calculated above.

gripen

[bozon]

the trouble with aerodynamics and many other science and engineering is that we can hardly improve over some initial accuracy.

Using "better" data will not improve much since the errors are not in the data but mostly in the model. Cooling drag, effects of the props on the airflow behind it and turbulance for example are complicated and therefore poorly modeled.

If you want to argue 50 mph error out of  350mph, i'll belive theory. If you want to argue anything under 10 mph for 350mph plane, no matter what super-computer and accurate data you use i'll only belive actual tests.

That's my confidence level. Yours might be different. Science is not entirely unlike faith.

Bozon

[Crumpp]

The only difference is the e factor which according to Lednicer is better in the Spitfire than in other two .

Yes, and it was found to not be very different from the P51 or the FW-190.  In fact it was not elliptical due to the wing twist of the Spitfire.

Your data is based on assumptions.

Bozon says:

Using "better" data will not improve much since the errors are not in the data but mostly in the model. Cooling drag, effects of the props on the airflow behind it and turbulance for example are complicated and therefore poorly modeled.

Totally Agree.  However, David Lednicer's data is much more encompassing than anyone can present in this thread.

 

If you want to challenge my calculations on turning performance, the only way is to calculate and point out errors.

That issue is solved.  Refer to Hitechs reply and the conditions that exist in a turn.

Your attempting to attack the validity of David Lednicer's analysis.

So far I have not found real world tested data which supports assumption that the Fw 190 had signifigantly lower drag than the Spitfire.

It does NOT have less drag than the Spitfire.  Area per Area it has MORE drag than the Spitfire.  When you factor in the fact that the FW-190 was a physically smaller aircraft with less surface area THEN it does have LESS parasitic drag.  Big Difference.

Lednicer's admits directly that he has choosed the data which he believes to be best.

Yes, he picks the data he believed was the most accurate AND the BEST for ALL THREE PLANES.  

You are accusing him of playing favorites.  

Actually he admits directly that he has made assumptions as noted above.

No, He exposes assumptions OTHERS have made thereby making the point that assuming in aerodynamics leads to wrong conclusions.

Anyone can do an output based analysis with accurate speed and output data without anykind of engineering tools. As can be seen above, this method appears to be quite accurate and perfectly fine for relative comparisons.

No.  You are not accurate and in fact are comparing aircraft that are different states of energy and trying to draw a conclusion.

Example - You list the Horsepower rating of the FW-190A (which one we don't know) at "Climb and Combat Power" for some models and "Emergency Power" for other FW-190A variants.  
You have the horsepower for the BMW-801D2 at full throttle height yet you have the altitude set at sea level.


http://www.fourthfightergroup.com/eagles/merlin66hpchart.jpg

http://www.terra.es/personal2/matias.s/bmw801d-1024.jpg

By reading the charts above you can see the output of the BMW-801D2 was significantly lower at sea level and even lower at velocity.  The RAF test is horsepower while flying and the dotted line on the NACA test of the BMW-801D2 is adjust for Horsepower at velocity.

Besides, Lednicer's analysis contains no Cdi nor energy comparisons which are actually subject of this thread and which I have calculated above.

Aeronautical engineers and Hitech answered that question already.  IT DEPENDS on the stick inputs for the turn.

Your statement that Lednicer uses no CDi in his CDwet is correct.  However it is completely contrary to your earlier statement of:

Lednicer says clearly (page 6) that his Cdwet values are for cruise lift coefficient ie the values contains induced drag.

Regarding Lednicer's flat plate values, it seems that these are for total drag ie include induced drag which mean that his values are actually quite close my quick and dirty values depending if flat plate area is calculated for Cd 1 or 1,28 (square).

So which is it?  

Crumpp

[gripen]

Originally posted by Crumpp
Yes, and it was found to not be very different from the P51 or the FW-190.  In fact it was not elliptical due to the wing twist of the Spitfire.

Your data is based on assumptions.

I assume e factor 0,9 for the Spitfire and 0,8 for the other two. BTW you claimed e factor 1 for the Spitfire above.

Originally posted by Crumpp
However, David Lednicer's data is much more encompassing than anyone can present in this thread.

Well, my calculations are based on true tested data and resulting speed at given altitude is exactly same as measured in the test as well as relative performance between planes.
 

Originally posted by Crumpp
That issue is solved.  Refer to Hitechs reply and the conditions that exist in a turn.

Well, as Hitech said 08-26-2004 09:30 PM:

"Do the math crumpp: That is the only thing that will even put a dent in this argument. We have all done the math. It is your turn."

And 08-26-2004 08:23 PM:

"Crumpp: You do not have the background to even begin to evaluate that situation.

You might wish to do a lot of research before making that statment. Infact you better be able to post exact numbers on the amount of speed loss for a given condition. If you can't post the calculations and numbers required for that evaluation. Then it is imposible to even make an evaluation on your claims. Please start listening to other people like sable,karnak,tango,gripen and myslef who do have a strong knowledge in this subject area."

So far you have not done any level turning calculations.

Originally posted by Crumpp
It does NOT have less drag than the Spitfire.  Area per Area it has MORE drag than the Spitfire.  When you factor in the fact that the FW-190 was a physically smaller aircraft with less surface area THEN it does have LESS parasitic drag.

Well, when someone says "less drag" it's a absolute scale not relative. And when someone says"lower Cd" it's a relative scale. So above you first admit that "It does NOT have less drag than the Spitfire" in the absolute scale. Great logic.

Originally posted by Crumpp
Yes, he picks the data he believed was the most accurate AND the BEST for ALL THREE PLANES.  

Well, real world test data indicate that the Fw 190 had more drag (in absolute scale) than the Spitfire as pointed out above.

Originally posted by Crumpp
No.  You are not accurate and in fact are comparing aircraft that are different states of energy and trying to draw a conclusion.

Well, the test data gives speed at given altitude and engine chart gives output. The rest is simple physics and energy state is given by you ie 300mph and same for all three planes.

Originally posted by Crumpp
Example - You list the Horsepower rating of the FW-190A (which one we don't know) at "Climb and Combat Power" for some models and "Emergency Power" for other FW-190A variants.  
You have the horsepower for the BMW-801D2 at full throttle height yet you have the altitude set at sea level.

http://www.terra.es/personal2/matias.s/bmw801d-1024.jpg

By reading the charts above you can see the output of the BMW-801D2 was significantly lower at sea level and even lower at velocity.

I'm directly using that chart and it gives 1740 ps at sea level with RAM (2700rpm 1,42ata). And the critical altitude with RAM in the engine chart is 1400 m (same as in the A-8 speed chart) so I know that the curve is for top speed.

Originally posted by Crumpp
Aeronautical engineers and Hitech answered that question already.  IT DEPENDS on the stick inputs for the turn.

Well, great logic again. What I have done is a quick and dirty comparison of momentary energy state change in various g loads. The stick input is adjusted for wanted g load and I have calculated resulting change in the energy state.

Originally posted by Crumpp
Your statement that Lednicer uses no CDi in his CDwet is correct.

Such statement I have not done:

"Lednicer says clearly (page 6) that his Cdwet values are for cruise lift coefficient ie the values contains induced drag."

This means that Cdwet value is for total drag.

"Regarding Lednicer's flat plate values, it seems that these are for total drag ie include induced drag"

This means that Cdwet value is for total drag too.

gripen

[VO101_Isegrim]

Originally posted by gripen

Well, real world test data indicate that the Fw 190 had more drag (in absolute scale) than the Spitfire as pointed out above.

Hmm, to me it appears the FW 190 would reach equal or higher speeds than the Spitfire with less power involved.

At least the A-5 did 530 km/h at SL with 1490 HP, the Spitfire IX LF did 530-540 km/h with 1680 HP (with similair power, the A-5 did 560 km/h).

So the Spitfire had slightly more drag. Which is quite shocking, but logical, considering it`s "aerodynamics".