DVL data on Bf 109 roll rates

[Kurfürst]

Originally posted by gripen
Infact values used Kurfürst might contain type specific corrections making them less comparable.

[/B]

I`ve got another version. Gripen doesn`t like the Bf 109 too much. The greater conversion difference between IAS and TAS, the worser the Bf 109 will look like. So gripen argues for the highest possible difference value so the plane would worser than the actual data, despite being shown that his conversion was wrong.

Now explain us how this makes any sense, ie. how does Me 109 type specific corrections invalid for the Me 109..?

Yep, thats exactly the same plane as used for the NACA comparison between  Spitfire, Hurricane, P-36 and P-40 and it shows same unlogical roll rate curve..

[/B]

What makes it unlogical ? The Hurricane displayed exactly the same

It`s a bit funny, becasue I remember you arguing that the relatively high values for the P-40 in test are invalid, but back then you argued the reverse way, that the 'spikes' on roll rate curves show it`s not from testing. Now you argue the exact opposite that the spikes should be there, why is that, back then you didn`t liked the P-40 rolled faster than the Spit, now you don`t like the NACA made independent tests on the Spit, too?


 

Yes, there is a corner but unlike RAE and RAAF test, the roll rate increase still after corner. No other plane in the charts with frise type ailerons show similar curve (except Hurricane in the NACA test, which probably got similar mainteance). The most likely explanation for this is loosenes in the linkage.

Perhaps because no other plane had as serious problems with wing flexing like the Spit.

Besides it should be noted that NACA choosed to use RAE values for the Spitfire instead their own test values in their after war summary of lateral control research (NACA 868). IMHO for a good reason.

Yep, the NACA test did not included 50 lbs tests results, so their own 30 lbs results wouldn`t be comparable with other 50 lbs results. Btw it`s interesting to note that the NACA test takes notes that the pilot was unable to effect more than 40 lbs force on the stick, making the RAE results at 50 lbs a bit hypothetical isn`t it?

[gripen]

Originally posted by Kurfürst
Gripen doesn`t like the Bf 109 too much. The greater conversion difference between IAS and TAS, the worser the Bf 109 will look like.

Actually I originally gave this data without any kind of conversion except claiming that speed is TAS and roll rate rad/s.

Originally posted by Kurfürst

Now explain us how this makes any sense, ie. how does Me 109 type specific corrections invalid for the Me 109..?

EAS is IAS cleaned from type specific corrections ie comparable with other EAS values while IAS values might not be.

Originally posted by Kurfürst
What makes it unlogical ? The Hurricane displayed exactly the same

The shape of the curve makes it unlogical. And as noted above the NACA Hurricane had been in the similar use and mainteance as NACA Spitfire.

Originally posted by Kurfürst
It`s a bit funny, becasue I remember you arguing that the relatively high values for the P-40 in test are invalid, but back then you argued the reverse way, that the 'spikes' on roll rate curves show it`s not from testing. Now you argue the exact opposite that the spikes should be there, why is that, back then you didn`t liked the P-40 rolled faster than the Spit, now you don`t like the NACA made independent tests on the Spit, too?

The P-36 and P-40 curves does not show a sign of wing twist while the later measurement with P-40 show wing twist (see P-40F curve in the NACA 868).

Originally posted by Kurfürst
Yep, the NACA test did not included 50 lbs tests results, so their own 30 lbs results wouldn`t be comparable with other 50 lbs results.

The 50 lbs curve can be easily calculated from the data given in the Spitfire report and NACA did that at least in the case of the F4F and P-39 (ie the original reports give 30 lbs curves).

Originally posted by Kurfürst
Btw it`s interesting to note that the NACA test takes notes that the pilot was unable to effect more than 40 lbs force on the stick, making the RAE results at 50 lbs a bit hypothetical isn`t it?

Feel free to use double standards if you believe that it increases your credibility.

gripen

[Knegel]

Hi,

If i dont look wrong the Spitfire have a max aleron deflection on 160mph in the picture, with 30 lb!



Even 140-150lb is not close to as tested by RAAF!!! 100-110mph to 140-150mph, thats a lost of minimum 30-50mph!! To explain this with a loose linkage cant fit. Look to the 'initial roll curve' , there we would see this 'loose' linkage, in form of a big delay in the beginning, but there isnt a delay!

With "something wrong in the aileron linkage" you get close to it, cause wrong or messed up is the leverage setting to alerons.

Here again what the Hurri II test say to this phenomen:
"It is interesting to to note that the force requiered to attach the rolling velocity of 0,6 or 0,8 radian per sec decreased as the speed was increased from 100 to 200miles per hour. This unusual condition results from the rapid increase of stickforce near maximum deflection"

If the leverage setting now got adjusted to provide a smaler 'max aleron deflection', the max stickvariation can get reached on higher speeds and the "flat curve effect" get minimized(smaler aleronvariation = smaler rapid increase of stickforce near maximum deflection and more max force at higher speed on the alerons, due to the longer leverage).

Iam still sure the leverage did change from the early SpitfireVa to later models! If the lincage would be loose, the rollratio would be less good all over, but the SpitVa show similar values at 320mph like the later Spit.

Actually i only wanna explain why the later Spit´s rolled faster!


Greetings, Knegel

[Knegel]

btw, the german test is given in TAS, therfor IAS = EAS!!
TAS dont need any correction!

[gripen]

Originally posted by Knegel

If i dont look wrong the Spitfire have a max aleron deflection on 160mph in the picture, with 30 lb!

Ah, that look's something like 160 mph, I did just a quick look an it looked like a bit over 150 mph IAS.

It's still quite close aproximated value for the RAE tested plane and it actually indicates that the slope of the force curve did not increase progressively. At 400 mph IAS the values (30 and 50 lbs) are almost linear as well as shape of the curve is almost linear.

Originally posted by Knegel
Look to the 'initial roll curve' , there we would see this 'loose' linkage, in form of a big delay in the beginning, but there isnt a delay!

Actually I wrote above that at 100 mph IAS the curves are quite similar and the loosenes start to show above that ie the tension of the cables might be wrong.

Originally posted by Knegel
With "something wrong in the aileron linkage" you get close to it, cause wrong or messed up is the leverage setting to alerons.

I wonder how many times it should be pointed out: There is no difference in leverage between these planes, AFAIK stick geometry and aileron movements were same in all production Spitfire Vs.

gripen

[gripen]

Originally posted by Knegel
btw, the german test is given in TAS, therfor IAS = EAS!!
TAS dont need any correction!

That's what you and me did, but I don't know from where the value Mr. Kurfürst used came from ie if it contains type specific corrections.

Still we don't know the conditions the TAS was measured.

gripen

[Kurfürst]

Originally posted by gripen
Actually I originally gave this data without any kind of conversion except claiming that speed is TAS and roll rate rad/s.

[/B]

Oh yeah - you were constantly arguing that the IAS conversion from Rechlin should not be used, and your rought 20% conversion is correct, which of course would yield worser numbers.

The shape of the curve makes it unlogical. And as noted above the NACA Hurricane had been in the similar use and mainteance as NACA Spitfire.

[/B]

Nope, there is no such thing about use and maintaince in the NACA report, it was made up you, and also the worn Spitfire theory was made up on this board.

The P-36 and P-40 curves does not show a sign of wing twist while the later measurement with P-40 show wing twist (see P-40F curve in the NACA 868).

[/B]

Funny, the NACA 866 P-40F curve which now you claim to include wingtwist, is exactly the same shape as the NACA`s previous trials.

That`s means the RAE Spitfire tests do not included the effects of wingtwist, while the NACAs do, hence the difference, as was suspected before.

The 50 lbs curve can be easily calculated from the data given in the Spitfire report and NACA did that at least in the case of the F4F and P-39 (ie the original reports give 30 lbs curves). )

[/B]

That`s merely your claim, nothing supports it.


 

Feel free to use double standards if you believe that it increases your credibility.

gripen [/B]

Only you apply double standards here.

[gripen]

Originally posted by Kurfürst

Oh yeah - you were constantly arguing that the IAS conversion from Rechlin should not be used, and your rought 20% conversion is correct, which of course would yield worser numbers.

Feel free to use what ever conversion factor you ever like to use but the factor you now use might contain type specific  stuff.

Originally posted by Kurfürst
Nope, there is no such thing about use and maintaince in the NACA report, it was made up you, and also the worn Spitfire theory was made up on this board.

The evidence is in the curves which show unlogical shape and it's know that the planes spent long time in the Wright Field before NACA.

Originally posted by Kurfürst
Funny, the NACA 866 P-40F curve which now you claim to include wingtwist, is exactly the same shape as the NACA`s previous trials.

Feel free to compare. Early measurement from Spitfire, Hurricane, P-36 and P-40 comparison:



The P-40F measurement:

Originally posted by Kurfürst
That`s means the RAE Spitfire tests do not included the effects of wingtwist, while the NACAs do, hence the difference, as was suspected before.

Actually, as pointed above, the RAE tests certainly contain wing twist:

Originally posted by Kurfürst
That`s merely your claim, nothing supports it.

Just check the corresponding reports.

Originally posted by Kurfürst
Only you apply double standards here.

Well, IMHO planes should be compared with similar stick force limits. Apparently you disagree.

gripen

[Knegel]

Hi gripen,

"It's still quite close aproximated value for the RAE tested plane and it actually indicates that the slope of the force curve did not increase progressively. At 400 mph IAS the values (30 and 50 lbs) are almost linear as well as shape of the curve is almost linear."

If you realy think that 50mph are a close aproximated value for the RAE tested plane, we also can assume that a other Bf109F2 have the same curve like the 109F2 at 50mph higher speeds, but thats rubbish. The late Spit show a 50% greater speed of max stick deflection, thats far outside of close!
Sure are the curves at 400mph almost linear, cause the aleron deflection is very smal! Dont we talk about the somewhat strange results between 110mph and 220mph of the SpitVa and HurriII??

"Actually I wrote above that at 100 mph IAS the curves are quite similar and the loosenes start to show above that ie the tension of the cables might be wrong."
The "stickforce / aleron deflection" tests are made at 108mph, 190mph and 295mph. And, yes, the tension of the cables is wrong, but what cause a different in the tension?? The leverage!!
If the cables of the old SpitVa would be loose, the speed of max stickdeflection would be higher than that of the later Spit (dont mix it up with max aleron deflection, did it myself several times)!!

"AFAIK........................ .."
Yes, thats it! I would say the testresults show that the leverage did change.

Actually i dont know exact what they did change, but the tests obvious show a significant different in leverage force from the handgrip to the alrons. Actually i call it strange, if the leverage wasnt adjustable somehow!

Geetings, Knegel

[Kurfürst]

Originally posted by gripen
Feel free to use what ever conversion factor you ever like to use but the factor you now use might contain type specific  stuff.

I feel free as it`s certainly to better than guessing the atmospheric or standard conditions which could significantly vary, or using "roughly 20%" which is just about useless if you want accurate results.

Originally posted by gripen
The evidence is in the curves which show unlogical shape and it's know that the planes spent long time in the Wright Field before NACA.

[/B]

What evidence are you talking about? Your own posts prove your own posts?

Originally posted by gripen

Feel free to compare. Early measurement from Spitfire, Hurricane, P-36 and P-40 comparison:



The P-40F measurement:

[/B]

It looks like the later P40F measurement has very similiar results as the NACA`s own Spitfire measurement, the curve is very similiar. And you say the early P-40 test didn`t have wing torsion added.

The only conclusion that can be derived that the RAE Spitfire/190 test doesn`t show wing torsion effects, just like the early NACA P-40 report - the similiarity in curve shape is striking.

Originally posted by gripen
Actually, as pointed above, the RAE tests certainly contain wing twist:

[/B]

Where does it say that? Can you qoute the line? For again I can see you claim a document saying something, but when I look at the document it doesn`t say anything what you claim. This happens quite often.

Now, considering the later NACA P-40F tests include wing torsion effects, and are very similiar to NACA Spit tests, we can conclude the RAE tests which are rather dissimilar to either do not include wing torsion.

Probably that`s why the RAE tests show abnormally high values, and in conflict with both the NACA`s test results, and in fact even other RAE test results :

Just check the corresponding reports. [/B]

Ok, until then there is agreement that gripen claimed something, and then couldn`t back it up.

 

Well, IMHO planes should be compared with similar stick force limits. Apparently you disagree.

gripen [/B]

Appearantly you have reading comprehension problems gripen for I said the RAE roll rates of the Spit are a bit hypotethical, considering they show performance at a stickforce that according to the NACA was not possilbe to be used in the Spit cocpit (50 vs. 40lbs usable) :

To qoute myself :
"Btw it`s interesting to note that the NACA test takes notes that the pilot was unable to effect more than 40 lbs force on the stick, making the RAE results at 50 lbs a bit hypothetical isn`t it? "

I wonder how can one deduct that I suggest planes should not be compared with similiar stick limits. I said the RAE results are hypothetical, given they are both using stick forces above real values, and they don`t take into account the wing twist of the aircraft, hence their values are higher than any other test, by far.

[gripen]

Originally posted by Kurfürst
I feel free as it`s certainly to better than guessing the atmospheric or standard conditions which could significantly vary, or using "roughly 20%" which is just about useless if you want accurate results.

We have no idea about the conditions the DVL data was measured, only the temperature can be derived from the mach number. Basicly there is no way to give more than rough estimates without knowing the exact conditions of the original test.

Originally posted by Kurfürst
What evidence are you talking about? Your own posts prove your own posts?

The curves show unlogical shape which is not supported by other measurements:



In addition even NACA choosed to use RAE data in their later works.

Originally posted by Kurfürst
It looks like the later P40F measurement has very similiar results as the NACA`s own Spitfire measurement, the curve is very similiar. And you say the early P-40 test didn`t have wing torsion added.

The early measurement shows linear curve up 280 mph IAS where the stick force limit is reached ie no sign of wing twist. Later measurements show wing twist above 200 mph IAS ie the curve start to bend downwards.

Apparently you can't read the graphs.

Originally posted by Kurfürst
The only conclusion that can be derived that the RAE Spitfire/190 test doesn`t show wing torsion effects, just like the early NACA P-40 report - the similiarity in curve shape is striking.

Here we have further evidence that you can't read the graphs, RAE curves show clearly wing twist as well as data in the report gives the aileron reversal speed.

Originally posted by Kurfürst
Ok, until then there is agreement that gripen claimed something, and then couldn`t back it up.

F4F report can found from PRO as DSIR 23/12325 and P-39 report from here.

Originally posted by Kurfürst
Appearantly you have reading comprehension problems gripen for I said the RAE roll rates of the Spit are a bit hypotethical, considering they show performance at a stickforce that according to the NACA was not possilbe to be used in the Spit cocpit (50 vs. 40lbs usable) :

Well, not according to RAE and also NACA moved to 50 lbs limit later.

gripen

[gripen]

Here is the curves showing wing twist for the Fw 190 from the RAE test, all other planes in the test were tested same way.

gripen

[Kurfürst]

Originally posted by gripen
We have no idea about the conditions the DVL data was measured, only the temperature can be derived from the mach number. Basicly there is no way to give more than rough estimates without knowing the exact conditions of the original test.

[/B]

That`s true for most of the other tests as well, so?
The reason you argue about IAS/TAS conversion is because you want the actual DVL data look worser.

The curves show unlogical shape which is not supported by other measurements:

http://www.onpoi.net/ah/pics/users/852_1128467483_r5.jpg

[/B]

Well that`s merely a claim, nothing more. It is not supported by anything, and will be not, knowing gripen.

In addition even NACA choosed to use RAE data in their later works.

[/B]

That`s another unsupported claim again.

 

The early measurements shows linear curve up 280 mph IAS where the stick force limit is reached ie no sign of wing twist. Later measurements show wing twist above 200 mph IAS ie the curve start to bend downwards..

[/B]

Exactly like RAE`s curves for the Spit. Those also show a linear curve up 200 mph IAS where the stick force limit is reached ie no sign of wing twist.

Obviously, neither NACA and RAE test that exhibits the very same curve shape contains the effects of wing twists. They are a simpliefied set of data.

The case is quite clear, neither the P-36/P40 or the RAE Spit grahps include wing twist in the results.

Apparently you can't read the graphs..

[/B]

Appearantly you can`t discuss in a normal manner just froth in the mouth.

Here we have further evidence that you can't read the graphs, RAE curves show clearly wing twist as well as data in the report gives the aileron reversal speed..

[/B]

Stop frothing in the mouth, it is not very convincing except for the case that you are unable of normal discussion.

The RAE curves show the exact same thing as the NACA curves which you have already admitted that they don`t show wing twist at all. Hence why the RAE report doesn`t agrees with any other test :



The RAE clipped/nonclipped curve shows 40 deg/sec at 400mph EAS with 50 degree force, and does not include wing twist.

Actual testing also by RAE show the requirement for 40 degree/sec roll rate at 400mph, 71 lbs - 50% greater force!

The difference is due to the fact that greater for is required if you also have to overcome the wing twist, which is not included in the first RAE roll graph.

Well, not according to RAE and also NACA moved to 50 lbs limit later.

gripen [/B]

NACA says 40 lbs is the maximum a pilot could exert in a Spitfire. That makes 50 lbs curves somewhat of a suspect, and hypothetical.

Again you claim something using credible names, but actually checking those source reveals nothing what you claim from them.

In other words, you make bogus claims using credibly institutes to make up for your own lack of credibility.

[Kurfürst]

Originally posted by gripen
Here is the curves showing wing twist for the Fw 190 from the RAE test,

Actually it shows theoretical 100% rigid wing vs. measured figures on the poorest of the 3 FWs.

all other planes in the test were tested same way. [/B]

Again you claims something that is not actually told by your sources. Showing a FW 190 curve hardly proves anything else other than for the FW, now does it?

If you want to prove the Spitfire curve is similiar, why you wouldn`t  post the similiar Spitfire curve?

The answer is quite simple, you don`t have anything from the Spitfire tests, you are simply making guesses on the conditions, and as usual, taking the best case for your beloved plane, worst case for the plane you hate.

[gripen]

Originally posted by Kurfürst

That`s true for most of the other tests as well, so?

Well, no one has argued here that the data in other tests is some how exact but in the RAE data the results are  made comparable at least some degree, by giving them in EAS.

Originally posted by Kurfürst
The reason you argue about IAS/TAS conversion is because you want the actual DVL data look worser.

As pointed out above, I have given the data originally without anykind of conversion.

You are the one here to argue about the IAS/TAS conversion.

BTW in the beginning you were claiming that the DVL data is in IAS.

Originally posted by Kurfürst
Well that`s merely a claim, nothing more. It is not supported by anything, and will be not, knowing gripen.

The charts are posted above several times, any one can compare the curves.

Originally posted by Kurfürst

That`s another unsupported claim again.

The 50 lbs chart from the NACA 868 has been posted above several times even by yourself.
 

Originally posted by Kurfürst
Exactly like RAE`s curves for the Spit. Those also show a linear curve up 200 mph IAS where the stick force limit is reached ie no sign of wing twist.

The curves show start of bending and the chart in the report gives reversal speed.

Originally posted by Kurfürst
Appearantly you can`t discuss in a normal manner just froth in the mouth.

Can't you see the bending of the curve in the P-40F graph?

Above you claim that:

"Funny, the NACA 866 P-40F curve which now you claim to include wingtwist, is exactly the same shape as the NACA`s previous trials."

Originally posted by Kurfürst
Stop frothing in the mouth, it is not very convincing except for the case that you are unable of normal discussion.

Well, any one can check your discussion abilities from this thread.

Originally posted by Kurfürst
The RAE curves show the exact same thing as the NACA curves which you have already admitted that they don`t show wing twist at all.

No, RAE curves show the wing twist.

Originally posted by Kurfürst
NACA says 40 lbs is the maximum a pilot could exert in a Spitfire. That makes 50 lbs curves somewhat of a suspect, and hypothetical.

Couple years later NACA choosed RAE data on Spitfire over their own measurements and, in addition, used 50 lbs limit in their research summary.

Originally posted by Knegel
If you realy think that 50mph are a close aproximated value for the RAE tested plane, we also can assume that a other Bf109F2 have the same curve like the 109F2 at 50mph higher speeds, but thats rubbish. The late Spit show a 50% greater speed of max stick deflection, thats far outside of close!

The Spitfire V is not a late Spitfire and difference between NACA and RAE/RAAF measurements is probably caused by condition of the plane.

Originally posted by Knegel
The "stickforce / aleron deflection" tests are made at 108mph, 190mph and 295mph. And, yes, the tension of the cables is wrong, but what cause a different in the tension?? The leverage!!

Actually more simple and logical answer is out of spec tension of the cables.

Originally posted by Knegel
If the cables of the old SpitVa would be loose, the speed of max stickdeflection would be higher than that of the later Spit (dont mix it up with max aleron deflection, did it myself several times)!!

Actually that depends on geometry of the linkage.

Originally posted by Knegel
"AFAIK........................ .."
Yes, thats it! I would say the testresults show that the leverage did change.

Believe what ever you want to believe but to make others to believe it, you should have evidence. At least Morgan's and Shacklady's bible does not claim control changes.

gripen