Spitfires and High Speed Roll Rate

[RTHolmes]

(who isnt )

[Anaxogoras]

for someone with a passion for luftwaffe planes this seems a little unhealthy obsession.  Is there anything you want to tell us gav.






(closet spit dweeb perhaps?)

  Bruv.  It's a long story, but I just finished testing the roll rate of our fighters at 200, 300, and 400mph and the Spitfire data stuck out like an infected toe.  I'm only bringing this to light because I want our Spitfires to perform their best when I shoot them down.

[thrila]

lol gavagai.

I would expect the VIII to be similar to the XIV because the spit14 is essentially a spit VIII, with a griffon thrown in.

[Anaxogoras]

lol gavagai.

I would expect the VIII to be similar to the XIV because the spit14 is essentially a spit VIII, with a griffon thrown in.

It seems like our IX rolls like the VIII and XIV even though in appearance it has the wing of the V.

[Angus]

I recall that the VIII had different ailerons etc to eliminate flutter and such. Bear in mind that it appeared later than the IX due to the IX being hurried in while the VIII was finished.

[Cthulhu]

AFAIK the wing flexing was somewhat a problem until the new type of wing (in Mk21?) which was more rigid although initially that had some problems too, don't recall what exactly.

Guys, just to clarify the terminology, it's not wing flexure (bending) , but torsional stiffness that affects high speed roll-rate. Once you stiffen the aileron attachment points (stiffer rear spar?) and control cable mounts (cable stretch is also an issue), the only real way to significantly increase the wing's torsional stiffness (provided the external dimensions are fixed) would be to increase the aluminum skin thickness or go to steel. No way Supermarine went to steel, and I doubt they made any significant increase in wing skin thickness.

So I think you're right to suspect there's something fishy here.

just my .02 

[Karnak]

I've never read anything that suggested the shorter ailerons on the Mk VIII or Mk XIV reduced the roll rate.

[Angus]

What Quill has on the VIII, ailerons and vs the IX:
"It also featured ailerons on which the the long overhang outboard of the outer hinge was shortened in order to increase the stiffness of the aileron structure. "
Later..
"The Mk VIII however was by far the better aeroplane"

[Bruv119]

Bruv.  It's a long story, but I just finished testing the roll rate of our fighters at 200, 300, and 400mph and the Spitfire data stuck out like an infected toe.  I'm only bringing this to light because I want our Spitfires to perform their best when I shoot them down.

If you want them rolling better you have my full support. 

 Knock yourself out trying   

[Angus]

Just read up a bit more.
They changed the aileron hinges again on the Mk 21. Piano hinges that time and a wing 47% stiffer. Resulted in much better roll rate.

[Brooke]

The only thing that matters is whether the performance in AH matches the flight-test data.

All of this arguing about what should or shouldn't be based on how big the ailerons look in the game, whether the wing is clipped or not, etc., is all just a philosphical discussion.  You can't guess the roll rate based on such things -- there are too many other things that matter.  In the end, you have to look up what the real plane actually did in flight testing and have the in-game plane match that.

[RTHolmes]

true, shame that most of the RAFs test data seems to concentrate in detail on speed/climbrate at different alts/weights/boost/gearing/props. theres barely any mention of roll rate except comments like "not much different". the only thing I found for the VIII was along the lines of "the shorter ailerons dont seem to reduce roll rate." The only rate/speed graph I found was a ?V vs 109 comparison.

[dtango]

The only thing that matters is whether the performance in AH matches the flight-test data.

All of this arguing about what should or shouldn't be based on how big the ailerons look in the game, whether the wing is clipped or not, etc., is all just a philosphical discussion.  You can't guess the roll rate based on such things -- there are too many other things that matter.  In the end, you have to look up what the real plane actually did in flight testing and have the in-game plane match that.

Thank you Brooke .

On top of Brooke's comments, rolling unfortunately does not occur in one degree-of-freedom.  Roll, yaw, and sideslip are coupled so they affect one another.  Until you can isolate all that on top of all the other variables you have to consider in just the roll axis it's kind of meaningless.

Here is some more general info regarding rolling:
http://bbs.hitechcreations.com/smf/index.php/topic,253393.msg3138691.html#msg3138691

Tango, XO
412th FS Braunco Mustangs

[RTHolmes]

... add in the fact that roll rate is like turn rate - instantanious and sustained rates are different - and its quite a hard thing to quantify. knowing the time to roll 360deg doesnt have much relation to ACM, 90deg might be a more useful measure.

[Anaxogoras]

The only thing that matters is whether the performance in AH matches the flight-test data.

All of this arguing about what should or shouldn't be based on how big the ailerons look in the game, whether the wing is clipped or not, etc., is all just a philosphical discussion.  You can't guess the roll rate based on such things -- there are too many other things that matter.  In the end, you have to look up what the real plane actually did in flight testing and have the in-game plane match that.

Naturally, but if test data said that the IX rolled far worse than the V at 400mph, would you believe it?  I hope not.  It's a better explanation that the test data was flawed than that the same airframe yielded far different results depending its designation.  That the latter explanation is absurd is known a priori.