Author Topic: The effect of 'clipping' Spitfire wings (Read 10188 times)

Kev367th · « **Reply #30 on:** June 17, 2005, 06:52:13 PM »

Few more in there also Karnak

"Clipping wings definately improve "Spitfire" in rolling"

"Definately an improvement"

Ditto comments on Dan etc and the clipped vs full wing Spits.

Kurfürst · « **Reply #31 on:** June 17, 2005, 06:58:04 PM »

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Originally posted by Karnak
Nobody in this thread has been claiming that the clipped wing Spit could stay with a 190 in the roll.

[/B]

Nobody except Nashwan perhaps.

Nashwan dismissed every document save one that shows the clipped wing Spit actually outrolls the FW 190. Nashwan claims it the sole representative data, everything else was to be dismissed.

So Nashwan has been claiming that the clipped wing Spit could stay with a 190 in the roll.

Real life Spitfire pilots disagree with him.

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There you hve two quotes from the document that you posted in which the RAF pilots clearly indicate that the clipped Spit rolls significantly better than the full Spit, but still not as well as the Fw190. In other words, exactly what is being claimed by Dan, Nashwan, Angus and others in this thread.[/B]

One of your qoutes say it`s much better when clipped.
The other say it`s better.
A third one says it`s slightly better.

They all agree it`s better, but not in how much.

The first document I posted clarifies that only planes with poor set of ailerons benefited a lot, thus easying up the contradiction.

It also says that all things weighted, clipping the wings does not worth to big some sub-standard planes to equal footing at the loss of turn rate and climb.

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I would also point out that thousands of Spitfires had clipped wings. It was not nearly so rare as you make it out to be. If it had an overall negative effect, why were thousands of them clipped? [/B]

that`s funny... snake bites it`s own tail, prime example of circular logic.

Claim : Clipped wing Spit rolls significantly better
Proof/Claim : Thousends of Spits had clipped wings
Proof : Clipped wing Spit rolls significantly better
GOTO LINE 1
Makes no sense.

Kev367th · « **Reply #32 on:** June 17, 2005, 07:01:32 PM »

What the hell are 'good' ailerons?

Sorry, but your first document clarifies NOTHING.

Mk, metal/fabric ailerons, short or normal span ailerons, etc ,etc?

At low alts (were they were designed for) the turning circle of a clipped wing Spit was almost the same as a full wing Spit (55ft difference I believe).

Kurfürst · « **Reply #33 on:** June 17, 2005, 07:02:15 PM »

I see the RAF guys run out of breath.
How typical.

Karnak · « **Reply #34 on:** June 17, 2005, 07:04:18 PM »

Kurfurst,

It isn't worth posting to you. You see nothing but what you want to see and ignore all else.

It isn't a debate when all we are is a hostile audience for you to rant at.

Kurfürst · « **Reply #35 on:** June 17, 2005, 07:05:26 PM »

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Originally posted by Kev367th
What the hell are 'good' ailerons?

Sorry, but your first document clarifies NOTHING.

Mk, metal/fabric ailerons, short or normal span ailerons, etc ,etc?

Perhaps read the first page of the doc in my 2nd post.

As for 'good' Spitfire ailerons :

"...........4.21 Controls and general flying. The type of fin and rudder incorporated in this aircraft caused a decrease in the change of directional trim with speed compared with JF.319. Rudder forces were of a similar magnitude. The ailerons, despite an absence of reflexing, were noticeably heavier. Variations in the weight of ailerons on Spitfire aircraft are common and are due to manufacturing differences between individual sets. This aircraft presumably had an inferior pair of ailerons; it is desirable that such ailerons should be rejected during production testing. "

Bull***** -(tm)Guppy- from Boscombe Down, Nov 1943
http://www.spitfireperformance.com/rb141handling.html

Kurfürst · « **Reply #36 on:** June 17, 2005, 07:07:46 PM »

Quote

Originally posted by Karnak
Kurfurst,

It isn't worth posting to you. You see nothing but what you want to see and ignore all else. It isn't a debate when all we are is a hostile audience for you to rant at.

Realizes he isn`t up to it, tongue-in-cheek, exit left.

thrila · « **Reply #37 on:** June 17, 2005, 07:08:28 PM »

Kurfurst why are your posts always so hyper-aggressive?

Kurfürst · « **Reply #38 on:** June 17, 2005, 07:10:03 PM »

Why is that you never even remotely consider that I could be right in it and instead you get things personal rather of thinking it over ?

Kev367th · « **Reply #39 on:** June 17, 2005, 07:11:25 PM »

Fair enough it mentions the Mk...

Wheres the rest?

Kurfürst · « **Reply #40 on:** June 17, 2005, 07:14:05 PM »

I wanted to post the whole thing but my onpoi is full.

Can post you the whole thing, if you are interested.

Crumpp · « **Reply #41 on:** June 17, 2005, 07:27:53 PM »

Interesting discussion.

Maybe I can shed some light on what maybe going on between these reports.

On one hand we have "measured" roll rates. The only allied report to actually measure an FW-190's roll rate is RAE 1231. The NACA copied this curve when they did their report quoted earlier in this thread.

The discrepancy between pilots comments fighting in the air with clipped wing spitfires vs. the measured results is not due too the Spitfires measured roll rate being off but rather the FW-190's the RAE tested.

The ailerons were out of adjustment. Not surprising as the Luftwaffe had a hard time keeping them adjusted in the Geschwaders. It is unrealistic to expect the allies to know it's importance or how to do it.

This chart comes from RAE 1231:

Here is the measured rate of roll vs rigid wing:

The measured results should be closer to the ridgid wing. How much is debatable. However I encourage those interested to exam the wing construction of both the FW-190 and the Spitfire.

The FW-190's ailerons were difficult to keep adjusted. It is a constant and reoccurring theme in FW-190 maintenance and the adjustment regulation is 13 pages long.

One of the pilot checks for aileron adjustment is stick forces. The FW-190 had very light stick forces when properly adjusted.

The stick forces as measured in RAE 1231:

The stick force tolerances for a properly adjusted FW-190:

Focke Wulf factors frise aileron force variations into these tolerances.

This was even noticed by the RAE test pilot who flew the FW-190:

Who simply chalk it up to natural Frise variation. Not surprising, as they did not know the importance of proper aileron adjustment to FW-190 performance much less have a copy of the aileron adjustment regulations nor a maintenance crew trained on the type.

Here is the ADM 45 standard as measured in RAE 1231. The FW-190 should be much closer to its calculated rate:

Now this issue is further complicated by the fact the FW-190 could mount three different ailerons. The hinging and internal structure was changed. According to Oscar Boesch, each type gave slightly different performance based on altitude and speed.

Hope this helps to gain some insight!

All the best,

Crumpp

Kev367th · « **Reply #42 on:** June 17, 2005, 07:29:23 PM »

Don't need the whole thing, just the aircraft configuration.

An example -
The test lists a Mk IX with a Merlin 61, so OK this makes it an F IX.
F IX introduced hurriedly in 1942 to try and counter the 190, we already know early ones were a MK V airframe with a Merlin 61.

Document is dated Mar 1943 so can we draw any conclusions -
a) We know already that during 1943 produciton switched to the L.F IX with a Merlin 66.
b) Is it possible that the Mk IX aircraft in the test therefore is nothing but an old Spit V airframe with a Merlin 61?
c) "Old" = tired airframes etc, poor control response etc.
d) Clipped wings were primarily for low alts, something the F IX wasn't designed for.
e) The purpose of clipping the wings was to improve roll, and it did. (as shown in Crumps graphs, Tks Crump)

In fact in Crumps graph the Spit V with normal wings can't roll with a 190 at any speed. A clipped wing Spit V outrolls a 190 up to approx 215mph.
At 325mph and over with a clipped wing its close, but again the Spit V with a normal wing can't get anywhere near.

Which PROVES what we're saying, a clipped wing Spit rolled better than a standard wing Spit.

Nashwan · « **Reply #43 on:** June 17, 2005, 07:55:24 PM »

Isegrim, I'll keep it brief, because you are simply repeating most of the stuff.

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Hmm, it`s seems you dismiss the opinion of the NACA, RAAF, Boscombe down and RAF pilots.

Me extrapolating?

No, I have posted the only test I know of that shows the Spitfire roll at 50 lbs stick force.

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Which Nashwan refuses to post in it`s complete form. Why?

Why? Because it is a 12 page report on the Fw 190, which has a comparison with some other fighters. Posting a page showing a drawing of the 190 wing layout would be a waste of everyone's time and bandwidth.

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Of course you didn`t, you only had a part of it back then. Fascinating story.

OK. I deliberately held back the part that says it's tested rather than calculated, because, why exactly? Because I didn't want you to know it was tested? Don't be silly, that's what I've been arguing all along.

In fact, if you do a search on the forum, I have said before that it was tested, because I had notes, just not the scans.

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Would this be a detailed and professional NACA evaluation two spitdweebs dismiss like many others with a claim they don`t even have source for?

I think Dan provided a source. It was, iirc, from Tuck's (auto?)biography.

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Well OK, Nashwan, here`s a simple question then :

Who to believe, RAE`s single, suspicious shaped curve which claims very high roll rates for a Spitfire (aircraft details unknown) and which is in disagreement with many other tests,

Why is it "suspicious"? Because it shows a peak, like the vast majority of aircraft did, and the Aussie report shows the Spitfire did?

And what other tests is it in disagreement with? Please, lists the tests that disagree with it. All the other tests of Spitfires at 50 lbs stick force you know.

When you've done that, we can have a basis of comparison as to whch tests are most representitive, if they are different.

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Nobody in this thread has been claiming that the clipped wing Spit could stay with a 190 in the roll.

Nobody except Nashwan perhaps.

I'm not. The 190 is clearly better across the vast majority of the roll range.

Crumpp · « **Reply #44 on:** June 17, 2005, 08:33:32 PM »

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In fact in Crumps graph the Spit V with normal wings can't roll with a 190 at any speed. A clipped wing Spit V outrolls a 190 up to approx 215mph.

Hello Kev,

I don't know if your read my post throughly.

It is a fact that the FW-190 the RAE tested is clearly on the lower end of the roll rate capability of a FW-190A fighter. It represents one that is out of adjustment.

That curve should be higher for the FW-190 which would correspond then with the clipped wing spit pilots comments on air combat experience. The clipped wing spit most likely came close at speeds below 220mph but I highly doubt it outrolled a properly serviced FW-190A.

Several things would combine to make this an improbability.

1. Construction of the Spitfire wing: Multipiece wingspar vs solid.

2. Aileron size/effectiveness.

3. Control cables vs Solid control rods.

With that said. Even the Luftwaffe had a hard time keeping the ailerons on the FW-190A properly adjusted.

All the best,

Crumpp