Spitfire Mk 21 redesigned wing.

[spicmart]

"Redesigned late wing
As the Spitfire gained more power and was able to fly at greater speeds the risk of aileron reversal was increasing so the Supermarine design team set about redesigning the wings to counter this possibility. The original wing design had a theoretical aileron-reversal speed of 580 mph (930 km/h), which was somewhat lower than that of some contemporary fighters.[8] The new wing of the Spitfire F Mk 21 and its successors was designed to help alleviate this problem; the wing's stiffness was increased by 47 per cent and a new design of aileron using piano hinges and geared trim tabs meant the theoretical aileron-reversal speed was increased to 825 mph (1,328 km/h).[8][9][10] This wing entered service on the Spitfire XXI. The standard armament was now four 20mm Hispano IIs or the shorter, lighter Hispano V cannons, each with 150 rounds per gun."

This is from Wikipedia (I know). So would that mean that this Spitfire wing had surpassed all other WW2 fighter wing designs in stiffness?
Taken these numbers it must have given the Spit a tremendous advantage at roll rate and in a dive recovery.
Has anybody the stiffness/aileron reverse rates of other fighters?

 

[T. A. Gardner]

On load factors, you might consider that North American redesigned the P-51 in the F model to be a "lightweight" fighter for British use and did so by lowering the American standards they were building the D to to British load factors. That is, they reduced the weight of the F by using British instead of US load factors and in doing so reduced the weight of the plane by nearly 1500 lbs.

North American's Lightweight Mustangs (P-51H/P-51M/P-51L)

 

[Calum Douglas]

"Redesigned late wing
As the Spitfire gained more power and was able to fly at greater speeds the risk of aileron reversal was increasing so the Supermarine design team set about redesigning the wings to counter this possibility. The original wing design had a theoretical aileron-reversal speed of 580 mph (930 km/h), which was somewhat lower than that of some contemporary fighters.[8] The new wing of the Spitfire F Mk 21 and its successors was designed to help alleviate this problem; the wing's stiffness was increased by 47 per cent and a new design of aileron using piano hinges and geared trim tabs meant the theoretical aileron-reversal speed was increased to 825 mph (1,328 km/h).[8][9][10] This wing entered service on the Spitfire XXI. The standard armament was now four 20mm Hispano IIs or the shorter, lighter Hispano V cannons, each with 150 rounds per gun."

This is from Wikipedia (I know). So would that mean that this Spitfire wing had surpassed all other WW2 fighter wing designs in stiffness?
Taken these numbers it must have given the Spit a tremendous advantage at roll rate and in a dive recovery.
Has anybody the stiffness/aileron reverse rates of other fighters?

I have a few papers relating to the Mk XXI wing. I paste below some snippets which you may find of anecdotal value.

Keep in mind that the intial Mk XXI wing was supposed to be laminar, but that had to be ditched as of course narrowing the leading
edges meant having to move the main wing spar backwards, which was judged an unnaceptable production compromise. So the XXI wing actually used was not that first envisaged.

The new wing apparently had unnaceptable pilots view, and there is much discussion on this.

You can find all this (i.e my comments above and the images below) in AVIA-46/119 at Kew.

 

[spicmart]

Thanks Calum.

May I write if or not I'm understanding the pages you posted as I am no native English speaker and technical English can a bit difficult to understand? I hope that is okay for you.

What does "severe" standard in this case mean?

What are "bank requirements"?

What version/plane of the Fw 190 series were they testing?
Afaik one or some of the A-versions had defective or not properly aligned ailerons which then showed distorted test results.
The only realm the Mustang was superior in roll rate was when going fast (over 350 mph?) otherwise the Mustang rolled slower.
What does a "heavy" Fw 190 mean?

So the firm was working to best the Fw 190's rate of roll by 40 to 60 %?
What is the specified figure which was better than the 190's: 90° in 1 sec or 45° in 0.5 sec?
Which is the" latter" performance which was approached by the 190?

And did they finally manage the goal of a Spitfire which could (decisively) outroll the Fw 190"

Regards, Huy

 

[T. A. Gardner]

If that was the goal, wouldn't it have been easier to do what Lockheed did and simply power the ailerons?

 

[riggerrob]

If that was the goal, wouldn't it have been easier to do what Lockheed did and simply power the ailerons?

Powered controls were only in an early stage of development during World War 2. Powered controls were not widely used until well into the jet age.

 

[Calum Douglas]

If that was the goal, wouldn't it have been easier to do what Lockheed did and simply power the ailerons?

I suspect because if the wing is insufficiently torsionally rigid, it is irrelevant how much power you put into the ailerons,
although that is just a generic point on wing design, and not something from archive papers I have on this
aircraft - I admit.

 

[perttime]

Apparently, "aileron reversal" was the issue. It means that, when you deflect the ailerons at high speed, the whole wing twists in the opposite direction, and you start, rolling in the wrong direction.

 

[HoHun]

Hi,

Apparently, "aileron reversal" was the issue. It means that, when you deflect the ailerons at high speed, the whole wing twists in the opposite direction, and you start, rolling in the wrong direction.

Mike Crosley's "They gave me a Seafire" confirms this, and describes the serious and sometimes lethal consequences of wings twisting at high speeds. Great book for the technically minded, by the way.

Regards,

Henning (HoHun)