The Gardner 6lw was a fair way down the power to weight ratio scale, producing something like 102 bhp, but revving to only about 1800rpm, at least it didn’t need a reduction gear….. they did produce an 8 cyl (8lw) but pilots complained the nose was too long, and visibility was restricted.

To Stuart Gowans,

I think you made a small error. 😉

First you use a thorough investigation as proof that they knew what there were doing at Supermarine and then it seams that this investigation was done after the last Spitfire left the building. I have never met a designer who started to make calculations when the product is already flying around. So if this investigation was made by Supermarine afterwards they must already have know that the elliptical wing was probably a poor choice.

Then you use this investigation that concludes that there wasn’t a significant differance between the elliptical Spitfire wing or a trapered wing to proof again that they knew what they were doing.

So if the design department of Supermarine knew what they were doing then they knew that aerodynamics gains would minimal ( your qoute doesn’t say by the way which design is 1% better ) why in the hell would you go for elliptical wing platform which is very difficult to produce ?

My conclusion : If they knew what they were doing there can only be 2 reasons for an elliptical wing – space requirements or estetics

Then a small afterthought. An elliptical wing I can understand but an all elliptical tail section must have been pure estetics and has nothing to do with common sense

Cheers, Pim 🙂

Well you got the first bit right, I made an error in responding to Joglo’s first post…….

There must be a language barrier between us Pim, as I thought that what I had posted was fairly straight forward, but to reiterate; the investigation into the Spitfire wing was carried out (as far as I am aware) independantly from Supermarine some years after.

Whilst I can’t (and don’t) speak for Reginald Mitchell, if I were designing something that had two options, one of which was asthetically more pleasing, I know which one I’d go for, irrespective of cost or manufacturing issues.

Tony, is this really “willy waving”, is this a defence of a dead mans reputation, or is it merely an attempt to stop internet revisionist theorys from propagating to the point where the truth is lost?

Ross, sorry for the thread hijack; I’ll be off now.

Clearly the design staff at Supermarine didn’t understand the basic idea behind the elliptical shaped wing . The Aerodynamic goal is to achieve an elliptical lift profile, this is quit different than an elliptical wing. The easiest way to achieve this is to use an elliptical wing platform and to use only 1 airfoil for the whole wing with a constant incidence.

For a better explanation see : http://courses.ae.uiuc.edu/AE440-A/files/Aerodynamics_Overview.pdf

If you then use 2 different airfoils ( spitfire naca2213 – naca2208 ) and you apply washout then you kill the whole idea behind it. 😮

The designers at Republic knew the basic idea , because they used for the P47 an elliptical wing, 1 airfoil and no washout.

With a trapezium shaped wing it is possible to come close to an elliptical lift profile by carefully choosing the taper , the inboard and outboard airfoil and washout or washin.

To the defense of the Supermarine design staff , I must say that probably the elliptical lift profile was classified German information. They saw an elliptical wing with good characteristics and thought probably that the shape was the secret of success. If they knew the aerodynamic principle behind it then clearly the shape of the Spitfire was a result of putting all the stuff in a minimum thickness wing.

I ( as an design engineer myself ) think the truth is somewhere in the middle. As an engineer you constantly look to the competition for inspiration, but afterwards you cannot speak of an eureka moment in your own design.

Cheers Pim

Quoting from the one book that will surely feature on Joglo’s christmas list; Spitfire the history, “an aerodynamicist has calculated that to arrive at an accurate total weight, each rib, spar, etc, must have been investigated and the whole assessed for aerodynamic performance; after all this effort by the drawing office, it was estimated that the aerodynamic performance difference between the straight taper and elliptical wing, was less than 1% at high speeds”.

If “the design staff at Supermarine didn’t understand the basic idea behind the elliptical shaped wing” they put a hell of a lot of effort into not understanding it……

To join with Chumpy in broadening the topic I can add that in late 1927 R.J. was accused by elements of the Italian and French press of having copied Macchi’s M39 design with his S5. The basis being, similar to the current Spitfire wing debate, that the S5 was very different from his previous designs and shared general layout with the M39. There are a succession of editorials and letters in both Flight and Aeroplane relating to this.

Cheers

Ralph

How much of a difference was there between the S4 and the S5 then?

The S4 had an unbraced cantilever wing, the S5 wing was braced, because of concerns regarding wing flutter; subsequently this has been investigated at length, and the suggested cause of the accident was a stall induced by aileron flutter, the latter being something that Mitchell and his team put huge effort into avoiding on the Spitfire.

This one won’t go away will it?

On page 10 of Spitfire the history it shows Mitchell’s proposed alteration of the type 224’s wing, which is strangely elliptical, and with much less of a pronounced gull will section.

I attempt, (for the third time) to draw attention to the six engine flying boat of 1929 (designed by Mitchell) to comply with air ministry specification20/28, this design of flying boat had, not only an elliptical wing, but also, the mainspar arrangement that Mitchell carried through to the spitfire; that is most significant, as apart from being absolutely integral (no pun intended) to the Spitfire wing, it could not have been copied from the He70.

There were also two Vickers types (037/34 and f9/35) of 1936, both with an elliptical wing.

Mitchell’s last design, the four engined bomber, designed to the specification B.12/36 had a strangely swept wing, but he probably nicked that idea from the Germans as well…….

Link doesn’t work, 404 not found.

It’s always good to remember that Mitchell had the benefit of viewing the HE-70 at Derby and at the very least being able to study photos of it before he came up with the same elliptical wing idea, something that had never featured on any of his previous designs.
In fact the type 300, was basically a scaled down version of the HE-70.

For some unknown reason and thankfully, no one in Germany realised the full potential of the HE-70 design.

Why are you persisting with this idea that Mitchell copied the HE-70?

Mitchell’s design for a six engined flying boat (1929) had an elliptical wing, it also had the same mainspar arrangement as the Spitfire.

As a designer the easy bit is the basic shape, the internal structure of (for example) the wing, that allows for retracted U/C, radiators Guns and amunition boxes is something quite different.

I’ll be at home, my thoughts, elsewhere.

Spare a thought, not just for those who died, but for those who survived,but part of whom did die (like a friend of mine who, working as a Merchant seaman, was torpedoed, and as a result, has spent nearly seventy years unable to be in a dark room, or to sleep with the curtains closed).

I would desperately like to believe that more people “remember” now, but it’s not my experience; my wife returned home from work yesterday, and said that she was the only one wearing a poppy; (she’s a nurse) not even the doctors (the insultants don’t work weekends obviously) I don’t believe it was a biosecurity issue either…..

One for “Golden Arrow” and one for “Miss England” . I wonder if one of the two gave slightly more power than the other and was switched for that reason. That might mean one of them took both the land and water speed records?

Thanks for the link to Flight – I notice in the text at least another “E. ” number. Yes I agree with your suggestion about “Series 2”.

Stuart – thanks for the confirmation the Shelley engine is a Mk.V. Are you able to confirm the engine no. as 50108? any other numbers/markings on it? Is it Michael Shelley’s intention to keep up the collection and is “Billericay” a correct location?

Roger Smith.

Roger,I will try and visit again, to confirm engine no.; Billericay is indeed the correct location, and Michael will continue to look after his engines, (which number about 20!) the Napier has pride of place in the display window.

Interestingly, when in conversation with Michael, I mentioned the display of crashed Merlin bits, that was in the newsagents window (almost opposite his Garage), I’d always assumed they were from his collection, but was surprised to discover that, not only were they not his, but that he had no recollection of them ever being there.

I should point out that this was 30 years ago, clearly one of us is wrong, and whilst Michael is advancing in years, my only purpose in visiting the high st (at that time), was of an alcoholic nature….