# Elliptical Wings (1 Viewer)



## GrauGeist (Aug 18, 2013)

I've always been curious about the advantages of the elliptical wing on certain fighter aircraft over the Moderate or High Taper wings.

How well would the Spitfire performed, for example, if it had been given a different wing planform.

This of course, could be asked of the P-47 as well.

Only three fighter aircraft of WWII had the Elliptical wing, the Spitfire, the P-47 and the He280 which all had excellent handling characteristics for thier designs.


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## fastmongrel (Aug 18, 2013)

Dont forget the Hawker Tempest


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## GrauGeist (Aug 18, 2013)

Ahh right, the Tempest as well!

Didn't they change the Typhoon's wing to the elliptical design to accomodate the armament more than flight performance when it became the Tempest?

I will admit that I am not all that well versed in British aircraft :/


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## swampyankee (Aug 18, 2013)

An elliptical lift distribution provides the least amount of induced drag for a given span; the easiest way to produce an elliptical lift distribution is to have an elliptical planform and no twist. Usually, designers do not use elliptical planforms as the difficulty in manufacture is not worth the small reduction in induced drag: careful selection of taper and twist will get quite close to an elliptical lift distribution, at least in a range of lift coefficients. Incidentally, the wing on the Spitfire has an elliptical planform but it also has washout, so it does not have an elliptical lift distribution. The reason for the elliptical wing is to provide more internal volume outboard, to accommodate landing gear and armament.

There were many ww2-era fighters with excellent handling that did not have elliptical planforms, _e.g._, the Hellcat, P-36, P-40, and Hurricane.

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## drgondog (Aug 18, 2013)

swampyankee said:


> An elliptical lift distribution provides the least amount of induced drag for a given span; the easiest way to produce an elliptical lift distribution is to have an elliptical planform and no twist. Usually, designers do not use elliptical planforms as the difficulty in manufacture is not worth the small reduction in induced drag: careful selection of taper and twist will get quite close to an elliptical lift distribution, at least in a range of lift coefficients. Incidentally, the wing on the Spitfire has an elliptical planform but it also has washout, so it does not have an elliptical lift distribution. The reason for the elliptical wing is to provide more internal volume outboard, to accommodate landing gear and armament.
> 
> There were many ww2-era fighters with excellent handling that did not have elliptical planforms, _e.g._, the Hellcat, P-36, P-40, and Hurricane.



True - The elliptical wing planform provides minimum Induced Drag for a given span over trapezoidal/tapered wing - as you noted.

All so called elliptical wings, by necessity for low speed performance handling qualities, required LE twist to provide aileron authority as the inboard sections stalled out at high CL, but the twist only changed the shape of the elliptical like lift distribution to a small degree - and less than a trapezoidal wing planform. 

Curiously the FW 190 wing had LE Twist from root to 80% semi span - then zero twist thereafter which is the dominant suspected reason for such nasty high speed stall behavior... as the 'up wing' (Higher relative AoA and higher drag side) stalled first.

The Spitfire wing is The classic example of large chord/thin section ratio which was more optimal for critical delay of onset mach characteristics at high speed - yet provided a sufficiently deep inner chord height to allow wheel and armament internally. The Mustang had a fatter wing but the NACA 45-100 airfoil had its max T/C at approximately 45% of chord (versus 24% for the Spit IIRC), making the velocity gradient smaller and achieving almost the same benefit in onset mach divergence/drag rise.

Offhand - There is no reason that I can think of where handling qualities improve in favor of an elliptical wing as wing stiffness, aileron size and controls design are entirely independent of wing planform whereas reduction in induced drag affects performance only where CL/CDmax is crucial and meaningful?

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## GrauGeist (Aug 18, 2013)

Ok, stupid question here...

Actually two:
1) suppose the Spitfire was designed with a Moderate Taper wing, how would this have effected it's performance?

2) would the Elliptical wing have been a benefit to the P-51 or a hinderance?


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## drgondog (Aug 18, 2013)

A Mustang with the Spitfire wing and span would have had as much drag (nearly-except for radiator) as the Spit... not worth consider not only for drag reasons but also wing volume for fuel

Remember, with same engine the Mustang was 30 mph faster while carrying 1000+ pounds more weight - and the wing parasite drag comparisons dominate.

The Spit with a Trapezoidal wing?

1. The T/C ratio has to be enough to permit the gear and guns to be installed - doable with say, a Mustang plan form. If the same area is desired it seems that the trapezoidal wing must have a similar root dimension to maintain the same T/C ratio - suggesting that the span of the wing must be a little shorter to permit a .2 to .3 taper for tip chord to maintain same equivalent area. That implies smaller Aspect Ratio creating more induced drag.

Thus - if same airfoil, with same T/C, and same area with less AR - the only design performance impact would seem to be slightly more Induced drag for the trapezoidal wing. If you put a Mustang wing with same area on the Spit you should get a.) same or slightly less climb rate, poorer turn, slightly less dive speed but b.) better speed, better roll than any Spit except for clipped wing. This Spit could go to Berlin(Lower wing Profile drag and fuel tanks in wing) and be as effective or moreso than all original Spit in air combat.


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## davebender (Aug 18, 2013)

He-112B


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## davebender (Aug 18, 2013)




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## Clayton Magnet (Aug 18, 2013)

Also the Re.2005, albiet only semi eliptical.

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## davebender (Aug 18, 2013)

I suspect that higher production cost is a significant disadvantage. 

He-112B was more expensive then Me-109. P-47 was one of the most expensive single engine aircraft produced by anyone during WWII.

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## wuzak (Aug 18, 2013)

davebender said:


> P-47 was one of the most expensive single engine aircraft produced by anyone during WWII.



Don't think that was just down to the wing Dave.

Lots of aluminium required for that beast.

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## Shortround6 (Aug 18, 2013)

davebender said:


> I suspect that higher production cost is a significant disadvantage.
> 
> He-112B was more expensive then Me-109. P-47 was one of the most expensive single engine aircraft produced by anyone during WWII.



Was that because of the elliptical or in spite of it? 

As a general rule the cost of a plane can be _estimated_ by the weight, exceptions do happen but the heaviest single engine fighter _should_ be the most expensive _IF_ everything else is the same. This is NOT a surprise. 

The P-47 used one of the largest, most expensive engines used in a single engine plane. 

The P-47 used one of the largest, most expensive propellers used in a single engine plane. 

The P-47 used one of the most complicated armament setups of any singe engine fighter. 

The Ducting for the turbo was not easy to manufacture or install. 

The people making the wings were _NOT_ handed a pile of aluminium sheets and pairs of tinsnips and told to start making wing edge panels. Tooling was set up for production rates of hundreds of aircraft per month. With proper tooling an elliptical wing is no more difficult to make than a straight wing. And in fact, much of the rear of the elliptical shape is in the ailerons. 

See: http://www.mnbigbirds.com/images/3 Views/P47/expld.jpg

Or any decent 3 view drawing.

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## Aozora (Aug 18, 2013)

davebender said:


> I suspect that higher production cost is a significant disadvantage.
> 
> He-112B was more expensive then Me-109. P-47 was one of the most expensive single engine aircraft produced by anyone during WWII.



More than likely the He 112 was more expensive than the 109 because the 109 was mass-produced whereas the He 112 was almost hand-built in small numbers. Had Heinkel been able to mass produce the He 112 no doubt costs would have been lower. As well as that, even with the redesign of the He 112 B series, the entire structure was still more complex than that of the 109.


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## nuuumannn (Aug 18, 2013)

Although not a fighter, let's not forget the beautifully elegant He 70 Blitz.

I remember an incident when at a place I used to work at there was a P-47 that no longer flew and was on undercarriage supports. We had to move it and I was placed under one of the tailplanes and used my back to arch up and lift the back end off the tail wheel supports, but the guy under the opposite tailplane got out early, which meant I had the full weight of a P-47's back end land on my back!

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## Aozora (Aug 18, 2013)

nuuumannn said:


> Although not a fighter, let's not forget the beautifully elegant He 70 Blitz.
> 
> I remember an incident when at a place I used to work at there was a P-47 that no longer flew and was on undercarriage supports. We had to move it and I was placed under one of the tailplanes and used my back to arch up and lift the back end off the tail wheel supports, but the guy under the opposite tailplane got out early, which meant I had the full weight of a P-47's back end land on my back!



Owwww! I take it you went down with a Thud?

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## nuuumannn (Aug 18, 2013)

> Owwww! I take it you went down with a Thud?



 Yep, sure did. Ended up prostate on the hangar floor a bit winded but not too worse for wear.

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## Zipper730 (Feb 8, 2019)

It seems the only American aircraft designers that used elliptical wings that I can think of was Seversky/Republic -- at least that I can readily think of -- anybody know of any others?


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## Glider (Feb 8, 2019)

GrauGeist said:


> Ok, stupid question here...
> 
> Actually two:
> 1) suppose the Spitfire was designed with a Moderate Taper wing, how would this have effected it's performance?
> ...



The Supermarine Spiteful was effectively a Spitfire fitted with a mid chord wing and the first was simply that, a Spit XIV with the new wing. The performance was significantly increased to about 480mph, but at the cost of slightly worse handling issues around the stall. These were considered acceptable but development was basically dropped as the RAF recognised that the Jet fighter was the way forward

An aside but back in the day I used to have a share in a Discus glider and this had an elliptical wing. It was very popular as its performance was extremely good winning a number of championships, but it was a very safe design allowing inexperienced pilots to fly it without difficulty. An ideal combination

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## GrauGeist (Feb 8, 2019)

Zipper730 said:


> It seems the only American aircraft designers that used elliptical wings that I can think of was Seversky/Republic -- at least that I can readily think of -- anybody know of any others?


Technically speaking, the P-35 had a semi-elliptical wing, like the He280.

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## Graeme (Feb 9, 2019)

Zipper730 said:


> It seems the only American aircraft designers that used elliptical wings that I can think of was Seversky/Republic -- at least that I can readily think of -- anybody know of any others?



The Berliner-Joyce XF3J-1...

Berliner-Joyce XF3J - Wikipedia

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## Zipper730 (Feb 9, 2019)

Graeme said:


> The Berliner-Joyce XF3J-1


Interesting design!

It has confirmed a suspicion of mine -- we really didn't see much use in the elliptical wing.


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## GrauGeist (Feb 9, 2019)

Zipper730 said:


> Interesting design!
> 
> It has confirmed a suspicion of mine -- we really didn't see much use in the elliptical wing.


The years between WWI and WWII saw a fantastic range of wing configurations in an attempt to find the right combination for maximum performance.

It seems that the Europeans used the Elliptical or semi-elliptical in their designs more than U.S. designers. And I think that there is no coincidence that the P-35, P-43 and P-47 used that in their design, since the P-35 was designed by Alexander Kartveli, who studied aircraft design in Paris amd worked for French aircraft firms before coming to the states to work for Seversky.

Seversky became Republic, the P-47 was developed from the P-43, which in turn came from the P-35 and that was derived from the original Seversky SEV series...which had an elliptical design.

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## pbehn (Feb 9, 2019)

The powers that suggestion and language have to make people disregard what they see never fail to surprise. The Spitfire had a beautiful curved wing but it wasn't elliptical, more a combination of elliptical type curves.


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## Crimea_River (Feb 9, 2019)

More accurately described as TWO ellipses but even so, the wings don't match mathematical ellipses. From this article: ‘As British as Queen Victoria’

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## pbehn (Feb 9, 2019)

Crimea_River said:


> More accurately described as TWO ellipses but even so, the wings don't match mathematical ellipses. From this article: ‘As British as Queen Victoria’
> 
> View attachment 528786


When something looks nice you have to have a name for it.


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## Zipper730 (Feb 9, 2019)

GrauGeist said:


> It seems that the Europeans used the Elliptical or semi-elliptical in their designs more than U.S. designers. And I think that there is no coincidence that the P-35, P-43 and P-47 used that in their design, since the P-35 was designed by Alexander Kartveli, who studied aircraft design in Paris amd worked for French aircraft firms before coming to the states to work for Seversky.


I did not know that detail about Kartveli.

Other than Berliner Joyce and Seversky/Kartveli, the only other elliptical winged designs that were produced seemed to be the Arup designs, the V-173, and XF5U that I know of. I assume there was some literature in the United States that covered elliptical wings as a possibility?


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## GrauGeist (Feb 10, 2019)

Zipper730 said:


> I did not know that detail about Kartveli.
> 
> Other than Berliner Joyce and Seversky/Kartveli, the only other elliptical winged designs that were produced seemed to be the Arup designs, the V-173, and XF5U that I know of. I assume there was some literature in the United States that covered elliptical wings as a possibility?


There's a long list of wing designs that were tried in the golden age of flight.

The Vought V-173 and X5FU weren't an elliptical design, they were a Circular design. Aurthur Sack built one also, known as the AS-6 and flew several times in 1944.


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## Graeme (Feb 10, 2019)

Zipper730 said:


> Other than Berliner Joyce and Seversky/Kartveli, the only other elliptical winged designs that were produced seemed to be the Arup designs, the V-173, and XF5U that I know of.



Boeing? XF7B-1 and YP-29.


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## GrauGeist (Feb 10, 2019)

I don't know, Graeme, that illustration looks quite like a combination of elliptical type curves.


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## Glider (Feb 10, 2019)

When considering the wing it's important to recognise that the first priority is what you want the wing to do. The wing of an F15 doesn't have any similarity to that of a C17 they are designed to achieve different things.

The following link covers this for gliders, very different craft but the principals or aerodynamics are the same.

Of the gliders mentioned I did do an advanced aerobatic course in the Fox which was a lot of fun but isn't one I would choose to try a cross country in, do any thermalling and it definitely isn't for beginners. On the other extreme they mention the ETA glider with a hugely impressive glide ratio of 70. I haven't even seen an ETA but I did have a few flights in an ASH 25 with a 26m wingspan and a glide ratio of 60 which even today is pretty exceptional, that said, I really didn't like it at all. Thermalling was to me difficult (to be fair others did better than I did) it's roll rate was very slow and I found it cumbersome. Landing it with such a huge wing was daunting at the start but you got used to it, I wouldn't want to go near an ETA and to the best of my knowledge an ETA hasn't won a major championship yet, despite having on paper, the best performance 

The morale is be careful what you wish for, the extreme performance is often a mirage, as it normally comes with limitations. 

https://www.quora.com/What-is-the-best-most-efficient-glider-wing-design

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## swampyankee (Feb 11, 2019)

GrauGeist said:


> Ok, stupid question here...
> 
> Actually two:
> 1) suppose the Spitfire was designed with a Moderate Taper wing, how would this have effected it's performance?
> ...



1) If done right, it wouldn’t. Remember, the Spitfire had an elliptical wing, but not an elliptical lift distribution. A linear taper would be easier to produce, so the same effort would give more Spitfires. 

2) Probably neither, but it would be harder to make.


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## fastmongrel (Feb 11, 2019)

swampyankee said:


> 1) If done right, it wouldn’t. Remember, the Spitfire had an elliptical wing, but not an elliptical lift distribution. A linear taper would be easier to produce, so the same effort would give more Spitfires.
> 
> 2) Probably neither, but it would be harder to make.



I don't understand why a linear taper Spitfire wing would be any easier to build. Especially if it used the same building technology and tooling. Once the tooling is set up to form the components and drill the rivet holes a wing can be built in any shape desired all the way to a Delta. The Spitfire contrary to what the internet thinks was not hand built by elves in a wooded glade it was built from panels and sections stamped out by giant flywheel presses. Castle Bromwich once it got into its stride in 1941 (only interrupted by bombing) was churning out Spits at over 4000 a year.


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## Zipper730 (Feb 13, 2019)

I was looking at this image, courtesy of the Journal of Aeronautical History (paper 2013/02)...






... and I've noticed that the spar was placed roughly where the 1/3 chord mark was with a longer and shorter ellipse ahead of and behind these points.

If one was to take an airfoil that was more like the P-51, would it produce a longer forward ellipse?


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## swampyankee (Feb 14, 2019)

Zipper730 said:


> I was looking at this image, courtesy of the Journal of Aeronautical History (paper 2013/02)...
> 
> View attachment 529065
> 
> ...




No. Prandtl worked out the elliptical platfom based on a spanwise lift distribution; the details of the airfoil weren’t considered.


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## Jugman (Feb 14, 2019)

GrauGeist said:


> The years between WWI and WWII saw a fantastic range of wing configurations in an attempt to find the right combination for maximum performance.
> 
> It seems that the Europeans used the Elliptical or semi-elliptical in their designs more than U.S. designers. And I think that there is no coincidence that the P-35, P-43 and P-47 used that in their design, since the P-35 was designed by Alexander Kartveli, who studied aircraft design in Paris amd worked for French aircraft firms before coming to the states to work for Seversky.
> 
> Seversky became Republic, the P-47 was developed from the P-43, which in turn came from the P-35 and that was derived from the original Seversky SEV series...which had an elliptical design.



The P-35 wing is essentially the same as the SEV-3 amphibian. It was designed circa 1931 by Seversky's first chief engineer Michael Gregor and Seversky himself. The S3 airfoil was designed at the same time by these two but not used until the AP-2 in 1937. Kartveli was trained as an electrical engineer and became an aeronautical engineer specializing in structural desgin. His actual knowledge of aerodynamics was limited. He did hold the patent for the S3 airfoil but his patent wasn't even filed until after the Seversky Aircraft Corp. was reorganized in Republic Aviation Corp. The patent apparently lists Seversky or his new business venture (I can't remember which) as the assignee.


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## KiwiBiggles (Feb 14, 2019)

swampyankee said:


> No. Prandtl worked out the elliptical platfom based on a spanwise lift distribution; the details of the airfoil weren’t considered.


I think you have missed the point of Zipper's question.

Clearly the Prandtl planform has been designed in the knowledge that, realistically, a wing will be built with a more-or-less straight spar at the thickest point of the section. And as most pre-laminar aerofoils had their maximum thickness at around 20-25% chord, you end up with a planform made of two separate half-ellipses with a common major axis. If Prandtl had only been concerned with the aerodynamics, the planform would have been a simple ellipse with two axes of symmetry.

I would guess that if anyone bothered to make an untwisted elliptical wing with a section whose thickest point was at 50% chord, then it would be pretty much a true ellipse.

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## P-39 Expert (Feb 15, 2019)

Graeme said:


> Boeing? XF7B-1 and YP-29.
> 
> View attachment 528815



Monty Python never disappoints.

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## spicmart (Nov 21, 2022)

What is the difference of washout and twist on a wing?


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## pbehn (Nov 21, 2022)

spicmart said:


> What is the difference of washout and twist on a wing?


Same thing, however not all wings are the same. Most were twisted along the full length but some like the Fw 190 only had the twist inboard, the outer section of the wing was straight. (no twist)

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## ThomasP (Nov 21, 2022)

I may be wrong about this, but I thought most WWII era wings only had twist for the minority of the span - on the outer section near the tips, not most of the span?


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## PlasticHero (Dec 6, 2022)

I have a hazy memory reading that the Wildcat wing has straight leading and trailing edges for ease of production.





This has been a subject I have been curious about for a long time. Thanks all.


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## swampyankee (Jan 1, 2023)

GrauGeist said:


> Ok, stupid question here...
> 
> Actually two:
> 1) suppose the Spitfire was designed with a Moderate Taper wing, how would this have effected it's performance?
> ...



1) If the span and area isn't significantly different, not by much. It may be a trifle tougher to get good high speed and good departure performance, but not all that much tougher. One should note that elliptical planforms are _quite_ rare, as they do not provide significant performance benefits.

2) No.


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