Footless Halls
14th Feb 2008, 16:31
Naughty me. In the TSR2 discussion the assertion was made that 'no heavy bomber was every produced with elliptical wings'. In a shameless creep of the thread, I responded with the He111. Another poster put up a plan of an He111 which showed that it was NOT elliptical - and the thread crept away. We all had our wrists gently smacked for threat creep, a fair cop, but it is an interesting topic so I thought I'd start a new thread to continue the discussion. And also explain why I volunteered the He 111.
Let's examine the elliptical plan briefly. As I think was already noted, Heinkel made a number of beautiful aircraft in the '30's with elliptical plan wings, including the He 77 and the He 119. I'm doing this from memory but I have a Heinkel book at home I can pick up the details from later. (Possibly not this evening as my wife might think it an inappropriate topic for the Feast of St. Valentine). I believe Heinkel got there before Mitchell with the Spitfire. And of course Heinkel also produced the beautiful He 100 racer and He 112 fighter, with wings which were close to elliptical if not actually so.
The point of my post in the TSR2 thread was that the early marks of He111, the airliners and the bombers up to, I think, the 'G' model, DID have a most elegent elliptical wing planform. So it was slightly a 'catch' answer. Interestingly this was changed to the simpler plan wing famous for the 'H' model and subsequent models, and this was the plan shown by the previous poster. I believe the reasoning behind this was that Heinkel saw advantages to the elliptical plan but as production built up they simplified the plan of the wing for ease of manufacture, resulting in the H and subsequent design. By mid-'30's standards the He 111 was pretty much a 'heavy' bomber so I think my assertion is broadly correct. Again, if I remember rightly, both the He77 and the He115 served in a limited way as bombers (torpedo in the case of the He115) in the Luftwaffe, but probably not very effectively and certainly not 'heavy'.
The change from elliptical to a simpler wing plan also happened with the Spitfire in the end, with the Mk 21 and the Spiteful having a simplified wing plan.
The advantage of the elliptical wing seems to have lain more in the thin section resulting from the very deep chord, rather that the plan as such. Can other posters confirm this? So was the fashion for elliptical wings just than, an aesthetically-driven 1930's design fashion, which inadvertently had a huge aerodynamic advantage. Hawker produced the Typhoon, and Westland the Welkin, both with enormously thick wing sections. Maybe if they'd followed the fashion for the ellipse those aircraft would have been more successful as fighters (ignoring the Typhooon's formidable effectiveness at low altitude and as a close support aircraft).
Another 1930's fashion in aircraft design which may be analagous was that for creating gull-winged gliders like the beautiful Minimoa, which did not have the aerodynamic advantages assumed? Slingsby also introduced gull-winged gliders, I think. I don't believe the gull-wing carried any aerodynamic advantage over the straight wing. So was this just a fashion too?
Surely both of these concepts, the elliptical plan and the gull-wing, could have been tested against conventional alternatives easily enough in wind-tunnels and shown to have no real advantage? Yet a designer as brilliant as Mitchell persisted with the elliptical wing, not least for his un-built 4 Merlin bomber as well as the Spitfire.
I'd be interested to see what other posters think about this. And anyone who introduces the TSR2 as an elliptically winged bomber will be well out of order...
Let's examine the elliptical plan briefly. As I think was already noted, Heinkel made a number of beautiful aircraft in the '30's with elliptical plan wings, including the He 77 and the He 119. I'm doing this from memory but I have a Heinkel book at home I can pick up the details from later. (Possibly not this evening as my wife might think it an inappropriate topic for the Feast of St. Valentine). I believe Heinkel got there before Mitchell with the Spitfire. And of course Heinkel also produced the beautiful He 100 racer and He 112 fighter, with wings which were close to elliptical if not actually so.
The point of my post in the TSR2 thread was that the early marks of He111, the airliners and the bombers up to, I think, the 'G' model, DID have a most elegent elliptical wing planform. So it was slightly a 'catch' answer. Interestingly this was changed to the simpler plan wing famous for the 'H' model and subsequent models, and this was the plan shown by the previous poster. I believe the reasoning behind this was that Heinkel saw advantages to the elliptical plan but as production built up they simplified the plan of the wing for ease of manufacture, resulting in the H and subsequent design. By mid-'30's standards the He 111 was pretty much a 'heavy' bomber so I think my assertion is broadly correct. Again, if I remember rightly, both the He77 and the He115 served in a limited way as bombers (torpedo in the case of the He115) in the Luftwaffe, but probably not very effectively and certainly not 'heavy'.
The change from elliptical to a simpler wing plan also happened with the Spitfire in the end, with the Mk 21 and the Spiteful having a simplified wing plan.
The advantage of the elliptical wing seems to have lain more in the thin section resulting from the very deep chord, rather that the plan as such. Can other posters confirm this? So was the fashion for elliptical wings just than, an aesthetically-driven 1930's design fashion, which inadvertently had a huge aerodynamic advantage. Hawker produced the Typhoon, and Westland the Welkin, both with enormously thick wing sections. Maybe if they'd followed the fashion for the ellipse those aircraft would have been more successful as fighters (ignoring the Typhooon's formidable effectiveness at low altitude and as a close support aircraft).
Another 1930's fashion in aircraft design which may be analagous was that for creating gull-winged gliders like the beautiful Minimoa, which did not have the aerodynamic advantages assumed? Slingsby also introduced gull-winged gliders, I think. I don't believe the gull-wing carried any aerodynamic advantage over the straight wing. So was this just a fashion too?
Surely both of these concepts, the elliptical plan and the gull-wing, could have been tested against conventional alternatives easily enough in wind-tunnels and shown to have no real advantage? Yet a designer as brilliant as Mitchell persisted with the elliptical wing, not least for his un-built 4 Merlin bomber as well as the Spitfire.
I'd be interested to see what other posters think about this. And anyone who introduces the TSR2 as an elliptically winged bomber will be well out of order...