Comments by "Keit Hammleter" (@keithammleter3824) on "Real Engineering"
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This video repeats a common misconception, and completely misses a most important aspect of the Spitfire's wing design.
1. Misconception about who designed the Spitfire: This video states that R J Mitchel designed the Spitfire, a very common misconception that began with wartime British propaganda. Mitchell was dead from cancer by the time the propaganda came out, so there was no longer any issue with making him a target for German agents.
Mitchell was, at the time the Spitfire was being designed, Supermarine's Technical Director - a managerial and engineering guidance position, involved in hiring, monitoring, and firing technical/engineering people. Calling Mitchell the Spitfire designer is like saying the hospital director of surgery did your appendix operation, which was actually done by the abdominal specialist surgeon, backed by an anesthetist and theatre nurses. And the director probably never even saw you.
The principal designers of the Spitfire was B S Shenstone, an aerodynamicist who designed the shape of the Spitfire and its wings, and R Smith & A Faddy who were responsible for structural design. The design and engineering of even a simple WW2 fighter involved a lot of drawing and calculation - over 200,000 hours went into designing the Spitfire - that is about equal to an average man's entire working life. Shenstone, Smith, & Faddy had dozens of people working under their direction on the Spitfire. Clearly, one man, whether Mitchell or Superman, cannot have done it all. Mitchell was like a hospital director - he was responsible for hiring the right people to get the job done, and monitoring their progress to ensure it got done.
2. The virtue of the Spitfire wing: In an aircraft intended for dogfighting, it is essential that the pilot know just what its limits are, so he can fly it right to the limit. It's no good is stalls happen suddenly without any warning. In turns a sudden stall will kill you, so the only option the pilot has is to not fly near the stall limit. The Spitfire had a graduated stall that by a "mushy" feeling gave the pilot warning he was at the limit. If controls felt firm he knew with 100% confidence he was safe. The Spitfire remained fully controllable in a stall.
This was due to the design of the wing and the way the fuselage was faired into the wing. The wing changes from one aerodynamic shape (cross section) to another as you move outward along the wing, and the wing has a slight twist. These features meant the wing begins a stall at a specific location (just where Shenstone designed it to be), and not in front of control surfaces, and unless the pilot is stupid, the stall does not spread from the intended area. A stall means turbulent air - turbulent air over control surfaces means loss of control.
This stall characteristic is so important in letting a pilot fly with 100% confidence right to the aircraft's limits, Shenstone actually sacrificed a little bit of performance to achieve that safety.
Incidentally, to any problem there is usually more than one solution. So it is with designing wings with safe stalling characteristics. The double elliptic design with a slight twist is not the only way, that's why you don't see many elliptic wing airplanes. In many airliners, the stall is confined by means of stall fences, for example. Probably a key reason why the Spitfire had twisted elliptic wings, is that it was a solution learned by Shenstone when he worked for German aircraft companies before he went to Britain and was hired by Mitchell.
The claim is this video that the forward biased elliptic design permitted a straight main spar at the point of maximum lift is clearly nonsense. An infinite number of elliptic and non-elliptic shapes can give centre of lift along a straight line.
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