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#31
05-06-2011, 03:34 PM
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#32
05-06-2011, 03:53 PM
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90º bank = descent
89.99999º bank = very large, but finite g required to maintain altitude without recourse to slip. 4 g is about 75.5º IIRC; vertical component of lift varies as the cosine of the bank angle, thus load factor required to maintain altitude is 1/cosine of the bank angle.
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#33
05-06-2011, 04:01 PM
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#34
05-06-2011, 04:32 PM
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There is an awful lot of rubbish written about the Spitfire's wing. It has a pretty elliptical planform, but it also has washout, so it doesn't have an elliptical lift distribution. In fact, if you look at the early project drawings, you'll see that it started out with straight taper and four guns. The elliptical planform came in when the Air Ministry decided that they wanted to increase the armament, first to 6 guns and then to 8; going to an elliptical planform provided the structural depth required to accommodate the extra guns outboard. This is covered in some detail in Spitfire The History by Morgan & Shacklady IIRC... The real genius of Mitchell's wing design was that he realised that a low t/c would result in good high speed performance; the Spitfire had the highest tactical Mach number of any WWII fighter, and could not be out-dived by any aircraft under control until the advent of the XP-86 in 1947. It certainly wasn't delicate: it had one of the highest limiting speeds of any WWII fighter; 450 mph EAS for the Merlin Spitfire's wing, and somewhat faster for the Griffon Spitfire (IIRC Henshaw states 520 mph; but this is probably IAS assuming about 20 mph position error; Henshaw dived Merlin Spitfires to 470 mph IAS routinely as part of their production testing, and from what I can gather this was because the position error was assumed to be 20 mph IAS at this speed). That's not what I'd call a flimsy wing. Furthermore, we know that the absolute load factor that the Spitfire's wing could take was >>10 g; the RAE high speed flight had an unfortunate habit of breaking props & reduction gears away from their PR.XI Spitfires in high Mach number dives, with extensive instrumentation aboard, and rather impressive figures (c.12 IIRC) were recorded without structural failure (although the aeroplane was comprehensively bent and subsequently scrapped). The main problem with the Spitfire's wing was that it was hard to build because it's a collection of compound curves. It was also uncomfortably thin for carrying the armament required. Naturally being hard to build, it was also hard to repair in case of battle damage. But as for the amount of damage it could take, I haven't seen anything like as much gun camera footage of Spitfire wings being knocked off, even by cannon fire, as I have of other types. Of course, there's an obvious bias problem with guncamera footage, because there's relatively little German footage. But the Germans undoubtedly had big guns, so they'd arguably have more chance of dismantling aeroplanes for the camera than for example the Americans.
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#35
05-06-2011, 05:27 PM
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Did I say that I luve yo ?
 (quoting AB  ) i am so glad to read you.let's go a step behond if you don't mind : The elliptical theory is a misunderstanding of a Math tools applied to aero. It does not hve a real bckgrd unless with biased assumptions. The fact is (as stated by Vip above) that thickness ratio and the wonderful Merlin made the spit what it was as a real performer. And the all genie of R. Mitchell was to build the Spit as a weapon platform that any average pilot could use and perform where German's Nazi kept arguing with their elitist theory (the UberMensh bulls***etc...). The result was that the 109 was harder to perform than the Spit or the Hurri.... As a side note lets say that it is sad that the elliptical wing was made as a brand mark for vick-Sup. IMHO it leads to the rapid demise of the Supermarine design bureau as soon as the war ended (mid 50's). It is also funny to see how history can repeat itself nowadays in Eu But this is way out of topic ~S!
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#36
05-06-2011, 08:42 PM
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Viper, you know that I respect you because of your factual approach, and yes, there are a lot of misconceptions about the Spit wing design, but according to a gentleman in the UK who owns and regularly flies his Spit MkIX, his Hurri IIb and P-51D, the maneuverability of the Spit is unparalleled, simply because its wing behaves and performs better, albeit being more prone to torque along its span and flex ("the whole plane feeling is of extreme agility and flimsiness, it was obviously an aeroplane that has been based on a sport design and not conceived for war").
As for wing sturdiness, I have walked to the wingtip of a Mustang without the plane making a single movement, but you wouldn't be able to do the same on a Spitfire. A cannon strike on the single spar Spit wing is more likely to do more damage and above all weaken the structure enough to cause a fracture than on a robust Mustang double spar. Let's not forget that a Mustang is almost twice the weight of a Spitfire!
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#37
05-06-2011, 10:16 PM
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Walking to the wingtip without making move the plane (Mustang) is barely an indicator of the wing strength. I'd say it didn't move because the landing gear is set so much more apart from each other in a P51 than in a Spit that made the difference here.
One thing is fact which in turn is exploited today on purpose for modern fighter design but which also extends to other domains: The less stable a device is the more prone is it to change its state. This principle can be exploited in a beneficial way. If you make something instable it is more easier to move around. For instance designs like the Eurofighter is instable and only kept on course because of computer software. This inherent instability allows to be more manoeuverable than a stable plane because anythings stable will tend to maintain its current status and is highly unwilling to assume another state (that is another attitude or flight direction). So if the Spit is as manoeuverable it is likely on the edge of stability and thus somewhat nerveous.
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#38
05-06-2011, 10:24 PM
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^^^
This. A lot of the veteran Spitfire pilot interviews have them talking about "strapping a Spitfire on and becoming part of the machine", however, they all comment that it wasn't an easy aircraft to fly for the inexperienced and it took a lot of hours to become fully proficient at throwing it around the sky. More than a few Spitfires were written off or damaged as a result of poor landings by inexperienced pilots, usually wingtip stalls during or nose-ups after landing. Let's not get into a peeing up the wall contest as to how much we each know about WW2 aircraft, eh? I'm beginning to think that I need a check shirt, a top pocket full of pens and glasses two inches thick to come on here.... 
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#39
05-07-2011, 01:22 AM
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Clostermann describing a Spitfire IX versus Me 109 G combat from 26th September, 1943: "He knew that my Spitfire turned better and climbed better…" (See attachment) Clostermann describing a Tempest V, Me 109 combat during 1945. "I kept on reminding my pilots to keep their speed above 300 m.p.h., for “109’s” could turn better than we could at low speed…" (See attachment) Something fishy…
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#40
05-07-2011, 07:02 AM
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Linear Mode
