any thing on the acceleration of the Spitfire

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Always debatable, but equally always calculable when presented with enough good flight test data... The Mustang CDo with racks varied between .016 at SL to ~ .0175 at 29,000 feet max speed due to increased drag rise of supersonic prop tips. At 440mph for the P-51B-1 with 1650-3 engine at 3000 rpm and 61" the 51 was at .646M at 29,000 feet. At this speed the calculated CDo, ignoring Compressibility Drag, is about .0175 - but of course the Compressibility drag does matter in this bandwidth so CDo is in fact still ~ .016 with Compressibility Drag + ~ .0015
 
Hmmm, clearly someone is shading you then.

"Building on MY work!" (old Star Trek reference)
 
Well they've got the Spitfire IX and Mustang a lot closer than other sources, a difference of 0.002. The speeds and altitudes were quite high. It sort of reinforces my point above.

At the risk of igniting a previously extinguished fire, once again the Spitfire is listed as a single spar wing, just like Mitchell, Smith, Shenstone et alter referred to it.

Cheers

Steve
 
Well, I guess people can call it what they want (define spar?) but it had a plate/beam/hunk of metal that went from wing root to wing tip that the flaps and ailerons were attached to and that was used as an attachment point for the wing to fuselage. What it provided for bending strength or torsional strength for the wing I have no idea, may 0%, maybe 2% maybe 10%.?????
P-47 had 5 "spars", one of them went ALL THE WAY(sarcasm) from the outer edge of the wheel well to the inner edge of the gun bay. Started at one rib, crossed two others and stopped at the fourth. It was basically a reinforcement for the landing gear attachment point but it was called a spar.
 
There is a reason for all the above referring to the wing as a single spar (and D box) structure and there is a reason for that spar being where it is. The shape of the wing and position of the spar were determined by Shenstone, based on earlier work by men like Prandtl, Glauert and Tietjens, and more contemporary work, particularly by Lippisch, to mention a few. Funnily enough they are all German and Shenstone was fluent in German and a translator of technical German, having lived and worked there for some years

We can debate what does and does not constitute a spar, its been done ad nauseam before. I'll go with what the men who designed and built the thing called it

Cheers

Steve
 

Steve - that drag chart is comparing against the Mustang X, not the III or the IV.. big honking carb intake, mismatched cowl to lower wing surface, probably sorry drag performance into Radiator/Oil Cooler intake because of lack of time to study it..
 
The trouble we are having is that the men who built the things at the time didn't seem to agree on what a spar was. Which is not surprising as many had NOT been to school for aeronautics and some of these guys were making it up as they went along. A lot of times they may have shortened the "technical" description to something handier.

2 full span spars plus 2 partial span spars plus one local reinforcement spar= 5 spar or even = multi-spar.

1 D box spar + one aux spar carrying very minor load= D box spar or single spar

2 Full span spars + reinforcement for aileron/flap (even if full span) = two spar.

What the designers called it is how they thought of it. Designing a single D box spar wing is certainly different than designing a conventional 2 spar wing and plenty of 2 spar wings had spanwise reinforcements for aileron attachment or flap attachment or both without being called 3 spar wings
 
The backgrounds of the men are different.

Mitchell started as an apprentice at Kerr, Stuart and Co. which was a locomotive engineering firm based in Stoke-on-Trent.

Smith was originally an apprentice at Herbert Austin's motor works at Longbridge, though after WW1 he did move to the aircraft section as a junior draughtsman.

Shenstone was a true and highly qualified and trained aerodynamicist. Before his work in Europe he had become the first scholar at Toronto University with a master's degree in 'the Applied Sciences of Aeronautical Engineering'.
I would have no problem arguing that by the early 1930s Shenstone was amongst the top five aerodynamicists in the world. Some have argued that he was THE foremost, though he would certainly have denied that.
Shenstone, who was not only the most aerodynamically qualified but also the man who designed the Spitfire wing, consistently referred to it as a single spar design.

Other important but largely forgotten figures who would make important contributions at Vickers Supermarine, like Bird and Porte, Westbrook and the Spitfire team itself including Blazdell (who designed the ingenious Spitfire landing gear locks), Clifton, Holroyd, Kettlewell, Gedge, Shirvall, Lovell-Cooper, Simmonds and Faddy (who at least had a long history in the aero industry) had equally varied back grounds.
In listing those largely forgotten names I have left dozens out, but they all made important contributions.

Cheers

Steve
 
To add fuel to the fire. Definition of a spar from The Aviation Dictionary for pilots and aviation maintenance technicians, published by Jeppeson Maintenance; "The main or principle, spanwise structural member of a wing or other airfoil.
 
A main or Primary Spar is not a sufficient definition for a "Spar". Any bending load carrying structure within a lifting surface, designed to provide local resistance to bending and act as a load path to the fuselage is a better definition of "Spar". From that definition you may progress to any adjective that fits your fancy - up to and including 'favorite spar', primary spar, 'biggest and best spar", "prettiest spar", 'single spar', 'One of several but not as big as the biggest spar'..or, 'It COULD be a spar, but we won't give it a name'..

Independent of popular names for load carrying structure, which was attached to the Spitfire fuselage, any such structure could be appropriately described as a 'spar' - or not.
 
nuuumannn said:
Well then, call it a main spar.
Click to expand...

Or forward spar
I've seen a quote from Alf Faddy in which he refers to the spar on the Type 224 as the 'forward spar'. He also refers to the Type 300 as a single spar and D box design and relates it to the sort of wing structure that Shenstone had seen in the German gliders with which he had become so familiar at the Wasserkuppe when working with Lippisch.

You pays your money and you takes your pick

Cheers

Steve
 


In the text of the Type 327 proposal the wing is described as a single spar wing. Yet on the drawings there are labels for the rear spar and front spar.
 
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