Spitfire does it have a single-spar wing

[FLYBOYJ]

Obviously your ignoring the point of why its called a single spar wing FBJ, fair enough then, talk only about your own countries aircraft then. It got feth all to do with marketing, and all to do with loadings and stresses, that's why.

Put a hole in the "aft" spar of a spitfire wing and start pulling some Gs, see how long it stays together. It's a load carrying member. It doesn't matter if its a British, American, Russian or Martian aircraft, it has TWO (2) spars!!!

 

[stona]

Here's a couple of pages of a report on the Spitfire wing from the Journal of Aeronautical History (from the Royal Aeronautical Society) which give a modern view of the structure.

They refer to the spar as the main spar which is self explanatory. Nobody has attempted to deny the existence of a secondary structure towards the rear of the wing to hang flaps etc on. Shenstone and Smith didn't refer to this as a spar at all and both repeatedly referred to the wing as "single spar".

The structure of the wing was and is nonetheless a single spar design.

Cheers

Steve

 

[FLYBOYJ]

"Single mainspar" And the "aft" thingy?!? IT'S A SPAR!!! Oh ok, let's call it "a secondary structure towards the rear of the wing to hang flaps etc on."

Call it a "secondary spar," it's still a spar!

Again I repeat;

"SPAR - any of the main longitudinal members of the wing of an airplane that carry the ribs"

If it looks like a duck, quacks like a duck......

 

[Shortround6]

Every aircraft engineer will call it a single spar design. Show me one plane with aileron and flaps without a rear spar to attach them. I don't know any.
cimmex

If you look you can find some planes with "false" spars, a structural member that ties a number of ribs together and provides an attachment for ailerons and flaps. However it does not attach to or carry though the fuselage ( and thus connect to each other) and in some cases there are TWO false spars that do not meet directly. One for the aileron and one for the flap. They may both attach to the same rib but at different points on the ribs length.

 

[stona]

Well Flyboy let's just agree that you are right and Shenstone, Smith and the Royal Aeronautical Society as well as JAD Ackroyd CEng, FRAeS (who will almost certainly google nicely) are all wrong and leave it at that

Cheers

Steve

 

[FLYBOYJ]

Well Flyboy let's just agree that you are right and Shenstone, Smith and the Royal Aeronautical Society as well as JAD Ackroyd CEng, FRAeS (who will almost certainly google nicely) are all wrong and leave it at that

We'll do that. And I'll also bet I've repaired more SPARS then all of them put together!

 

[razor1uk]

It could be worse, it could be connected with nautical terminology...

We/They I weren't disputing that FBJ, and nor what you have done too or what on the ground what the grunts/erks etc call things they work upon.

A file is a file, either if it is a bastárd file or a roughing file, but they both do different jobs along similar lines - you wouldn't say that braizing, mig welding or tig welding are all the same would you or that a V6 is the same as a V8, V12 or a gas turbine?

Yes that wing does have two, but only one is the main, you could include the 'D' box leading edge as a possible third in that case, but still only one main fuz to wing that handles all the loadings.

 

[stona]

I just found a note that Cole wrote that what we call today the secondary or auxiliary spar "mounts to the main spar". If this means it transfers some of its load to the main spar might this be why the designers and other Supermarine engineers in the 1930s considered the wing to be of a single spar construction? It also attaches to the fuselage but both the attachment and the element itself are extremely flimsy when compared to the main spar and it's attachments. The strength of the wing certainly does not come from the box formed by the skins between the main spar and this rear auxiliary.
Cheers
Steve

 

[Kryten]

Hell guys , your arguing semantics, Flyboy is correct when he says it's twin spar when considered in the context of span wise load bearing members, it has two to carry separate loads, however if your referring to main load carrying structure then it can be considered as single spar, as in it has one main load carrying spar, lost in translation or what!

 

[Aozora]

If you look you can find some planes with "false" spars, a structural member that ties a number of ribs together and provides an attachment for ailerons and flaps. However it does not attach to or carry though the fuselage ( and thus connect to each other) and in some cases there are TWO false spars that do not meet directly. One for the aileron and one for the flap. They may both attach to the same rib but at different points on the ribs length.

Them's what you call spar-ribs...great with barbeque sauce and hot fried potatoes Barbecue sauce spare ribs: Recipes: Good Food Channel

 

[drgondog]

Every aircraft engineer will call it a single spar design. Show me one plane with aileron and flaps without a rear spar to attach them. I don't know any.
cimmex

You are playing with Semantics. I am an 'aircraft engineer', with focus on airframe structures and aerodynamics.

The 'structural item/spar/thingy' at the training edge with sustain lateral, torsion and bending loads. The latter places it in the category of 'spar' - you used the term yourself.

Whether someone wishes to say the Spit is a single Spar design only begs the question - define 'spar'.

 

[stona]

Whether someone wishes to say the Spit is a single Spar design only begs the question - define 'spar'.

You are absolutely correct. All I can say is that Shenstone (and several other Supermarine employees including Mitchell himself, at least on one initialled document) did not consider the secondary/auxiliary/ rear spar, whatever we want to call it today, to be a spar by their contemporary definition. They all considered the wing to be a single spar construction.

Modern engineers, as cited in the RAS paper, extracts of which I posted, seem to call this a "single main spar" construction which obviously indicates that they would call the secondary or rear spar a spar.
Times, definitions and usages change.

I also agree that we are arguing semantics. The structural strength and integrity of the Spitfire wing comes from that main spar and D box.

Cheers

Steve

 

[FLYBOYJ]

"SPAR - any of the main longitudinal members of the wing of an airplane that carry the ribs"

The single spar semantics IMO was just a marketing tool to make an aspect of the aircraft look better on paper. Call it a "main spar" or call the rear "thingy" a secondary spar, as Bill pointed out...

"The 'structural item/spar/thingy' at the training edge with sustain lateral, torsion and bending loads. The latter places it in the category of 'spar'

 

[razor1uk]

Not another spin cycle please, I think we all agree it there is a spar at the rear of the wing yes!?; which in the posted design pic, that the rearwards one is not even 2/3's the structural thickness of the front one - some of the ribs where they attach to the front main spar, next to the gun mountings, are thicker than that rearwards located (secondary/parasitic) spar, or the offshoot from the the same main spar that travels rearwards along to the rear root-wing attachment point.

The apparent discussions are about the different semetnics the rear/auxillary/parasitic/secondary/trailing spar and how that is termed (by its usage), or by its apparent 'marketing appeal' or some such other modus operadai.

Ok, should some persons locate post and discuss and compare that design to the design other WW2 era wings, what are the similarities between them and differences relating to the Spitfire design? or not?

While the description of a "SPAR - any of the main longitudinal members of the wing of an airplane that carry the ribs" is undoubtably correct, I can't help but feel its of a very simple explanation. Some like to stir the pot and watch where the bubble go it would appear - following post number 2.

 

[Edgar Brooks]

Gentlemen, it might well be that, in aeronautical engineering terms, the Spitfire wing was referred to as a "single-spar design," but, in purely physical terms, it also contained two spars. The mainspar attached to frame 5, with 7 bolts, while the rear spar used a single bolt; however, before somebody says that it did nothing, at the end of the war, Park, in the Far East, was told not to use certain Mk.VIII XIVs, because their rear spar attachment points were faulty, and the wings could fail during heavy manoeuvring.
Drawings 30008 sheets 2509, 2425, 2427, 2428 show the construction, and assembly of the component parts of the "rear spar," which was attached to the wingribs, wingtip, and fuselage frame 10. These drawings, and their annotations, must have come from Shenstone and Mitchell.
There are general assembly drawings, which refer to a rear spar, and drawing 30027 sheet 12, for frame 10, also shows "rear spar attachment points," so all this argument would seem rather pointless.

 

[Shortround6]

People can go to the cut away drawing section of this web site and look at quite number of different wings. Some aircraft had a rather confusing array of "spars", granted in some cases these are artists interpretations of wing construction. But you can find some 'different' configurations. The P-47 used two 'main' spars and 3 auxiliary spars. One Auxiliary "spar" runs from rib #4 to rib #7 about 1/2 way between the front and rear main spars and helps take the landing loads and brace the wing for the landing gear cut outs. Another Auxiliary "spar" runs from rib #1 to rib #12 and supports the flap from rib #1 to rib #9. It doesn't appear to attach to the fuselage or carry through the fuselage. The last Auxiliary "spar" runs from rib #9 to rib # 19 (last rib) and supports the aileron. it runs behind the flap spar and meets the rear main spar about were the last rib is. While these auxiliary spars do stiffen the wing and resist bending of the wing panels themselves they do NOTHING to keep the wing from bending at the fuselage joint and transfer NO load to the fuselage structure.

The rear "thing-a-ma-bob" in a Spitfire wing does even if it is only a few percent of the total load.

 

[OldSkeptic]

You are playing with Semantics. I am an 'aircraft engineer', with focus on airframe structures and aerodynamics.

The 'structural item/spar/thingy' at the training edge with sustain lateral, torsion and bending loads. The latter places it in the category of 'spar' - you used the term yourself.

Whether someone wishes to say the Spit is a single Spar design only begs the question - define 'spar'.

Well said. To prevent us all going through this one ... again...

How about we just say the "Spit had a primary front spar which carried all the major wing loads, with an secondary, non load bearing but stiffening, rear spar".

Or even "it had 1.5 spars" .............................

 

[Gixxerman]

Main secondary spar seem fair descriptions to me, 2 spars or 1.5 if you like but not just 1.

 

[fastmongrel]

2 nice pics of a Spit wing from -- Welcome to Avspecs Ltd -

I am saying nothing about how many spars I can see

 

[OldSkeptic]

Nice pics. And a reminder that, th0ough everyone tends to concentrate on the aerodynamic designers of the Spit wing .... the structures people had to male it work and be strong and light enough to be functionlal.