F1 wing manufacturing

[Mystery Steve]

When I see pictures of the inside of air plane wings they also have sections inside to strengthen it (Ribs?). So You would make multiple wing Ribs along the span. Of course the ribs are shaped like the wing profile. [Imagine bending the wing.. the top fibre is in compression and the bottom in tension.. the carbon fibre at the bottom i feel is supposed to be thicker because the main attribute of CF is it's tensile strength.

The tension/compression thing depends on how the wing is supported. If it's supported in the center then you have tension on top and compression on bottom. I'm assuming you meant that it was supported on the ends? And CF doesn't just have tensile strength. The fibers themselves have high tensile strength (they're useless in compression by themselves), but the matrix contributes a fair amount of compressive strength as well. And in addition to any bending stresses, there is also a load along the chord of a wing due to the aerodynamic moment about the quarter chord.

A lot of the bending stress is handled by the spar(s) running the span of the wing, while the outer skin is likely tailored more towards avoiding skin buckling as the wing does inevitably bend and flex. If they do in fact use unidirectional chord-wise (cannot verify that myself since I've never built a wing from CF) then I would suspect that would be a possible reason.

[marcush.]

some of those ideas are discussed in this little booklet:
http://shop.r-g.de/Composite-Medien/Bue ... cnid=00122

unfortunatelly only in german language.

also their website is quite informative as is their handbook wich is bilingual G-E

as of the moldmaking and procedures to build a wing I have personally not seen
a lot of molds I would have done the same way.My guess is thats simply because I´m a modelmaker by profession..with some serious thoughts you can arrive at very very light assemblies with out the need to resort to shaping big cores again and again for every part you produce..but thats another story.
My feeling is you will be better off to put the material where you need it instead of having a homogenius inner core with all the hassle to integrate something to actually transmit the forces reliably to the wingstays.But then again ,it seems the F1 guys do really build foam core wings..

[James_graham]

What University do you attend?

[ubrben]

Last time I spoke to someone involved in F1 composites a lot of things like flaps and endplates were being made using a solid Rohacell core. The proceedure was to machine the core to be very similar to the mould shape then wrap the carbon around it and then put the whole lot into the mould. Controlled crushing of the core provided the consolidation.

Ben

[marcush.]

Post subject: Re: F1 wing manufacturing

* Quote ubrben

Last time I spoke to someone involved in F1 composites a lot of things like flaps and endplates were being made using a solid Rohacell core. The proceedure was to machine the core to be very similar to the mould shape then wrap the carbon around it and then put the whole lot into the mould. Controlled crushing of the core provided the consolidation.

Ben

this does not lend itself to a controllable process... if you build the core oversize and wrap it with prepregs you cannot close the mold ,or at least closing the mold will tend to misplace ,kink or strain the fibres of the prepregs as there will be no possibility to apply any crushing near the parting lines ,it remains at least mysterious to me how something like this should remain true to the blueprints after consolidation ,as you will never be able to get the same uniform
pressure as with vacuum bagging which of course was not really on when wrapping the core with the fibres as the surface would be ...coarse.
Also how do you get rid of the air? is it possible to deair thru the core? also at least something questionable.
also the big question remains how to transmit the forces from the wing to the wingstays ...so in the end you will always have to have something of stringers ribs and spars to actually transfer the loads to the main vessel.

[PlatinumZealot]

Here is a video of manufacturing Toyota f1 rear wing flap.

[youtube]http://www.youtube.com/watch?v=MT3XbSvQ14I[/youtube]

Seems that they edited out (or missed) many steps from when they put the first sheet of fabric in the lower mold up to when they put the whole thing (without the upper skin and upper mold?)into the autoclave...

[marcush.]

this looks like the bits I have seen before:2halves cured separately and then bonded together in a final step.The parting line you can see in the video is what you would normally do for a molding process ,as you cannot allow any undercuts.unfortunatelly
this aproach will put the parting line exactly on the leading edge of the profile-
very bad idea,as you will need to do finishing work in an area best not to be touched or sanded at all .i would have done either a piece mold or better yet put the parting line on top of the profile ,accepting the undercut,but this is effectively of no consequence as the skin will easily come of the mould anyways.In fact by clever design of the two wingskin halves you could even create a spar inside helping the final bonding of the two skins as well as making any foam core obsolete...but what do I know...

[scarbs]

Post subject: Re: F1 wing manufacturing

* Quote ubrben

Last time I spoke to someone involved in F1 composites a lot of things like flaps and endplates were being made using a solid Rohacell core. The proceedure was to machine the core to be very similar to the mould shape then wrap the carbon around it and then put the whole lot into the mould. Controlled crushing of the core provided the consolidation.

Ben

this does not lend itself to a controllable process... if you build the core oversize and wrap it with prepregs you cannot close the mold ,or at least closing the mold will tend to misplace ,kink or strain the fibres of the prepregs as there will be no possibility to apply any crushing near the parting lines ,it remains at least mysterious to me how something like this should remain true to the blueprints after consolidation ,as you will never be able to get the same uniform
pressure as with vacuum bagging which of course was not really on when wrapping the core with the fibres as the surface would be ...coarse.
Also how do you get rid of the air? is it possible to deair thru the core? also at least something questionable.
also the big question remains how to transmit the forces from the wing to the wingstays ...so in the end you will always have to have something of stringers ribs and spars to actually transfer the loads to the main vessel.

No Ben is right, this is how many parts are moulded from flap to wishbones. I have seen this at several F1 teams and suppliers. The core is oversize by a small amount merely to apply the pressure to consolidate the fibres. A part will be laid up in the lower half of the mould with outer plies overlapping out of the mould, the foam core and the inner plies of the upper surface are laid next then the overlapping sections wrapped up over the top. The upper mould half is fitted and then the part is vacuum bagged and cured.

This process is preferred as it’s a one stage process, where as two piece part bonded together needs several stages, some of which include messy machining and glueing stages. The monolithic part created is as strong and repeatable.

[marcush.]

I´m totally amazed by your statement and would surely not try to manufacture a wing or a wishbone that way ...
also I do not understand where the vaccum is applied here :
You do layup the carbonfibre into the machined lower half of the mold put in the core put on the top half of the mold already layed up with the carbon fibre ,close the nold and put this into the vacuum bag ? -this way the vac only does provide a closing force ,similar to a press or a set of c-clamps ,no way this is providing uniform pressure distribution over the whole partsurface.Something in the whole process discription is missing I think.the only answer I can imagine you deair thru the core ,which might be feasible but still I don´t get the advantage of a ll this.
Why rely on crushing the core when you got an autoclave and vacuum to apply controlled pressure on the layup? If you feel the part needs a core it would be a much better idea to put in the foam as a last production step and expand it in the finished part.

The three or more piece layout will not be messy at all as if your parts fit correctly together you will be able to bond by laying up small thermoset epoxy filmstrips in the bonding areas and just do a final heat cyle with under vaccum to get proper pressure to the bonding areas.No mess, no finish work .Easy and reliable

Still I´m sure F1 guys know what they do...still I do not get around the problem of how you deal with the leading edge area with the oversize core .This simply does not go into the mold ,so you basicaly have to reduce oversize in the leading edge area to zero for the core ,so the crushing will happen only on top and bottom surface ...
but then stranger things happened in the world.

[scarbs]

My explanation may be overly simplistic, but in essence thats the way they do it. I was also told foaming resins and bladders have been used to apply pressure in th epast, but the oversize core is the current route.

[marcush.]

bladder was what I knew as a possibility ,expanding foam is obvious -but thanks for giving me something to chew on...will make up my mind about it.

[ubrben]

Marcush - I spoke to the owner of a company that subcontracted at the time for Honda, McLaren, etc. So I believe my source is good despite this not being my area of expertise.

There is no vacuum bagging as such because the core crushing applies pressure. It's a much simpler process.

Edit: re-read Scarbs' post and I suspect that they might put the whole assembly in a vac bag, but I'd need to confirm that.

Ben

[Tim.Wright]

+1 for this manufacturing method in F1. I too was quite surprised when my old boss explained the process to me, but apparently closed moulds were commonly used for wings and wishbones.

I found composite manufacture to be a bit of a black art at times.

Tim

[marcush.]

There is no vacuum bagging as such because the core crushing applies pressure. It's a much simpler process.
hm ,yes perfectly understood ,pressing is of course not something new in laminating processes.


Edit: re-read Scarbs' post and I suspect that they might put the whole assembly in a vac bag, but I'd need to confirm that.

that was what I thought they do, as you can see the bagging tubes and sticky tape in the videos if i remember correctly.Still it seems at least to me not to be a very safe method of producing the parts so thumbs up to those collegues of goony to still produce the obvious quality.It is a rare occurance having wishbones desintegrate.

what is beyond me is just why they do not do a spar and stringer type work ,as here you could still find a useful amount of weight for stiffness ...as obviously the foam core is uniform in density- apart from the crushing of course-but still it is mass you could get rid of . I´m aware that they will have at least some strings of carbonfibrerovings laid into the areas of tensile stress ,in effect slots machined into the formcore ,I guess..

[polarboy]

Hope this is some help to the OP so here is a brief history of carbon wings,there are lots of other options and variations but this is the basics
1-early days,the 1st carbon wings were made in the early 80,s using solid foam cores.It started with a block of foam that had the element profile marked on each end with a set of matching datum points on each end,2 people would then use a hot wire cutter moving datum to datum till they had cut the complete profile from .
The foam element was then covered with carbon an epoxy resin an release film an placed back in the original block it was cut from which acted as a 1 off mould foe that element.Front wings were 2 small flaps either side of the crashbox and normally had a carbon/ali tube going through or supported by the crashbox