F1 wing manufacturing

[polarboy]

-Im posting a reply in several parts as im soooooooooooooo slow at typing,i did this in 1 lot an had timed out on the site and lost the lot so not going through that hassle again !
2-component wings,this was the next big change which came about as prepregs came more into use most of which were oven cured.The wings were made in 2 halfs an then cured,normally the would be a core in the laminate of nomex honeycomb or foam.The wing would be glued together with a selection of various spars/ribs glued in place depending on the size/shape of the wing.
In the area of the ribs/spars the foam would of been removed during manafacture so the glue would be acting on solid carbo surfaces.Front wings became 1 piece and became attached under the nosebox and being fitted using solid inserts that were glued in along with the spars and were drilled/counterbored etc after bonding or the wing was drilled an 2 part bobbins glued through the skins

[polarboy]

+3-modern day single shot wings,things changed in the early/mid 90,s as autoclaves became more to the fore and set the basis for the modern day,there are lots of diffrent ways,types,tweaks but this gives a basic outline
Wings are still layed up in 2 halfs but normally its just a carbon layup with no core,after the layup,s completed carbon spars are fitted an held in place by various methods.One of the favorite at the moment is bushes in the bottom half of the mould which are used to drill through the uncured laminate (usually 3mm)the holes are in pairs and the distance between them is the thickness of the spars an then they are used to hold the spars in place with a pair of 3mm nylon pins that are pushed through the bushes/laminate.Carbon is laminated on the bottom skins,up the spars and bent out from the spar at 90deg to form a set of mini I beams.Release film is then placed in these sections and then small vac bags which go all the way across the wing,thetop mould/laminate is then placed on top an bolted in place.A tube bag is threaded over the completed assembly and the small tube bags that run through the wing are joined into it an the whole lot vac,d down,the outher bag vac,s down onto the mould an the small bags vac out pushing the laminates onto the spar an the whole assembly is autoclave cured.Sometimes its not possible for the bags to go all the way through the wing (there might be wing mounting inserts in the way which create a blind channel or you can get the same thing due to thtapered shape of some wings,with the through bags if 1 blows you can fix a new one too it an pull it through but on blind channels its easy to turn the bag on itself before you join the mould once its joined if the bags blows its VERY hard to fit a new bag an the wing gets scrapped

[polarboy]

One poster got a bit of disbelief when he mentioned Rohacell but he was spot on,nearly all flaps and endplates have it in (51 grade) and you will find 71 grade in chassis and other structual items.On flaps with say a 3 ply layup you will have a 2 part mould (in most cases)and in the bottom half the 3 plies of the laminate is fitted 5,10 an 15 mm past the join/split line,on the trailing edge the carbon is laid to the edge of the part which will be machined into the mould (normally ali moulds now),On the trailing edge if the finnished thickness is say 1.6mm each half of the mould will have a .8mm recess an normally your laminate would start out ,9 mm before joining to give some compression on joining.On the top half of the mould the laminate is fitted to the edge of part on the 1st ply an staggered 5 an 10mm back on ply 2+3
Before the parts are joined both parts will get a vacum debulk,the foam is placed in the bottom half of the mould,the foam maybe covered in film glue but it depends on the resin system being used in the carbon.The overlap on the front is folded round the core and the top mould/laminate is placed onto the bottom half.The joined mould can just be bolted but if you vac bag it you get a totally constant force joining it.The foam will be slightly oversize so when the moulds join there is pressure on the laminate an the foam also expands as its cooked adding more pressure, ita a very controlled process an leads to a very good part
If you need to fit inserts (for a flap pivot pin say) the foam is removed in the desired area and the insert added.On areas like the trailing edge where the item is thin the foam will stop short an it will go to all carbon laminate,redux 204 or araldite 212 (both foaming adhesives) will be used to blend the transision with the edge of the foam

[marcush.]

thanks polarboy ..
good food to the thread and in effect leaving me a lot more satisfied with my own
ideas of wing manufacture.
of course very thin and small chord wings wil never make sense with the spar-ribs
manufacture ,so rohacell type core is for sure a good way to do those.
With long cords the balance will soon move towards the spar and rib type approach ,as theres simply more to gain in terms of stiffness for weight.

[tc9604]

Thanks for the information Polarboy

[PlatinumZealot]

Polarboy, what is the autoclave temperature? since the foams and bags seem to go in the oven too without melting.

edit: found the answer in this video, 140*C at 7atm

[youtube]http://www.youtube.com/watch?v=h6RZKqzAaHY&[/youtube]

[polarboy]

Temp and pressure will vary with the material used,this is a bit genral but mainly you will have 3 resin systems (not types) low,medium an high temp but mostly on flaps an endplates you would be using a medium temp system and you would be looking at a cure temp of 125-135
On the pressure front if its a closed mould or a pure carbon layup you would be looking at 90psi (if your doing somthing complicated like a front wing with lots of internal bagging you might knock the pressure down due to the chance of the bag bursting.If you have core/foam involved where it will see direct pressuer i.e not a closed mould,you would cure at 30psi so as not to crush the core

[marcush.]

so in the end not really autoclaving ...but vakkumbagging at high temps...looks like the autoclave is more used as a big oven then..

[polarboy]

when something is vac bagged you can only achieve "ultimate" vacum which means if you suck out every bit if air you will have full atmospheric pressure bearing down on your bag,something like -29.83psi
When you go in the clave it works on positive pressure so you can go upto what pressure your clave/part is rated,30psi bearing down on a already vac,d component will still give you a very nice part
With a closed mould alough the pressure isnt acting directly on the item it ensures total closure of the mould an also stops any opening of the mould as the part cooks

[marcush.]

don´t worry I did go over the top a bit to question the autoclave thing a bit..of course you will try to get all the piece of mind you can get when producing these parts ...

[conni]

2 ways of making wings open or closed moulds open moulds use nomex core and a bag through them but they need to be a simple design nice and straight!!

curvy front wings are closed molds with rohacell and arnt bagged as there is no need they could go in an oven but as you r running the claves anyway you chuck them in with everything else although it does slow down the cook due to the time it takes for the molds to heat up as they are ally and they rohacell gets lightly crushed when the mold is closed and crushed again as the mold heats due to expansion this gives the positive pressure required to achieve a nice consistant part

conni

[riff_raff]

In aerospace, there is currently a big effort to adopt "out of autoclave" techniques and materials for producing high performance composite structures. There are resins and pre-pregs that achieve material properties very close to what you can get with an autoclave, simply by using pressure bladders and ambient pressure ovens. Much lower costs, shorter cycle times, and much less hassle with the lay-ups and tooling.

[stl0]

Post subject: Re: F1 wing manufacturing

* Quote riff_raff

In aerospace, there is currently a big effort to adopt "out of autoclave" techniques and materials for producing high performance composite structures. There are resins and pre-pregs that achieve material properties very close to what you can get with an autoclave, simply by using pressure bladders and ambient pressure ovens. Much lower costs, shorter cycle times, and much less hassle with the lay-ups and tooling.

http://www.fiberforge.com/

This is a company that makes CF parts using a press. Currently I think they're making seat shells for the 787 and turbine blades for GE.

[polarboy]

Presses have been used for years,starting with flat bed heated presses to do insert sheets there are lots of things now from cricket helmets an skateboard bases to aircraft parts but all are simple compared to the structures you would find on a f1 car

[imightbewrong]

Found this to be of relevance since you see a bit of the innards: