Does anybody know of any good books or websites that contains some decent information on how to go about building a carbon fiber chassis using aluminium honeycomb?
I’m curious to see how the aluminium honeycomb is placed side by side (i.e butt joints or lap joint etc) and also how you can shape/bend it in corners and around various bends and curves.
Another aspect is seeing how ‘hardpoints’ are made for mounting the suspension.
Any help/direction is appreciated.
Good times!
this covers a lot of it
very useful construction method. Butting pieces are joined with core splice.
It doesn’t like to curve too much, slight curves. There is over expanded core that curves better. IT’s also very expensive. Metallic core especially. The metallic is also more of a pain to cut and chamfer. nomex/kevlar can be cut with a blade, chamfer with a saw, grinder, or CNC.
To mount stuff there are many ways. Can be bonded pieces together. There are various through type connectors that are the same thickness as core, as if you torque down on it it’ll crush the core. Again these types of connectors are expensive. You can also pot in studs and such. It’s not rocket science, but there are some caveats… all in all it’s one of the lighter and stronger methods. As you know such things as F1 cars and space vehicles use it for it’s light weight high rigidity capabilities.
let me know if you have more questions.
It will be hard to find a lot written on the net. you might try searching heavy aircraft it is the same method. hard points are mostly made of alum and bonded to the tub core with structural adhesive film. the adhesive is handled like pre-preg.
it comes in a roll and has a backing. some adhesives have a scrim to add strength. the hard points and suspension mounts are indexed to the tool/mold as a fixture type thing. I have found secondary structure hard points made from micarta and alum.
I used micarta hard points building this floor potted with adhesive. this would be typical for bodywork mounted hard points
](http://s14.photobucket.com/user/S2Wizard/media/shop%20work/IMG_4200_zpsogaxvzpd.jpg.html)[/IMG]
inside this old INDY car you can see at back where the bulkhead meets there is a billet alum block fitted and bonded to the inside.
(that space is where the fuel cell is located)
Ferrari uses it in this pic of a 488 floor.
and I am always fixing alum hard points on the diffusers because of impact damage
](http://s14.photobucket.com/user/S2Wizard/media/shop%20work/IMG_7572_zpsjlq5mchq.jpg.html)[/IMG]
](http://s14.photobucket.com/user/S2Wizard/media/shop%20work/20160330_080509_resized_zpsqdn3086w.jpg.html)[/IMG]
these parts take a pounding and I keep fixing them.
thank goodness for vinyl wrap
](http://s14.photobucket.com/user/S2Wizard/media/shop%20work/20160614_122135_resized_zpshnkxweve.jpg.html)[/IMG]
Brilliant pictures! Thanks Tom.
In the picture of the Ferrari floor where you have to fix the diffuser mounting points; what you can see of the alum insert - is this the size all the way through the carbon fiber, or is it bigger behind the carbon to help distribute load?
The diffuser H/P’s are large. as they tear the damage area gets larger each time it’s repaired. this one has been repaired more than once
it is kind of a balance for weight-size-and the service involved in the part. During racing season I do not get much time to spend repairing and have to improvise because the cars will leave in a week for another race.
the parts department makes a lot of money on replacement parts. this strake that is damaged is part of a E>14,000 EURO section that was fixed in a few hours.
it is on The La Ferrari. I did not even know what a La Ferrari was until I googled it. If you get a chance look it up
If you want to learn about the early days of chassis build have a look at both of Keith noakes books
They cover the early flat sheet,cut out an fold up methods and the later male mould forming
Also has info on bulkheads,bobbins an fixings
For the “modern” era (91/92ish) your onto female moulds where the bodywork was done away with an the tub becomes the bodywork
Mostly 2 section moulds made of multiple parts normally the bottom part being 1/3 of the car an the top 2/3 inc the roll hoop or hoop mounting being the other
“should” be 3 shot but a dallara or other formula type tub being built to a price might be 2 for costs reasons
1st shot is outer skin,no Kevlar these days an very little ud. Very specialized layup taking into account suspension an other loads
Also has to take into account the crash test and deflection tests,specific plies are placed in certain areas with no other reason other than to pass these tests
“passive” cheating almost
Laminate will be peel plied an have a 90psi autoclave
With major inserts (which will be Ali)I.e engine mounts an suspension are either
1-cooked in at this stage with the first skin
2-placed above the release film when you bag an used as a pressure plate the fitted with the core
3-left out completely then cold bonded in before the core stage
Personally having done over 350 chassis (150/160 of which are f1) think methods 2+3 are total crap but who am I to criticise young composite designers who have been to uni for 3 years an know all of the “theory” !
Core is “dry” fitted,several different thicknesses and different density’s (stiffness)a bit of 4.5 will go round all but the tightest corners where as 8.1 isn’t doing anything but flat areas !
Very easy to work and shape and easier than nomex as you can form it an it retains that shape
LOTS of tricks of the trade to make life easier like not joining on corners an working on transition areas post 2nd cure
Once your happy with your “dry” fit its all pulled out,300gm film glue is fitted in the tub an your core goes back in but with 212 core splice on all joining faces
Little"fill in" in any dodgy areas with redux 212 before peel ply over the joins an 30psi cook
Core will always need work post cure but I aim to have to do as little as possible, core is sanded to shape where it has been left high an any low spots are filled with redux 252 light weight filler (blue ice as its called in the trade)
When complete 150gm film glue an inner plies
Joining both half’s is either cold bond tounge an groove or you will of staggered your core and h/c and will go for another cure and a hot bond join
Just fit your bulkheads an drill the whole thing off and your done !
Lots I have missed out,any specifics you want to know just ask
Should of put all of your minor inserts are normally put in the core on the 2nd stage
Ali or carbon depending on the loadings it will get once threaded
That’s perfect, thanks f1rob!!! That’s exactly the sort of info I was after. Just wish I could fully understand everything (my failings in knowledge)! haha.
Which bits you having trouble with ?
F1 Rob well done!
as I have not been involved in manufacturing of tubs & bits.
I did spend time in the clean room, a lot of what we did on aircraft was repair to a piece that was damaged so badly we took a small bit of it to use as the original part # too make whole again.
For instance Boeing 747 radomes where cut a few inches past the attachment ring and placed in the mold with the rest made new from fiberglass prepreg. that way it could be said the part was repaired and bypassed first article requiremants
Many on this forum will be interested with this document regarding
the structure of our “Black Matter”
It was our guide to sell the Inspection Dept. (note: this is a safe link to a US gov. document)
http://www.tc.faa.gov/its/worldpac/techrpt/ar03-74.pdf
I have a hard copy and use it as a basis for the repairs on sports cars all done for the last 15 years from my two car garage at home. except for the many field trips I have taken from Van Nuys California to across the US, Canada, & LeMans
here is a pic of me 36 years ago with a dome
Awesome photo Tom!
That’s how f1 use to be ,working all night repairing floors an chassis an wings
Hell of sa buzz working against the clock
Boring now the just bolt a new part on
Another very good book to try is Simon mcbeath-competition composites (a practical handbook) by Haynes
Start is similar to noakes but goes more modern an technical at the end
He use to be the composites manager at williams
