No chips, beer, chocolate etc for a year or two would also help power to weight ratio, (certainly would mine:-)
Caber
Or have I got it wrong and you are going to put lot of Kevlar in to make the ultimate bulletproof drive by shooting vehicle!
does the aluminum paneling offer more rigidity? or can other materials be used to save weight such as carbon fiber? what would be a good way to attach CF paneling if so?
I'm also thinking of using CF paneling on the underside of my MK (when its ready to pick up) I dont have much experience with it but I am
thinking of the following:
layer 1 - 300gsm plain weave CF
layer 2 - Kevlar
layer 3 - 300gsm plain weave CF
bonded and riveted to chassis just like ally panels. anyone think this wont work?
Was thinking of doing the same after SVA on my Tiger CAT. Was also thinking of a 3 layer weave with Kevlar sandwiched between to layers of CF. My only concern was with the riveting of the panels to the chassis. My plan was to mould in metal sleeves of some sort to aid with some rigidity where the pop rivets go through. Oli.
so i'm not alone then : )
yea i am wondering how to attach the CF panels to the chassis. riviting might crack the CF. I am wondering if it doesnt need to be attached so well
to the chassis. Drilling holes and just bolting it to brackets seems to be the best way in my mind. Glue is out of the question because i want to be
able to take it off easily. but i want to use CF panels so i can mould it to any shape i want to get some better aero on the body and ofcourse weight
reduction. I just want to know if the chassis will lose substantial rigidity if its not aluminum panels rivited on.
I dont think the carbon would split if rivets were used as long as you had a sandwich of kevlar. Kevlar doesnt seem to 'explode' so to speak
like CF does.
However, you stated that you would like to be able to take the panels off - how about using Dzus clips like on motorcycles? In terms of rigidity you
could do what I am going to do and weld in extra crossmembers in the chassis under where the seats go. This should compensate for any loss in rigidity
from not permanantly attaching aluminium panels.
The above is all theory that I will apply to my MK Indy, but I am no expert on any of it. I would be interested to see what you do in the end.
Phew!!
Erm, if anyone sees the Carbon Fibre underneath you will be in serious trouble! Weight at the bottom of the car is better than higher up, I would keep
ally or steel for the floor and put the carbon fibre/kevlar higher up, bonnets, side panels back panel etc.
No chips, beer, chocolate etc for a year or two would also help power to weight ratio, (certainly would mine:-)
Caber
Or have I got it wrong and you are going to put lot of Kevlar in to make the ultimate bulletproof drive by shooting vehicle!
How about making up panels and glassing them on to the chassis and to each other this would certainly increase structural rigidity giving a composite
frame / monocoque construction. If you completely glass in the tubes you could probably use smaller size or wall thickness. This would also be
interesting to see where stress cracking happens in the gelcoat first as these would be the areas of maximum flex or stress.
I would deffinitely look at bonding rather than mechanical fixings as these will always be stress points in the composite and it really doesn't
like point stresses.
Caber
Waste of time fellas if you wanna get exotic just build the fecking car in CF. If you hand lay up the resin/kevlar/CF for a floor undertray to
save weight, and at the same time expect to match the stiffness achieved by welding or riviting the panels to the chassis tubes by dzus fastners or
some other temporary mechanical fixing you need to take yer head out that pot of glue and plastic bag
Try going on a diet before you climb in it,
trust me it works better
Shug.
well i was planing to make the bottom steel like in the book and weld that on, but i want to do like the side panels and bonnet in CF so i can do some aero moulding. i was also wondering, would doing something like filling all the chassis tubes with an expanding foam help with rigidity?
not sure about filling the chassis tubes with foam - if you have seen this done in industries such as aerospace or motor racing then it might be worth
trying, but I dont recall ever seeing anything like that.
I included the kevlar layer in the floor pan because if when driving along something flicks up from the road, it wont puncture.
I am also looking at making all the panels from CF, and possibly the floor with rear airsplitter. I am not that interested in saving weight in the
car, as I am adding extra structural bracing, using CF will allow me to sculpt bodywork that is quite different to the Lotus 7 style. I dont see the
point building a car that looks like everyone elses.
I wont be using much glassfibre because I want to see the CF weave on the finished panels.
quote:
Originally posted by kaizokuace
i was also wondering, would doing something like filling all the chassis tubes with an expanding foam help with rigidity?
There's another aspect of composite not mentioned.
When a metal panel bends in a crash, the sheet just bends. A composite panel will, depending on the amound of bend, break and splinter, like a thin
sheet of wood, leaving VERY sharp splinters. Simply handling my carbon chassis was always a test to keep from bleeding by catching my hand on a
hardened threads of carbon.
I can see in an accident being shreaded alived by a broken composite panel.
Won't all this be irrelevant unless you use pre-preg and baking it under pressure?
Pat...
hi Pat,
you can do a wet lay-up with a hard roller then vacuum bag (so yes pressure is good) this gives a nice even distribution of resin and minimises air
bubbles. You need a breather layer too.
thanx guys, i decided to do the aluminum paneling for the sides and around the tranny tunnel and make the nose cone, bonnet, dash and fenders from CF. Has anyone made like a removable hard top? that might be a fun CF project. Or would a hard top just look funny? It would be cool just for the sake of being cool to have a roof that slides forward like the batmobile.
Hammerhead, you said in a earlier post (when its ready to pick up) The Indy that is.
Does that mean you have been waiting long?
Its just that I have just put the deposit for mine in the post.How long have you waited?
Cheers.
Steve.
hi stevec. Only been waiting 4 weeks, so not too long. I've made some special requests' so now they are waiting for me to take the elise engine to them so they can make engine mounts. Its just that i didnt realise that they were waiting for me!
Thanks for that. I was hoping to get mine for Christmas, Give me something to do on christmas day,( fat chance) Not sure what engine yet, we have a couple of brand new Rover 1.8 K16 turbo engines at work but I fancy a Bike engine.
quote:
Originally posted by Hammerhead
hi Pat,
you can do a wet lay-up with a hard roller then vacuum bag (so yes pressure is good) this gives a nice even distribution of resin and minimises air bubbles. You need a breather layer too.
it works fine in racing rowing boats, so is very strong