Aprilia MXV 450 : Motocross full carbon project completed.

Talk Composites - The Forum for Advanced Composites

Back

Aprilia MXV 450 : Motocross full carbon project completed.

Author	Message
Thanasis	Thanasis posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 36, Visits: 234	Here it is the Mk.2 version of carbon subframe. Better than the first version in every aspect, both aesthitically and in strength particular in the critical points. It weights 1145 gr. Sunday will be riding it at motocross track for testing.
	Reply Like 3
Thomb	Thomb posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 656	nice work!!
	Reply Like 2
Rich (Staff)	Rich (Staff) posted 8 Years Ago HOT Post Details
Group: Administrators Posts: 167, Visits: 4.6K	That is great news; I can imagine that it was a little tense whilst building up confidence in the swing arm but I'm glad to hear that it has worked out well - It looks amazing and the work is a real credit to you!
	Reply Like 3
Thanasis	Thanasis posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 36, Visits: 234	Weekend is over and MX training went pretty good! Thumps up for the carbon subframe! During the first sessions it was impossible to focus on my riding, in the back of my mind was always the thought that I will sit after a jump and the seat will collapse together with the rear end : ) Till the end of the day eventually I had no concerns about the strength of subframe at least for the normal suspension bottoming during jumps. But I have a positive feeling that it will go well also in case of over jumping or coming short to a jump with severe bottoming. An issue that it worried me a little bit is the possible overheating of epoxy in the points were the mountings of exhaust pipes are. It was a really hot day and after a 15-20 minutes session you couldn't touch more than two seconds the area near that point. After a few minutes it cooled down to normal temperature. I will try to isolate the trasfer of heat from exhaust to carbon just to be in the safe side.
	Reply Like 3
Thanasis	Thanasis posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 36, Visits: 234	What ever the result of this piece will be, I will be back with a Mk.2 subframe and giving special attention to the points needed.
	Reply Like 3
Thanasis	Thanasis posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 36, Visits: 234	Finally the subframe is ready : It went pretty good in every aspect, except the bottom brackets which became too thin. Unfortunately the mould seems to close it's ends where the brackets are and there was no other way to fit in the frame than to sand down almost half thickness of it's bracket. The upper brackets though are looking promising to last since a few sanding was needed. The weight loss: Alu subframe = 1420 gr / Carbon subframe = 1150 gr. So it reached -19%. For street or enduro riding will surely be ok but for hard motocross use I have a lot of worries for the bottom brackets. In the weekend I will be riding it and I will see the results : )
	Reply Like 2
Thomb	Thomb posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 656	nice job mate want to see some high res pics with those parts on the bike
	Reply Like 3
Thanasis	Thanasis posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 36, Visits: 234	Hanaldo (07/03/2017) Just for future knowledge, core materials are not ideal in mounting points. They tend to have lower compression strength than solid laminate, so your fasteners can start to pull through. 15 layers will be PLENTY strong enough, so you've got nothing to be concerned about, but just be aware the core will be more of a hindrance than a help in there. Thank you very much for your advice! Hopefully I used only one layer of soric 2mm in the middle of the stack and nowhere else, all the other layers were 400 g twill. I was worried that maybe the stack is too much thick for the epoxy to wet it completely. I haven't got any experience so far with such a thick laminate, but I suppose there is no limit with the thickness of the laminate. Edited 8 Years Ago by Izo78
	Reply Like 4
Hanaldo	Hanaldo posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Just for future knowledge, core materials are not ideal in mounting points. They tend to have lower compression strength than solid laminate, so your fasteners can start to pull through. 15 layers will be PLENTY strong enough, so you've got nothing to be concerned about, but just be aware the core will be more of a hindrance than a help in there.
	Reply Like 4
Thanasis	Thanasis posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 36, Visits: 234	A tiny leak in the bag kept me asleep untill 4 o'clock in the morning....but it seems that the result was well worth it. The stack: - 2 layers of 200 g twill 2x2 - 3 layers of 400 g twill 2x2 - 1 layer of 200 g aramid-carbon hybrid In the 4 mounting points to the frame I really loose control how many layers were put to make them extra thick (at least 10mm wanted), maybe 15 layers and some soric. The subframe is looking good concerning both the weight and strength. I think it will be ok already from first attempt. It will need a lot of work to trim it, make bushings, glue fastening inserts etc... but the main job is done. Some photos: -the last layer of aramid-carbon fabric: -ready to bag it up: -The bag that kept me awake untill 4 in the morning... - Demoulding near the two side fins in the rear of the subframe was not so easy -
	Reply Like 4