Newb Project :: Crossfire Spoiler


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By Ail - 19/02/2013 03:38:15
Hello all, newbie trying to start a project. Have never done any CF work before but have done my homework.  Sorry in advance for the book, I feel like this could get long winded.  

Ultimate goal: modular retractable spoiler. (Different tops to attach to the base)
Realistic first time goal: replica of stock spoiler

If you are not familiar with the crossfire it has a retractable spoiler that deploys around 100kph this what I would like to recreate in carbon fiber.  My ultimate goal will be to create my own modular spoiler with various different styles.  

This is what the spoiler looks like removed from the car

Top side (about 3ft wide)

Bottom/mount

Mount/bracket close up

Both halves separated top looks to be glass,bottom is metal

My first order of business will be to recreate the stock unit.

My big question here is how to handle the brackets.  This is a spoiler I picked up used so I can tear into it if absolutely needed.  Do I recreate the brackets in carbon and bond everything together? Can I make a mold around them?

That will prob hold me over for now.

Future plans would include how to make some modifications to the base mold (would like to do some diffuser like strips on the bottom instead.

What to use to create an additional lip on the stock spoiler that can be used to make a mold

How to attach the two halves together so the top could  be swapped out with a different style. Etc.

Thanks for any help / guidance you all can provide.  Also I'm located in the US so not sure about the best place for materials.  I love the kits easy composites supplies but not sure how economical shipping and such would be.

Tanks again!
By Philimon - 19/02/2013 08:19:56
Hi! Interesting project !

I'm no pro, but I'd consider fabricating the mounting brackets out of metal and integrating them into the carbon layup. There are stresses and abrasion issues there that I don't fully understand. As a semi-functional aerodynamic device, the impact of failure would be considerable and for that reason I'd stick to metal for that part. 

Better engineers will do doubt come along and present a composite solution...
By wozza - 19/02/2013 11:33:15
Hi, nice shape for Infusion that one.
The shape of the spoiler means it won't create "huge" amounts of Downforce so I don't think the Mounts are critical. I suspect the current ones are a simple "L" shape. You could fabricate them from say aluminium angle and then bond them to the bottom skin from the inside. I would cut the originals off  and follow the EC "How to make a Carbon Fibre Bonnet video. (you could drill out the spot welds and use them on the new one)
If you do decide to change the shape of the spoiler and make it more "Wing" like remember that if you increase the Downforce on the rear of the car you "must" add something at the front ie a Splitter to balance things out. If you don't then the front of the car will become "light" and unstable.
Hope that helps.

Regards Warren
By pk_090 - 19/02/2013 13:00:17
For a wing such as this if you are actually making it practical in a sense of actually making some downforce at some point i would definately look at something on the inside such as a hard styrofoam or ally honeycomb or more carbon even just to stop it from A) being bent/manipulated by the wind, B) also heavy-ish so that it dosnt just get blown off the mounts. Personally i would make metal brackets to attach them too. I had a go at making differant forms iof carbon bracket (U, 45 degree angles and such) and they all came out pants, and not strong enough for the job i intended them for, thus making me stick to metals. 
Alex
By Ail - 19/02/2013 15:03:49
Thanks for the help/suggestions all, this place is great!  The spoiler produces 80 pounds of downforce in the back end once deployed. I am not sure how that translates to the forces that are placed on the spoiler itself. As far as adding to it, it would be primarily cosmetic (bout an inch lip or so) I would not really be increasing the angle or trying to purposefully add a lot more downforce. If it happened to make a little more It would just be a bonus side effect.

Startech created a stick on part for the back, it would be a similar style design.
Here is a shot of what it looks like deployed with the startech piece. This is another crossfire forum members ride, mine is black.
And with it down

The little extra lip makes the back end a little more interesting. I was thinking of multiple sizes to try out if I can actually accomplish the task.

Thanks again for the input! I will take all the help I can get.
By Philimon - 19/02/2013 18:10:42

"Thanks for the help/suggestions all, this place is great!  The spoiler produces 80 pounds of downforce in the back end once deployed. I am not sure how that translates to the forces that are placed on the spoiler itself. As far as adding to it, it would be primarily cosmetic (bout an inch lip or so) I would not really be increasing the angle or trying to purposefully add a lot more downforce. If it happened to make a little more It would just be a bonus side effect."



Uhm, that will put 40lbs per bracket. Not a lot, as you point out, but worth considering. You'll also get that same force spread evenly over the spoiler. Imagine 80lbs of sandbags stacked evenly along its length. That's the force you'd need to engineer for. 

I second the comments about using a core material for this. FYI, they work by increasing the thickness of the laminate and as a consequence adding a greater resistance to flexing.

PS is the quote function on this forum broken?
By wozza - 19/02/2013 18:26:07
This is the Wing I manufacture, it can produce 228 kg of Downforce at 140 mph. The construction is 200grm 2/2 Twill, 190grm Plain Weave, 2mm Soric and 190grm Plain Weave. It is made in two halves (upper/lower) and bonded together. The mounts are eight layers of 200grm bonded together, left hand/right hand.
By Ail - 19/02/2013 18:56:04
wozza (19/02/2013)
This the Wing I manufacture, it can produce 258 kg of Downforce at 140 mph. The construction is 200grm 2/2 Twill, 190grm Plain Weave, 2mm Soric and 190grm Plain Weave. It is made in two halves (upper/lower) and bonded together. The mounts are eight layers of 200grm bonded together, left hand/right hand.


Wow, that's on a whole other level right there.  Very nice!  Gives me confidence that the carbon should hold up just fine at my measly 80 pounds :p.  I will have to think on how to do the brackets. I've not done any real metal work either (besides hack jobs) so I'm going to have some things to figure out either way.  I suppose the first order of business will be the mould either way.  Will start putting a supply list together. I basically need everything/anything that will need to be used.

Thanks again guys, feeling good about this.
By wozza - 19/02/2013 19:17:31
If you can afford to sacrifice the spoiler you have then I would use the Mounts off that. That way you know they are up to the job. Just lay up some extra layers of reinforcement around where the mounts will be.
By Ail - 25/02/2013 19:18:04
That's looking to be the easiest option.  Was just thinking about future if I want to make another I will have to figure out how to re-create them somehow.  Baby steps first though :p

Looking on the easy composites site the regular unimold kit includes

Uni-Mould Tooling Gelcoat1kg
Uni-Mould Coupling Coat1kg
Uni-Mould Tooling Resin5kg
80g Chopped Strand Mat2sqm
450g Chopped Strand Mat2kg
MEKP Catalyst200ml
Plastic Finned Laminating Roller50mm Width
Laminating Brush2x 2"
Nitrile Gloves10 pairs

I'm thinking this should be enough to do both halves.

Main issue here for me is location. While I would love to use the kit and support easy composites for the videos and help I'm not sure how economical it will be.

This kit is £80 and shipping to me would be an additional £97
£177 = $236

With that being said, ill be hunting some US options for comparison.  If its not cool to be talking prices let me know, I just like to have everything documented for others to reference later on.  

Here is what I was able to find, I tried to locate items I think are a direct replacement. In this case I sourced all prices from us composites. I'm a Canadian living in the states, metric makes sense to me but have to do conversions so I could be off on amounts.

Uni-Mould Tooling Gelcoat 1kg -  Orange tooling gel coat  1 Quart $ 22.50

Uni-Mould Coupling Coat 1kg - ???

Uni-Mould Tooling Resin 5kg - 404 Tooling Polyester Resin-Isophthalic 1 gallon $39 

80g Chopped Strand Mat 2sqm - 3/4oz Chopped Strand Mat ~2sq yards $4.50

450g Chopped Strand Mat 2kg - 1-1/2oz Chopped Strand Mat ~5sq yards $13.75

MEKP Catalyst200ml - included with resins etc

Plastic Finned Laminating Roller 50mm Width - Fiberglass Detail Roller 2" $5.95

Laminating Brush  2x 2" - 2x Bristle Brushes Wood Handle $1.60

Nitrile Gloves10 pairs - Disposable Latex Exam Gloves (50) $10.00

The only thing I could not see a similar product for is the coupling coat.  Is there something I should be able to find or is it a custom mixture?  I figure its just resin but again I have no clue what I'm talking about.  Is it maybe a vinyl estor resin? 

With that and shipping I should save ~100 bucks so that would be nice.  Thanks for the help/input as always
By pk_090 - 26/02/2013 09:28:49
What is that fitted to wozza? Looks one hell of a machine? Some kind of Ultima GTR at a guess?
By Rivera - 02/08/2013 22:57:17
Wear can I get that crossfire star-tech replica...... I think ::::xfireon20 :::: is the one that made the replica mold but not shore, if Thera is some one that can help me find this.
my e-mail    758rivera@optonline.net   Thanksssssss🚗🚗
By Rivera - 02/08/2013 22:59:53
I want that lip wing