Production Woes

General Composites Discussions Composites Talk
#1

I’m a brand new member, and this is my first post. I joined this forum because I have a problem. I am starting a new business building wings for cars. After about 10 years of work, I managed to invent a way to make the wing self adjustable depending on how fast you are going, if you are in a corner, etc. The mechanics and electronics (it’s computer controlled) took me 10 years and about $50k to finally perfect. You have no idea how many times I would build something, throw it away, build something else, throw it away, and over and over, but finally I have a solid setup that works perfectly.

Now the hard part. I actually thought it would be the easy part, but it turns out, I’m at a loss of how to do it. The wing will be made of carbon fiber (an easy way I can justify to the layman the price of the package), and have two ribs inboard and two at the ends. The two inboard ribs will be attached to the wing struts that connect it with the car, and the back of the ribs will hold the actuators and several sensors to the wing assembly.

So, how do I build the wing? About 15 years ago I attended an EAA composites fabrication class, so I figured I would build a plug, make a mold off the plug that had the top half and bottom half of the wing, layup the bottom half, lay in the ribs, bond the top half to the ribs and bottom half, and then be done. But then I realized that the wing had to be different sizes depending on the car. A Corvette, for example, would use a 55 inch wing while a Mitsubishi Eclipse would use a 48 inch wing.

So I’ve been kicking around several ideas. Maybe make a giant mold of the wing halves, I don’t know, say 30 feet long and then cut them to the size I need. Or maybe use an injection molded plastic plug, cut it open and install the ribs where needed and then lay carbon over the plastic. Or several other ideas.

I’m probably wrong on all my ideas. So, if you, the gurus of composites, needed to make say 100 wings as I have described of different lengths in a manufacturing environment, how would you do it? Any advice would be greatly appreciated. Thank you.

#2

Oh, one other thing. I have a home made gantry style CNC router in the garage. It has a working area of 10" Z, 22" X 33". I thought about laminating some hard wood and routing out some permanent molds, but it would be tricky to mate up two perfectly since I need at least 60" for larger cars. Good plan?

#3

So the different size wings will all have the same profile? Talking about a big 30’ mould, that would have the same profile over the whole length, like an extrusion?

Have a search around here for ideas, pretty sure I saw someone else post photos of a wing recently - you may get some ideas.

Have you started making any sketches or drawings of the assembly? I’ve found that helps a great deal in working out any fitment/assembly conflicts. Google SketchUp is good for making 3D models to get your ideas out - not too hard for a novice to make some basic 3D shapes.

If I understand it right, I think the idea of making the upper and lower half, then attaching the internal ribs(and end caps?) and assembling, seems like a good method. Whether or not you make a big, long mould… or just individual sizes - depends on what facilities you have available, and it could be difficult to work with such a long part if you go for a 30’ length.

#4

The hardwood mold will not perform very well for production. Hardwood also expands and contract unpredictably with temperature and humidity. A 30’ mold would be rather cumbersome to handle. I would probably make multiple 60" molds. These will be easier to bag, handle, arrange the fabric, and fit into a curing oven.

#5

Forgt using ribs and use external L angle attachments. Since carbon fiber is a composite change your style of thinking away from the standard metal structural stance to a minccoque ideal of thinking. If L angle is not good enough star thinking T angle. Also consider a standard airfoil regardless of width but use inserts similar to the way surfboard fin boxes are installed. A simple router template and bond. Hopefully I understand your problem. Good luck

#6

Why are there internal ribs anyway as dallas mentioned?
Is it a single element wing? Do you have any pics / simple sketches you could upload (take out all your personal data) just to make sure we’re talking about the same thing?

#7

Thanks for all the replies guys. The wing is a consistent airfoil section throughout- so yes, you could extrude it. I have no idea how you can extrude a CF wing, but if you know how, I’d love to learn.

I need the internal ribs to hold the actuators and sensors that are going inside. When the wing deflects upwards for braking, there is about 300 pounds of drag at race speed- so the actuators are fairly substantial (though I have used the mechanical advantage of several levers to reduce the power required).

I have designed this wing structurally in Solidworks. I have completed load testing, aerodynamic testing, and structural finite analysis using several software packages that are included with Solidworks Premium.

I don’t want to upload photos that are too detailed because my patent was just filed last month and isn’t technically even pending yet… However, I am putting together a video for possible investors, so I’ll post the link as soon as I get it up. Here’s a simple rendering that shows how simple it is.

#8

Wow, I have absolutely no idea what any of that means. Lol. I guess I am stuck in the old style of thinking. I have no experience with a surfboard, so I’m not sure what a fin box is. I’ll do a google search. Thanks!

#9

I agree. A 60" mold would be better. So if a hardwood mold sucks, what should I use? Aluminum? Remember, this is for 100 wings, not just one or two. (ideally, if the planets align, I hope to sell thousands, not just a hundred)

#10

Here’s some pics

#11

Welcome aboard Dave. To do this in a proper production technique and flow will require much more grasp of Composites structures to really dial in the strongest and lightest parts. I realize no one wants a tall cinder block whipping in the wind attached to their tracked car.

Consider learning more about Carbon ‘tow’ and ‘weft’, as well as Uni and bi-directionals for controlling your design specifications.

You’ll be able to engineer out several weighty items in this if you study those things well.

Learn as much as you can about which resin system to employ that allows you the best stiffness and can be lower temp post cured in a narrow custom built oven.-( a must for good repute).

As others have mentioned, avoid screwing around with wood, for anything really. Use Carbon to build and reinforce your mold as well as a higher Tg resin than your final part will see so that your mold lasts.

At this point in your venture, perhaps you should employ a master mold maker to get you started and rolling. Your learning curve on this is a whole other period of many months if not years to get it right.

Ohio has many composite workshops and engineers.

#12

Thanks for the input. I’ll look into it. Any suggestions of a reputable mold maker?

#13

There is always a google search in your area. Speaking with local composites shops on your project and goals might yield a good tool maker.

#14

What about glassing over a wood mold? Would that work?

#15

Aerodine composites makes wings for top fuel cars maybe talk to us about production

#16

I have a web page how I build the wings ,
http://curedcomposites.com/wing.html
I don’t know that will help you any , your problem is starting on absolute zero you don’t know enough even to ask the right question and if someone tries to explain how to do it you wouldn’t understand what they are saying
Looks like after 10 years you still have a ways to go , maybe you are half way there

#17

Great stuff sychrovsky. When I said 10 years, I meant the project was 10 years old and I worked on it in my off time. The electronics has only recently become cost effective, and that along with the actuator design have been my primary focus until now.

Are your molds made of wood? I thought that was a no no. Or is this just a one off thing?

Out of curiosity, what do you get for one of those wings? Looks as strong as a tank!

#18

I will not comment on the wing construction, as I do not see enough detail yet, but for the mould you could route a piece of wood, or preferably a piece of tooling board. Finish that with primer and 2C PU paint. Do a top and bottom side.

These plugs can get you decent moulds.

Your moulds should be able to withstand production temperature (postcure) and that depends on resin used. The resin used depends on demands on the product.

Assuming you go for a high quality product, the heat resistance of your resin should be some 100-120C. This makes for postcuring at about the same temperatures, and effectively rules out polyester and vinylester moulds. Which brings you to epoxy moulds. These require a freestanding postcure (your toolingboard does not survive high temps) and thus a controlled oven.

The other route is aluminium. If you have the funds or can route aluminium, that is great. You can polish the mould surface to a high shine, and mould detoriation is not much of an issue.

As for the product itself, I would strongly consider prepreg, as the parts should be high quality, and top class finish. It is all doable, but requires a steep learning curve, and an apprenticeship at a prepreg user is highly recommended. It can make nice products though. Consider outsourcing the composite part.

#19

I’ve contacted Aerodine but still no word back. I may just have somebody else do the composite work, though I would like to learn. I’ve spent the last two days watching youtube videos about how to do CF composite work, and I’ve gotten the bug to learn it myself. I saw a video of a guy making his own prepregs with a huge sheet of glass. The most interesting thing to me, though (and the subject I’ve spent most of this day learning about) is the infusion technique. Oh, and I have always intended on using epoxy. What little hands on experience I do have, it has been with epoxiy resin (aeropoxy). I laid up a fiberglass wing section about four feet long with it, and it went pretty easy, though it was not vacuum bagged and needed some serious sanding after it was cured.

I do have two fairly large temperature controlled ovens. One is 10’X6’ and the other is 6’ X 6’. My dad owns industrial real estate, and he just evicted a guy who was doing powder coating. He left all his stuff, and time has expired for him to come pick it up. Dad was going to auction it off, but I told him to wait until I decided if I was going to do this myself or not.

Thanks for all the input guys. Keep it coming. I’m learning a lot.

#20

If you really want to learn, all I can say is keep watching videos and searching around the forums here. I spent about 3-4 months of my spare time, which was quite a bit at the time as I was only working part time, searching and learning about composites before I even started on my current project doing custom motorcycle bodywork. And that was just finding answers to allow me to do wet layup.

Keep at it - there is nothing you can’t learn. I don’t want to put you off, but if you really want to do it you’ve got to be fairly dedicated and realise it’s going to take some time. But you already spent 10 years to get this far - I’d say you can do it. If you really want to do it, just go for it! :smiley:

The way I approached it was that I didn’t even touch any composites until I had a clear understanding in my mind of the process. That approach makes sense to me, otherwise you just fumble around - whether or not you make mistakes or it comes out great, you’ll not know why it failed or succeeded. Gain the knowledge first, then start putting it into practice on small projects/test pieces/samples etc.

Not that I’ve made anything too great yet, but I can say that it is extremely satisfying creating something from scratch!

When I very first got interested in starting composites years ago, I basically just read a book and went at it (it didn’t even occur to me that there might be a forum dedicated to the subject!). For someone completely new to composites I would highly recommend Competition Car Composites. The reason I found this so great is that everything is explained in simple terms, and the book actually sets out your first composites pieces/tests - it can be daunting knowing what to do first when you have no experience. But you can literally just follow what the book says, then you’re on your way, before you know it you’re using composites and starting to get an idea of how they work. From memory it covers mostly wet layup and polyester resin - but I would say that is the perfect way to start. The basics don’t change, things just get more complex (with infusion etc.). As they say, you need to learn to walk before you can run.

I guess what I’m trying to say is, don’t get all caught up trying to learn about infusion and other techniques until you are competent with wet layup. At least that is my opinion on the subject, and it’s worth everything you paid for it. :cheesy:

I think that book also covers some basic wing construction…