I’ve been debating building my own carbon fiber wing for a while now. I guess it boils down to that I’m not an aerospace engineer and it’s a little intimidating. I’ve voiced that thought to several friends and I get a look back like “are your crazy”. It’s then followed up with “You can build an entire car, but you can’t build a wing?”. After talking to a former pro driver, a race car builder, and my friends that were nudging me, I figured I’d give it a shot.
Custom carbon fiber wings are very expensive. Not to discredit the work or the price tag, it’s just not in the budget right now. I’ve done quite a bit of homework, from construction methods (typically 2), wing profiles, and mounting. I wanted to show you guys how I’m going to build mine. There are a couple of different ways, so heres mine.
You can build a wing with a foam core or a two piece mould. Nicer wings are typically built with two separate carbon fiber wing halves (top and bottom). They are then bonded together. To go with that method, you need to build a wing from foam, shape it, finish it, and build fiberglass molds to copy the out side dimensions. This is perfect for production or manufacturing wings.
For the guy who just wants to build their own, another way is to shape a foam core and wrap the the foam in carbon fiber. Now the latter option seems a lot easier, but it has some trade offs. That being said, I’m going to go with the second option.
I was having a tough time finding a place online that carried foam cores specifically for cars. I found a lot of sites that built custom foam core wings for RC planes. I called a few and they had no clue what I wanted to do. One place said they could cut the foam, but I would need a profile shape. Well shit… I didn’t think about that. So, I started googling legit wing profiles and I came up with a few. I ended up tracing a shape from a Porsche race car in person. To my surprise it was pretty basic and it was similar to shapes I was finding on the web from top notch wings. I printed out the profile to scale on a piece of paper and traced it over to some scrap aluminum sheet that I had. They next step was to cut 2 matching profiles. I used my trusty electric sheers to make the cuts and switch to my angle grinder to smooth them out. You can also make these out of wood.
I kept reading that people were cutting their own foam cores with hot wire bow cutters. It’s pretty simple, but the last thing I needed was another project. Check out this link on how it works. The art of hotwire.
My last ditch effort was to call a local RC shop. I asked to speak to someone in the airplane department. “Hello, this is Spencer”. I asked Spencer if he knew of anyone who could cut a foam core for me. I knew it was a long shot. “I do. I actually cut them myself.”. I then explained that I needed it for my race car. The next questions was “Do you have profile templates and how big?”. I new this would be the kicker… I said I did have profile templates. The cord length needed to be 11″ and I needed the width to be 70″ wide. The width was going to be an issue, but he said he could glue 35″ spans together.
The next day I stoped by the local RC shop and met Spencer. He was really excited to do something different. I left him with my aluminum profiles and a few days later he gave me a ring. “Shawn, your wing is ready”.
End Plate Mounts
The core came out really nice. I’ll be honest, this next part is a little confusing for me to explain. Feel free to post in the comment section if I lose you. The endplates of the wing need to mount to something substantial. If you’re limited on fabrication skills, I’ve seen people use wood to build a end plate bracket. CNC’ed aluminum is what the pro’s use. I’m on a budget, but fortunately for me I’m pretty handy. I decided to fabricate mine out of aluminum sheet metal. This requires a lot of work, but I’m building the mounts with scrap material.
Remember the 2 aluminum profiles I cut 2 sets out? Im now going to use them as my end plate mounts. In my research, I saw a few DIY’ers glue thin plates to the ends of the foam core and call it a day. I’ll be generating a serious amount of down force and I’ll have sizable carbon fiber end plates. They are going to generate a lot of lateral force. The endplate brackets need to have some meat on them. It will make more sense later.
I then hand formed some 3/4″ wide strips to match the profile to add some width to the mounts. This was tricky to say the least. If you’re not handy with metal or limited on tools, 1/2″ or 3/4″ plywood will work.
The next step was to weld them. I have plenty of projects going on with the Z, so I looked to my good friend and great welder, Chris, to buzz them together for me.
I had a lot of fun with this next step. I needed to grind the welds down. I really wanted to spend some time on these (even though no one will ever see them). The vision was to create perfect 90° angles to ensure the mounts were laster flat. I bolted the 2 end plate mounts together to get the exact same profile. My bench belt sander was perfect for the job. I constantly checked them to the foam wing for reference. I was really happy with the work I put in.
I needed to attache Riv-Nuts to the brackets. This will give me the ability to attach carbon fiber end plates later. The Riv-Nut head sticks up about a 1/16 of an inch off the surface. To make sure my carbon fiber end plates sit completely flush to the wing, I needed to counter sink the Riv-Nut head. It’s hard for me to believe that this started from scrap aluminum.
Bonding the mounts to the foam.
The next step was to epoxy the end plate mounts to the foam core. Since the mounts had the exact same outer profile as the foam, I needed to put a step in the foam. Then the mounts could slide over the foam for a seamless and flush fit. I made a depth mark on the foam and busted out my trusty Dremel. A few minutes later the mounts slid over tightly. I also cut out recesses for the Riv-Nuts.
After the test fit, I mixed up some EPOXO 88 epoxy (this stuff is great) and generously coated the inside of the mounts and slid them on the foam. I then made sure they were flush to the foam and secured them with tape.
Once the epoxy dried, I removed the tape. When the foam was originally cut with the hot wire, it left the surface “notchy”. So I gave the entire foam wing a light hand sanding with some 80 grit sand paper and made sure everything was smooth.
I’m getting close to the carbon fiber stage, but I have one more task before I can start. I’ll be mounting the wing to the chassis, so I’ll need some solid mounting points. I fabricated these 3″ X 7″ aluminum brackets, then I shaped then to match the profile of the wing.
I want them flush mounted. So my dremel came back out. The foam cuts very quick. A steady hand is required.
The next step was to add 1/4-20 Riv-Nuts.
Then I mixed up some epoxy and glued them in place. It’s critical to make sure the mounts are aligned correctly with the foam core. Once everything was aligned with my marks, I used masking tape to keep them in place.
Well that’s it for this part. I want to know if you guys have any questions, so be sure to leave a comment below. In the next post, I’ll begin the carbon fiber process. As always, thanks for the read.