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Old 05-18-2014, 08:10 PM   #1
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Default Where can I buy chassis like Traxxas Evo?

Err XO-1 lol.

I've noticed a tendency at speeds above 50 that any upset usually results in the car becoming airborne. I watched my TC4 do a reverse wheelie, front tires on the ground, rear end to the sky, after spinning at high speed. The air caught under the rear baffle and pushed the rear end up for about 25feet.

I would like to put some serious aerodynamic stabilization on the chassis of my TC4. Does anybody make add on's, or a chassis that will fully encase the wheels, and side wings that go all the way out to the side of the body so that there is an airtight seal all the way around body and wheels?

You know what I mean, like a skirt that goes around the chassis and wheels with a defuser at the back so that the body gets velcroed to it and becomes structurally supportive.

If nobody makes anything like that I think I might try to fabricate one using Instamorph plastic. Has anybody else tried underbody aerodynamics?

Last edited by kodack10; 05-19-2014 at 10:37 AM.
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Old 05-18-2014, 09:44 PM   #2
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Originally Posted by kodack10 View Post
I've noticed a tendancy at speeds above 50 that any upset usually results in the car becoming airborne. I watched my TC4 do a reverse wheelie, front tires on the ground, rear end to the sky, after spinning at high speed. The air caught under the rear baffle and pushed the rear end up for about 25feet.

I would like to put some serious aerodynamic stabilization on the chassis of my TC4. Does anybody make add on's, or a chassis that will fully encase the wheels, and side wings that go all the way out to the side of the body so that there is an airtight seal all the way around body and wheels?

You know what I mean, like a skirt that goes around the chassis and wheels with a defuser at the back so that the body gets velcroed to it and becomes structurally supportive.

If nobody makes anything like that I think I might try to fabricate one using Instamorph plastic. Has anybody else tried underbody aerodynamics?
I have fabricated an under tray on my Rally GT8 from XO-1 car.
https://www.youtube.com/watch?v=CTp-...w&noredirect=1
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Old 05-18-2014, 09:59 PM   #3
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Even with that, at high speeds if the car isn't going straight it will likely catch air and flip or fly. Those are meant to reduce air buffering and smooth out flow underneath the chassis, not support the body. It could work for the support piece though.
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Old 05-19-2014, 10:41 AM   #4
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Yeah, the defuser is more to help with the low pressure that tends to build up at the back of a car as it runs at speed. The chassis being body wide and velcroing the sides to the chassis is more what I meant by structural. Lexan is quite tough but it bends easily. If you can secure the body all the way around the chassis without gaps it ends up being quite strong and as long as you don't hit anything, you can flip, roll, slide on the roof, etc and usually nothing breaks.


Cool video, you should show the inside of the car too. PS am I the only one that can't see a car pass at speed and hear the "WAAAAAAAAAAAAaaaaaaaaaaa" sound of an indycar in my head?
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Old 05-19-2014, 06:47 PM   #5
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I put bumper foam under the body to keep it from bucking in at high speed, if you look at the video again at the end you see the foam.

yes the under tray is to reduced air captured inside, once you get the speed you don't really need that much steering adjustment as long as your wheels are set-up right.
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Old 05-20-2014, 09:44 PM   #6
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Yeah I saw some pictures on a wordpress site someone set up. They put bumper foam over the chassis to keep the roof from caving in if it flips, and bumper foam with velcro on it for hte sides. Not a bad idea. I still think I'm going to give Instamorph a shot though. I've been able to frabricate some pretty cool things with it and while it's not very stiff, its' strong and resilient, perfect qualities for a skirt material.
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Old 05-20-2014, 10:15 PM   #7
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Old 05-21-2014, 07:56 AM   #8
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Damn, that looks pretty well made. Can we see on the car? For a speed run that probably would stabilize a car. Run it and let's us know how it goes.
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Old 05-21-2014, 08:50 AM   #9
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The rear wing isn't finished in this photo, but you get the idea. No jokes about the paint job.
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Old 05-21-2014, 09:00 AM   #10
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Anyway, my point to the OP is, just make one. I think there's more fun in making something yourself, then just buying something and bolting it on. Don't accept what people tell you can't be done.
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Old 05-21-2014, 12:28 PM   #11
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That seems a little over engineered making it out of metal, is it aluminum or sheet steel? But then again I guess weight only affects getting up to speed and that is weight almost *below* the center of rotation of the wheel which should be pretty stable so thats pretty good. Did you use longer chassis screws to off-set the thickness of the metal or is that your actual chassis and not a underneath bolt on?

I was thinking of doing something like that, but using it like a skirt, that goes around the stock chassis.

Instamorph if you don't know is a low temp thermoplastic that you put in very hot water, and then work by hand before it sets up. I liken it to a stiffer and more plastic like hot glue.

I was thinking I would roll it out like dough to get a flat uniform sheet, and then work it with a heat gun and modelling tools to get it into shape.
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Old 05-21-2014, 07:57 PM   #12
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Quote:
Originally Posted by kodack10 View Post
That seems a little over engineered making it out of metal, is it aluminum or sheet steel? But then again I guess weight only affects getting up to speed and that is weight almost *below* the center of rotation of the wheel which should be pretty stable so thats pretty good. Did you use longer chassis screws to off-set the thickness of the metal or is that your actual chassis and not a underneath bolt on?

I was thinking of doing something like that, but using it like a skirt, that goes around the stock chassis.

Instamorph if you don't know is a low temp thermoplastic that you put in very hot water, and then work by hand before it sets up. I liken it to a stiffer and more plastic like hot glue.

I was thinking I would roll it out like dough to get a flat uniform sheet, and then work it with a heat gun and modelling tools to get it into shape.
The car is designed to go pretty fast, so I don't think you can over engineer it. It's made out of aluminum, and it screws to the bottom of the stock chassis. It's an 1/8 scale car, so any plastic or carbon fiber wouldn't be stiff enough. It also has flexable skirt/seals to channel the air to the rear diffuser.

If I were you I would make a mold of the shape you want and vacu-form it out of .090 lexan. It's light, super strong, and you can easily duplicate it if you crash.
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Old 05-22-2014, 08:02 AM   #13
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If you are still looking do 1\10 chassis with wind dam. Look at Sakura d3
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Old 05-23-2014, 10:34 AM   #14
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Quote:
Originally Posted by reracer View Post
The car is designed to go pretty fast, so I don't think you can over engineer it. It's made out of aluminum, and it screws to the bottom of the stock chassis. It's an 1/8 scale car, so any plastic or carbon fiber wouldn't be stiff enough. It also has flexable skirt/seals to channel the air to the rear diffuser.

If I were you I would make a mold of the shape you want and vacu-form it out of .090 lexan. It's light, super strong, and you can easily duplicate it if you crash.
Did you build your own vacume forming rig? Was it hard?
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Old 05-23-2014, 11:27 AM   #15
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Did you build your own vacume forming rig? Was it hard?
I don't vacuum form anything. It doesn't look that difficult though. Look on YouTube, there are a bunch of videos. The hard part is making the form, but once you have that done, you can make as many as you want. You can also vacuum form carbon fiber, but that's much more difficult.
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