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Old 01-28-2019, 02:19 PM   #261 (permalink)
Bicycle Bob
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Location: N. Saskatchewan, CA
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Quote:
Originally Posted by arcosine View Post

35 mph is pretty fast for flat ground and no wind. Yes a suspension is good. I rode on a bumpy bike trail, with cracks across, and it was like being inside and someone kicking the sides of a cardboard box. I put zote foam between the frame and coroplast.


Yes the nose it from Warrens Barracuda mold, and it is too long, I tried it out 20 mph down hill into a 25 mph wind and 23F and was buffeted quit a bit, I want to make a new nose. I find the noses are the hardest to get right. I should just bite the bullet and carve up some Styrofoam make one from fiberglass.
John Tetz makes whole velomobile bodies from Zote foam, and after riding inside a Coroplast drum, I'd do the same. I have excellent suspension, but the body also needs isolation from road rumble, a far higher frequency. That's why car sub-frames are rubber mounted, as well as all the suspension bits.

Bikes need that long nose for stability, but it works against a trike. I try to design everything so that if it hit a patch of wet ice in a bad crosswind, it would only move over, not yaw.

For one-off molds, I stack and glue a hollow shape of styrofoam to carve, and then finish it with wall spackle. Sometimes, I even make a mix of spackle, latex paint, and microballoons which sands just as readily as the foam. Once it is sanded to the perfect shape, a coat of shellac or other paint gives it a glossy finish, ready to be very lightly sanded, waxed and used once as a mold. A fairly shallow nose cone can be draped with a single unwrinkled sheet of fiberglass cloth. Satin gives extra compliance. Or, you can pull a mold, and make really light parts that are semi - disposable.

If you would like to try something faster, you can clamp some thermoplastic to a surface, using a cutout the shape of a cross section of your fairing. Then, add a bit of constant-fed air pressure behind the plastic, and soften it with a heat gun, controlling the shape with your aim. I'd buy enough plastic for one test piece, and have a cutoff handy on the pressure.

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