Making a more efficient, aerodynamic soapbox gravity race car

[BamZipPow]

I'm surprised you didn't try some Coroplast instead of the sheet metal.

[freebeard]

I don't like to work with fiberglass, but I'm curious where the process fell apart. There was a rough form at permalink #201. Was it smoothed? Did you apply any cloth and resin?

The new nose: One piece of... aluminum? galvanized steel?

[Frank Lee]

Whatever method of fabrication you wind up with, I suggest nice generous radii on all leading surface transitions. And pay as much attention to the rear of the machine as the front, if not moreso.

[orengomotors]

Originally Posted by BamZipPow

I'm surprised you didn't try some Coroplast instead of the sheet metal.

Well, haven't worked with coroplast before, and i didn't even thought on it.
But i'm interested to know how to work with it if is useful for other parts of the car.

I don't like to work with fiberglass, but I'm curious where the process fell apart. There was a rough form at permalink #201. Was it smoothed? Did you apply any cloth and resin?

The new nose: One piece of... aluminum? galvanized steel?

It wasn't for the smoothness of the mold, it was for time reasons ( the race season starts on January 12 ) and because the mold wasn't perfect , in fact far from it, it was asymmetrical and kind of " dented".
So after losing so much time with the foam, It annoyed me, i got angry and i decided that doing it with metal was the best option.
Galvanized steel 0.7 mm of thickness.

Whatever method of fabrication you wind up with, I suggest nice generous radii on all leading surface transitions. And pay as much attention to the rear of the machine as the front, if not moreso.

The Rear is the Next Project!


i think that no one liked the nose

on January 17 i will race the gravity racer, i will record the race and use dashware, what do you think, should i use the wool test on the race to see the aero effects of the nose?

[aerohead]

I think that you're going to see a bunch of vorticity due to the hard edges.
I'm with Frank,recommending radius'd edges everywhere.
You're kinda 1/2-scale,so maybe a 40mm radius minimum.

[freebeard]

i think that no one liked the nose

I never said that. I'm glad you gave up on that marbelized foam thing. Fiberglass molds need a high surface finish.

Leave it to Frank Lee to say "Everything you do is wrong!" The angled edges above the suspension might need a little eyebrow. The objections are to the edges across the flow. Look for the solutions where trailer owners have put half-round on their boxes.

Well, haven't worked with coroplast before, and i didn't even thought on it.
But i'm interested to know how to work with it if is useful for other parts of the car.

Coroplast is, in the words of Lt. Niedermeyer, "weak and worthless".*

Use prefinished sheet material (galvanizing counts), save hours compared to finishing a raw fiberglass part. Here are solutions to seaming along and across radii. Curved edges result in pseudo-compound curved surfaces.



Most builder run the gores lengthwise, the 1947 Roswell goes against the grain.






*Coroplast with welding rod slipped into the flutes might work.

[Frank Lee]

I said no such thing.

Besides, the only person that has to be happy with it is him.

[freebeard]

The cowl areas has a lot of constraints. Clearing the suspension and all.



It's not so far off from this. A curved plexiglass low windscreen would give any vorticular detachment a place to go die. The sharp front corners are unfortunate. Simply cap them with a forward facing bullets. Or a 1/3th scale bull horn.

[renault_megane_dci]

What about moving front struts inboard ?
Or at least add a fairing on them.

I assume you will also do the back of the vehicle ?

I am looking forward to see numbers on how that translates on the track !

[gone-ot]

I LIKE the "welding rod-in-coroplast" stiffening idea!