Aero Dynamic Supermileage Car

[smvssd]

We are a High School Super Mileage group searching for a good way to make a very aerodynamic cone for the front of the car. Needs to be at least 24 inches long and be strong enough to hold the weight of a persons legs. Cone does not have to be detachable and should be as light as possible but still have strength. Approx diameter of large end is 15in. Rest of the car is made with Aluminum tubing and fiberglass covering. Any Ideas?

[Vekke]

Round shapes are easy to make without any tool if you know how to make fiberglass parts.24 hour human powered distance record attempt

For nose like that I would build that about 15" "roundish" cross section from styfoam etc. After that attach some nose cone shape like this bowl with some wood sticks to get proper length 24".

Google Image Result for http://www.greenfeet.com/mmGF/Images/Salad_Bowl_all_colors-actual.jpg

After that strecth some fabric over it and put the bowl towards ground and laminate it with resin. Let it dry and then laminate more glasfiber layer over it. That fabric should be something that can soak lots of resin in it. After its cured you can remove the inside bowl and brackets and make some reinforcements with styrofoam ribs etc...

To get it smooth then just add polyester padding and lots of sanding.

Thats how I would do it without any tool.

[Bill in Houston]

get a beach ball the right size, put it into the hole, and glass over it. if the resin melts it, do a layer of paper mache first, then resin. once the resin hardens, pop the ball and pull it out from the inside.

[ChazInMT]

Uh....Have you not really read much in this forum??? Make the front as aerodynamic as possible, and prepare for huge disappointments. Make the back of your vehicle as aerodynamic as possible, and you'll run away with the top prize. It is the back of your vehicle where 70% or so of your aero gains can be made, hear me now, believe me later. Shape the back using the many guides in this forum. Post a drawing or pic er somthin of what yer thinkin and I'll do a quick sketch of what would work well.

[Tango Charlie]

Check out what other teams have done.

Mind the aft body, as ChazInMT has advised.

Good luck, have fun!

[Ryland]

Most of those competitions limit the speed to 30mph so vehicle shape is not as important as drive train, tires, weight and alinement, I've built two and a half of these super mileage vehicles and if your contest allows you to coast then a drive train that allows low friction coasting is important, so is a good clutch so you can feather the clutch for starting from a dead stop, as that is where a ton of gas is burned up.
But if your task is to build the shell, then build it out of foam, glass over it and melt the foam out with solvent or cut it out by hand, two feet is not a great distance so it's just the weight of the drivers legs from the knees on down, a simple spar with a foot peg would support the feet, alot of the time tho you need a metal floor pan to comply with the safty rules, .032" thick aluminum is common and is strong enough to support the feet of a driver if it's bent in to a semi circle, use lexan for the top half with a 1/8" thick aluminum rib connecting the two and it will be plenty strong, but really, for a noise cone that has to hold up to 30mph, I built one out of packing tape, I made a foam form, stretched saran wrap over it and put about 3 layers of packing tape over that, it made a nice stiff noise cone that weighed almost nothing.

[euromodder]

Originally Posted by smvssd

We are a High School Super Mileage group searching for a good way to make a very aerodynamic cone for the front of the car.

Do you take cone literally, like this :


Such a cone is not the best aerodynamical shape @ the front.
You'd be better off with a rounded, bulbous shape.

Most importantly : make the rear of the vehicle very aerodynamic, and shield the wheels as much as you can.

Needs to be at least 24 inches long and be strong enough to hold the weight of a persons legs.

As people tend to support the weight of their legs on their heels, that's going to be a serious point load on a long lever.
It'd mean that the material should be quite sturdy, and heavy.

Why not extend the alu tubing forward to support the rider's feet and legs ?
Sure, that'll also add weight, but the nosecone could be as light as possible without any structural requirement other than being self-supporting.

Rest of the car is made with Aluminum tubing and fiberglass covering. Any Ideas?

Look into zotefoam if you want lightweight construction and have time for some experimenting with it.

Keywords : zotefoam, John Tetz, recumbent could get you started.

[Hauki]

Originally Posted by Vekke

Round shapes are easy to make without any tool if you know how to make fiberglass parts.24 hour human powered distance record attempt

Thanks for the link! Great reading! Cannot believe he didn't just have a front mounted camera and monitor and ditched the viewing window! But much respect to him. 24 hours in a tin can, no thanks!