CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car From Scratch

[NeilBlanchard]

Originally Posted by Grant-53

If wind tunnel time is pricey look around for someone with a camera drone. You could do tuft testing on a lonely road with the drone.

That would require a functioning car - which would be a lot more work. If I can at least test the aero, I could make molds and new body panels that could be used on a much more conventionally built chassis. And possibly get to a working car with less time / money / effort.

Another way to go, that I have been thinking about, is to build a new prototype with the method used for the Trev:

https://teamtrev.com/

Which is a folded "box" of composite sandwich panels, with foam added on the outside. This is MUCH quicker and has much better 3D accuracy, and has structural strength built in.

[freebeard]

Camera drones are good for maybe 25mph. Racing drones are good for 120mph.

I suggest a camera on a tripod at the center of a 100ft circle. That way you can characterize cross-wind flows.

NeilBlanchard: I've watched the adventure over the years and wondered about starting over. That's a lot of work to just melt into a puddle, but you've learned a lot and I support your eventual decision.

I've thought about an Inrekor style chassis, but made with swing-door material.


http://ecomodder.com/forum/showthread.php/so-why-do-you-think-there-no-cheap-32312-5.html#post487108

PlyMetal™ Swing Door - PLYWOOD CORE WITH INTERIOR AND EXTERIOR ALUMINUM LAMINATES

[Galane]

Convert the body to polygonal models of different sections then use Pepakura to make a folding pattern.

To achieve symmetry, figure out how to make a mirror pentagraph with a 1:1 ratio. Then you hand shape all of one side. Build up the other side with material thicker than needed everywhere. Trace the finished side with a stylus while a router mirrors the Y plane (in-out from vehicle axis) on the other side while moving the same as the stylus in Z and X planes. A 2 axis tilt on the stylus, copied by the router, would help reproduce finer details.

With a stylus and router bit of the same shape and the positioning correct so it's not carving too much or too little, it would make fast work of finishing a body plug for making molds.

In short, like a giant Copy Carver that works in more than two axes. If it fails, hack it up with a pair of axes.

[freebeard]

I'm not sure how the Pepakura Designer software helps with routering foam.

However the peel pattern it generates could substitute for the stage of hammer-forming sheet aluminum that Randy Grubb uses. Make a wooden buck that egg-crates together like he uses. Make one half, dissassemble and reassemble in reverse for the other half.

[Grant-53]

I have been looking at some paper model software and the HPV Shell Design program of Wayne Shook at recumbent.com. The tub I might try to make from my stock of 9mm aluminum honeycomb (Testori America) per cut and fold and the skin from 0.062" ABS since I would not be making a mold.
There are new drone models coming out each year and our son just bought a DJI Phantom which goes right fast. When he gets proficient he could do highway speed camera work for tuft testing for say $200/hour.

[samwichse]

Is this project dead? It was looking so cool...

[NeilBlanchard]

It is dormant. But not dead. The foam plug that I built is still sitting in my (tiny) garage, and the Saab 900 I bought for its suspension is still sitting in my yard.

My hope is to get a layer of fiberglass on it, and take it to a wind tunnel. But, my attic addition has to be worked on, enough to use it. (See my posts on my solar PV system.)

[DFBVT]

Thanks for the update. Life does have a way of getting in the way of some of our dreams.

Dave

[Galane]

Originally Posted by NeilBlanchard

It is dormant. But not dead. The foam plug that I built is still sitting in my (tiny) garage, and the Saab 900 I bought for its suspension is still sitting in my yard.

My hope is to get a layer of fiberglass on it, and take it to a wind tunnel. But, my attic addition has to be worked on, enough to use it. (See my posts on my solar PV system.)

So you've decided to give up on the idea of coating it in wood glue?

[NeilBlanchard]

I will use Titebond III with the fiberglass.

I should mention that I will need to have a larger work area - either an addition to my garage, or possibly a fabric hut, so I have room to move around it.

Another possible path is to make an accurate 1/4 scale model and test that in the 2X atmosphere pressure Wright Brothers wind tunnel at MIT.