Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Underfloor and Body design of Greenpower Car (similar to Electrathon)

stealth · 03-02-2016, 09:17 PM

For that first body, I exported that model into a paper folding software called Pepakura and once I got the pattern which wasn't perfect, had a quite a few broken panels, I had to modify it in Draftsight, and used that to cut the big corroflute sheets.

If I'm doing a body similar to the catamaran design, I think I would use the underside of the body as part of the chassis which is a very wide upside down 'U' shape and use a laminate structure to form the backbone of the chassis. The front 200-300mm will be a foam structure for the crash protection. The whole top and side surfaces of the body will be a single piece of carbon fibre or fibreglass shell with minor reinforcement. All depends on time as always

The channel underneath makes it useful for making the chassis stiffer but I have to make sure that having a channel underneath is good thing, the tests tells me that it helps a lot for having really low drag. If I remove the side flanges of it, it tends to increase the drag (10%) by exposing the more of the wheels and as the wheels are static in the virtual wind tunnel, the effect would be greater when the tiny wheels are actually spinning around at 40mph. This is usually minimised by using wheel fairings underneath.
So its a case of whether having 4 individual wheel fairings (smallest FA) or two long sweeping fairings like the catamaran design (slightly bigger FA) or completely lowering the ground clearance down to 30mm and reduce the draggy underflow (biggest FA). What would your choice be?

03-02-2016, 09:17 PM	#27 (permalink)
stealth EcoModding Lurker Join Date: Feb 2016 Location: Cornwall, UK Posts: 18 Stealth II - '16 Stealth Racing Stealth II 90 day: 2117.65 mpg (US) Thanks: 5 Thanked 11 Times in 7 Posts	For that first body, I exported that model into a paper folding software called Pepakura and once I got the pattern which wasn't perfect, had a quite a few broken panels, I had to modify it in Draftsight, and used that to cut the big corroflute sheets. If I'm doing a body similar to the catamaran design, I think I would use the underside of the body as part of the chassis which is a very wide upside down 'U' shape and use a laminate structure to form the backbone of the chassis. The front 200-300mm will be a foam structure for the crash protection. The whole top and side surfaces of the body will be a single piece of carbon fibre or fibreglass shell with minor reinforcement. All depends on time as always The channel underneath makes it useful for making the chassis stiffer but I have to make sure that having a channel underneath is good thing, the tests tells me that it helps a lot for having really low drag. If I remove the side flanges of it, it tends to increase the drag (10%) by exposing the more of the wheels and as the wheels are static in the virtual wind tunnel, the effect would be greater when the tiny wheels are actually spinning around at 40mph. This is usually minimised by using wheel fairings underneath. So its a case of whether having 4 individual wheel fairings (smallest FA) or two long sweeping fairings like the catamaran design (slightly bigger FA) or completely lowering the ground clearance down to 30mm and reduce the draggy underflow (biggest FA). What would your choice be?