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Old 06-25-2008, 12:29 PM   #37 (permalink)
MechEngVT
Mechanical Engineer
 
Join Date: Jun 2008
Location: Richmond, VA
Posts: 190

The Truck - '02 Dodge Ram 1500 SLT Sport
90 day: 13.32 mpg (US)

The Van 2 - '06 Honda Odyssey EX
90 day: 20.56 mpg (US)

GoKart - '14 Hyundai Elantra GT base 6MT
90 day: 31.25 mpg (US)

Godzilla - '21 Ford F350 XL
90 day: 12.1 mpg (US)
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The problem with the VW front end is that you will be limited to a vehicle that's approximately as wide as a VW. This would work great on side-by-side reverse trikes but increases your frontal area over a tandem.

Decreasing the frontal area is one of the easiest ways to improve aero, plus by lengthening the vehicle it will be easier to improve the Cd.

I would go reverse-trike tandem like the VW 1L concept and even knock off their general shape (I'm guessing trikes have fewer anti-regulatory advantages in Europe). That concept uses an 8.5hp/13.6 ft-lb 300cc diesel to get between 235 (quoted range of 404 mi on 6.5L fuel) and 317 (stated in the article) mpg according to the link. I wonder what could be done with a Honda iGX440 (438 cc, 12.7hp@3600, 22ft-lb@2500). It has electronic start/stop built in and has application-configurable electronic speed control. You could pair it with a CVT and it would be ideal for pulse-glide, plus it would be nearly off-the-shelf for a DIY trike project and even though you'd be lucky to get 50% the economy of the VW 1L, you're still talking 117-158 mpg. Based on the height/width of the 1L and the stated Cd I estimate the CdA at ~.16m^2, so if aero was the only drag the iGX should push you to 93 mph assuming 25% drivetrain loss, so add in rolling resistance or hedge drivetrain loss and you're still above highway speeds. I wouldn't want to accelerate uphill with two-200lb riders plus groceries, though.

Because of a tandem setup I would go with SLA suspension. Given the single rear wheel I wonder what geometry would be favorable and stable, but you'll either have to go negative-SLA to put the roll center below ground for an understeer gradient or get extreme with a x-over positive SLA and put your roll center above the vehicle's CG and it will actually lean into the turns

Since the car will be narrow and long with SLA front it would be ideal for a longitudinal torsion beam front suspension more in line with late-60s Chryslers (E-bodies, B-bodies).
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