09-12-2014, 10:43 AM
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#1 (permalink)
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Master EcoModder
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Wind Power- Attaining Negative Cd
I found this in the IHPVA archives... it may not be applicable to our vehicles today or ever, but it's fun to think about.
Pages 5-7
Pages 17-18
http://www.ihpva.org/HParchive/PDF/33-v10n2-1992.pdf
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Last edited by Sven7; 09-12-2014 at 10:49 AM..
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09-12-2014, 10:55 AM
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#2 (permalink)
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Master EcoWalker
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The concept of crab steering is quite interesting, even for full size cars at high speed.
I can see by how much side wind affects fuel economy. Allowing the car to turn into the wind a bit would help a great deal.
Should not be too hard to do on a FWD car, especially on those that came equipped with 4 wheel steering.
I doubt whether it is road legal. It would also shift the headlight beam pattern.
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09-12-2014, 04:17 PM
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#3 (permalink)
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Master EcoModder
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If it's not illegal, it's legal, eh? Eh? 
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He gave me a dollar. A blood-soaked dollar.
I cannot get the spot out but it's okay; It still works in the store
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09-12-2014, 04:44 PM
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#4 (permalink)
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Master EcoWalker
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It would be if it were a motor bike. I mean, 'motor bike'. 
I've done some calculating. In a solid sidewind the pressure pushing the car sideways could be, say 500 Newton.
Under a 5% slant that would make a net forward force of 25 N.
At 65 mph, almost 30 meter per second, that saves 750 Watt on power. You would see that on your per tank average.
Better still, if you build your own 200 mpg super light 3-wheeler, this trick would still yield about the same advantage, and then it really stands out.
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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gigameter or 0.13 Megamile.
For confirmation go to people just like you.
For education go to people unlike yourself.
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09-12-2014, 04:47 PM
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#5 (permalink)
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Master EcoModder
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What if the wheels and frame pointed straight but the passenger compartment and majority of the body angled into the wind?
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09-12-2014, 06:05 PM
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#6 (permalink)
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Not Doug
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Quote:
Originally Posted by Hersbird
What if the wheels and frame pointed straight but the passenger compartment and majority of the body angled into the wind?
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Quote:
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Crab steering is a special type of active four-wheel steering. It operates by steering all wheels in the same direction and at the same angle. Crab steering is used when the vehicle needs to proceed in a straight line but under an angle (i.e. when moving loads with a reach truck, or during filming with a camera dolly), or when the rear wheels may not follow the front wheel tracks (i.e. to reduce soil compaction when using rolling farm equipment).
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Steering - Wikipedia, the free encyclopedia
I needed to look it up.
 
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09-12-2014, 06:16 PM
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#7 (permalink)
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Master EcoModder
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Here's an application for adaptive skin that would change the vehicle shape. Vertical sail panels could aid in propulsion. Great student project.
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09-13-2014, 12:55 PM
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#8 (permalink)
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Master EcoModder
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It's done like this:
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09-13-2014, 06:22 PM
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#9 (permalink)
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EcoModding Apprentice
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It's exactly how windsurfers work, you can do 2.2 x the wind speed in 15-25mph winds. So applying it to a car is possible but it'd be difficult.
Always thought you could use to a gravity racers advantage though
I used to hold the windsurfing record for speed over windspeed  28mph in 12mph winds
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09-13-2014, 11:11 PM
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#10 (permalink)
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Master EcoModder
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While I accept it's possible, I have trouble wrapping my head around it. Windsurfers can tack, right? I don't get the rigid airfoil, it must be toed-out or toed-in or something. In the picture it appears to be convergent.
This I can Understand:
Edit: I've thought about it and have decided it's like the Wells turbine used in the Ocillating Water Column power plants.
Last edited by freebeard; 09-14-2014 at 12:08 AM..
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