Quote:
Originally Posted by examorph
Wow, so many replies and some very good information! Thank you, now, I have a new question, length vs height vs width?
I have changed some things around on the car to reduce the length of it by almost half! but it has added a bit to the width but the material used to compensate for the width is no where as near as much as the material saved on length, also I have took the advice the majority of you have given and covered the wheels up.
so in conclusion, is it worth increasing the height and width to compensate for the reduction in length or should I really not worry as much about length and try keep the car as slim and low down in height as possible?
Also, one last question, is there any disadvantages of allowing the airflow under the vehicle?
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*For an 'enclosed-wheel' car,the air 'see's the car and it's reflected mirror image below the ground.
*For this 'ground-reflection' situation the air likes a car which is 5 times as long as it's height,or 2.5:1 for the body and reflection.This is demonstrated with the Aerodynamic Streamlining Template.
*If you're doing an exposed wheel design,you might want to treat the body as an aerodynamic section instead of a body of revolution,where the majority of air goes around the body.With sections,the lowest drag is reached when the length of the body is about 3.8 times the body width,just as with the TNE-3 car mentioned earlier.
*With faired-in bicycle wheels you're looking at Cd 0.10.
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*you're trying to minimize frontal area,reduce unnecessary body surface area (and it's friction),and slip in with the lowest coefficient of aerodynamic drag by shrink-wrapping the body around the driver and mechanicals while respecting aerodynamic minimums for attached flow.
*length of the body will be dictated by whether you're going to do a streamline body of revolution or streamline section.
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As to the under body flow,it appears that some of the 'special' shapes fair no better than bodies with 'normal' ground clearance (as the TNE-3 car).
*You've probably seen NUON's NUNA series of solar racers.They have exceedingly low drag coefficients.For a battery-only EV this shape might not have the interior packaging capabilities you'd need.You should check these cars out if you haven't already done so.
Sounds like a really fun project!
