Quote:
Originally Posted by BabyDiesel
The fact that you used "two lousy hundredths" as the title cracked me up 
ECOSCORT might get in trouble as well, since I have no side mirrors  I am legal as far as the state of NC is concerned. And wow, I did not realize how much side mirrors affected the Cd!
I recall that if the template was followed exactly on my car, the total length would reach between 20-21 feet! That is longer than an extended cab long bed Chevrolet Silverado, but it is still shorter than this -
How is that for elongation??
An active diffuser, hmm... what is wrong with a set height diffuser that is low enough for good aero,flexible enough to withstand city driving and rigid enough to survive 60 mph?
The inflatable boattail is a wonderful thought! I am unsure how to implement it in the real world. I'll think on it and weigh between it and the rigid tail.
That is what I love to hear
I am planning on a 2" suspension drop front and rear, keeping the car as level as possible. I MAY try to drop it a little less in the rear so my belly pan acts as a diffuser. It will work out the geometry when that time is closer.
I actually have access to a smoke machine at my church  so I am tempted to borrow it and do a mock-up wind tunnel test! This will have to be on a super calm day, or even indoors. First thing I will have to do is see if the fog can even get thick enough to see and if I can get a fan to generate 50+ mph winds. I could make scale models and test them out easier.
Right know, I am trying to figure out how to attach tire boat tails to my car along with outer and inner side skirts, and it is more difficult than it first appeared. Then I want to redesign the rear fender skirts along with designing the front fender skirts!
...Gotta take it one day at a time...  |
*It's great that you can do the inside mirrors.
*Hucho and others will have you figure on a final length equal to about 4X body height to get a slick fineness ratio.Here you can see Jaray's length to get Cd 0.13.
*The 'active' tail provides a 'practical' length for parking and driveway ramps.
*The active diffuser allows the 2.5-degree angle of lowest drag,which will get knocked off if you drive it around town.
*My 1st inflatable was a bean bag chair envelope stapled to a wooden box and 12-V inflation fan.A later,Naughahyde envelope saw road duty
*If you do models,you've got to watch your dynamic similarity,verisimilitude.In full-scale you need at least 20-mph for critical Reynolds number.
*At 1/2-scale you need 40-mph
* 1/4-scale 80-mph
*so on.
*It's actually easier and cheaper to do full-scale.
*The template works as far as drag reduction,although we can't control how your engine's BSFC will react.MetroMPG proved this to us in his latest CIVIC testing.
*For the wheel boat tails your minimum contour would be the center form in the table below,but actually the better the longer as the SAE Ecomarathonners and solar teams have found.
*As to the boat tails themselves,if you had access to a sewing machine;the fairings can be foam rubber cut with an electric carving knife,inside a leatherette envelope (made exactly like a seat cover),attached to an aluminum plate,which has Velcro taped on.The units are Velcro'd onto the belly.Very light.Relatively fast build.Low tech.
*For the wheel skirts,have you been to the AEROCIVIC thread where Mike illustrates how he did his.It's kinda how I did mine on the T-100,although my rollers are inferior to Basjoos' setup.