Locostdude Posted November 8, 2006 Share Posted November 8, 2006 Has anyone done or know of someone who has done CDF (airflow) testing of a Lotus 7 type vehicle. Del Long Link to comment Share on other sites More sharing options...
Boxologist Posted November 9, 2006 Share Posted November 9, 2006 Outside of Caterham, possibly the makers of teh Dax. Link to comment Share on other sites More sharing options...
slomove Posted November 9, 2006 Share Posted November 9, 2006 Maybe just too depressing..... http://www.usa7s.com/aspnetforum/images/emoticons/biggrin5.gif Link to comment Share on other sites More sharing options...
KENLUDE97 Posted November 9, 2006 Share Posted November 9, 2006 This is what i recieved in my locost "yahoo" list. " The typical modern automobile achieves a drag coefficient of between 0.30 and 0.35. SUVs, with their flatter shapes, typically achieve a Cd of 0.35–0.45. Notably, certain cars can achieve figures of 0.25-0.30, although sometimes designers deliberately increase drag in order to reduce lift." 2.1 - a smooth brick 0.9 - a typical bicycle plus cyclist 0.7 to 1.1 - typical... Formula 1 car (downforce settings change for each circuit) 0.7 - Caterham Seven 0.6 - a typical truck 0.57 - Hummer H2, 2003 over 0.5 - Dodge Viper 0.44 - Toyota Truck, 1990-1995 0.38 - Volkswagen Beetle 0.38 - Mazda Miata, 1989 0.36 - Honda Civic, 2001 0.34 - Chevrolet Corvette Z06, 2006 0.33 - Mazda RX-7 FC3C, 1987-91 0.29 - Honda CRX HF 1988 0.26 - Toyota Prius, 2004 0.25 - Honda Insight, 1999 0.195 - General Motors EV1, 1996 0.137 - Ford Probe V prototype, 1985 I went to: and none of their "7s" had the body mounted "wing" type front fenders but, had the suspension mounted "cap" [?] fenders. I know that the drag difference would be quite a bit between the two fender types. I went back to the image list in the Wikipedia article and it showed a correct Caterham 7 with the capped fenders, no top, with a roll bar so, the numbers ought to be useful enough for Locosts. Link to comment Share on other sites More sharing options...
powderbrake Posted November 9, 2006 Share Posted November 9, 2006 The high drag coefficient , coupled with the light weight, make it feel like I popped a drag chute every time I lift from the go-pedal. The high compression ratio of the Honda engine plus my 4.44:1 differential probably have something to do with it as well. The exit off the interstate near my home is a 1/4 mile long right , then left sweep to a stop sign. I generally hit it at about 70 and lift, then coast to the stop sign. One day a guy pulls up next to me at that stoplight and says,"your brake lights don't work". I told him,"yes they do, I just didn't use my brakes". Link to comment Share on other sites More sharing options...
slngsht Posted November 9, 2006 Share Posted November 9, 2006 2.1 - a smooth brick 0.7 - Caterham Seven Great, now I can tell for sure that the Seven IS more aerodynamic than a brick http://www.usa7s.com/aspnetforum/images/emoticons/thumbsup.gif Link to comment Share on other sites More sharing options...
Boxologist Posted November 9, 2006 Share Posted November 9, 2006 adding to the Cd list, the 1990-91 Eagle Talon had a drag coefficient of 0.29, and the 'boxy' Guiagro designed Eagle Premier/Dodge Monaco had a drag of either 0.31 or 0.33. its all air flow and turbulance. all se7ens wiil suffer from the outrigger front wheels, but the open bottom, flat windshield, and open passenger bay really do us in. Link to comment Share on other sites More sharing options...
solder_guy Posted November 11, 2006 Share Posted November 11, 2006 Dennis Hedges made a pair of half moon windscreens for John Bowman's Rotus 7 in Peachtree City, GA. Rob Mitchell Link to comment Share on other sites More sharing options...
whittlebeast Posted November 19, 2006 Share Posted November 19, 2006 Aero tubing and front pushrod suspension, dunp the windshield and add a cover over the passenger seat and fill in the side of the clamshell fenders that does not change the side profile of the car. .... a little creative paint will help the profile. If none of this creates downforce.... I bet we can get all the way down to .6 Just thinking http://www.usa7s.com/aspnetforum/images/emoticons/smile5.gif AWwhittlebeast2006-11-19 06:17:54 Link to comment Share on other sites More sharing options...
Kitcat Posted December 1, 2006 Share Posted December 1, 2006 Isn't drag the combination of Cd times frontal area? If so, why isn't the 7's somewhat brick-like Cd offset by its tiny size? Link to comment Share on other sites More sharing options...
slngsht Posted December 1, 2006 Share Posted December 1, 2006 it is... but the cd is about twice a normal car, and the frontal area is not quite half a normal sedan, so the overall drag is marginally more. Now, when you lift of the gas, what's carrying you is your momentum, which is a function of your speed and mass (weight). Seven is a feather weight, so it slows down more quickly given the same drag as a normal car. Link to comment Share on other sites More sharing options...
calvin Posted December 1, 2006 Share Posted December 1, 2006 It should be noted that the electric or electric hybrid cars have low CD's because they don't flow air through a raditor, or for the hybrids they flow far less air through a very small radiator. The air going through the radiator and hitting the firewall, is the biggest component of CD, which has nothing to do with the slipery shape of the car. The bottom and the firewall shape are important. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now