Quote:
Originally Posted by cfg83
Hello -
Back in this thread I was given feedback on what a proper Kamm-Back might look like for my car :
http://ecomodder.com/forum/showthrea...html#post41152 - Post #16
This led me to this design, which was deliberately limited in length by the distance to the back bumper :
I haven't done any serious work on this because I want to maintain rear-view visibilty, third brakelight visibility, the complexity of the gently curved roof shape, and the risk of a "parachute" effect if the top got loose.
Then I noticed this from the 1970's Pinto mods :
$11 worth of mods plus new tires - Car and Driver improves MPG by 25%
This made me wonder if I could compromise and create a simple flat spoiler that would emulate the endpoint of the kammback :
From an aero POV, do you think this would help? I am thinking that this is similar to Ernie Roger's new-Beetle Wing Spoiler.
IMO the positives are easier construction, good rear visibility because only a "single flat line" of coroplast is in the way, third brakelight visibility, and (hopefully) less risk of a parachute effect. The only bad thing is that I would need to disable the rear-window wiper (one fuse), unless I made a gap between spoiler and the rear-window (Ernie did this for other reasons).
CarloSW2 |
I think that as long as the rear edge falls along the template line,that the air will re-attach,forming a locked-vortex above,and the outer flow will skip over it.It won't be as effective as the ideal Kamm roofline but you'll have good rear vision and it will be relatively easy to fab.All the air below it will be in the turbulent wake.A second wing below,and also extending to the template line would create a second locked vortex and even lower drag.Ford proved this with the 1980s Merkur XR4T1 which sports their patented bi-wing spoiler.