Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Tuft Testing on Insight Hatch Glass (2006 Honda Insight, 1st gen.)

aerohead · 11-02-2011, 06:51 PM

On GOOGLE IMAGES there is a wind tunnel image of the North American Solar Challenge-winning car from the University of Michigan.
It's just a still photo of smoke going over the solar cars body.
The thing that gets me,is that the smoke is literally trying to grind the finish right off the car,all the way down the aft-body to the trailing edge.
This is my interpretation of perfectly attached flow,with the smoke hugging right at the surface.No wiggling.Perfect surface contact.
I believe that this is our objective,however there's is not a lot of 'science' to draw on.
Renault's Vest II is significantly shorter than the 1st-gen Insight and is credited with Cd 0.187 vs 0.25 for Insight.
Vesta's roofline is very close to the Template.I do not have a proper plan-view of the car so I can't really address that,except that it appears to have significant plan-taper as with EV-1.
Mercedes Boxfish is also shorter,appears to be right on Template,and also has Cd 0.19.
So to Jim's question about raising the hatch,I think it would be worth the investigation,although I don't like to play fast and lose with other's time and resources,as I myself would not be doing all the work.
There are many 2012 cars out now with Template roofs of various lengths and some a year away from showrooms.
My gut feeling is that raising the roof on the HONDA would 'show' at the gas pump.
You would in all likelyhood lose total rearward vision.( you'll notice that Bugatti uses an upright backlight reminiscent of the 1967 Lotus Europa for their Veyron.

11-02-2011, 06:51 PM	#41 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 16,364 Thanks: 24,463 Thanked 7,401 Times in 4,795 Posts	University of Michigan On GOOGLE IMAGES there is a wind tunnel image of the North American Solar Challenge-winning car from the University of Michigan. It's just a still photo of smoke going over the solar cars body. The thing that gets me,is that the smoke is literally trying to grind the finish right off the car,all the way down the aft-body to the trailing edge. This is my interpretation of perfectly attached flow,with the smoke hugging right at the surface.No wiggling.Perfect surface contact. I believe that this is our objective,however there's is not a lot of 'science' to draw on. Renault's Vest II is significantly shorter than the 1st-gen Insight and is credited with Cd 0.187 vs 0.25 for Insight. Vesta's roofline is very close to the Template.I do not have a proper plan-view of the car so I can't really address that,except that it appears to have significant plan-taper as with EV-1. Mercedes Boxfish is also shorter,appears to be right on Template,and also has Cd 0.19. So to Jim's question about raising the hatch,I think it would be worth the investigation,although I don't like to play fast and lose with other's time and resources,as I myself would not be doing all the work. There are many 2012 cars out now with Template roofs of various lengths and some a year away from showrooms. My gut feeling is that raising the roof on the HONDA would 'show' at the gas pump. You would in all likelyhood lose total rearward vision.( you'll notice that Bugatti uses an upright backlight reminiscent of the 1967 Lotus Europa for their Veyron.