Wow! what a day!
With some wood and a tire hammer we were able to restore the skirt enough to run.
Doug was out of town and Tyler did the tunnel duty for us.(a really great guy!)
We started the session doing the smoke imaging.They use polypropylene,forced under air pressure up to the wand head,where the heating element flashes it into the smoke.
I ran the smoke while Gary used his Cannon digital camera on video mode.We used up a 2-Gb SD card for 15-minutes of recorded images.Airspeed started at 25-mph to guarantee a turbulent boundary layer.Later we increased the velocity during the last of the wake survey.
For the force measurements we ran the three 150-200hp air handlers at maximum for a 76-mph airspeed.
Run #1 indicated Cd 0.268.
Run #2 indicated Cd 0.267
Run #3 indicated Cd 0.251 (mirrors folded)
At 75-mph the mirrors are absorbing 1-hp (nasty!)
Front axle was -30-lbs downforce @ 130-mph (extrapolated )
Rear axle was +22-lbs lift @ 130-mph (extrapolated)
There is not a lot of contrast when viewing the smoke but I think everyone will be able to see everything okay.
I could see counterflow only behind the mirrors,tires,and tail truncation.
We spent only 2-hours so there's going to be a cash reserve for our next members trip to Ogden.
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We had all been discussing the CAR and DRIVER tunnel tests at the A2 Tunnel in North Carolina and Tyler was curious about what the numbers correlation between Darko and A2 might be.And since Gary had his 2010,Gen-3 Prius,Tyler said,what about throwing it in the tunnel for a comparison for free!
We juumped at the chance and after reconfiguring the load cell carriers we put Gary's car for a 76-mph run.
The Gen-3 came in at Cd 0.285.We can compare that figure with A2's number.
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So it looks like the T-100 is lower than the Prius,Insight-I and II,LEAF,VOLT,Corvette,and is close to the 1988 Opel Calibra,and not quite as clean as the Tesla-S.
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With a custom bed box which begins plan-taper just behind the cab,and provides tumblehome and radii, blending into the aeroshell,it should be easy to go below 0.20.
Smaller mirrors will help.(Tyler guestimates that a mirror delete would give Cd 0.24).
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We took the SD card to OFFICE MAX,I bought a thumb drive,and for $4 they transfered everything onto the drive,so both Gary and I have a copy of the images.
Tyler gave me a CD of the EXCELL Spreadsheet which has custom features for interpolation/extrapolation of the force measurements.
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Tomorrow we head for the salt flats.I'll continue to collect fuel data.
At Cd 0.267-268 she's at around a 39% drag reduction and it will be interesting to see what the aggregate mpg values look like.
According to Hucho's 30%/10% top speed relationship,it would predict the new top speed at 107.35-mph.I ran 108-mph back in 2007,with a little bit left,so I'm not sure about that.
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It's been a great day.Thanks again to all who got behind the project.When I get back,I'll get into the video stuff so we can get that into YOU-TUBE for all to see.
Let's get some more members to Darko!
