Quote:
Originally Posted by serialk11r
860 miles? That sounds too optimistic to me.
Offroad tires have really freaking high rolling resistance because tread hysteresis. I recall looking at some tire RR list some number of years ago. Most passenger tires were in the 0.006-0.012 range, but some offroad tire stuck out like a sore thumb at 0.017.
Just looking at the Tesla, I think the wheels are going to contribute way too much drag to hit 0.30 Cd. Maybe miracles happen though.
I think Elon's range targets might be hit with some special street-friendly tire, and the people ordering the knobbly tires are going to be pretty disappointed with the range.
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*I just used the performance of the Model X as a shoot-from-the-hip guide.At 55-mph,the long range version has a 426-mile range.70-mph knocks that down to 325-miles.Again,you really pay for speed.
*As to the tires,they remain an unknown quantity.However,as I've said elsewhere,Tesla has control over tire design.We know from Class-8,88,000-lb ,18-wheel semis,that their 10-wheel companions,with flotation tires have 20% less rolling resistance.Those big fatties may actually have lower R-R than what you think.And their size could play into a virtual area-rule,sectional density function,enhancing the pressure profile down the entire length of the truck,mitigating spanwise-flow,boundary layer contamination-induced longitudinal vorticity.Cybertruck has two other features which play into this same issue.
I've slept with Hucho since last Saturday.I can't imagine Cybertruck's naked body coming in,any higher than Cd 0.28.Cd 0.30 with honkin' truck mirrors.
*Cybertruck is a fastback.Fastbacks have the lowest drag of all body forms.Cybertruck is a 'Kammback.' 'Kammbacks' have the lowest drag of all fastbacks.Cybertrucks proportions are identical to Volkswagen's XL1,Cd 0.189.
Cybertruck's front champfer,body side camber,tumblehome,and raked greenhouse (an industry 1st) probably compensate for the hard leading edges.Cybertruck's boat-tailing is an industry 1st.Cybertrucks stagnation point is an industry 1st.Cybertruck's bonnet,frunk profile is an industry 1st.Cybertruck's windscreen saturation is an industry 1st.Cybertruck has an industry 1st belly.Cybertruck's backlight slope,at 10-degrees to horizontal,is incapable of producing edge vorticity.Cybertruck's roof camber is an advantage.
*Aerodynamically,Cybertruck is an F-117 Nighthawk.It uses every trick used by Lockheed.
*Dassault System's, Exa Corporation POWERFLOW CFD is a full-Navier-Stokes Equation program.It's results rival any world class wind tunnel.I suspect that Elon Musk and crew already know the numbers.It's unimaginable that they wouldn't.If Tesla's hit their 'combined' range at a constant 70-mph,and Cybertruck is rated 500-miles combined,It ought to return 500-miles at 70 mph,and 860-miles at 55-mph.You can test the velocity difference relationship with your own vehicle.