Quote:
Originally Posted by AeroMcAeroFace
Isn't the point though, that we are starting with a 0.3-0.35 vehicle? There are huge gains to be made, even if there are vortices, downwash, and attached flow. I don't think there is anybody here realistically expecting to get to 0.09 without starting from scratch.
" 1) so remove the constant-diameter cylindrical section.
2) join the nose and tail section to form the streamlined body of revolution.
3) use Hucho's drag table from Hoerner to ascertain the Cd of the streamlined body you've just created.
4) subtract out the skin friction no longer present from the elongated body.
5) bifurcate what's left, longitudinally, to create the half-body.
6) double the Cd of the streamlined body to get the drag of the half-body.
7) now add wheels, and wheel drag, as Jaray and Buchheim did, and tell me what you come up with."
what you come up with is something that has no relevance to anyone here. If we were going for 0.09, why wouldn't we use CFD to guide the shape, much like they do for solar cars.
This is a disconnect, between aerohead and most people on ecomodder. Instead of starting with a normal car with pressure drag and hoping to make a 20% difference, aerohead believes that we are all here starting out with the creme egg van and looking to go to extreme low levels of drag.  |
If you can afford Dassault's Exa POWERFLOW go for it. I considered that EcoModder members might pool funds together to obtain use of it. A number of calls went un-returned. They wouldn't tell me what hardware was necessary to run it, nor what leasing the software, or using their online resources would cost. I gave up.
Which left only the dimensional analysis.
Some of the solar cars winning the World Solar Challenge are already using the template. The lowest drag 'car' ever measured uses it. It was relevant to them. What do I make of your comment?
The 'template' works in their wind tunnels and CFD, but not at EcoModder?