Quote:
Originally Posted by NeilBlanchard
I got to see the 2nd Edition of Hucho from the MIT library, via my wife who is a librarian at Harvard. I now own the 4th edition that I bought from Amazon. Here's the Amazon UK page for it:
Aerodynamics of Road Vehicles: Amazon.co.uk: Wolf-Heinrich Hucho: Books
If you can find the 2nd edition (used?) then buy it. I think it had several very useful things that seem to be edited out of the 4th edition; including several pages on air flow inside the wheel well with a spinning wheel. But, I think only the 4th is available new - and it is certainly well worth buying, in my opinion. |
Neil,here are some highlights of wheel drag from 2nd Ed.:
*Wheels and wheelhouses essentially double the drag of a low-drag car.(VW's long-tail 'flow' body goes from Cd 0.0915,to Cd 0.14 when wheels are added)
*The closer the wheelhouse volume is to the volume of the wheel the lower the drag.
*The drag coefficient of the wheel does not vary as it is submerged within the bodies wheel well,only a drag reduction due to lower frontal area is actively involved.
*Open wheels,such as with Rumpler's Tropfenwagen,can double the drag (from Cd 0.14,to Cd 0.28,as per Wolfgang Klemperer's measurements of the Tropfenwagen at the Zeppelin Werke).
*Rear skirts cut drag if flow is already attached upstream.
*Front skirts,as,Adler-Jaray,Probe-IV,and AeroCivic can cut drag (9% with respect to Ford's Probe-IV).
*Just moving the wheels out flush with the body sides can mean up to a 16% drag reduction.
*Drag coefficients approaching those of basic bodies of Cd 0.07-0.09 can only be achieved through integration of the wheels into the body (2013 Cambridge University CUER eco racer is a current example,@ Cd 0.11,also NUNA series,and PACCAR.)