Quote:
Originally Posted by Jim Bullis
aerohead,
Hoerner's book is also informative but not all that free of the conventional automobile straight-jacket.
I think the Los Angeles is another airship along the lines of the 1906 Fuhrman (Prandtl's student) airship. They really seem about the same, and the only reason I specifically use the USS Akron zrs4 is that the testing reported by Freeman 1934 is by far the most complete and the best explained. It also was done at a scale where the actual test body was about the size of a car, so no real scaling is even needed. That report is free and very well detailed.
|
Jim,I think the Los Angeles is patterned after Jaray's LZ-126 Graf Zeppelin of which all post LZ-126 Zeppelins owe their design,including Hindenburg.
I looked up the Akron and for its Length/Diameter came up with a free-air,frontal area Cd of 0.058,with Cd 0.05 skin friction and 0.008 pressure drag.
If you did your body as small as my 1984 CRX ( around 42-inches ) the body would be 19-feet in length and would require 8-feet of ground clearance to nullify the drag increase due to ground proximity.
For comparison,a 1/2-"Akron" pumpkin seed form with skinny tires and 'normal' ground clearance would have Cd 0.15.
I don't know how to figure the lower portion of your car.The 1947 Taruffi twin=boom "Tarf" tunneled out at Cd0.10,so it's possible to make the lower section really clean.
I don't remember strut drag minimum ratios but they're tabulated.
The only cautionary note I'd like to share is on safety.If you'll remember,Bucky Fuller had a German industrialist aboard his Dymaxion Car who was killed when an over zealous rubber-necker collided with them,causing the roll-over crash.