Quote:
Originally Posted by kach22i
Thanks for the link Jim.
Figure 11 is also interesting. A Cd of .27 for the truncated aerofoil, puts that shape in the same ballpark as the NASA sphere.
Shape Effects on Drag
Cd of .07 to .5 with the sphere, so a lot depends on the length of the aerofoil (Gurneyless goldfish FRONTAL AREA) to do a comparable. Why does the sphere have a "range" at all if the frontal areas are all the same in the NASA diagram?
http://ecomodder.com/forum/showthrea...pes-11183.html |
The sphere,when utilized as a cannon ball was evaluated for drag and tables developed for its Cd by ballisticians as a function of sub-sonic and supersonic velocity to aid in firing solutions for the artillery branches of armed forces.
The Cd is usually portrayed as a function of MACH number and its Cd is quite literally,all over the map.