[Christ]

Originally Posted by aerohead

The car guys always defer to 'drag-factor',or,CdA.And Cds are always in the context of frontal projected area.
Since most modders aren't going to chop the roof off their car or do extreme alterations to frontal area,we've kinda defaulted to drag coefficient as the thing of primary interest.
Jaray got the whole 'Streamlined body of revolution in ground reflection' going back in 1922.
Jaray,Kamm,Lay,and so many others ended up using the body of revolution as their starting point,it seems like the convention with road vehicles.
Hucho used it at Volkswagen and he's the one who cited the L/D 2.5:1 Streamline form,or elliptical form as the 'minimum' for drag.
He chastised Mercedes_Benz for not honoring it with R&D of their C-111 III.
I've been looking for anything which demonstrated the lowest Cd with minimum structure and so far,for something in ground-effect,which cannot benefit from the jet pumping action of a body in free-flight,I've never come across anything "shorter" than L/D 2.5,which would translate to a vehicle with Length,5X it's height.
Al's closing gotta go,will pickup tomorrow.

I was just pondering this point earlier today and part of last night... I wonder though, if the ideal really should be 5:1 in ground effect, or if ground effect changes some part of the design?

In other words, if a body of revolution of L/D 2.5:1 were placed in ground effect without being halved, would the 2.5:1 fineness ratio still be most effective, or is that the most effective ratio for an airship-type vehicle?