[aerohead]

[QUOTE=Bicycle Bob;52205]

Originally Posted by aerohead

RiseAbove,in the phil knox aerodynamic photo albums,under Book Illustrations,second row from bottom of 1st page,is an illustration of Walter Korff's zero-drag,cooling system design.I---------------------------------------------------------- (reply aerohead)
Within the 1963 SAE Paper,in which Korff published the cooling system diagram,he suggests,that for passenger cars,a cooling system,as depicted,could impart no drag,elliminating 12% of overall drag.I have no means to verify his claims.And as he is the Phd.,with access to the best wind tunnel facilities in the U.S.,I am in no position to argue his claims.----------------------------------------------------------(quote=Bicycle Bob)
The label actually reads "ideal low drag cooling system." I used to be inspired by the North American Mustang aircraft, on which it was claimed that the radiator enclosure had negative drag - sort of like a hot-air jet engine. However, the Voyager team did their own testing, and could not get the cooling drag to be less than 20% of the total on their whole aircraft. One has to assume that they were competent researchers.------------------------------------------------------(reply aerohead)
It is claimed that the outlet of the P-51 heat-exchanger did produce thrust,as a function of air expansion.Again,I can only report what is published,and make a leap of faith,that the authors know what they're talking about.With respect to Voyager,I hold the Rutan Brothers,and their team at Scaled Composites with the highest esteem.If they say they could not go below 20% drag with the cooling system,I'd bet on those numbers any day.However,the topic was motor vehicles,and I would still consider Korff's claims with high confidence.---------------------------------------------------(quote= Bicycle Bob)
The front end provides the most direct flow to the rad, and does not have to disturb the rest of the shape. There may be some existing cars that could be improved by relocating the rad and ducting to the rear in a combined effort to solve other problems - it is not that difficult - VW did it on the wasserboxer Vanagon, in the other direction. ----------------------------(reply= aerohead)
The Ford Probe and GM PNGV concepts use rear cooling,and achieve lowest Cds for "producible" concepts.Ford GT-style cooling,up front might have offered as low,or lower drag.Different themes.Different approaches.
However, I agree with Mr. Lee - a front engine is good for stability, which becomes much more important on a light, streamlined car.

------------------------------------- (reply=aerohead)

The issue of CG vs CP was important enough that Hucho devoted a good portion of an entire chapter on it.Evidently,crashes,if not fatalities are associated with high speed aerodynamics,as played out in events since the 1920s,when streamlining took off.Perhaps it would be prudent to take each vehicle on a case specific basis.When L.J.K.Setright road tested the Citroen CX,in the 1980s,he claimed that the front-engine/front-drive layout was the defining criteria for the cars rock solid stability,even at top speed,with crosswind.