Rule of 7's
Just got the burb back on the road and took her down to the lake over the hills and dales in SW KY. Ran better than it ever has, smooth as glass and plenty of power. It occurred to me that I can tow...
Forum Discussion
BurbMan wrote:The aerodynamic resistance increases approximately as the square of the relative air speed,
Thanks guys, will try 65 on the next trip out and report back....I recall seeing that wind resistance increases at the square of the speed or something like that so that is likely the killer here.
but the power required to overcome aerodynamic resistance increases approximately as the cube of the relative air speed.
The power required to overcome drag force at 70 mph is approximately 25% greater than at 65 mph.
(In keeping with the title of this thread, the power required at 65 mph is about 77% of that required at 70 mph.)
The difference in fuel consumption would depend on how much of the engine power is being used to overcome aerodynamic drag, along with any difference in engine efficiency at 70 mph versus 60 mph.
Ron
