View Single Post
Old 08-10-2011, 12:27 AM   #41 (permalink)
PeterS
Master EcoModder
 
Join Date: Aug 2011
Location: East coast of Australia
Posts: 393

Yella Peril - '80 Mercedes 240D sedan
Thanks: 15
Thanked 41 Times in 17 Posts
Quote:
Originally Posted by redyaris View Post
One other point about motorcycles aerodynamics and cross winds is the mass of the bike. If you have two bikes with the same side aera to work on and one of the bikes is twice as massive, then the more massive bike will be less affected by the cross wind F=ma. That is why; as you reduce the mass of the bike getting the aerodynamics right become ever more critical as well as the location of the center of gravity and the center of pressure... Take a look at the side area of one of the big touring bikes like the
goldwing and then ask the owner what its like in a cross wind? I ride with a friend who has a gold wing and it leans much less than my GS500 or my KLR650 both of which have less mass and less side area.
I plugged some numbers into this calculator Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com ,doubling the weight of the machine but keeping everything else the same .Remarkable !

121 mpg US at 50 mph at 330 pound .
114 mpg US at 50mph at 660 pound .

Not that I would build something at 660pound but there seems little disadvantage to the extra weight and it could aid cross wind stability if placed low ?

  Reply With Quote