Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Motorcycle aerodynamics, a slippery and windy, slope?

PeterS · 08-05-2011, 08:01 PM

dcb, good info but the problem is more the unexpected burst of wind from the side at any angle.I can't work out how a wind from say 15 degrees off the front would effect things but if it was a constant it would probably be OK .

There seems some small advantage in the higher ''fuselage " ,a slower roll period.The shorter the structure ,the faster it will lean but how this relates to the distribution of mass and the balance of the areas ....I have no idea !

A couple of bicycle related links which discuss gyroscopic effects and side loads .Not perfect for this discussion as bikes are pretty porous from side wind perspective .
http://en.wikipedia.org/wiki/Bicycle...xternal_forces
http://www.sheldonbrown.com/brandt/wind.html

and a review of the Hucho book
http://www.recumbents.com/wisil/demma/aero_review.htm

I'll keep reading through this excellent forum and try to learn something !

I really wish I could put a question to Allert's builder ...I'm sure he could put me right in a second !

Edited to add .In the original 1957 article on the Dreamliner there was mention that a prototype fairing that was 'slabsided ' had been rejected as bad in cross winds ,the final Dreamliner was the same as an unfaired bike , the reason given by the designer was the indented sides .The flat sides of the original had been much worse .

08-05-2011, 08:01 PM	#39 (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	dcb, good info but the problem is more the unexpected burst of wind from the side at any angle.I can't work out how a wind from say 15 degrees off the front would effect things but if it was a constant it would probably be OK . There seems some small advantage in the higher ''fuselage " ,a slower roll period.The shorter the structure ,the faster it will lean but how this relates to the distribution of mass and the balance of the areas ....I have no idea ! A couple of bicycle related links which discuss gyroscopic effects and side loads .Not perfect for this discussion as bikes are pretty porous from side wind perspective . http://en.wikipedia.org/wiki/Bicycle...xternal_forces http://www.sheldonbrown.com/brandt/wind.html and a review of the Hucho book http://www.recumbents.com/wisil/demma/aero_review.htm I'll keep reading through this excellent forum and try to learn something ! I really wish I could put a question to Allert's builder ...I'm sure he could put me right in a second ! Edited to add .In the original 1957 article on the Dreamliner there was mention that a prototype fairing that was 'slabsided ' had been rejected as bad in cross winds ,the final Dreamliner was the same as an unfaired bike , the reason given by the designer was the indented sides .The flat sides of the original had been much worse . Last edited by PeterS; 08-06-2011 at 07:53 AM..