View Single Post
Old 06-30-2010, 05:51 PM   #29 (permalink)
Master EcoModder
aerohead's Avatar
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 14,140
Thanks: 21,988
Thanked 6,606 Times in 4,157 Posts

Originally Posted by miket View Post
The truck/cap is 6 flat sides so i'd have to transition from flat to round some how.

Again why would it be back to have the flat roof slope down slightly, i would think that would be a positive benifit of slightly negative rake.
miket,if the roof is raked backwards,so too will be the grille/bumper (maybe not so bad a thing),the hood ( maybe not a good thing ),windshield ( not bad ),how the airstream is divided at the nose/windshield ( potentially harmful ),also,how the undercarriage is 'presented' to the air.
During development of the truck,it's Cd may be totally dependent upon the factory rake and could be degraded if tilted back as this would impact flow penetration.In addition,the weight bias can be altered which will affect braking and handling.
Concept cars and supercars with active suspension typically drop the nose for better performance,I've never seen an instance where the tail was dropped,unless the nose went with it.
The forward rake maximizes the amount of car within a positive pressure regime,maximizes the available energy aft of the point of max cross-section,providing the most energetic boundary layer from which further streamlining can benefit.
  Reply With Quote