Wow, made it to the end. I can't believe I read the whole thing. Teri_TX hasn't posted in his thread since April the 7th. I can only hope he gets email notifications. Because—
In all this discussion there was no mention of the difference between sit-on and sit-in two-wheelers. He should know about that.
There are techniques from other areas that may have application. I'm thinking of
Development of Pneumatic Aerodynamic Devices to Improve the Performance, Economics, and Safety of Heavy Vehicles
Robert J. Englar
Georgia Tech Research Institute
I can't find an un-paywalled version of the paper. The original link 404's. The link I obtained from the SAE website appends a "/%E2%80%8E" to the URL and then can't find it . Just delete that and press return.
Quote:
The potential of pneumatic aerodynamic devices applied to Heavy Vehicles can be summarized as:
• Pneumatic devices on back of trailer, blowing slots on all sides and/or front top can yield:
• Aerodynamic control of all three forces and all three moments plus boundary layer control
• Separation control and base pressure recovery =
drag reduction, or Base suction = drag increase
• Leading-edge (LE) suction on trailer = drag & tur- bulence reduction
• Additional lift for rolling resistance reduction (FRolling = μN, where N = Wt - Lift), or Reduced lift (increased download) for traction, braking and reduced hydroplaning
• Blowing locations instantaneously switchable • Partial slot blowing or differential blowing for roll con-
trol & lateral stability
• One-side blowing (LE or TE) for yaw control & directional stability
• No moving parts, small component drag
• Very short aft addition = no length limitation
• Splash, Spray & Turbulence reduction
• Use of existing on-board compressed air sources (exhaust, turbocharger, brake tank)
• Advanced Pneumatic Cooling Systems • Safety of Operation
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Then there's semi-permeable membranes to relieve pressure differentials without impeding the overall air flow.