brainstorming of ducts and shafts and other similar devices

[aerohead]

m,f,a, I've located some materials which are germane to your ducting proposal.
We left work early today and I came straight here to the copy center,did not expect the short day and do not have those with me but will post Saturday.
If you have Hucho's book,it will have info helpful to you.
Also:
*Theory of Wing Sections by Abbott and Von Doenhoff
*Aerodynamic Drag by Sighard Hoerner
*Aerodynamik Des Kraftfahrzeugs by Koenig von Fachsenfeld
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You won't like any of it but it will save you a mountain of time and money.There just simply does not exist any empirical evidence from scientific inquiry that suggests that the ducting will help you.
You'll be able to read it for yourself.

[aerohead]

max,I put together the following list of references which would dovetail into the ducting thesis.Specific data is presented in Fachsenfeld's work,the rest can be deduced.
* Aerodynamik Des Kraftfahrzeugs,Baron Reinhard Koenig von Fachsenfeld,1951,pps 74-79
* Boundary-Layer Theory,Dr.Hermann Schlichting,Seventh Edition,Chapter 2,p.395,Fig.14.15 ( suction slot flap )
* Hucho: Ch.4,7,8
* Aerodynamic Drag,Sighard F. Hoerner:Chaps.3,4,7,8,9,10
* Race Car Engineering & Aerodynamics,Paul Van Valkenburg,last chapter,end of book photos of Corvette with and without suction.
* AIAA Paper: 'Trapped Vortex Flow Control For Automobiles,' 1974,J.J.Cornish,III,AIAA meeting,Los Angeles,California
* Theory of Wing Sections,Abbott & Von Doenhoff,Fig.134,p.228 ( Clark Y wing with slots and flaps ).
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[mcrews]

Originally Posted by Frank Lee

I've long wanted to see tractor trailers and yes even the tractor cabs height adjustable, like a telescope, with the top half able to go up or down over the bottom half, for aero. I want to do that with my own trailer too.

THERE are travel trailers with just such a feature. kinda like a box lid with long sides.

[Frank Lee]

Yes folding travel trailers are out there, in several configurations! I wonder why the notion hasn't spread to trucking or other areas.

[Otto]

For ducts and vents, check Lopresti Speed Merchants and NACA data. NACA looked at cowl flaps and heat vents ~70 years ago, found gently radiused curves that let cooling air rejoin the slipstream flowing as parallel as possible work best and with least drag. Venturi effect and exhaust heat can, if theory and legend are correct, actually make a bit of thrust. That's the story with the P51 radiator, at least.

[nitro-nige]

My understanding of the F-duct is that it extends the chord of the wing into a lower drag profile.
Assuming my understanding is correct then maybe you could make a duct that created an "air boat tail". Basically use the duct to direct air into the turbulent wake.
How you would design such a duct is a completely different matter.