Pickup truck aerodynamics

[aerohead]

If one looks at Sighard Hoerner's 'Aerodynamic Drag,' there's a discussion of bullets and artillery projectiles, like Barrett's triple-ringed, boat-tailed sniper round, and the US ARMY's howitzer, 'Aberdeen' supersonic artillery projectile.
As these structures advance through the air, there's a jet-pumping action, attempting to pump the wake full of air, as an airship experiences when the thick turbulent boundary layer sloughs off the rear of the envelope, filling a rather blunt, steeply-sloped rear, creating a 'phantom' ( fluid ) tail.
Dornier found out in the 1920s that you could lob off about 5% of the trailing surface of wings, and they'd fly as if 100%.
Aft-fuselage gun turrets use the same phenomena.
Some high-end golf clubs ( 'woods').

[freebeard]

My rat rod design is a 'bobber'

[redpoint5]

It's not clear to me if aerohead would be in heaven or hell if he lived on the moon.

[freebeard]

I contend that Space is the ultimate retirement home.

Subsurface on the Moon it's 68F degrees month-round. With an oxygen-rich hyperbaric room at 1/6th G. It would be Heaven if there were anime.

[aerohead]

Originally Posted by redpoint5

It's not clear to me if aerohead would be in heaven or hell if he lived on the moon.

Aerostealth and I did some thought experiments over the decades about driving on the Moon and turned it into a book.
I'm a lightweight when considering space fairing. I'll let the more adventurous have my ticket.

[aerohead]

Originally Posted by aerohead

Apology for another 'better late than never response.'
This is a really important question. I skimmed the old Sport Truck Magazine pickup aero article recently, and I believe that they directly address this question.
So as not to get it all wrong, I'll review it over the weekend and have something to bring next Monday.

From Glen Sharpf, Senior Development Engineer, General Motors Corporation:
During R & D of the GMT 400 project truck ( which became the 'new' GMC/ Chevrolet pickup ), a full tonneau reduced aerodynamic drag: It increased air pressure on the front of the box and decreased pressure on the front of the tailgate.
A half-tonneau was more effective in reducing drag... It did so by relieving even more pressure on the front face of the tailgate.
( a bulkhead placed beneath the leading edge of the half-tonneau isolated the front face of the tailgate from the low-pressure core of the bed vortex, increasing drag ).

[freebeard]

Which brings me back to Permalink #124. A concave curved bulkhead might be more effective.

[aerohead]

Originally Posted by freebeard

Which brings me back to Permalink #124. A concave curved bulkhead might be more effective.

Is it the 'augmented Coanda nozzle' that we're to be looking at?
If so, it's remarkably different than the architecture of the half-tonneau.
As to a 'concavity' associated with the margins of the bed vortex, it already exists in the form of Lanchester/ Prandtl surfaces of discontinuity surrounding the transverse tornado. Just like at the front of all cars.

[aerohead]

KNON, an all-volunteer radio program out of Dallas, continues to showcase any and all manner of G D live concert broadcasts every Friday, early evening.
It's always 4:20! I can smell it from next door!

[freebeard]

Let the record show that an ephemeral Signature comment triggered this comment.

KNON made this list: gdhour.com/stations.html#other along with two stations in Eugene and two in Portland. Note the #other -- there appears to be a vast, subterranean network centered on NY State. gdhour.com/stations.html

Ontopic: Could a 55-gallon drum substitute for the captured vortex? On powered rollers for A-B testing?