Aerocap Thesis from 2009

[Big Dave]

My homemade aerocap was too steep at 17%. But it was easy to make.

I concur that the lower the air dam, the better. The reduction in coefficient is greater than the increase in frontal area. My 1.5" clearance air dam worked great but was a4 karat pain in the butt. My 8" clearance air dam doesn't work at all but doesn't drag things. Maybe 3 or 4 inches might be best.

The study stayed with add-on stuff on a stock bed.

What if the bed itself curved to a 12 degree taper (in the plan view) aft of the wheel wells? The space lost is not highly useful. Dead-cat space IMO.

The tangent of 12 degrees is 0.212. So the top deck of my 80 inch long bed should be about 17 inches below the top of the cab.

My tailgate sits about two feet behind the wheel wells. Using a twelve degree taper that would reduce width by 5 inches on each side or 10 inches overall. That would represent a 12.5% decrease in wake area.

[redneck]

Originally Posted by t vago

I can definitely tell you with 100% certainty, that the answer to your question is a firm and definite maybe.

I can kinda sorta, with a 100% uncertainty, say that was maybe the best possible answer...

>

[bondo]

Originally Posted by redneck

Would adding tailplates lower the cd on the 3D aerocap?

>

Not being an Aerodynamic expert, I can not say a definite yes. I should construct some tailplates and test them on my truck which has an Aerolid on it.


Bondo

[t vago]

The only thing that I can think of, that could give us an idea as to if tailplates would really work with a aerocap, is this here discussion on partial Kammbacks.

I am tempted to add some form of tailplate to my version 2 aerocap, but it would interfere with the ABA testing of the cap itself.

[Frank Lee]

That was y'alls idea of a good read? The first 70 pages were a not necessarily accurate regurgitation of prior work; then when he FINALLY got to the new stuff he didn't run any CROSSWIND sims even though x-winds were properly noted as being crucial in the prior art; running and including crosswind results COULD be a game-changer as far as conclusions reached. And then all the typos/grammatical errors in a THESIS. Oy.

[NeilBlanchard]

Table A1 says it all... (the 114th page, labeled page 96)

[t vago]

I just realized something...

This 2009 thesis briefly addresses front air dams for pickups, but it appears that the author assumed a perfectly flat bottom for his CFD model. Therefore, he saw minimal gains from his simulated front air dam.

The Naval PostGrad paper, on the other hand, made an attempt to accurately model the bottom of a pickup truck, and larger theoretical (and actual real-world) gains were seen as a result.

[slowmover]

That was y'alls idea of a good read? The first 70 pages were a not necessarily accurate regurgitation of prior work; then when he FINALLY got to the new stuff he didn't run any CROSSWIND sims even though x-winds were properly noted as being crucial in the prior art; running and including crosswind results COULD be a game-changer as far as conclusions reached. And then all the typos/grammatical errors in a THESIS. Oy.

Welp . . . some a us ain't as famili-ar wid it as the rest'a ya'lls.

(And I've seen crosswinds ignored around here more than once).

But we remembered our manners in saying thank you for having linked it.

The D-I-Y part of me continues in fascination. Keep it up, all y'all.
.

[t vago]

Originally Posted by slowmover

(And I've seen crosswinds ignored around here more than once).

What are these "crosswinds" of which you speak? Is that some dadgum furriner word?

[slowmover]

Headwind and tailwind are parallel to direction of travel. Anything else is a crosswind. And those are harder to "control" in a manner of speaking. Flow is upset when they are strong enough.