brainstorming of ducts and shafts and other similar devices

[max_frontal_area]

Upon JasonG*s suggestion (thank you) i am starting a new thread for the purpose of discussing and hopefully furthering the developent of venting ducts.

here are links to 2 prior threads where this phenomenom was discussed:
http://ecomodder.com/forum/showthrea...ler-14374.html
http://ecomodder.com/forum/showthrea...html#post73478

alternatively do a google f-ducts - Google Search to see the usefulness
of ducts but for an entirely different purpose!

and of course one of my 2 personal quests: http://ecomodder.com/forum/showthrea...ake-15155.html

everyone is invited to join even our friends from the underworld including
Trolls, leprechauns, gollums and other mythological creatures.
i would kindly request: when disseminating ideas or introducing new concepts please provide tangible data. references to moon schedules, feelings, premonitions or employing techniques like comparing the THC concentration
of cannabis plants in september vs. early october in order to emphasize your point, will not be appreciated

[Frank Lee]

Well done, you found something re: ducts (f-duct)! Unfortunately that is not a circumstance of straight-forward drag reduction; it is a special racing circumstance of desiring to control the downforce and drag characteristics of a wing via skirting the rules that state one cannot have moveable wing elements. While they welcome drag reduction whenever they can get it, their main goal is downforce production. I don't see it being applicable to the street unless your street machine is designed for illegal speeds and sports a wing.

You could do an Ecomodder search for "duct" and find 124 hits to dig through...

[max_frontal_area]

Originally Posted by Frank Lee

Well done, you found something re: ducts (f-duct)! Unfortunately that is not a circumstance of straight-forward drag reduction; it is a special racing circumstance of desiring to control the downforce and drag characteristics of a wing via skirting the rules that state one cannot have moveable wing elements. While they welcome drag reduction whenever they can get it, their main goal is downforce production. I don't see it being applicable to the street unless your street machine is designed for illegal speeds and sports a wing.

You could do an Ecomodder search for "duct" and find 124 hits to dig through...

"" to see the usefulness of ducts but for an entirely different purpose! ""

been following F1 aero since the 14.4 modem days.
now that IS wichcraft!
the f-duct is soon to be outlawed

[donee]

Hi Max,

The Cd of a F1 racer is on the order of 1.0. Yea, that high. And this is because of the wing.

Your goal is minimum Cd. Any kinda of duct or wing will make Cd worse. Air forced through a duct takes more energy than the air simply flowing over the car.

The only way this can be advangeous, is as a control mechanism. Which is what the f-duct is, as I read your link. The very small amount if air is used to switch the wing from lift to no-lift. They apparently have designed the wing to be close to stall. Loosing the extra flow from the F-duct results in a stall of the wing.

But, if you do not have a wing to start with, you do not have the drag due to the lift generating air flows. So, there is nothing to switch....

[max_frontal_area]

simply to be a reference to a contemporary ducting system, just to let ppl know that ducts other than those intended to cool brakes, exist.
i am not interested in copying or replicating it.
i am shooting for a freeflowing environment, no negative or positive lift,
no wings unless they prove advantageous in some odd way.

the inherent design of the f-duct forces airflow to make directional corrections numerous times, i would like to go relatively straight, the way the air naturally wants to go, as much as possible.

donee, did you have an opportunity to see the jetta http://ecomodder.com/forum/showthrea...html#post73478 airflow simulation of a duct shot through a 2D model. did you see what it did to the wake, usually landvehicles biggest trouble spot but particularly pronounced on large vehicles?
longtail endurance racers would struggle to shoot for such a wake!

[Frank Lee]

Time for a thought experiment: Say you have a Jetta with 100 cu. ft. (random number selected for easy in-head math) interior volume. Say the size of the duct necessary to have a positive impact on the rear wake takes up 10 cu. ft.

I maintain that, if you have 10 cu ft of interior to spare, you'd get better aero by chopping the top down until there is 90 cu. ft. interior volume. You'd get less frontal area, and even moreso, less oblique frontal area that is presented to x-winds. You'd get a skosh less weight. You'd get a better fineness ratio. These things by themselves would reduce wake. You'd avoid the extra drag, skin and otherwise, that ducts have.

[max_frontal_area]

FL, i agree completely. passenger cars usually have 1 warm body sloshing abound in there somewhere, here in the US we prefer to use larger vehicles such as pickups and SUVs.
cargo areas are usually unused therefore frontal area could be reduced tremendously and they would look more fun - to boot.

remeber the 80's, cold war was freezing up technology was leaking and beginning to impact our lives especially in cars. they had the potential to become lighter, faster, efficient, more fun, sexier... but what do we want, vehicles that are anything but.
4, 5, 6k lbs behemoths - what went wrong?

once again, the shot through jetta was just an example.
my focus is for large cargo vehicles for which frontal are reduction surgery/sexy aero mods are just not pratical since unlike our overgrown passenger vehicles, they are frequently packed to the hilt with the exception of a bit of headroom (space for the duct) unless you are haulin' lightweight TP in which case you will want to stuff it.

[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.

[dcb]

Originally Posted by max_frontal_area

...here in the US we prefer to use larger vehicles such as pickups and SUVs...

Not this American, not lots of Americans. Let's not perpetuate stereotypes if we can avoid it.

[max_frontal_area]

FL, your plan would be tricky to squeeze by DOT, NHTSA as well as our friendly insurance ppl. look at crashworthyness itself, then added weight, and increased complexity/ production costs. finally try explaining to the beancounters at a large crapporation how the ROI on the extra $20k per truck will work.

cabheight, i feel could be easily reduced as is. how much headroom does a tractor really need, and those silly visors are they really nessesary or just a statement? of course you will have to run a taller truck cap with an even steeper angle and ...

dcb, i have been attempting to perpetuate change since i got off the boat 1/4 century ago. ppl generally smile when i attempt to introduce new concepts to the general public. never sure if they actually understood the point i was attempting to make or if it was their way to politely blowing me off.
!!idling!! where i live you can have your head blown off by suggesting to shut off an unused engine after 5 minutes. it is their birthright. they paid for the fuel, damnit!!
i'll make you a deal when the responsible ppl in this country approach 50% i will sign up for charm school with a P.C. elective.