AIRTABS...could be worth a bit of mpg
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hmmm...interesting, but, I'd have to see more than the manufacturer's information.
All nice "articles". What I'd like to see is a CD number on an actual vehicle, measured in a wind tunnel, at real-world speeds. I have no doubt that some sort of benefits are observed in some applications at some speeds, a measured Delta CD could quantify the benefit. I would guess that different shapes/placement are ideal for different locations on a vehicle, as well as at different speeds and types of vehicles.
I tried them on my station wagon. No big fuel economy change, though I only tested once. I noticed more noise, and less dirt on the rear window when driving on a wet dirt road. In that test, I made 4 runs, alternating with and without the vortex generators, taking a photo of the previously cleaned rear window after each run.
If this induced Vortex can truly decrease the CD to provide a significant benefit in efficiency, I could see how this could be applied even to various undercarriage surfaces. Then again, I SUSPECT that effective Vorteci result from devices of different shapes at different speeds at different locations. If that is true, it would be best if the vortex-creating device could change shapes as speed changed, allowing for maximal effectiveness at more than one specifically ideal tuned speed range.
It would be interesting to have an aerodynamic study done in a wind tunnel similar to how some bicycle racing teams experiment. Of course, there is the possibility that such experimentation has been performed, and benefits haven't been significant enough to warrant further testing.
It would be interesting to have an aerodynamic study done in a wind tunnel similar to how some bicycle racing teams experiment. Of course, there is the possibility that such experimentation has been performed, and benefits haven't been significant enough to warrant further testing.
Big Square ended vehicles would probably benefit the most. The problem is placement...how far away from the trailing edge should they be placed based on speed ranges (mph) where you want the most improvement. I know from racing for Mazda for over 10 years that other devices such as spliters ect do work, but you have to place them precisely to get the desired effect. I definitely think these would work in a few places on my Jeep Liberty...in fornt of wheelwells, on fuel tank skid, back section of roof and sides, ect. Wishbone shaped air ducts work great getting air in hood, fenders for brakes and windows for cool air. Just thought they were something different. If you do a lot of highway travel, they would probably show a slight increase in mpg on a "Block Shaped" vehicle like a Commander.
I'm actually interested in running these on my semi. Most of it is quite aerodynamic(it's a volvo VN), but the problem is the trailer gap is huge. 39", I've been told you should run 24" at most. I cannot move up the trailer(by sliding the fifth wheel) due to weigh distribution problems. I'd rather run after market fairing extensions, but I can't seem to find any.
You should keep this very quiet. You don't want the equipment manufacturers to find out about this and start putting them on the trucks/trailers at the factory. So when you dialog on this site about vortex generators, type very quietly. Otherwise they will find out.
They also create more drag, so if any reduction in drag from spill-over doesn't equal what they lose in aerodynamics, the result may be a loss. Aircraftspruce sells the metal ones BTW.
What's the drag coefficient of a smoke ring?
allen5oh you may want to spend some time reading this article from Cummins.
Cummins Fuel Economy
Cummins Fuel Economy
ALS, I can't get the link to work.
It looks like Cummins took it down from the web site. Sorry.
Yeah I read kenworths white paper on fuel mileage, it is probably related. It was extremely detailed.
Unfortunately I do not own the trailer, and we are mostly a drop and hook operation so a dedicated trailer is out of the question.
One article I read had a trailer with all of those aftermarket things added for wal-mart. Made by great dane I believe. Very nice unit. The back-end was quite a bit narrower, instead of a squared off end. I'm not sure shippers would like that!
Unfortunately I do not own the trailer, and we are mostly a drop and hook operation so a dedicated trailer is out of the question.
One article I read had a trailer with all of those aftermarket things added for wal-mart. Made by great dane I believe. Very nice unit. The back-end was quite a bit narrower, instead of a squared off end. I'm not sure shippers would like that!
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