Kevin Rutherfrauds $200000 Signature glider truck has complete engine failure!!!

And Microblue

 

The Honda Civic Test:

1) It did not actually use air tabs. This test was done in 1982 using the "wheeler wishbone" -- which is the basis for the design that became air tab.
2) The test measured the change in coefficient of drag and found a 4% improvement. The test then calculated the horsepower using a pre-defined frontal area of 19 square feet. 14 air tabs on each side of the car at 2.67 square inches each would add 0.5 square feet of frontal area -- a 2.6% increase. The net improvement in drag -- CdA -- would therefore be just 1.4%
3) sample size insignificant.


The Sprinter Van Test:

There was no scientific data presented -- only a testimonial from someone claiming to have had students from a local college find a 10% reduction in air drag in their wind tunnel. No data, no methodology, and 10% improvement is simply unrealistic (Cd would have to drop from 0.32 to 0.29). Lunch counter story got printed in an expediter magazine...



The BATC study:

2 identical trucks, getting 0.2mpg difference from each other, get 0.15mpg better fuel economy with air tabs when driving during a different part of the day with 10mph slower winds... Again, sample size laughably small compared to the outside factors.



Independent results showing no statistical difference:

https://www.tc.gc.ca/media/documents/programs/AERODYNAMICS_REPORT-MAY_2012.pdf
http://ecomodder.com/forum/showthread.php/tested-vortex-generators-airtabs-toyota-corolla-2390.html
http://ecomodder.com/forum/showthread.php/tested-airtabs-mini-van-b-no-measurable-effect-6381.html


Independent test showing a 6+ % loss:
http://ecomodder.com/forum/showthread.php/scion-xa-aero-mods-2969-7.html

Independent test showing a 3% increase:
http://www.autospeed.com/cms/articl...ortex-generators-to-a-threebox-sedan&A=113000


Independent tests showing -6 to +6% differences:
http://busride.com/2013/12/operators-put-airtabs-to-the-test/


We know vortex generators can work, the trick is to have the correct shape in the correct location (see that last link where they played with airtab placement on an Acura Legend). This requires far more testing than just haphazardly slapping a product on the side of your truck -- so yeah -- I'd like to see a real scientific study using honest statistics to show precisely with what certainty airtabs can show a "2-5%" reduction in drag.

 

Schneider tested vortex generators on some of their trailers. They were not airtab brand VGs, they were little boxes with some funky stuff going on inside (possibly Vorblade?). You still see them every now and then on the occasional trailer, but they did not implement them. They did implement wheel covers though...



Edit: Vorblade vortex generators are actually smartway certified for the trailer. You use a lot of them though:


But they have been proven to decrease drag by over 5% http://epa.gov/smartway/forpartners/technology.htm


Absent from that list? Airtabs...

 

In my opinion, 5% is pretty far fetched for something like this.

http://www.airtab.com/faqs.htm#Answer_25:_

If you look down toward the bottom of the link, Airtabs manufacturer says NASA has evaluated the product, and is using them in a wind tunnel.

Be that as it may, I stuck a set of them on my tractor, and the handling improvement in a cross wind is quite noticeable. Now that's not a scientific test by any means, but I can tell you I'm thoroughly satisfied that it was money well spent. Now that's the bottom line in any of this isn't it? Satisfaction by the consumer.

 

I'd agree, but at least Vorblade backs it up with data & a detailed account of the test methodology: http://www.vorblade.com/wp-content/uploads/2013/02/VorBlade-TechInfo-full-document1-1.pdf

And Texas A&M's transportation institute was the independent tester used to meet the EPA smartway certification -- they found a 7% improvement: http://www.movinout.com/archives/December 2012/article31.html


Personally I'd rather have a trailer tail, but I'm very impressed with Vorblade's documentation (which, going back to the point of this thread, stands in stark contrast to KR-backed airtab).

 

You should see some of the documentation accompanying some of the most outlandish junk that gets foisted on the trucking industry... a lot of it coming from places that purport to be institutions of high education. Just goes to show that paper with words on it can be easily bought.

The idea that all of these devices are designed for is to get some higher pressure air that the truck is moving through into places that are generating a lower pressure zone- in the gap between the tractor and trailer, and behind the trailer. Since I swap out trailers frequently its difficult to put a number on it, but I agree that a trailer tail seems to be more effective than either of the other two devices. However, what can you do about the gap? Those Vorblade thingies look like they're just waiting to pull themselves off by grabbing the first tree branch that obliges. LOL!

So, how do you judge whether you should spend some money on any of this stuff, and whether its working? First, anyone claiming really big gains should be viewed with suspicion. 10% or 20% increases in fuel economy probably aren't going to be obtained by any single device. Testing done on a small vehicle probably isn't going to be directly applicable to something the size or weight of a class 8 CMV. I suggest that one applies a "reasonableness" standard to evaluating any of this stuff. Then comes cost... $250 for some Airtabs isn't a big gamble. I couldn't tell you what they want for Vorblades, but its probably the same ballpark. Take your pick, its probably going to be similar either way.

As far as determining if you have a gain, you need to be tracking your fuel economy closely, have a baseline, and then compare what your getting after the change. The best time of year for this is going to be the summer... that gets you out of winter fuel blends and low temperatures, and the really windy conditions we see in spring and autumn.

And then? Well, they do say a fool and his money are soon parted. I might be willing to try $250 for Airtabs (NFI puts them on all of their equipment,) but shelling out $200k for a tractor takes this all to another level, or ten. So far all I've seen is an awful lot of speculation, and a lot of axe grinding. OTOH, unless someone is willing to try out new ideas, technology doesn't get advanced.

 

Seems to be more people speaking out about their dealings with Bruce.

http://solutions.letstruck.com/Answers/View/11741/WTF+Pittsburgh+Power+did+what

 

Sounds to me like he didn't do the "hard work", if you did the "hard work" as he is so fond of saying, you wouldn't have to listen to his bs. KR is so full of himself and makes some of the most outlandish statements I can't believe anybody would buy what he's hawking. Change your oil, drive your truck the right way, know your per mile expenses and treat your customers right and you'll succeed in the trucking business. Don't listen to or throw your money at snake oil salesmen like KR or BM.

 

More unsuspecting victims

 

http://solutions.letstruck.com/Answers/View/11741/WTF+Pittsburgh+Power+did+what