Vortex Generators

[Iain_U1250]

I was already planning on adding vortex generators to the back of my truck ( the main reason for the chamfer rear) to reduce dust potential on the rear window, but looks like there are some commercial things called Air-tabs, might just get these instead. They seem to do a great job. Anyone had any experience with these?


[video=youtube;f80a9jssUFU]https://www.youtube.com/watch?feature=player_embedded&v=f80a9jssUFU[/video]

 

[tarditi]

A lot of SUVs and wagons had air deflectors on the rear top edge to blow dust and water (from road/tires/etc.) off the rear window... something like this may fare better.

I've seen vortex generators on some cars, but they were usually high performance cars and they were to disrupt the air a bit for a rear spoiler to be more effective and reduce lift at speed - not sure how it would work on a slower moving truck.

They have cheap adhesive ones on ebay for a few bucks - may be worth trying.

 

[UpperCrust]

Definitely an interesting idea..... if it works. How many would you need in order to make a difference?

 

[OCD Overland]

I did a bit of research on these last month for my trailer build. You'll find anecdotal evidence that they do something, but the only decent before/after comparisons I could find showed mixed results...

http://busride.com/2013/12/operators-put-airtabs-to-the-test/

Airtabs™ put to the test

Already proven to be effective in the trucking industry, Airtab, LLC, asked BUSRide to test the product on motorcoaches. BUSRide selected five motorcoach companies that represented a variety of climates and geographic conditions. Airtab, LLC, supplied each motorcoach company with Airtab® vortex generators to install, test and evaluate during the summer.

BUSRide asked the participating operators to keep a careful record of mileage and fuel efficiency both before and after the product trial, and to report any noticeable changes or improvements.

The drivers participated in evaluating vehicle stability and handling of the coach in actual service on the open road. Maintenance techs weighed in on the overall cleanliness of the rear of the coach, particularly from splash and spray during trips in adverse weather.

The results are in:

All Aboard America!
Mesa, AZ

All Aboard America! installed and tested three coaches with AirtabsTM, for product trials on the same line-haul run from its Midland, TX, location. The coaches ran from May through June for evaluation prior to installation. Two coaches ran July through August with AirtabsTM, while one continued without the product.

BEFORE Airtabs™ fuel mileage:
Coach 478: 6.30 miles per gallon
Coach 454: 6.35 miles per gallon
Coach 474: 7.11 miles per gallon

WITH Airtabs™ fuel mileage:
Coach 478: 6.54 (a 2.8-percent improvement in fuel mileage.)
Coach 454: 6.53 (a 3.7-percent improvement in fuel mileage.)
Coach 474: 6.87 (Continuing without AirtabsTM, Coach 474 showed a 3.5-percent decrease in fuel mileage over the first period.)

One driver reported noticing improved stability and better handling with the AirtabsTM through gusty West Texas cross winds.
___

Cyr Northstar Tours Lines
Old Town, ME

Cyr Northwest reported a “neutral experience” after a 10-day before and 10-day after trial period, comparing fuel data with and without the Airtabs™. For the most controlled conditions, Cyr installed Airtabs™ on one coach that runs the same line-run route daily from Bangor, ME, north to Caribou, ME, with the same three drivers doing the testing at highway speeds.

BEFORE Airtabs™: 6.9 mpg

WITH Airtabs™: 6.5 mpg (a 6.2-percent decrease in fuel mileage.)

Cyr notes that none of the three drivers reported noticeable change in the handling of the coach, and none was aware of the coach feeling any differently. The wash bay personnel did not notice anything different in the way of a cleaner appearance to the rear of the coach. They did say, however, that the washer brushes did not damage the Airtabs™.
___

Pacific Coachways Charter Services, Inc.
Garden Grove, CA

With Airtabs™ installed on one MCI J4500 coach, Pacific Coachways sent it out with the same driver on several extended trips as far away as Yellowstone, WY. Comparing fuel records from previous trips without Airtabs™, the company reported the same fuel consumption for both before and after installing the product.

BEFORE Airtabs™: 5.82 mpg

WITH Airtabs™: 5.82 mpg (0.0-percent gain in fuel mileage.)
___

Winn Transportation
Richmond, VA

Winn Transportation installed the AirtabsTM on a Prevost H3-45. As Winn does not run regular scheduled service, the company tested its AirtabsTM on coach charters with one senior driver to various destinations.

BEFORE Airtabs™: 4.56 miles per gallon

WITH Airtabs™: 4.86 miles per gallon (a 6.2-percent improvement in fuel mileage.)

Winn notes the short test period, along with conditions like differences in idle time, traffic, accident delays, and speed limits. In his time with the coach, the driver did not notice any difference in handling or less sway in the coach. The company says it will continue to monitor fuel mileage with the AirtabsTM over a longer period and offer its findings.
___

Arrow Stage Lines
Omaha, NE

Arrow Stage Lines installed AirtabsTM on four coaches at its Denver, CO, facility. The company provided 6-1/2 months of data before having AirtabsTM along with data from 3-1/2 months of testing.
BEFORE Airtabs™:
Coach 508: 7.34 miles per gallon
Coach 509: 7.26 miles per gallon
Coach 510: 6.99 miles per gallon
Coach 511: 7.35 mpg

WITH Airtabs™:
Coach 508: 7.46 miles per gallon (a 1.6-percent improvement in fuel mileage.)
Coach 509: 7.55 miles per gallon (a 3.8-percent improvement in fuel mileage.)
Coach 510: 7.06 miles per gallon (a 1.0-percent improvement in fuel mileage.)
Coach 511: 7.85 mpg (a 6.4-percent improvement in fuel mileage.)

Arrow Stage says its driver reported nothing different as to the handling of the coaches.
___

Tour West America
Phoenix, AZ

Tour West America installed AirtabsTM on a 2013 MCI J4500. Prior to the product trial, the company reported fuel mileage for one-month. The company tested the AirtabsTM on coach for approximately two months.

BEFORE Airtabs™: 5.79 miles per gallon

WITH Airtabs™: 6.13 miles per gallon (a 5.5 percent improvement in fuel mileage.)

Of the three drivers who drove the bus before and after, one reported the rear of the bus staying cleaner throughout his trips. Another stated that the rear end of the bus felt a little more stabilized.
The company intends to install Airtabs™ on a 2003 Prevost H3-45 and test the product for an extended period. With the Airtabs™, the seven coaches showing improved fuel economy averaged a 3.51 percent increase in mileage. Based on a $3.85 per gallon diesel fuel price as of November, this represents a savings of 13.5 cents per gallon.

I decided to pass for now, but I'd be interested to hear if anyone finds better info on them than I did.

 

[OCD Overland]

Some other interesting info here:

http://spinoff.nasa.gov/Spinoff2008/t_3.html

I was looking also at whether a topper on a pickup made any appreciable difference in MPG when towing a taller trailer, but the answer seems to be no, since the distance between truck and trailer is too great. However, I do wonder if a combination of a topper and AirTabs would successfully bridge the gap and give better results.

 

[pappawheely]

I've been curious about a couple aero aids to increase fuel mileage. Thanks for the info.

 

[HenryJ]

... ( the main reason for the chamfer rear) to reduce dust potential on the rear window, but looks like there are some commercial things called Air-tabs, might just get these instead. They seem to do a great job. Anyone had any experience with these?...

Sounded like a good idea to me. Dust and snow tend to pile on my rear cover. These might just help that out.

I have been trying to find a replacement rear spoiler for my Vega Panel too. Trying them there too:

 

[loudboy]

Bump to an old thread, but do you guys have anything to report back? I'm curious to see how these might help my rig. The gap between cab and camper on the truck seems like the right use for these, as well as on the very blunt rear.

 

[TernOverland]

There are lots of videos and testimonials out there. There is no doubt that the science is sound. I have yet to see a well done comprehensive study on rigs like ours. I do plan to try these devices though. There are a number of devices out there, but they are not created equally. The "Airtab" design appears to be the best for our use, in the studies I have read. If you have a Scangauge or similar engine monitor, you can utilize the "instantaneous horsepower" readout to evaluate the reduction in drag. Properly done, It can give more conclusive answers on a smaller data set.

 

[loudboy]

I think I'll have to try some out, especially if I can find a cheap way to 3-D print or mold some for myself.

Apparently a friend of a good friend of mine is a high ranking engineer at Daimler trucks, whose testing facility includes the largest land-vehicle wind tunnel in North America, and it's right here in my backyard of Portland OR
Hopefully I can sweet talk myself into some time in there (normally rents for over $10k/day though, so I dont have my hopes up)

 

[TernOverland]

I think I'll have to try some out, especially if I can find a cheap way to 3-D print or mold some for myself.

Apparently a friend of a good friend of mine is a high ranking engineer at Daimler trucks, whose testing facility includes the largest land-vehicle wind tunnel in North America, and it's right here in my backyard of Portland OR
Hopefully I can sweet talk myself into some time in there (normally rents for over $10k/day though, so I dont have my hopes up)

I would love to see the wind tunnel tests. Heck you might even contact Airtab and see if they will kick in some help. That type of result would be a huge marketing tool for them.

 

[loudboy]

If I do score some free time in there by some crazy grace, I'll definitively be thorough about it. If nothing else, I'll just pick this guys brain for any info and tips and report back.

 

[BigSkyBrad]

Sorry to drag up an old thread, but did anyone have success with these. A truck came into work today with them fitted, which got me wondering if fitting them to my build would be beneficial.

 

[Trail Talk]

Some interesting reading here: North American Council for Freight Efficiency.

Under Cleanliness Benefits they state: Many drivers report that using these devices have keep their trailers cleaner due to the revised air flow.

Unfortunately, this is reported under Fuel Economy Benefits: The improvement in fuel economy is small enough as to be below the noise level in test data. None of these systems is EPA Smartway certified as of August 2020 and they are not available as a factory installed option from tractor or trailer manufacturers yet.

 

[Iain_U1250]

I've had them on mine for a couple of years. I have records off each tank of fuel since 2015, and I can't see any difference after when I put them on.


Where it did make a difference was the amount of dust getting on the storage bag at the back, there is less dust then before. Next time we are on a very dusty road, I'll shoot some video of what it looks like when at speed.






We did change the way we would fill up when we were living up in North Queensland. The local prices for fuel were quite high, but there were some much cheaper service stations a few hundred kilometers away on the way out west or down south, so I'd only put a little bit a fuel in to get to the cheaper stations, then fill up both tanks when we were at the cheaper stations, sometimes also filling up another 80lts in the jerry cans as well. This gave some very strange figures, so the rolling average is a better way at looking at it.