I am still hunting around for ways to increase mpgs. I have unloaded my camper for the season and have my Leer canopy back on the truck.So I have decided to conduct another experiment by installing vortex generators on the canopy to see if I can gain any benefit.I use vortex generators on my plane to give me a lower stall speed and still maintain control of the airplane and keep it flying at lower speeds.The vortex generators create a turbulent air stream aft of the generators and that keeps the air attached to the wing at higher angles of attack (steeper pitch of the wing).The theory is that vortex generators on a truck canopy will create spiraling turbulent air that will stay attached to the surface of the canopy and bend around the end and sides to break up the vacuum drag that the truck creates as it travels down the road. This vacuum pocket pulls on the back of the truck creating a drag on the truck. To overcome this drag requires more hp (fuel).Therefore, if I can reduce this drag somewhat I might be able to realize a small increase in mpgs. So I have invested about $85 to buy the vortex generators and paint them and install them on my canopy.Reports from others that have tried installing AirTabs (vortex generators) have yielded improved road handling in high winds and when large trucks pass you (eliminates the buffeting) in all cases. But when it came to seeing an increase in mpgs the results were a mixed bag. Some saw measureable improvements while others didn't see any improvement in mpgs or the improvement was so small in wasn't really measurable.But I spent the $85 so I am going to try it out for my truck and my driving style.

I have seen those exact units advertized. I don't run a cover on the bed & never thought of running them there. I thought about installing them on my camper but it would have been a whole lot more cost for the few runs I make with the rig. I'll be very interested in your results VS the advertising.

Interesting, please post back your findings. Did you paint them to match your truck cap or did you get that lucky to find a set in that color? I've got the exact same truck cap on my 2nd gen, I love the extra head room it offers over the standard caps. Only thing I don't like about it is it is dark blue (my truck is red) and does not match at all. I've been contemplating having it painted for some time now. JR now Free

Did you paint them to match your truck cap or did you get that lucky to find a set in that color?

The Airtabs come in white or black only. So I got the white ones and painted them to match the truck and cap.

What is the verdict?

Still working on data collection. Only on the 2nd tank of fuel.

What did you get mileage wise on the first tank?

My first tank was my hunting trip to Montana. 625 miles one way. On winter fuel. Last year the exact same trip (and driving style) netted me 19.34mpg (hand calculated). This year the trip netted me 20.4 mpg. (note: I have new 50hp injectors this year and in reality that may be the major reason why the mpgs were better this year) I am on the second tank now but it is driving to and from camp and errands to town so this tank won't be useful as a data source at all. Trip home I would expect to gain some more comparison data. I had a fair amount of rain and windy weather on the way up which was different from my trip last year. With the rain and slush etc., my rear window did not stay clean as it got lots of spray from the wheels and back of the truck. Did not have any buffeting at hiway speeds or when passing big rigs. :-) I have not been able to identify any other benefit at this point. But I also didn't expect too because I have so little driving time with these vg's.

Where did you buy the vortex generators, and did they come individually or in sets of ?

You can buy them individually or they make them in some kits also. I couldn't see any price difference per item regardless if you bought them individually or in kit form. https://www.buyairtab.com/

Until today it has also been unseasonably warm, which will have a big effect on mileage. I don't recall, where did you get Marine bodies with 50hp nozzles? Are they the OEM 124° angle or the 03-04 243° angle like OEM marine nozzles?

I don't recall, where did you get Marine bodies with 50hp nozzles? Are they the OEM 124° angle or the 03-04 243° angle like OEM marine nozzles?

PM sent.

I am getting ready to remove my Leer canopy and put the slide in camper on my truck.  So I sat down and looked at all my mpg calculations over the last 5 months to see if I can come to any conclusion on the use of these vortex generators on my truck canopy.

 

I have just short of 5K miles with them on now and have driven in all kinds of weather.

 

What I can say about them is that there has been no noticeble driving (performance) behavior as a result of the install. I just couldn't feel anything different at low speeds or high speeds (highest speeds were 72mph ).  I didn't see that it kept my rear window any cleaner when it was raining or snowing.  On trailers etc., these are reported to keep the dust and debris off the back of the rig.  They are also reported to stablize the drive when big rigs pass you by.  I just didn't notice any of this on my truck with just the canopy on.  I might see that on the slide in camper because it is so much larger and more likely to be influenced by the pressure wave of big truck sailing by.  I'll have to report back later on that issue.

 

Also I was not able to identify any increase in mpg's in any driving around town and limited hiway miles at 65 mph.  However, when I drove at higher freeway speeds (such as 70-72 mph) I noticed a slight increase in my mpg's.  I have many tanks of use driving at 65 mph over the up and down roads of Idaho getting 19.5-19.6mpg (with canopy on and no vortex generators).  Well I ended up making 3 trips over to Idaho Falls this winter and driving it at 70-72 mph and getting 19.8-19.9 with winter fuel.

 

So I can't tell you exactly that I got .3 of mpg increase due strictly to the vortex generators, I can tell you that I have never seen this result in the past and I am inclined to believe the implied benefit of the vortex generators was likely more noticeable on my truck at the higher speeds than my normal driving style (which is usually 65 mph).

 

I do plan to install these on my slide in camper and I will report back if I see any difference in handling or mpg's

Good to get a report!

 

Although, IMHO, .3 is too much of a negligble difference, that I would say its a moot alternative. If it made atleast 1 mpg difference, then I'd say there may be something to it.

 

Also, because planes have these, is there something about the relation of these and aeronautics? Maybe they only become effective after you go over a certain speed? Speeds that planes get to, not vehicles?