Has anyone installed Airtabs on their 5ver?

[Dkevdog]

John, regardless of what you have on the side of the trailer the airtabs do thier thing. Your trailer is pushing a huge amount of air mass out of the way when you are going down the road. That void creates a vacuume behind your trailer that must be replaced. The reason the air tabs are at the very end of the trailer is so they can create the vortex there, that fills that air void and reduces drag. Probably a bad job explaining it, but that is why they must be placed at the end of the trailer. As for your Covers and heater doors, etc... . the air is simply pushed around those. But because it is not the end of the trailer, there isn't much drag created by them.



Kev

 

[ARARAR]

Airtabs? I thought you said Air bags. Why would anyone put air bags on a 5er????? My bad.

 

[Sarge]

Naw, the airbag is the mother-in-law... ... .....

 

[johnrv4]

I think that the theory is good, and I know they work good on airplanes(got one installed in front of my cabin vent on my RV-4). I was just thinking that they might not see real "clean" air back there by the time it bounces off of the awning arms and other projections. But, they must work to some extent, if the back of the trailer is staying cleaner. My rig would probably make a good test bed to try them on. I usually pull the trailer faster than I should, and I know it pushes a lot of air when I pass other towing rigs and blow them over to the shoulder .

 

[Dave Zuber]

I have them on the back of my Gemtop Contractor canopy. The canopy sits about 2 ft above the cab and it has 'meatcleaver' styling. I've noticed about 1/2 mpg increase (16. 5 > 17. 0). But, I need to add up all my fillups to really get an accurate number.



The road spray used to cover both lanes and part of the ditch behind my truck. It looked like I was driving a boat with a large wake. I could back up the tailgators by just driving through a puddle. With the Airtabs I have no road spray visible out the back. I can drive through water and the tailgators just hang in behind me. (One just tried to drive under, but the hitch stopped her). So, this alone convinced me they were working. If my truck is not disturbing the air 20 feet on both sides it must make a differance.



Cross winds don't effect the steering as much any more with the airtabs.



One drawback, the original white color matched my truck and canopy exactly when I installed them. Now after about two years they are turning yellow. I'd recomend that you paint them, even if it is white. If you put these on a curved surface, water and dirt will get underneath, so seal them with clear rtv on the edges.



How well these work depends on each application. Mine would work better if I had a better wing on the front, so the air coming over the top would be smoother. On long trailers, length over 3x the width or height, these should work very well.



I work at a hi-tech firm. I get about one question per week on the airtabs. It is really funny to explain what these are supposed to do, half of the 'engineers' don't get it. Lots of the 'high school grads' do get it. All of the hot rodders and motorcyclist get it. Guess you can be educated beyond your intelligence.

 

[MrFixit]

Never thought they would be good for much mileage if any but do seem to break up the wind behind the trailers.



Here are some interesting sites

http://www.gmi.edu/~sroy/sae00c99r.pdf



Can't seem to find the one that has the Truck in the wind tunnel with the red smoke blowing over it. The one that has the tailgate up, down, toneau cover and shell. A university study. I have found the text to it but not the report with the actual pictures.



Also, the only way to gain mileage while towing is to go from gas to diesel! :-laf