Trailer Or RV: A little sheet metal can save fuel

I haul an enclosed trailer 25K - 30K miles per year. Before adding the sheet metal vanes to the top rear edge, and side rear edges (pics below), I averaged 14-15 mpg. With the vanes I average 16-16.5 mpg.

Anyone who hauls an enclosed trailer, or a square backed RV, would benefit from adding a bit of sheet metal. The vanes duct air into the wake region and reduce the wake "suction".

TOP OF TRAILER



The vane stands off the top and sides using a 2 inch "Z" bracket. For RV's and larger trailers, I would use 3 inch "Z" brackets. The vanes and z brackets are 18 ga. galvanized steel.

At present gas prices, a 2 mpg increase in fuel economy represents over $300 in fuel savings per 10K miles.

BTW, the round edged "Airstream" RV's will not benefit much from this treatment.

Slick

Similar vanes have been used to blow dust off back of station wagons and always wondered if added drag or helped. Kenny Dreer had some business with vortex generators for semi's. I've definitely thought along these lines on motorcycle application. Maybe add vanes on sides too?

hobot said:

Similar vanes have been used to blow dust off back of station wagons and always wondered if added drag or helped. Kenny Dreer had some business with vortex generators for semi's. I've definitely thought along these lines on motorcycle application. Maybe add vanes on sides too?

Click to expand...

Re: drag ......they do add drag, but the reduction of drag from wake suction is of greater benefit.

Re: semis.....semis would similarly benefit, but the law does not allow....they would exceed height and width restrictions.

Re: motorcycles.... Best place to put the vanes would be on the rear edge of the rider, but a tear dropped shaped fiberglass shell suit would be better....or perhaps an inflatable "hump" on his back?

Re: vanes on sides....look closer at the first pic....there are vanes on each side. If dragging in low places were not a concern, I would put a vane on bottom edge....might pick up another 1 mpg!