Sleepy - what if you attached a strip of plastic to the two angled sides such that it naturally curved around producing that rounded front?
Also, I notice your air foil is perforated. Have you experimented to see if covering the perforations would improve mileage? E.g. just by taping over them and then experimenting over a couple of tanks of diesel to see if the consumption changes?
Steve
When I tried to extend my Airfoil further forward it left a unsuppoted area... the wind is pretty strong as you know from holding your hand out the window in a verticle way.. palm flat to the wind as you drive at the upper speed limits.
I started out with solid wind deflectors... making the proto types out of PVC siding for houses.
I was originally increasing my fuel economy from 13.5 mpg to to more than 14.0 mpg and I totally eliminated the bugs from the bulkhead above the rear of the trucks cab....
... but I had created another mess... the solid wind deflector created a low pressure area on the back side of the wind deflector as the total volume of air packed up againest the solid wind deflector and slide off the wind deflector to the outside. This negative air (vacuum) pulled road dirt, rain water, asphalt dust, oils, etc... up through the space between the trucks cab and the trucks bed. It was a bigger mess that the bugs that were originally plastered in a much smaller section of the verticle area of the bulk head.
I intutitively knew that I had to allow some air into the low pressure area to prevent that syphoning of the road dirt.
While looking at materials I had seen the GutterGard with the holes... it doesn't take a genius to know that drilling a lot of holes in the thin PVC was difficult... the drill bit hangs up and grabs the PVC. I decided to make a prototype out of the guttergard... It was easier to tape large sections in minutes with 2" wide plastic tape.
I was surprised when I found that leaving all of the holes in the Guttergard worked very well... no tape needed... I attached knitting yarn along the "wings" in the areas of the holes and watched the mostly laminar flow as we went down the highway.
As the truck built up speed the incoming air pressure hit the wind deflector and seemed to "sheer" the air right accross the holes (after all... there now was air pressure on the backside of the wind deflector pushing back a small amount. The yarn strips smoothed out flowing to the outside... I starting calling it an airfoil about this time.
The airfoil got rid of the bugs on the bulk head which was my goal and prevented road dirt from being a problem. And I was surprised at the slightly increased fuel economy
Serendipity.... again (sometimes I'm just Lucky.
I drove the truck in some back road areas where I got a lot of dust on the truck camper and truck. When we got home I was going to wash the truck camper and truck.
I noticed that the last 10" or so of the Truck camper sides had a verticle line of dirt that was heavier than anything forward of that point.
I documented it... to give it some thought.
I had originally "guessed' at the swept back angle of the Airfoil... just to be able to use an existing screw in the edge of my Lance camper.
I then moved the outside end of the airfoil back about 1" total on each side in a couple of increments. Moving the verticle dirt lines to just behind the back corners of the camper.
The fast moving air from in front of the camper is now flowing all the way back to the "drag" area behind the camper... breaking up the drag... (it appers to be flowing as far as 12" or so away from the sides. of the camper ( I guess that this fast moving channel of air would appear to be about an arc like the air flowing over a wing)
How can I be sure... the back of my TC is never dirty (you can examine it in mt thousands of pictures that I've posted over the years
My fuel economy started at 13.5 mpg... it has averaged 15.1 mpg for over 60,000 miles in 48 states and much of Canada. I have posted many pictures of the Odometer and mpg indicators on my GMC, crewcab, Duramax/Allison.
Steve aren't you sorry that you asked?
Sleepy
