I just returned from a 2000 mile road trip in a good friends SOB up to the frozen north. He is a VERY interesting fellow. He spent most his live in the racing business and was the car owner, builder, and crew chief for one of Dale Earnhart's first Winston cup rides.

He says that a couple dozen rules are now in the NASCAR rule book because of things he did. (If not specifically prohibited, it's legal)

Anyway, somewhere along this trip after we had solved all the worlds problems and started on the second round of lies...er...war stories, I asked about ways to improve fuel mileage on my motor home.

The short answer of the long discussion is "REDUCE DRAG". Without knowing or discussing how much of an impact these would have on fuel mileage, some of the things that he suggested are:

- Get the crap off the roof...AC, Pod, Roof rails, etc.
- Lower the front end as much as practical (yeah...yeah more later)
- Bring the front bumper back to the body and down to the lower edge of the body work.
- Put a soft spoiler on the bottom of the bumper to block airflow under the coach.
- Put an structure from the top of the grill opening to the top of the radiator to force air through it and over the engine.
- Streamline the mirrors and other protrusions
- Shorten the rear bumpers and bring the ends even with the body sides (they currently stick out and catch the wind just like cupping your hands and sticking them out the window.)
- Put fender skirts over the rear wheels (I was already going to do that just because I can... )
- Put an "awning" over the rear window to smooth airflow over the butt of the coach and down to the toad. (Next best would be a spoiler on the top and sides to create turbulence and break up the vacuum that naturally forms behind the coach.)
- Put a real spoiler on the toad.

There are probably a few more but I was drinking from the proverbial fire hose and can't remember more at the moment. I asked him how much difference each would make and he responded:

"How would I know? But improving aero is a collection of minor improvements that add up."

He has some manometers (air pressure gauge) he's going to let me borrow to play around with. I will be able to measure differential air pressure in various areas.

I don't know how much of this I will do but my brain never shuts off and it's something interesting to think about.

He has one of these air conditioners that impressed me. It is VERY quiet and he runs it instead of the roof air on his big square SOB (Winne Sightseer). I was looking at it and thinking that the internals could probably reconfigured to fit in some underutilized spaces like under the fridge or beds to get the AC unit off the roof. They come in various sizes, the 10000 btu model only pulls 9.1A and is 120V. (1100Watts). A couple of those units and a smaller generator.....hummmm

We drove home (1000 miles) in one 20 hour day and I'm still dragging a bit and just thinking out loud....

Harry wrote on Tue, 06 May 2014 14:10

...How about putting a spoiler in front of the roof air?

I was telling Will that I had been thinking about shaping a streamlined full length aluminum cover that covered the front vent, AC, and included a narrower 'pod' for storage. His response was that while that might make a difference, getting EVERYTHING off was by FAR the best. "You want to reduce the size of the hole you are making through the air..."

Realizing that you can write on the head of a pin what I know about aero and hydrodynamics, I THINK this is similar to why boats are long and thin. I seem to recall my Navy Captain cousin saying something about the length of the waterline having an effect on speed although this conversation was several decades ago and I've probably misremembered it. From a common sense standpoint a smaller cross section makes all the sense in the world to me as does applying methods like spoilers and such to smooth the flow of air over the body.

What I have absolutely no clue about is if these will return any advantage that is worth the cost and effort....probably not but, like I said...a subject for discussion.

Harry wrote on Tue, 06 May 2014 14:10

...How about putting a spoiler in front of the roof air?

I was telling Will that I had been thinking about shaping a streamlined full length aluminum cover that covered the front vent, AC, and included a narrower 'pod' for storage. His response was that while that might make a difference, getting EVERYTHING off was by FAR the best. "You want to reduce the size of the hole you are making through the air..."

Realizing that you can write on the head of a pin what I know about aero and hydrodynamics, I THINK this is similar to why boats are long and thin. I seem to recall my Navy Captain cousin saying something about the length of the waterline having an effect on speed although this conversation was several decades ago and I've probably misremembered it. From a common sense standpoint a smaller cross section makes all the sense in the world to me as does applying methods like spoilers and such to smooth the flow of air over the body.

What I have absolutely no clue about is if these will return any advantage that is worth the cost and effort....probably not but, like I said...a subject for discussion.

... I'll go for convenience.