Roof splitter...better front end aerodynamics

Aerodynamics is an under explored topic. We could use more experimental here.

Since I have a late model truck with an older camper, I needed a spacer to clear the cab and bed rails. Not exactly sure how high to go, I built my first spacer with 1x6's sandwiched between 3/8" plywood.

I've since replaced the spacer with one two inches shorter made of 2x4's and plywood. On my last two trips (990 miles and 485 miles), I averaged 14.6 mpg. Typically, I've been getting 13.2-13.3 mpg.

Less wind resistance?

I'd like to try a roof wedgie, but am reluctant to risk scratching the truck's paint.

Keep those ideas coming.......

Sleepys airfoil is listed in the TCU under exterior section. I would think as far as results probably as varied as truck & camper combinations.
I know on ours-std cab with long nose camper the air passing over truck roof is being compressed like a turbine. It would briefly be entertaining to see real numbers on what’s occurring.
The buffeting on ours was horrendous- couldn’t open a window-make your ears hurt. Shortly after we got the camper I replaced truck fixed window with a slider. First trip with it we had bugs being splattered on the INSIDE of windshield. But it did get rid of the buffeting. I made a screen for the rear slider, we usually have it open bout 1/8-1/4. No buffeting, even opening the side windows. I attribute to the air passing over the cab, forced down the back between cab and bed. Force was air enough to pull air out the pressure flap vents sort of venturi, creating a vacuum in cab. Just a guess who knows..

If I wasn’t so lazy Id copy Sleepys-I don’t need the anti-buffeting but minimizing the smeared bug juice would be nice. Unlike front of nose where bugs get stuck and easily washed off later, they don’t on front wall off camper, just leave tracers, 'evidence' of their passing.

I would think that not having that air forced over cab would have to help, at least with buffeting, how much couldn’t say. I get way too much movement between camper nose and truck though to place something that contacted both.

This is mine, got the idea from Sleepy.

Wayn's right. This precise roof-to-cabover inflatable boot topic discussion goes waaaaaaaaaaaaaaaaay back, and was prolific. Eg. in 2003 (10 years ago) in this very Forum, the following was discussed:

"I used a blow up boot on my last camper between the truck and camper. It worked great, but it rubbed the paint off of both my camper and the truck."

and,

"I have seen the boots used and the principal was great, but unfortunately they did not work as stated. Most I saw used had problems rubbing the paint off the truck and camper and another problem with staying in place"

and,

"I tried air up boots many years ago and they all ended up in the trash can. They rub off the paint and when going to and from the mountains the pressure in them keeps changing because of the altitude changes. A real pain!!"

....just a small sampling of the very negative issues with this route.

Go the tried and true route, with Sleepy's air foil system, here--> And here is Sleepy's post on how shapes affect drag, NASA--> . Those with square jack legs will experience appx 4.56 x the drag when compared with round jack legs (quite significant). Sleepy and I discussed the relevance of jack leg drag n relation to "the big picture", in our driveway, using our camper as an example, when he last visited us.

Sleepy is an alumnus of Oak Ridge National Lab (ORNL), and a World-renown inverter. Have a look... think you'll like it and his build/test methodology.

Silver-

The Original poster has said nothing about inflatable boot, nowadays there are thin film products on the market that can protect the roof from abrasion.

Silver, good point about square versus round jack legs. I turn my front square happijacks in at a 45 degree angle using the pivoting dually jack mounts, creating a more aerodynamic shape. I then mount my air deflectors to the dually bracket.

Doesn't it depend on how far we want to go with aero? I find it strange that there is only one solution that is possibly viable, and that some feel there is nothing left to explore. Also, part of op point was to eliminate factors that had nothing to do with aero at all.

jimh425 wrote:
Doesn't it depend on how far we want to go with aero? I find it strange that there is only one solution that is possibly viable, and that some feel there is nothing left to explore. Also, part of op point was to eliminate factors that had nothing to do with aero at all.

I agree, one suit doesn't fit all and there are countless truck camper combinations. It's like saying a certain make, type, year of truck and camper is best for every application and everyone. There are many ways to skin a cat and we are just starting to explore aerodynamics. If one compares the amount of web space devoted to topics like, which is the best battery type or how to install a solar panel, there has been miniscule volume of info devoted to RV aerodynamics. Some people are interested in squeezing the last watt out of their batteries or solar system, others are interested in reducing their co-efficient of drag and sharing their experiences/ideas with other in the process. Last I knew that is what a forum is all about.

I believe the OP main concern was wind/aerodynamic buffeting. I have found with my truck/camper combination I was experiencing a buffeting/bucking effect at 64+ mph, With the deflector I installed there is no buffeting/bucking effect at 75+ mph speeds.

Is there any photo's of these roof splitters for one to look at? There seems to be some "Pro's and Con's" using these roof splitters, using magnets or anything that shows that they can do harm to the vehicle paint job, ect., anyone have photos taken that shows any damage?
Thank you.