Aero RV (custom boat tail for '95 Ford E-350 Class C motorhome)

[orbywan]

I'm sorry to say about all I've done to the RV since then is build a spring loaded cover for the open slot in the belly pan that allows the drive shaft to move up and down. That and we've managed to go camping and/or quadding several times. Life and my business have been so full speed I haven't had any free time to work on the front mods, or anything else for that matter.

I'm happy to say the all the mods have held up 100%, except I have 'modified' the monocoat on the two lower corners of the boat tail off roading in the desert. Monocoat doesn't stand up well to cactus. Ha. Interestingly enough, we haven't torn off any coroplast on the belly pans, even though I've scraped it a time or two.

The extended hitch has performed flawlessly so far also. Every time I've taken the RV out since the last entry it has had the quad and trailer hooked up so I haven't done any more mileage runs either. I did drive it to an RV show in Phoenix back in March, with no trailer for once. I was doing 65-70 the entire trip because my sales rep that I was following has a lead foot, there was a crazy crosswind/left front quarter headwind, all the way up, and it still got 15.45mpg on the way up, and 16.9 on the way back. The winds were so crazy I don't put much faith in the return number though.

I'm not wishing for it, but at some point business will slow down and I'll get to finish the front mods and the wheel fairings. I've got the raw materials, just have to find the time to do it. Now that I'm thinking about it, I did manage to weld together some frames for the dually wheel fairings. Everyone keeps telling me they are a waste of time but I'm stubborn enough to try it anyway.

It never fails, every time I have a day coming up where I think, yeah, I can work on the RV, something happens with her family, or my family, or one of my customers calls with a - gotta have it yesterday order. Anyway, it'll happen.

[slowmover]

We're glad for your "problems" in attending to the mods . . but the numbers speak volumes. I linked this and another of your threads to others last night (not for the first time) in a fuel economy discussion on Class C. Gearing and Aero as Big Dave put it in re diesel pickups . . . but moho's are already geared optimally (or ding-danged close to it) so a "Gear Vendors Overdrive" is an unlikely help.

But aero is a great DIY piece of work.

Who'd believe 15-mpg at 65 in a crosswind, huh?

(Best)

.

[chrisgerman1983]

Wow! very nice work I don't know if it has been mentioned?... but have you considered a hitch mounted storage platform? it could make the boatail even more useful as storage. Especially if you hinged the top so the entire thing could lift, possibly with hood lifts to assist. Also have you considered clear coroplast for the rear panel? that way your rear camera could still be utilized.

[aerohead]

Originally Posted by orbywan

I'm sorry to say about all I've done to the RV since then is build a spring loaded cover for the open slot in the belly pan that allows the drive shaft to move up and down. That and we've managed to go camping and/or quadding several times. Life and my business have been so full speed I haven't had any free time to work on the front mods, or anything else for that matter.

I'm happy to say the all the mods have held up 100%, except I have 'modified' the monocoat on the two lower corners of the boat tail off roading in the desert. Monocoat doesn't stand up well to cactus. Ha. Interestingly enough, we haven't torn off any coroplast on the belly pans, even though I've scraped it a time or two.

The extended hitch has performed flawlessly so far also. Every time I've taken the RV out since the last entry it has had the quad and trailer hooked up so I haven't done any more mileage runs either. I did drive it to an RV show in Phoenix back in March, with no trailer for once. I was doing 65-70 the entire trip because my sales rep that I was following has a lead foot, there was a crazy crosswind/left front quarter headwind, all the way up, and it still got 15.45mpg on the way up, and 16.9 on the way back. The winds were so crazy I don't put much faith in the return number though.

I'm not wishing for it, but at some point business will slow down and I'll get to finish the front mods and the wheel fairings. I've got the raw materials, just have to find the time to do it. Now that I'm thinking about it, I did manage to weld together some frames for the dually wheel fairings. Everyone keeps telling me they are a waste of time but I'm stubborn enough to try it anyway.

It never fails, every time I have a day coming up where I think, yeah, I can work on the RV, something happens with her family, or my family, or one of my customers calls with a - gotta have it yesterday order. Anyway, it'll happen.

My notes from Mythbusters haven't survived,but I seem to remember that during the F-150 Tailgate testing that the pickups returned on the order of 16 mpg at around 55 mph?
For your rig to be generating these kinds of mpg numbers at 65 mph is really inspiring.
And Edison was probably quite literal when he talked about 99% perspiration!

[orbywan]

Originally Posted by aerohead

My notes from Mythbusters haven't survived,but I seem to remember that during the F-150 Tailgate testing that the pickups returned on the order of 16 mpg at around 55 mph?
For your rig to be generating these kinds of mpg numbers at 65 mph is really inspiring.
And Edison was probably quite literal when he talked about 99% perspiration!

Hi Phil, glad to hear your boat tailer/trailer quest continues. I feel bad I haven't had time to do any more mileage tests on the Aero RV, everytime I've had time to do that we kinda had to go blow off some steam and relax
camping and quadding. All relatively short runs with lots of off road involved.

We just took a bunch of grand kids to the lake to teach them how to ski, and pulled the old Webbcraft, which was a serious test of the extended boat tail and hitch. Holding 3500 pounds of boat, trailer and gear at arms length (3 foot extension over stock) is a pretty serious load.

I was so totalled after four days at the lake dealing with equipment and kids I didn't fill the RV up after we got back into town, but I will as soon as I can. I can tell by the gauge it didn't do great mileage-wise, but the load was so severe I didn't expect it to. I'm just glad the hitch survived the trip.

I kept the 9-inch monitor in quad mode most of the time, see photos, so I was able to keep an eye on the hitch gyrations which were pretty minimal considering the load and varying road surfaces.

Something interesting happened on the way back. Once I got the beast back on the trailer and secured we took off down the road and I realized my seat belt was stuck in the door. I was doing maybe 50 and opened the door to get the belt out and the wind sucked the door open about six inches. It took three serious heave-ho's to get the damn thing to close.

Why is that interesting? If you drew a line from the front of the front fender to the widest part of the RV body right behind the door, the door was sucked right to the edge of that line and did not want to let me pull it back. In other words it was stuck in the vacuum or eddy created by the wind having to go from the width of the front cab to the width of the camper body. A pretty cool demonstration of aerodynamics at work, and a perfect demonstration of why I can't wait to modify both sides of the body to reduce that effect. That combined with the wheel fairings will put this beast over the top I think.

orbywan

[orbywan]

Why is that interesting? If you drew a line from the front of the front fender to the widest part of the RV body right behind the door, the door was sucked right to the edge of that line and did not want to let me pull it back. In other words it was stuck in the vacuum or eddy created by the wind having to go from the width of the front cab to the width of the camper body. A pretty cool demonstration of aerodynamics at work, and a perfect demonstration of why I can't wait to modify both sides of the body to reduce that effect. That combined with the wheel fairings will put this beast over the top I think.

orbywan[/QUOTE]

Forgot the photos - On the monitor view, the far right view is of the top part of the hitch that is inside the boat tail. This is what I used to monitor the hitch movement while driving.

The left top view is the pan and tilt camera view on the back of the boat tail, the lower left is a view of the belly pans looking forward from under the driver's seat area, the lower right view is looking at the bellypans from the driver's seat area looking rearward. It also has left and right mirror cams (turn signal triggered, or manually selected), and a forward looking and a rearward looking roof-top cameras.

Next up is to extend the transom camera cable on the boat so I can hook it into the system and have a camera view from the rear of the boat transom when towing. Yehaa.

[orbywan]

Originally Posted by chrisgerman1983

Wow! very nice work I don't know if it has been mentioned?... but have you considered a hitch mounted storage platform? it could make the boatail even more useful as storage. Especially if you hinged the top so the entire thing could lift, possibly with hood lifts to assist. Also have you considered clear coroplast for the rear panel? that way your rear camera could still be utilized.

The hitch is so big it provides somewhat of a platform, but I need to cut a floor for it. The pan and tilt camera was moved to the outside rear of the boat tail after I test drove it for the first time, that's my main camera! It's the black orb on the top center of the back of the tail.

[aerohead]

Funny! Just ahead of that corner,would be the minimum pressure location on the sides of the rig,so once you pushed the door out there,the air on the interior face of the door would be at a higher pressure than the outer skin and you'd be fighting that differential.It's quite a bit of 'wing' area!
On my CRX the flow is right against the outer door surface when closed.Descending into Chama,New Mexico at 1:00 in the morning,I've kicked the driver door open and held it with my leg for air-braking.It doesn't do that much,but it helps keep me awake,and the elk love it when insane people come by in the dark.

[skyking]

The low wing planes I flew would get stuck like that, you have to land to get them closed.
The high wing planes were a little more cooperative. You could always mess around with some rudder, induce a yaw that would alter the flow in your favor.

[orbywan]

Originally Posted by aerohead

Funny! Just ahead of that corner,would be the minimum pressure location on the sides of the rig,so once you pushed the door out there,the air on the interior face of the door would be at a higher pressure than the outer skin and you'd be fighting that differential.It's quite a bit of 'wing' area!
On my CRX the flow is right against the outer door surface when closed.Descending into Chama,New Mexico at 1:00 in the morning,I've kicked the driver door open and held it with my leg for air-braking.It doesn't do that much,but it helps keep me awake,and the elk love it when insane people come by in the dark.

To quote John Wayne's side kick, "You funny GI!"