advice and opinions required

[aerohead]

If you could pull a custom,lightweight,flatbed trailer,with an inflatable boat- tailed body,the drag reduction might compensate for the additional weight,leading to an overall mpg increase.
An automotive 12-VDC ventilation blower fan would be enough to inflate the envelope,and you could tailor the envelope with a semi-closed gap,only for highway use.
It would be something like this:

[Frank Lee]

Since I am required to respond, I think the first things to do would be deleting the awning, roof a/c, that other wart on the roof, and the roof ladder if you don't really use them anyway. Perhaps smaller, cleaner mirrors that come down on streamlined struts from the "cab over" could be fitted too. Looks like a good candidate for rear skirts, and perhaps all those louvered doors could have block-off plates when going down the road. The cab-over sure has sharp leading edges; somewhere on EM aerohead describes fitting quarter-round lengths to those edges for a nice drag reduction.

That bully bar block-off could be made of something lighter, like coroplast, and rounded on the top edge.

[Superfuelgero]

you said any ideas...

+


otherwise, you've got your work cut out. The more you move it towards mpg, the less utility you will have.

[kach22i]

I think Frank Lee has listed most of the low hanging fruit often found in other threads, this would be the least invasive route and the most affordable.

Remember, the larger and more ambitious the project, the more risk involved, mostly the risk of not finishing and ruining a completely good camper.

One suggestion even more obvious is to drive to shorter destinations, and more slowly. However, that's going to take most of the adventure out of the equation.

These are nice, and appear to have some aero-consideration.
http://www.yotatech.com/f123/holy-co...yota-rv-58777/




In 1982 I test drove a home made camper based on a early Japanese import pick up truck. It was very heavy, the guy had used plywood, coated with fiberglass and painted it.

I could not keep the truck going in a straight line on the highway, it was terrifying and exhausting.

I ended up with a full sized short box Ford van (E-100 in orange - I later painted tiger stripes on it).

[chefdave]

Hi
thanks for all the advice and diagrams. gives lots of food for thought. some will beyond my scope as addon to the back or adding a trailer with aero mods i will run in probs with length as it is 22 foot long chassis will be on max weight capticity. may also run in legal probs such as long vehicle and towing with a long overhang plus trailer may make some corners very difficult. on the toyota motorhome website they are known as 3slow going at the speed of parking. for cruising 60mph seems to give best performace and fuel ecomony. when i brought it home 500miles from where i bought it noticed inclines were slowing it down unless doing 60mph. i have maxed to a top speed of 97mph. not scary and very stable different in a 40+mph cross wind but better than my old nissan terrano ????? Motorhome was bought to replace tow vehicle and 6 berth caravan. terrano mpg dropped to 19 from 33mpg.
on aero mods im i better to put front air dam as close to ground as possiable. like the idea of the pick up cab rear wing that would be easy to install. on the roof 1 sky light is going and roof mounted air con unit all 40-50kg of it. ladder and luggage rack are up for removal. need to work out how to make a rear diffuser to go around rear black water tank then try to make underneath aero clean st moment its like a series of gaps and storage boxes. ideal solution would be make it totally flat but due to chassis and camping stablizing legs, water drainage pipes etc makes this impossable but might be able to half of under body. start at engine bay end at cat in exhaust then go from floor above rear axle in a curve to bottom of rear body work.
rounding out corners do i need to cut body work or can i cut a piece of drain pipe to fit over corner sharp edge.
Again thanks for all the reponses
dave

[kach22i]

Originally Posted by chefdave

on aero mods im i better to put front air dam as close to ground as possiable. ............like the idea of the pick up cab rear wing that would be easy to install.

Dave I believe the prevailing wisdom on chin spoilers is that they need not be any lower than the lowest thing underneath, such as your rear differential. On my own pick up truck, that is about 7-inches from the ground, although I haven't measured it.

On the second topic, some sort of treatment/garnish at the rear top edge may do something for you. I would not expect too much though, the scale of the project is just so overwhelming at first glance. Might be best to nibble around the edges before biting off too much.

http://ecomodder.com/forum/showthrea...1-a-19525.html

Originally Posted by kach22i

EDIT 11/21/11: This is pretty close to what I am first testing. Tonight I get to do some serious highway driving, will be doing more driving tomorrow as well (I work from home).

The Recumbent Bicycle and Human Powered Vehicle Information Center

NOTE: Last night I added plastic automotive button head plugs to the open holes on the trailing wing edge. I snipped and did some grinding to make it flush on the bottom (they were too long). I used a butane torch lighter to soften the plastic plugs before inserting, as they were a bit tight and got stuck half way in a test fitting.

http://ecomodder.com/forum/showthrea...a-19525-6.html

Originally Posted by kach22i

I took pictures of the Scion IQ yesterday because I noticed the roof spoiler is actually a 45 degree wedge which slides air flow though a slot - similar to my own roof device.

Aerodynamics Photos by kach22i | Photobucket

[chefdave]

Kach22
Hi read your last post with great interest on the paper of new spoiler on a van cannot find a picture of design but paper turns what know upside down. The spoiler on scoin is very similer to 4 runner rear spoiler. might well be a good project to try out. nothing to lose than materials and a couple of holes in roof. will get tape measure out and check lowest point on my toy. side skirts i would of thought would bring a benefit if not mpg then stabilitly improvement. found an easy mod to lower front by 1/2"-1" not a lot but then your quote of nibble at edges. so will start with air dam and side skirts easily fitted and removed if nessacary. then roof spoiler(?). see how that goes if improvments give me 20mpg then im doing well. shopping list here i come. :-) :-) :-)

[kach22i]

I wish that there was some way to install an air-fence on those corners near the cab entry doors.

http://ecomodder.com/forum/showthrea...ces-21242.html


I'd start with the list Frank Lee provided, maybe not very exciting to think about removing that roof ladder, but very effective.

[LeanBurn]

My vote would be to go 55mph or 90km/hr (or less if you can), get the engine running to best efficiency (synthetic fluids in the gears & engine if possible), clean air/fuel filter, clean radiator/condenser, tires to a good pressure and just drive it with fuel economy in mind. I wouldn't bother modifying anything that would take away from its functionality or ability as it defeats its purpose. My 2c

[chefdave]

Hi got tape measure out today. lowest hanging fruits means i need an airdam 5" off the ground. very to do. while under motorhome today discover my only exhaust silencer is very poorly from rust. been on internet for research. so far only two companies that make universal exhaust parts have responed. one rang me personally and was so helpful. exhaust will have a minor upgrade and i will leave end of exhaust coming out from rear. This hopefully will help my rear diffuser that i plan on fitting.following up on em aerohead about fitting quarter round lengths to front doors.
Will keep you posted and thanks for all your input.
Dave