Okay, here's a challenge (mod my Winnebago!)

[Whoops]

Ok, got a couple more suggestions.

First, put sidewall panels, between the front and rear tires. I'd use coroplast or something of that nature. It's lightweight and water proof.

Second, with a little work, you could take some 1/2 inch pvc pipe, bow it and attach it to the front and back of the vehicle. You could make two or three hoops and then attach coroplast to it, to give you a rounded shape on the front and rear, so that you reduce the turbulance coming off of the motorhome.

On the front you could come up until the windshield. In the back you could come all of the way from the bumper to the top of the motorhome.

[H4MM3R]

http://www.gearvendors.com/index.html

This an overdrive unit.

[Vanner]

Originally Posted by Who

Outside of maybe a small light fairing on the roof to shroud the AC and vent equipment along with maybe some more aero mirrors, I'd focus all efforts on keeping the weight minimized. Many aero mods could just add weight. Your frontal area is such that you should resign yourself to slowest speeds and visit places instead of driving in strong headwind situations. You may be able to benefit more FE-wise by keeping the weight low for climbing hills. Besides, you aren't aero enough to take advantage of it on the other side.

Not sold on this. Weight, of course, hampers acceleration and braking, but once up to speed I don't think weight really matters. Air resistance is responsible for at least half of engine load at highway speed http://www.everytime.cummins.com/eve...Whitepaper.pdf while I'm not sure weight affects anything except rolling resistance, and even then constitutes only a small part compared to tire design (Above link, from Bridgestone). The moral, especially in an RV, is that any level of benefit from any aero mod will almost certainly outweigh the negatives associated with its extra weight in a strictly highway situation. Besides, that weight is momentum for the next hill!

[Who]

Vanner, that's cool although I would like to point out a few things.

Never count on hill climbing as a good energy investment. The return is always much less than the investment, ask any cyclist or anyone using a ScanGauge.

No road stays level for very long and even a 10' rise takes serious energy to climb.

Weight reductions are dead nuts simple to measure and can't backfire.


Anyway, like I said, I'd clean up the easy stuff, drive slowly and not carry excess stuff up and down every rise.

The more opinions the merrier...

[Vanner]

All excellent points, Who, and I may be underestimating hills here. I think everyone agrees, if you're hauling around bags of sand go ahead and don't. Both weight and drag are wonderful things to eliminate, but because drag accounts for so much more of the engine load, reductions there surely offer more bang for your buck in a strictly highway/interstate application.

I'm new on this site, but I've seen civics and metros here with conversions I've never even dreamed of. If those cars warrant that kind of work, imagine what that % reduction in drag would do for an RV! If NovaEona is entertaining those ideas, as I am, I would not expect weight to be the limiting factor.

None of this matters if you can reduce speed, that's the best tip of all, especially for an RV.

[MetroMPG]

Hi, Vanner. Welcome to the site. If you're not shy, stick a "hello" in our introductions area and tell us a bit about yourself.

cheers-
Darin

[Vanner]

Will do! Thanks! Certainly have read a lot about you...

[johnpr]

hi fwiw i have traveled across country in an rv (a fleetwood 32 footer built of of a chevy g30 van) one of the best things for my fuel efficiency was adding 2,800 pounds of weight to the rear of my rv!!! ok i know what your thinking dead weight like that kills fe and why the h**l would you drive up a mountain like that. ok heres the scoop, i towed my trans am, its relatively aerodynamic (at least compared to the rv) and its 18' long, it really made up for the added weight. so heres what i recommend doing (off of my list of to dos before my next trip)

*grill block
*belly pan (you can go to rv parts stores and buy big sheets of fiberglass)
*tire pressure
*electric radiator fan
*the skirt thing under front bumper
*skirts around sides
*new shock absorbers/ springs
*tow something more aerodynamic
*make an angled roof extension (not to sharp of an angle)
*radius as many sharp angles as possible (anyone have a good idea of a radius? i was thinking 1.5 in??)
*get rid of useless mass
*switch to lighter materials (heavy wood counters -> fiberglass counters carpet -> vinyl)
*remove / relocate (or make an aero housing for) your antenna
*make a more aero housing for a/c and vents or other protrusions
* DO NOT REMOVE MIRRORS!!!!! they are extremely valuable, just make aero housings for those also
*drive around 55 mph, speed is the enemy!! if you have cruise control use it


anyhow, from my experience weight doesn't make as much of an impact as other factors (even at slower speeds there wasn't a noticeable difference in FE between towing the car and not) im not saying that weight is a good thing, by all means reduce it wereever possible (empty all holding tanks before trips unless you need/want water in your tanks for the trip but stopping at truck stops keeps you from hauling 80 + gallons of water)

so just out of curiosity, have you made a cross country trip in an rv before? with my travels i have found it to be both enjoyable (stopped at many great places along the way) and stressful (maybe not the best word for it but people are intolerant towards rvs and they can be quite vicious)

anyhow, i wish you a safe journey (and keep us updated!!)

John