What's the best RV/motorhome aerodynamically?

[dcb]

it doesn't smack of great mpg, but I still like it

[wagonman76]

Originally Posted by silverinsight2

Ther ya go!

Weird RVs: Airstream trailer? Well, sort of, but not really

Hmm, identical drivetrain to the GMC motorhome.

[Otto]

Originally Posted by wagonman76

Hmm, identical drivetrain to the GMC motorhome.

The front end of that thing is an Olds Toronado, circa 1969. My dad had a '69 Toronado, bought brand new January '69. They never could quite get the front end alignment sorted out, too much toe-in, and it would not exceed 80 mph despite 400hp and an otherwise not too bad shape for its day. 6-8 mpg, maybe 9 mpg at highway speed. With an Airstream glommed onto the ass end, this rig might get, oh, 5 mpg.

Anybody know of a modern-day RV along the Ultravan line, which reportedly got 16-19 mpg 40 years ago?

Or, perhaps better, a cargo van or small 2 axle truck that comes stock with a good shape, but suitable for further aero improvements and internal refit for RV use?

[TheEnemy]

Originally Posted by Frank Lee

The little Toyotas reportedly get really bad fe. Surprisingly bad.

Its because they are way too underpowered. I passed one recently and it was obviously struggling on the flat section just to maintain 55.

[dcb]

this one claims 25mpg, has a stick shift though, dunno

http://www.youtube.com/watch?v=0owNt...eature=related

dunno if the "underpowered" card makes a lick of sense, its a lot more complicated than that.

[TheEnemy]

Thats what I passed. I don't believe 25mpg under any real world driving for a second. Maybe on a fluke, but not even at 55mph steady should it be able to get 25mpg. Seriously, my pickup without all that extra weight and stuff hanging out in the wind got a max of 28 at 55mph, I usually get about 24 at 75ish.

If a car has to be driven at full throttle it will/should run rich, unless its been modified to do otherwise, and it will burn more fuel than a larger engine that is producing the same power at a lower throttle. When moving several years ago my father inlaw helped us move with his full sized truck, under similar loads my mileage droped from 26 at the time to 17, his droped from 20 to 18. He actually burned less gas because I was straining my engine too much, and his was just chugging along just fine. We even dropped down to 60mph for most of the trip.

[dcb]

I'm skeptical because most cars are much too low on load on the bsfc chart because they are overpowered. adding a bunch of drag (load) should bring it back towards the "sweet" spot, though total consumption still goes up. Even with enrichment, it is usually better to have too much load than too little.

so, if it had a saturn engine , if the thing makes enough hp at 2500 rpm and 124.8nm to keep moving then it would be a real good match.

[Otto]

Originally Posted by dcb

this one claims 25mpg, has a stick shift though, dunno

dunno if the "underpowered" card makes a lick of sense, its a lot more complicated than that.

This thing is the working definition of what NOT to do, aerodynamically,

Modification of it would start with a trip to the crusher, a la Breaking Bad episode a couple of weeks ago.

Now, does anybody know of any RV or truck sorta like the Ultravan, i.e., designed with at least some aerodynamic efficiency in mind, of, say the past 20 years? I have in mind a search for a good used RV motorhome, with nice gentle curvature in its sheet metal sorta like a VW microbus, only bigger.

[dcb]

lol, oh yah, aero

that aerostream mashup made me think a teardrop trailer/metro mashup would be sorta cool. if you scaled it up to something caravan sized it might still be pretty good on the mpg and have room for a table/bed.

[KamperBob]

Originally Posted by TheEnemy

Its because they are way too underpowered. I passed one recently and it was obviously struggling on the flat section just to maintain 55.

Well, considering they haven't made those things in a coon's age it ought to get some respect for still being on the job. I still see them in the wild. Amazingly durable. Most that I recall speaking with say 20+ mpg is typical. Hell I've got enough horsepower to haul my camper 100 mph if I wanted to. But I've also got the horse-sense to keep it at 55. It may not be about struggling...

Cheers
KB