Why there isn't an aerodynamic shaped RV

[freebeard]

Due to the extensive use of aluminum, the DecoLiner only weights about 7,000 pounds—much less than the 12,500-pound GVWR of the GMC chassis—yet the body is so rigid that it can be jacked up by only one corner.

http://www.hotrod.com/cars/featured/hrdp-1301-the-decoliner/

[me and my metro]

Due to grandchildren traveling with us from time to time now we have a motorhome. Our RV of choice is our 35' Avion pull trailer it is very aero, it has been referred to as looking like a big Twinkie. After the grandchildren outgrow traveling with the old people it's back to the Avion for us.

[jamesqf]

Originally Posted by Fat Charlie

Campers are about how much space you have when you're parked...

With an RV, space is what's inside, and how close you are to the RV in the next space. With a tent, I can easily go places where it's 10 miles or more to the nearest human :-)

[Fat Charlie]

I own a tent myself.

I had the kids out on a few hikes this summer, one was at night and one was to the top of a small mountain. I also started them on sleeping in the tent. Next year I'm looking at getting them up Chocoura.

But this isn't about camping, it's about vehicle design requirements. And I really do prefer being out there and not sleeping on the ground.

[aerohead]

Originally Posted by me and my metro

Due to grandchildren traveling with us from time to time now we have a motorhome. Our RV of choice is our 35' Avion pull trailer it is very aero, it has been referred to as looking like a big Twinkie. After the grandchildren outgrow traveling with the old people it's back to the Avion for us.

I've been chipping away at RV drag stuff,and Hucho published a work by R.Barth in Germany who tested a series of 'Twinkies' in the wind tunnel.
If you consider them as the body of an AVION,then:
*an 11-footer is Cd 0.38
*an 18.5-footer is Cd 0.230
*a 27-footer is Cd 0.205
*a 38-footer is Cd 0.200
*and a 45.5-footer is Cd 0.205.
So your 35-footer is near the bottom of the drag bucket for these shapes,making it the lowest drag length.

[freebeard]

Neat! My 35-footer is the most aerodynamic thing I own. Too bad it's been up on blocks and skirted since possibly 1962.

[ennored]

Originally Posted by aerohead

I've been chipping away at RV drag stuff,and Hucho published a work by R.Barth in Germany who tested a series of 'Twinkies' in the wind tunnel.
If you consider them as the body of an AVION,then:
*an 11-footer is Cd 0.38
*an 18.5-footer is Cd 0.230
*a 27-footer is Cd 0.205
*a 38-footer is Cd 0.200
*and a 45.5-footer is Cd 0.205.
So your 35-footer is near the bottom of the drag bucket for these shapes,making it the lowest drag length.

That's just the basic body shape, correct? Real numbers would be higher?

[jamesqf]

Originally Posted by Fat Charlie

But this isn't about camping, it's about vehicle design requirements. And I really do prefer being out there and not sleeping on the ground.

I can see that. OTOH, I see a lot of RVers who park the thing in the (not so) wide open spaces of a campground, then spend their time sitting inside watching TV - which suggests that someone is kinda missing the point :-)

[aerohead]

Originally Posted by ennored

That's just the basic body shape, correct? Real numbers would be higher?

Yes,he tested a smooth rectangular cylinder with all edges softened to a radius equal to 10% of body height,in ground proximity,from almost a flat plate,out to a fineness ratio above 10.5:1.
*No features
*no cooling system
*no wheel openings
*no wheels
--------------------------------------------------------------------------
He tested 5-different shapes,all have a 'sweet-spot.'
This has been important to me as I do the geometric comparisons.It's easy to fall into traps without this sort of data.

[Xist]

Originally Posted by freebeard

Neat! My 35-footer is the most aerodynamic thing I own. Too bad it's been up on blocks and skirted since possibly 1962.

It does not sound like you are wasting much gas fighting drag.