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Old 08-03-2015, 01:35 AM   #1 (permalink)
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Why there isn't an aerodynamic shaped RV

They are all rectangle boxes, really about the worst they can be.

Living/Storage space is highest on the priority list, and tops the efficiency,
so a rectangle is going to give the most space.

Lots of disussion about streamlining an RV, has anyone actually done it and how much efficiency improvement do you get after losing all the space?

I'm looking at 33ft motorhome with some rear side damage, and the back 24ft body could be totally redone.
I'm thinking the easiest most cost-effective way is to make the roof pop-up hinged on the front section, so it hinges down to give a nice slope while driving, and hinges up to give a big roofline and living space inside.
I'm planning to use for storage really, but if I rebuild the rear section, might be interesting to see how efficient I could make it while still having lots of storage space when hinged up.

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Old 08-03-2015, 02:07 AM   #2 (permalink)
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The Toyota Prius is popular, but it seems like many people purchase it for the smug superiority, while other cars are slowly trying to sneak in aerodynamic tweaks, like tapered cabins. I would be kind of surprised if you could not find an RV with some tapering, but I think there is a big difference between head and shoulder room and being able to walk around inside, store things in cabinets, etc.

People seem to think that actual aerodynamics are ugly, but it could just be that if you can afford an RV, you can afford to haul around a box.

If you found a superficially-totaled PriusV, could you turn it into an RV?
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Old 08-03-2015, 09:35 AM   #3 (permalink)
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Prius is not really big enough.

I would like to see a minivan sized RV camper.

Make it 4 cylinder fwd and add a rear hybrid drive. The beauty of such a system would be good performance/efficiency as well as a nice sized battery pack that could easily run the AC/misc electrics while parked for hours without a noisy generator
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Old 08-03-2015, 11:00 AM   #4 (permalink)
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You don't buy an RV for the driving characteristics.

Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 08-03-2015, 01:13 PM   #5 (permalink)
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There are a couple of members here that have done aeromods to their RV.
As others would say " It's fruit ripe for the picking".
I think of it this way : the worse off something is aerodynamically, the more easily you will see a noticeable change when doing aero mods.
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Old 08-03-2015, 05:58 PM   #6 (permalink)
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A boat tail is a mod that should make a big difference while not impacting interior space. This one increased mileage from 13MPG to 16 MPG according to preliminary tests.

Camry Thread
E-Bike Thread
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Old 08-03-2015, 09:06 PM   #7 (permalink)
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They are all rectangle boxes, really about the worst they can be.

Living/Storage space is highest on the priority list, and tops the efficiency,
so a rectangle is going to give the most space.
I see it from the other side, call it an 'obversation', an aerodynamic shell with the same drag as that little box would be immense. As a vehicle, it has legally defined length, width and height — a box. An ideal dwelling will be a circle.

This 33-footer, is it a class A- or class C-motorhome? Would you be willing to extend the length (and licensing cost) to increase the fineness ratio?

Consider all the side taper you can pull off, with a flat roof. If it has a radiused edge to avoid vortex generation wouldn't a Tropfenwagen shape give space without needing pop-up/outs.
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Old 08-04-2015, 02:00 PM   #8 (permalink)
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Last edited by gafhj; 08-04-2015 at 02:31 PM..
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Old 08-05-2015, 12:24 AM   #9 (permalink)
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Unfortunately, advanced aerodynamics wouldn't improve the space-savings in a motorhome so much as a boxy layout does. There is always some compromise. Anyway, I would eventually consider a platform with the engine closer to the driven axle such as the FWD Ram ProMaster in order to get a lower floor, since it would lead to an improved internal height even if the external height get lower than a comparable front-engined RWD van.
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Old 08-05-2015, 02:02 PM   #10 (permalink)
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Here is the front wheel drive motor home I had. Sold because I lost my parking space.

It was 18.5ft long. Here is a proposal for a new body with the same drivetrain.

At a fineness ration of 4:1, it would be 32ft long; with similar interior volume but 50% higher licensing fees. But it would have gone from worst to best case for aerodynamics.

The Clark is gone, but I still have a Lexus motor-generator* that could power an electric version about the size of a Dodge van or VW microbus. So it still could be built.

Edit: *Now that I think about it, the folks at EVTV are reverse engineering the Tesla drivetrain CAN Bus messaging. That would be an appropriate size for a motor home, about 400hp.

Last edited by freebeard; 08-05-2015 at 02:43 PM..
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