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Old 01-04-2012, 07:35 AM   #9 (permalink)
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
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With a 60" gap between TV and TT I am working from the assumption that, for aero purposes, one may as well run the vehicles side-by-side down the highway; that aero for each vehicle should be treated separately. Even with a more conventional hitch, one is still at nearly that length.

My "thinking" if that's what it is, was more along the line of extending the sealed bottom of the trailer out to its' maximum. Flip the trailer over visually and cover the frame extension gaps front and rear. A simple enough change.

A better set of pictures if I had them would illustrate what I "think" I was saying. That is, I think that the gap is better served by some other set of devices or aero aids if the battery box and propane tanks are mounted in the later year model configuration.

I walked outside to check dimensions. On a 1976 SS the hitch ball center to trailer wall front is 39". The propane tanks are 24" from the trailer wall front, with the battery boxes behind it.

Your point, KB, is well-taken that one could build that structure around the two in order to enhance frontal area flow (if I have stated that correctly). I used to have a picture of where this was done on a late 1960's Avion by an owner. I don't see these components as "filling" the gap, however, as something more extensive would be called for I would think. We'd be passing from the idea of separate vehicles, to a combined rig (as it is in fact), but we are waaay beyond the big truck ideal gap of around 24".

Let's use the example of a big winch on a bumper mounted two feet in advance of a pickup truck front bumper. One could enclose it as much as possible, but a winch mounted inside of and behind the dimensions of the stock bumper would be better overall I'd think.

I don't think there will be great deal of difference between hidden and open mounts. But any other changes, to either vehicle, might show up more easily.

That post above was more in line with what I'm thinking an Aerolid could do for my rig. If I am able to purchase a late model SS (through 1997) then a bit of cleanup (sealed frame extensions) might be about as good as I can take it short of really extensive work (nearly or fully sealed TV-TT gap; boat-tail, etc).

If my initial assumption is off, then . . . .

Edit: I haven't gone to the trouble of seeing what, if any, Aerolid extension might could work and not interfere with the WDH apparatus on a tow rig; thinking of the tailgate mounted "box" shown on a recent Aerolid post. Probably an add-on to the upper surface extending past the tailgate might be it.

The problem with any of this is the low annual miles of use for most RV's. If we take 5k annually as average, then one must keep the rig a very long time for any FE benefits to show. So also, changes that inhibit maintenance access become a problem. Etc.


Last edited by slowmover; 01-04-2012 at 08:42 PM..
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