RTT and better gas mileage

Yep and let's just throw some common sense on the table for a second.
He added weight. He added drag. He somehow made his brick 20% more efficient?
If so, we need to communicate this to the Pope because a miracle occured.

 

14.7%. Unclear if drag was added. Maybe, maybe not.

 

I believe I did gain some highway efficiency after I reversed my tent and lowered it. Don’t know why they don’t design them in a teardrop shape tapering towards the rear to begin with.

When I run without the tent, my city MPGs increase, but I haven’t noticed any increase in highway MPG. If anything it might even go down slightly.



I’ve experimented with all sorts of little tweaks to this. You’d be amazed how relatively small changes in the gap distance between the cab and tent can affect things. Small changes in tent height also seem to have pretty sizable effects.

 

I’m wondering if I can play with the wording here a bit. Given only the information in this thread we may be able to say that there isn’t enough information to support a conclusion but, since this is an empirical exercise and not an analytical one, with insufficient data we have to conclude that it’s not enough to reject the null hypothesis. That null hypothesis, which is being called common sense, is actually a theoretical framework built over a century with supporting data and experiments that have been collected and conducted by thousands of engineers and scientists. Neolithic hunter gatherers, or ancient chariot makers wouldn’t come in with the same expectations as a modern person because our models for reality are actually built on data. So there is lots of data, just not enough in support of a phone call to The Holy See

 

Exactly.

Provided the observed fuel economy increase is in fact real AND was not from other factors like fuel quality, driving style, terrain, average speed, tire pressure, wind direction, tailgaiting, tune, failures at math, someone slipping a Prius under his RTT....then the only conclusion is drag was reduced in some manner.

However, since none of those other factors can be ruled out (except maybe the Prius part) the cause, provided it is even true, is an unknown.

 

What I know from my personal experience is that I do not lose highway MPG with my tent mounted in the above shown config. I know this because my own empirical testing shows it to be true.

Other configs, specifically with the tent facing the “right way” and higher up, do lose highway MPG. Again, empirical data.

So for me, the jury’s out. I do think it’s plausible under some circumstances to gain hwy MPG with a RTT, again, in some circumstances. Is this one of them? Insufficient data.

 

Because offroad folks think they understand aerodynamics, but they don't. Didn't we have like 2 pages of discussion on it

 

On highways, I definitely can feel the drag with my RTT installed, it sticks up above the cab like 6”. City made no difference really.

If I stay around 65 it still gets decent MPGs though.

 

just so everyone is on the same page is there a picture ( from the side ) of the truck and RTT
in question. Might be able to make some guess from seeing the actual truck/RTT.
I use a small trailer to haul my crap and the rack is moveable up/down just to
get it out of the wind stream.

 

Sounds like you always drive down hills.

 

Get a CVT trailer, you'll thank me later. I did a 600mile trip yesterday, half of it with no trailer and other half with my new CVT trailer. Did the math and was getting 20mpg overall.

 

I went from 14 to 15 after i installed mine then again i am also not running the rotopax on the side since they don't fit and honestly i never used them they just came with the pickup. Probably going to sell them.