Buy a new 5th wheel, ripe project for a boat tail

[Hersbird]

I understand the best case is an equal truck and trailer but frontal aera is frontal aera. Ford's limit is not a limit of just the trailer that is exposed outside of the truck, but a limit in frontal aera of the combined truck and trailer.

[Hersbird]

I do want to try some kind of deflector on my SUV roof. My camper has somewhat of a sloped nose but it's not that steep. I get more and more tempted to try the pop outs deployed but am worried about the turbulence tearing them apart like you said. I got a rear view camera to mount, maybe I'll try and mount it so I could watch how much it shakes. I also have thought about pulling some extra conduit around them and then wrapping them in that shrink wrap they use on new boats and such when moving them across country. It might also help with the heat gain and loss in the tent ends but would lose the ventilation they provide.

[aerohead]

Originally Posted by Hersbird

I understand the best case is an equal truck and trailer but frontal aera is frontal aera. Ford's limit is not a limit of just the trailer that is exposed outside of the truck, but a limit in frontal aera of the combined truck and trailer.

The caveat with respect to Ford's limit,is that CdA is CdA,and if you can get the Cd down low enough,then it's the same as a smaller frontal area.
As far as physics goes,the Spirit of EcoModder is identical to a Porsche 928, 968, and Ferrari 348tb at 50-mph as far as Earth is concerned,even though the frontal area of the truck towers over the three sportscars.
We can do the same trick with RVs.

[freebeard]

I also have thought about pulling some extra conduit around them and then wrapping them in that shrink wrap they use on new boats and such when moving them across country.

I uploaded this for another thread; but maybe it's relevant here:



These are tempered aluminum and much stiffer than conduit. They are control arms for some toy with a sail. About $8 each [before any Veteran/senior discounts]; you could do a lot with 2 or 3 closely matched ones.

[aerostealth]

If the frontal area consideration for towing is the frontal area of the trailer minus the frontal area of the truck I am in the zone of roughly a net 60 sq ft. With a boat tail I would think this situation would be even better. Most box trailers have a horrific wake area and only a few of them have under body paneling which our Keystone does have. We in fact have roof taper so the wake area without a boat tail is roughly 64 sq ft. My truck has the proper gearing, a heavy duty tow package, and extra cooling.

The most I will be towing is around 2,000 miles a year with one 4,000 mile trip planned in a few years. So far without a boat tail I have only towed a maximum of 220 miles on one overnight camping trip. I have not seen any overheating issues which I think is a good indicator you are over working the vehicle beyond it's capacity unless you are having actual problems with your cooling system. I talked to one Ford F-150 Eco Boost owner at a gas station who was having cooling issues towing a larger plywood box on a trailer and it only occurred to me later he might not have had the enhanced cooling package. He was towing a aerodynamic nightmare.

[aerostealth]

Side of my truck and trailer taken at the Valareo in Deming, NM on October 22, 2016.

[aerostealth]

Front view of truck and 5th wheel taken in my driveway on Oct 22, 2016.

[aerostealth]

Rear view of trailer and truck taken at the Valareo in Deming, NM on Oct 22, 2016.

[slowmover]

Boat tail sounds great, but side skirts should also be considered. 5ers are unstable in crosswinds. (They tip to one side on super limited travel suspensions; a problem with that huge sail area). Keeping winds from under trailer would be a priority to me.

I'd also stop by a CAT Scale to see both truck solo against truck hitched weights. Be sure truck front axle is being returned to solo weight value when hitched. (Full
Propane, full fresh water and top off truck fuel tank before scale passes).

[skyking]

wind under the trailer does not tip it, the wind pulls on the back edge in the low pressure area. The tipping function is more pronounced on a taller trailer due to the leverage it exerts on that top corner. Your Airstream mitigates that with a much weaker low pressure area due to the generous side radius.