kehyler

Good catch, my 18 manual also says recommended towing weights. That lessons their force in my mind.

acdii

Reasons for those notes is due to lack of cooling for the transmission and engine. the Tow packages have a larger radiator and OTW cooler.

Flamingtaco

Frontal area... you don't need to do any special calculations for angles.

Surface friction, turbulence, and wake (vacuum) are the work that is being done. How well the air flows along the skin, around corners/sharp edges, and off the back of an object. Look at fighter jets from the side. The taper reduces front to back. The largest section of the fuselage is just aft of the nose cone. If it was more efficient to taper the whole length of a jet, pilots would be seated further back.

Having sharp angles of any degree on the front makes little to no difference, but a properly rounded front end can. Keep in mind, though, that about half to one-third of a trailer is in the wake of the tow vehicle, so you don't see improvement over the full frontal area. To be effective, you can't just round away on the front. The location and amount of transition is important and not something most trailer mfg's bother with. Rounded and angled trailer fronts is about perception, not real efficiency numbers.

Effectively, there isn't enough drag variance between the different possible trailer front end shapes to make a notable difference worth calculating. A true, full teardrop shape should have a significantly lower drag, but we only teardrop in one axis, and I'm not aware of any teardrop trailers that approach the frontal area limits of the 150.

Interestingly, Camp-Inn claims their 560 series, which is rounded (extensively... 5ft) on the sides instead of top in the front, with a traditional teardrop flare in the rear, is more aerodynamic than their traditional teardrop shape. Even says there are some (unlisted) vehicles that see a mpg improvement due to the trailer improving the flow off the TV. This is certainly possible, given a small enough spacing between the two. Can read about it here, post 5.

BCMIF150

Many if not most posts made on this forum related to towing (with a small exception) are a specific posters opinion, why would we want to start referencing facts like what the payload sticker says or what the owners manual references?

acdii

oh, I don't know, driving over the GVWR is not an opinion. There must be some reason manufacturers list it and tell you not to exceed it.

BCMIF150

You sir, are one of the exceptions I mentioned.

Jeff1024

You stop /w that logic. GVWR is just gives you an idea of where to start. You know that F150 in the commercial towing the Frisch's Big Boy was way over ratings. They don't call him the big boy for nothing.

kehyler

Would you also say, "oh, I don't know, driving over the altitude-altered GCWR is not an opinion. There must be some reason manufacturers list it and tell you not to exceed it."?

Jeff1024

I was just joking, thought the big boy reference would be funny.

We live in KY so I dont have to worry about many altitude issues and based on actual scale weights are well within the trucks GVWR, by about 400lbs depending on what is in the cab.

Smokey will yell at me but we do bend the rules on the Weight Carrying rating a bit with the boat behind the truck.

Flamingtaco

I would agree, except that to generate the same boost at increasing altitudes, the turbochargers have to work harder, which results in more heat in the intake charge. The loss is nothing like what N/A engines experience, but it is there, and you will not generate the same power at 5,000ft as at sea level unless you address the hotter charge with a larger cooler.