F250 and up, max 60 square feet frontal area

TucsonJim wrote:
My manual says the same thing, but the key point here is the part that states "Selecting a trailer with a low aerodynamic drag and rounded front design helps optimize performance and fuel economy. The 60 square feet would be used if the front of the truck and TT/FW were exactly perpendicular to the air stream. It the corners are rounded or the front of the truck and TT/FW is sloped to increase air flow, the effective coefficient of aerodynamic loading is reduced.

A simple trigonometry equation would be if you had exactly 60 square feet and it was sloped at 15 degrees. 90 degrees (perpendicular to the air flow)- 15 degrees slope = 75 degrees. Sin of 75 degrees is .966. Multiply 60 square feet by the inverse of .966 to get the equivalent square foot load. In other words, the recommended limit is 60 square feet at 90 degree impact angle, but 62 square feet at a 15 degree slope.

The example above is very simple, and there are many more factors which come into play. There are variable angles on the front of most TT/FWs, and there are usually rounded corners and edges. The actual wind load (equivalent square footage) could be calculated using trigonometry and/or calculus if we had the design standards of the unit.

One thing that Ford did not explain, was at what speeds this load applies, and what if any effect there is from ambient wind impacts.

Just another reason to NOT buy a Ford!
If it takes a Masters Degree in Mathematics to determine what is towable, I want nothing to do with it.
But then, I hold with the old-fashioned method of determining towability:
TWO questions
1. Will it move?
2. Will it stop?
If the answers to both questions is YES, you are good to go.
If the answer to either question is NO, fix it, then you are good to go.
That is much simpler than all the mathematical and trigonometric gymnastics.