kbroderick

D = Cd * A * .5 * r * V^2

Note that V (velocity) is squared. Cd is drag coefficient, r is density of the material through which you are moving, and A is reference area (from https://www.grc.nasa.gov/WWW/K-12/airplane/drageq.html).

Personally, I think that the incredible job Ford did optimizing the aerodynamics on the current-gen F-150 (at least as it leaves the factory) tend to exaggerate the impact of hanging a parachute, very large brick, or similarly drag-inducing trailer behind the truck.

Scarlet

Shortly after I bought my truck, I borrowed my brother-in-laws trailer to haul a few things to my place in West Virginia. This was before I bought my Polaris Ranger and trailer to haul it. His trailer was a small 10x5 aluminum with the tilt up ramp similar to what you have. On the way to my house from his is about 55 miles. Empty, going mostly 60mph, sometimes 65mph, I could only manage 11-12 mpg. I have an '11 Lariat with the 6.2. By contrast, today, I tow a 7x14 enclosed V-nose, with my Ranger in it. It was custom built with an added 1 foot in sidewall height, so it has a tall frontal area.. I average 11.5-12.5 mpg towing it. So I think you're dragging a huge sail behind you.

jag1886

I have found that gauge to be very inaccurate. Mine always says 12-13 and I find that when towing my 5500LBS trailer I'm actually getting 9-10 and with the trailer off it's getting 15-16. Use a calculator if you really want to know what milage you are getting.

BarabooBob

I have a utility trailer with a mesh ramp on the back. I loose about 1.5 mpg with the ramps up at 55 mph. On the highway, I am sure that it would be more.