Tonneau Cover Range Improvement numbers

[ZeusDriver]

A X4S was also my first purchase. Had it for about 18 months. I mainly got it because I liked the look of a covered bed better and it beats having to push snow out of the bed the once every 5-10 years we get any. Can't say I've noticed any discernible difference in mileage which lines up with every test I've seen. Shame mythbusters didn't do this test when they did their tailgate up v down. I averaged 2.2 at 60mph and 1.8 at 75 the month before I got it and still get the same. A brick is a brick is a brick after all.

Asked chatgpt to give me a more aerodynamic lightning. I ran out of tries to make it 4 door

How cool! I was an AI guy for a while when it was a hot investment in the mid 1980's -- and designed a quite successful expert system for diagnosing a packaging machine. Back then, I thought we'd be further along by now, but that second rendering is pretty impressive.

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[PJnc284]

this is a "futuristic ev truck design"

 

[FloridaMan655321]

I started covering my truck beds for one single reason, to keep asshats from using my truck as their garbage can. Too fking lazy to keep holding that empty until they get to an actual trashcan, no they just drop it in the bed. Infuriates me would be describing it lightly.

This is such a strange thing that happens. I've literally never been holding an empty container and saw a bed truck and thought "let me throw it in there"

 

[FloridaMan655321]

This subject is so tired that I remember reading a study back in the late 90s that tested tailgate up, tailgate down (because that was a thing back then), and then those weird tailgates that had holes in them and looked like snowmobile fencing (except not orange). It was stated even back then that the air kept in the bed with the tailgate up created pressure to keep the airflow over the whole vehicle. So even back in the 90s we knew putting your tailgate down or having those air tailgate things were useless. Still applies with a tonneau cover.

 

[Firn]

I expect the bed of the Lightning is too short to make any difference.

Everything i have seen or read, including Ford themselves, says the air needs a place to "land" for efficiency gains. This is part of the reason the tailgate top is so big. But on our trucks the airflow off the top of the cab won't touch down till behind the gate.

Fwiw I have done tuft testing and did not observe any airflow off the cab hitting before the tailgate.

I bet it works on long beds. But not our trucks.

 

[ZeusDriver]

Putting the truck in a wind tunnel and seeing what happens with and without the tonneau cover seems like the way to answer the question - but will it be enough for us to even notice with combined highway and city driving? I am doubious.

The SEMA tests were performed in a good wind tunnel, and I am inclined to believe their findings (of about a 5% improvement in Cd with a tonneau cover, and a 1% degradation with the tailgate down.) The latter is not enough to show up (in consumption) in even a well-controlled, correctly-instrumented track test on an oval track. The former could show up in a very good track test, (as a reduction of circa 2% in consumption) but I have not seen such a test yet.

My Zing, from 2010 or so, achieved slightly lower drag than the Aptera (of that time) I thought at the time. (We were both in the same contest, until I pulled out, in a huff, at rule changes that made it impossible to win with anything other than a pure electric car.) The Aptera Cd was probably lower, but my frontal area was substantially less, because the seating was tandem instead of side-by-side. (My weight was less than half of the Aptera's.) I think my Cd was on the order of .16 or .18. At the time, the Aptera had its suspension members hanging out in the breeze, which is problematic for good aero. (Three wheels are problematic for aero too, a minor problem we both had.)

Back then, reasonable people considered wells-to-wheels as being the valid measurement for "goodness" in high efficiency vehicles. The calculations are complicated, for sure, but only by going through with them can you determine if a Tesla or a Prius is the more benign vehicle in West Virginia (the Prius wins) vs New Hampshire (the Tesla wins). There were teams in the X Prize who had developed engines from scratch (burning biodiesel, ethanol, etc), which, after the rules went to plug-to-wheels, could not possibly win. Sad. Fabulous efforts. As I remember it, the rules shifted when Musk ended up on the advisory board for the X Prizes. I could be full of it, however. Many of the contestants were active in developing the rules, and then suddenly they went in a new direction.

Adding to the Irony: The GM EV1 could achieve 100mpge (which is what the metric went to instead of wells-to-wheel). The X Prize was about achieving a 100 mpg vehicle that could be marketed in significant numbers. GM had already done that, (a decade it turns out, if you view electricity as showing up at the outlet without any environmental consequence.

I remember thinking at the time: many people worry about the handful of watts difference between incandescent bulbs and LED's, but consider the hundreds of thousands of watts consumed by an EV as being benign.

Hrumfff.

But back to the point of the thread: No, you cannot measure the effect of either a tonneau cover or an active front air dam on the road. But both have an affect: the cover about 5% in Cd, the dam about 4% in Cd. Combined, maybe as much as 2% or 3% in consumption. Given that my consumptions varies from day to day by about an order of magnitude greater than that (in other words by 20% or 30% ) I am not able to say that it has a great affect on me personally, other than to say that over time, my $100 tonneau cover pays for itself. Woo Hoo!!

And.... AND.... this is where we should get weepy, cuz we are saving the world: the combined effect of those two features reduces CO2 production by some very large number of tons, across the Ford fleet.

 

[NW Ontario Ford Lightning]

interesting.
I bought the bed cover so I had ONE PLACE I don't have to shovel snow anymore...

 

[ZeusDriver]

Fwiw I have done tuft testing and did not observe any airflow off the cab hitting before the tailgate.

You must not have had the tufts in the right places. Just put a pile of leaves in your bed and go for a drive. You will see vortices that lift the leaves out of the bed, and the leaves will help you see the vortices.

 

[RLXXI]

This is such a strange thing that happens. I've literally never been holding an empty container and saw a bed truck and thought "let me throw it in there"

One of the benefits of living on a thruway of a major suburb. They need to outlaw sidewalks.

 

[RLXXI]

THANK YOU! I knew I'd seen something about this before. Didn't they conclude that the drag was actually WORSE with the tailgate down? That with the tailgate up, it created a sort of turbulent ball of air that kept the flow from sucking down into the bed. I seem to remember thinking that all those dudes with the tailgate net had wasted their money.

Myth busters did an entire episode on this very thing, you could probably find it on youtube.

Not Myth busters but similar testing. Tonneau is more efficient

 

[ZeusDriver]

Still applies with a tonneau cover.

 

[RLXXI]

About the same time in different threads, guess our googlefoo is strong.

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