An RV company tested this by pulling a large aerodynamic trailer, and a small light one that was not. The fuel mileage was better for the large trailer than the small one.
An RV magazine, I meant. https://rvlifemag.com/andy-thomson-canam-rv-hitch-hints/
If you look at No. 46 you will see that there are 6 loads on a vehicle's power source. They vary in relative magnitude depending on driving conditions. Some of them depend on vehicle weight. Some depend on vehicle speed. But drag depends on the square of vehicle speed. So if you drive fast enough eventually drag will become the dominant load. It is not at all surprising that a small trailer could present more drag then a heavier one and therefore, if driven fast enough, deliver poorer mileage.
why is there more drag on the 4% load?
In the article, they were towed at the same speed. Which is interesting. I’m sure at slower speeds, results would vary.
Because there was an error in my code. Thanks to you I am aware of it and have fixed it - tentatively. The earlier post has new numbers. They don't change the conclusions.
Yes, they would. Speed isn't the only factor in vehicle load. It gets most of the attention because drag related the energy consumption per mile depends on its square. But it also depends directly on air density, drag coefficient and frontal area. A streamlined trailer (one with low Cd and A) will beat one that isn't even if it is carrying more weight at the same speed.
"for a traditional truck, I know when I tow something heavy, my mpg reduces a lot. I think this should be same on cybertruck right?"
I don't think that at all. In fact range should reduce less for CT with the same trailer than it would with a gas F150. The same is true for a diesel vs gas. People try to argue that is because diesel specifc energy is denser but this is wrong.
So if a trailer adds an additional air load of 10 on a f150 it adds a larger load than 10 on a CT. It doesn't become more of a load just because the tractor is less of a load.
The drag of a trailer is not a static amount. The drag from the trailer is added minus the wake of the truck.
Yes I agree that potential interaction between the combination of the truck and the trailer could potentially increase the aero load for CT vs f150. But ignoring that the 1 stays the same. It adds that to both systems and increases energy requirement for both. The question of range reduction is a percentage problem though. A system that is more efficient at converting energy to power does not suddenly become less efficient when load increases than the less efficient system.
So you are saying if you artificially set both rigs as a box the more efficient rig has a greater change therefore it is affected more. But what is actually happening is that it was just further to change the efficienct rig as a box.. Since both f150 and CT are the same height and same width the total frontal area has to be the same. The CT slopes that area more effectively and just dropping that and saying now its a box the same as the 150 and because I had to do more to make it a box will not match the real world the .3 CT with additional trailer exposed of say .5 will become .8 and the f150 with .4 add .5 becomes .9
