Share Pics of People Hauling or Towing Something Wrong

[mikehaugen]

Mythbusters has done this one at least twice. The only way to improve on stock is with a tight tailgate net if I remember. Same airflow stuff as tailgate up & a bit lighter.

Or a tonneau cover so I've heard.

 

[Fallon]

Or a tonneau cover so I've heard.

Busted

MythBusters Episode 64: More Myths Revisited
MythBusters Episode 43: Sea-sickness – Kill or Cure?

 

[sklunk]

Actually better with it up.

With it up the flow is more laminer. With it down the air churns just behind the cab creating induced drag.

The gain is minimal, about 3% if I remember correctly from the wind tunnel test we did 20 plus years ago.

Chris

SAE Engineers have done quite a few studies as well. Here are just 2 (unfortunately you need to buy them to read the whole paper but you can read a summary here):

Pickup Truck Aerodynamics - Keep Your Tailgate Up
Further Analysis of Pickup Trucks Aerodynamics

Basically they determined you get better fuel mileage with the tailgate up.

 

[Jd5203]

Here's the idiot I saw today....70, yes 70 pallets on a half-ton. Any wonder why it's riding so low, the frame/bed seems bent and the tailgate is all mangled?

Surprised dot didn't get them. Here they would have been all over him he wouldn't know what to do.

 

[yelbike]

Mythbusters has done this one at least twice. The only way to improve on stock is with a tight tailgate net if I remember. Same airflow stuff as tailgate up & a bit lighter.

The net actually made it worse. All other configurations were negligible gains.

 

[edkemper]

The net actually made it worse. All other configurations were negligible gains.

Think about this:

It's all about the money.

The auto industry (mileage) is very regulated. It there was a fuel mileage advantage to keeping the gate open, they would have design something to accommodate that. Simply put, it'd be far cheaper to design a more fuel efficient tailgate to increase mileage than to re-engineer an engine with increase fuel mileage.

 

[GManBart]

Surprised dot didn't get them. Here they would have been all over him he wouldn't know what to do.

Yeah, I'm sure you're right....I've spent a lot of time in VA, and I know what you mean.

The funny thing is I posted this picture to my Facebook page, and one of my friends who lives near where the picture was taken says he's seen the guy doing the exact same thing, in the exact same area, multiple times. There is a pallet factory about 25mi south of where the picture was taken, and I suspect he's picking them up there....eventually something is going to go sideways, and that may be the back half of the truck, along with a bunch of pallets. Hopefully they won't fall on an innocent bystander.

 

[PhysAssist]

Ok, I will get all technical on you guys. The cab of a truck is working like the wing of a airplane.

The way a wing works is its basically flat on the bottom and curved on the top. Imagine a molecule of air hitting the leading edge and splitting in half then rejoining on the trailing edge. The half of the molecule on top of the wing has to travel farther so it must travel faster then the half going under the bottom. This creates a pocket of low pressure above the wing that literally "sucks" the wing up. This is how lift is created and how a airplane flies.

Same thing is happening with your trucks. Imagine the doghouse, cab, and bed as the wing. The low pressure being created on the top side is sucking things out of the bed.

Chris

You are correct, sir!

In fact, they proved that on one of my favorite shows "Mythbusters", when they looked at whether it was more economical to drive with your tailgate up, down, or absent. The tailgate up came in second to a tailgate net (on their second show about it, but inly becauee it still generated the rolling ball of air like having a tailgate does, while weighing less.

It seems that when you have an obstruction like a tailgate or net at the back of the bed, the air coming over the cab hits that and rolls back toward the cab creating a standing wave that reduces drag and saves gas, but if you have a tonneau cover or the tailgate open (or just off), the standing wave disappears and you lose fuel economy.

Tailgate nets have enough substance to act like a solid tailgate, but weigh less, so they are even more fuel efficient.

I have to admit though, I like the MB show better when they had Starr, Carrie and the other female staffers on board. Grant and Torrie were OK, but not as fun to watch.

Thomas

 

[PhysAssist]

You can see this if you have a little loose hay or woodchips in the bed of your truck and you drive down the road.
They will loop around in the back of the truck.

Aaron Z

Unless you have your rear slider open, then they come flying in at the back of your head- I learned that lesson PDQ!

 

[FredH]

My Bro sent this to me , found it somewere on the net . And " NO " this is not ME or My Trailer , ( I have a Big Tex Dump




Fred H.