Aeronautical Engineering and Tarps

[Beltzington]

A more honest title would be simple minds are easily amazed

I have for years fought with securing cheap tarps in place covering a load when hauling trash in the back of a pickup truck. Seems no matter what I did I would be stopping once or twice on the way to the landfill to secure the tarp.

Typically I would attempt and cover the entire bed of the truck and load with the tarp but at highway speeds the wind would inevitable loosen the tarp. Today I tried a new method which to my amazement works perfectly. Instead of securing the tarp over the truck bed next to the cab I attached a cargo strap between the front stake pockets and then attached the tarp to the cargo strap. The result was about a 4" gap between the tarp and the cab, apparently the airflow over the cab actually creates a vacuum in the front of the bed which cause the tarp to be sucked down into the bed. Honestly it looked like I had hooked a vacuum pump and the tarp was firmly in place even at 65 MPH. This also explains why loose trash in your bed always ends up against the cab.

Obviously the gap would not protect the contents from rain but with trash who cares.

 

[Wagtail]

Picture please (no 'load' required) to visualise exactly what you're saying.

Ta.

 

[RobS]

Seems reasonable. That area behind the cab is definitely a low pressure zone. I'll never forget the first time I hauled mulch and opened the back slider window. All that lightweight mulch wanted to come in through the back window!

 

[oosik]

Interesting. I've had "crap" come in thru the open rear slider also. Not the most pleasant thing as you are cruising along.

I'm very pleased to see that there are still folks who take garbage/trash handling seriously. I worked for two weeks at a regional trash/waste receiving site. Nothing more aggravating than a pickup pulling up - the young knothead jumps out - his load, being untarped, is all but gone - he turns around and heads home.

As Director of Environmental Health in Adams Co, WA - my two week experience at the trash/waste receiving site was most enlightening.

 

[square1]

A more honest title would be simple minds are easily amazed

I have for years fought with securing cheap tarps in place covering a load when hauling trash in the back of a pickup truck. Seems no matter what I did I would be stopping once or twice on the way to the landfill to secure the tarp.

Typically I would attempt and cover the entire bed of the truck and load with the tarp but at highway speeds the wind would inevitable loosen the tarp. Today I tried a new method which to my amazement works perfectly. Instead of securing the tarp over the truck bed next to the cab I attached a cargo strap between the front stake pockets and then attached the tarp to the cargo strap. The result was about a 4" gap between the tarp and the cab, apparently the airflow over the cab actually creates a vacuum in the front of the bed which cause the tarp to be sucked down into the bed. Honestly it looked like I had hooked a vacuum pump and the tarp was firmly in place even at 65 MPH.

That sounds like a "pro Tip"! Now if you can come up with a way to fold the cheapy tarps back up neatly....

This also explains why loose trash in your bed always ends up against the cab.

For entertainment on a particularly boring stretch of highway I was picking various items off the headliner (dandelion seeds, little pieces of leaves, bark, etc..) and tossing them out the driver's window. After ~20 miles of this I realized I wasn't making much headway and started to recognize some pieces. Sure enough, I'd toss them out, they'd circle around the cab and re-enter through the rear slider window and re-impale themselves in the headliner

 

[NoTrespassing]

On the subject of air flow, I once had a 91 ford ranger with a fairly tall fiberglass topper. That little truck was so underpowered you had to downshift out of overdrive in a headwind. One day I had the sliding windows open on the sides of the topper while traveling down the interstate. I rolled the front windows all the way down and opened up the rear sliding window. All at once, as I opened the slider, a huge rush of air came through it and rushed out the side cab windows. The truck seemed to pick up about 10 horsepower and gained speed immediatley. The effect was amazing! Unfortunately the amount of wind rushing through the cab made it unbearable to drive that way but I used to do it once in awhile just for kicks. It was like hitting a nitrous button!

Kevin

 

[GLyford]

I had the same effect on an '85 ranger when the "donut" gasket held on by that aggravating little 2-bolt flange in the middle of the exhaust pipe would burn through. Gain a sporty exhaust note and some throttle response which came in handy in rush hour on the expressway. Eventually I just hacked that flange setup off the end of the cat and swapped in a repair collar...did that one the next 2 rangers, too. Still don't understand why they deliberately designed that point to flex and fail.

That 85 was also the last of the carb models...it would ice over in hot humid weather. I put a small bolt on the heat riser flap so it was always drawing hot air in from around the manifold, no more icing.

 

[Howling]

Interesting. I've had "crap" come in thru the open rear slider also. Not the most pleasant thing as you are cruising along.

I'm very pleased to see that there are still folks who take garbage/trash handling seriously. I worked for two weeks at a regional trash/waste receiving site. Nothing more aggravating than a pickup pulling up - the young knothead jumps out - his load, being untarped, is all but gone - he turns around and heads home.

As Director of Environmental Health in Adams Co, WA - my two week experience at the trash/waste receiving site was most enlightening.

Spent beginning of week cleaning out FIL's house to sell. The Trash facility had signs up stating extra fee for loads without a tarp.