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Truck Campers - Smaller For Solo Trips


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#11 Advmoto18

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Posted 02 June 2015 - 02:26 PM

Anything that sticks into the air stream creates turbulence and ultimately an area of low pressure behind it.  The area of low pressure created by turbulence must be overcome to move and object forward.  And the larger the area of low pressure, the more energy required which ultimately degrades fuel economy and range in our trucks.

 

Remember roof top gutters on car and trucks?  They created turbulence and contributed to the area of low pressure behind them.  Now gone from automotive design for the most part.

 

I don't know where the idea of cab mounted air dams came from, but, the inventor seemingly was not aware of Bernoulli's Principle derived from Sir Issac Newton's 2nd Law.  And these 2 gents published their findings in 1738 and 1687, respectively. 

 

So none of this is new or voodoo science.


Edited by Advmoto18, 02 June 2015 - 02:38 PM.

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#12 Advmoto18

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Posted 02 June 2015 - 02:35 PM

Done well and placed right an air deflector on the cab roof will promote better laminar flow onto the camper. It is beyond the skill-set of most to build such a device that would be turbulence-free, but a reduction in turbulence is welcome.

 

It would have to be designed and installed in such a way as not to disturb adjacent boundry layer air.

 

I'm not sure such a device is attainable as an after-market item.  I think such a device would have to be intergrated into the design of the cab, as with modern motor cabs for 18 wheel haulers such as the Peterbilt 579 Highway model.

 

Peterbilt.png

The design minimizes disruption of air flow in and around the cab and trailer and accepts the size of the low pressure area behind the trialer.

 

atd_1.jpg

This is the Trailer Tail that attempts to reduce the area of low pressure behind the trailer thereby reducing drag from turbulence.


Edited by Advmoto18, 02 June 2015 - 02:37 PM.

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#13 ntsqd

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Posted 03 June 2015 - 01:40 AM

We're digressing this thread, so one more from me and I'll leave it alone. Take the typical failing water drop's shape. It isn't that shape by accident. The pressure of the air that it's failing thru combined with the surface tension of the water makes it take that shape. The frontal area, the hemispheric portion has the most volume for the least surface area. The tail shape is due to the air drag. There are other shapes that can be made to work well (witness not many cars look like a tear-drop), but need a wind tunnel to develop and fine tune. In building aero aids I keep the water drop shape in mind.


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Thom

Where does that road go?




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