a better bed cover

[IsaacCarlson]

I have been working on this for a while and finally made a small scale prototype. I started wondering why most of the other covers I have seen have square-ish edges/corners. A don't think a cap should have corners....they make turbulence when the air tries to go around them. It should instead be round to allow the air to simply expand and merge back together to fill the void behind the vehicle. This is what I came up with. I like to think aerodynamics in 3-D. Please let me know what you think.

[IsaacCarlson]

bump

[aerohead]

Originally Posted by IsaacCarlson

I have been working on this for a while and finally made a small scale prototype. I started wondering why most of the other covers I have seen have square-ish edges/corners. A don't think a cap should have corners....they make turbulence when the air tries to go around them. It should instead be round to allow the air to simply expand and merge back together to fill the void behind the vehicle. This is what I came up with. I like to think aerodynamics in 3-D. Please let me know what you think.

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Isaac,the square-ish bedcovers probably offer the highest potential for usable interior space,aiming at 'utility.'
The corners themselves may not be so much a problem if the flow velocity aside,and on top of the roof are matched properly.You'll find many 'minimalist' streamliners at Bonneville with rather square intersections.
If you're going to transition from a square corner to a radius you'll need to pay very close attention to vorticity which might be induced if your shape is improper.( too fast of a transition ).
Tuft testing can tell you if you've improved the flow,or added a new problem while solving an old one.
Your model looks pretty good,but better if mounted on a model vehicle of same scale.
The 'host' vehicle will determine the architecture of the modification,not vice versa.

[IsaacCarlson]

My son has a toy pickup with the same shape as mine so I will put it on there and see how it flows. I am not worried too much about utility since I will ba removing it to haul wood and other things. The wood makes a pretty cool kaam back.

[Christ]

A little small, ain't it?

Looks pretty good, though. What Phil said!

Honestly, when looking at it, I wasn't thinking about vortices forming, but he's right. Also, if the side-flow angle is too steep, it will hit the flat spot of the corner of the bed, and create a higher pressure zone there at the tail, which could disrupt high-speed flow. You'll see what I mean if you do the mini-air-chamber test. Water would show it more readily. You'll see that one of your streamlines will follow the shape and create a bubble effect at the rear corners of the bed, and if you then lift the streamer slightly, you'll see that it separates from the shape of the cover at some point about half way back, as it should be dipping over the side.

I'm not 100% sure that this will happen, but it's the biggest potential downfall I see to the shape, once it's on a vehicle.

[ChazInMT]

Issac, your concept is good, and if the trucks we all drove consisted of passenger cabins, you'd really have something. But the box which is the cargo bed is still there, and putting this shape on top will help, no doubt, but it leaves a fairly large amount of air which is at the rear outside of the bed at the top rim of it unmanaged. If you look at the design of my cap, I tried as well to manage the air as you have but I minimized the flat area's at the back rear corners. Also, you will want to figure out a way to make the bed able to be raised and propped in the rear so you can drive with it, even if your cap is very light, the size makes it very difficult to handle without 2 people, so popping it on and off isn't as simple as you might imagine.