How to improve fuel economy with a tonneau cover

[aerohead]

Originally Posted by Hersbird

I was thinking of something similar but bigger and attached to the bed not the cab. So something like this but with a long moveable center piece added.

I thought about the side wings as well as the camper is 8' wide, wider than the truck.

That would make the truck more like a conventional notchback car,or extended cab/shortbed pickup with tonneau.
If you camber the roofline down as you see in some of the contemporary concept pickups,you're going to see a drag coefficient which is closer to that of a passenger car.
When towing,hinging it up from the front and filling in the voids on the sides,like AeroStealth did with his F-150 Aerolid/APEX RV trailer combo would get you NASA-like performance.

[freebeard]

Apparently I took this picture in 2012 and never posted it. The manager said he knew it improved the gas mileage but he didn't know how much.

For trailer towing, I think the solution would involve overlapping plates that would unfold like a beetle's wings.

[Hersbird]

Or like those frilled lizards with the head crest. Maybe I can intimidate any would be predators as well.
Does anyone have any idea of what kind of forces a 6 foot wide, 3 foot long wing would see angled up into the wind at say a 45 degree angle or more at say up to 70 mpH?
I was thinking of making the frame out of conduit and maybe trying foam covered in fiberglass. Like a surfboard with conduit just under the skin all aroundbthe edge. Then hinged at the front with drop down adjustable legs to get the angle if towing, or taper if unloaded

[freebeard]

Non-overlapping plates with webbing for a serrated edge?

[kach22i]

Originally Posted by Hersbird

Does anyone have any idea of what kind of forces a 6 foot wide, 3 foot long wing would see angled up into the wind at say a 45 degree angle or more at say up to 70 mpH?

I used to post such questions in the forum below, looks like "Mechanical Engineering" not "General Physics" is the subsection you want.

https://www.physicsforums.com/

The answer is "huge", but don't quote me on that.

EDIT:

I went ahead and created a thread, maybe we will get a bite, maybe some deserved ridicule for being dummies, don't know yet.

https://www.physicsforums.com/thread...70-mph.906287/

[aerohead]

Originally Posted by Hersbird

Or like those frilled lizards with the head crest. Maybe I can intimidate any would be predators as well.
Does anyone have any idea of what kind of forces a 6 foot wide, 3 foot long wing would see angled up into the wind at say a 45 degree angle or more at say up to 70 mpH?
I was thinking of making the frame out of conduit and maybe trying foam covered in fiberglass. Like a surfboard with conduit just under the skin all aroundbthe edge. Then hinged at the front with drop down adjustable legs to get the angle if towing, or taper if unloaded

*no data has been published for a non-towing truck with up-swept wing.
*there hundreds of different airfoil shapes which have been tested,@ zero-lift,to maximum lift angles-of-attack.Abbott and Von Doenhoff's book would be the source for that data.
*a simple inclined surface at a fixed angle on the ground or on a wall has been tested but I don't have that with me.Sighard Hoerners book,Aerodynamic Drag, would have that.
*If you're running without pulling a trailer,the wing should be slanted downwards.Here are some examples of what a rear slope can do

[Hersbird]

Originally Posted by kach22i

I used to post such questions in the forum below, looks like "Mechanical Engineering" not "General Physics" is the subsection you want.

https://www.physicsforums.com/

The answer is "huge", but don't quote me on that.

EDIT:

I went ahead and created a thread, maybe we will get a bite, maybe some deserved ridicule for being dummies, don't know yet.

https://www.physicsforums.com/thread...70-mph.906287/

Thanks! Your post is hilarious over there BTW.

[freebeard]

Count the fasteners. Look at the size of the washers under them. Look at the thickness of the aluminum. Consider the engineering in the turnbucle/clevises to tune the flight altitude.

This is for downforce. They said they have to take it off to get the car on the trailer and that took 45 minutes; but it's worth doing, apparently.

I'm thinking beach umbrella ribs; maybe ten of then across the top rear, ganged together in parallel. There is your frilled lizard right there. No towed vehicle, retracted — no downforce. Extended with towed vehicle, it only has to maintain the bubble instead of a hurricaine-force onslaught. Fix the struts to the vehicle and move the ends of the ribs and it will extend backward.

[aerohead]

*Hoerner assigned Cd 1.03 for a 45-degree-angled structure.
*We know that the hypotenuse,C of this right-angled triangle is 3-feet.
*and from the Pythagorean Theorem : A-squared + B-square = C-squared.
*and @ 45-degrees,A = B.
*then,C-squared = 2A-squared.
*and C-squared = 9
*then A-squared = 9/2,or, 4.5.
*and the square root of 4.5 = 2.121-feet.
*so the frontal area is 6-feet by 2.121-feet,or 12.727-sq-ft.
*and CdA = 1.03 X 12.727 = 13.108 sq-ft.
--------------------------------------------------------------------------
*On say,a 2014 F-150 of Cd 0.402,and 36.0 sq-ft frontal area,we have CdA= 14.472 sq-ft.
*CdA of the truck and wing is 13.108 + 14.472 = 27.58 sq-ft,
*and adding 5% interference drag (as per Hoerner's methodology),we get CdA 28.96 sq-ft.
*The frontal area of the truck and wing is 48.727 sq-ft.
*dividing that into the CdA of the 'rig' gives Cd 0.595 for the pickup driving around with the wing on,but not towing anything.
*This would be like driving six 1st-gen Honda Insights simultaneously.Ouch!

[kach22i]

Originally Posted by aerohead

This was online,but no performance claims were made

I found a sister image to that image - I think.

https://www.rv.net/forum/index.cfm/f...print/true.cfm