Tonneau/half tonneau.....spoiler/half template

[kach22i]

Originally Posted by hat_man

kach22i.....

I like the chin spoiler. Did you use the round edge as the attachment point or the flat edge? I saw the cove base addition and wondered... if you used the flat edge as the attachment point would the rounded edge work like the cove base did?

The vinyl cove base was installed in the same orientation as it would be on a wall, cove at the bottom. See images in posts #29 and #35 in the link below.

http://forums.pelicanparts.com/off-t...fective-2.html

I used something like 100 screws to secure it to the old lawn edging for Phase II, that curve tube in the lawn edging was precarious.

The proper way to do this is to start out with conveyor belt material, and if you want a lip spiltter at the bottom find something at the hardware store "L-Shaped" that you can use as a bottom lip - rivet or screw.

See attached image - an untested idea, will need to bend in 3D.

Depending on depth of conveyor belt material you may have to back brace it the way I did with scrap metal.

[aerohead]

Originally Posted by kach22i

I wonder if shrink wrap like used to winterize boats would flex too much.

The material gumby 79 is using on his Dodge pickup aeroshell was rock solid at 76-mph airspeed at DARKO.And it's photochemically stable for many seasons.

[aerohead]

Originally Posted by hat_man

QUOTE=aerohead;271417]These values were published in Texas Tech's SAE Paper# 881874:'Pickup Truck Drag Reduction-Devices That Reduce Drag Without Limiting Truck Utility'
* For short bed pickup,drag min was achieved with a 24-inch wing @ 12-degrees ( a 19" wing @ 11-degrees was almost as low) and 1/2 tonneau cover [ back 1/2 ].
*For a long bed pickup,a 32" wing @ 8-degrees had the drag minimum when combined with the 1/2-tonneau.
*17 % drag reductions were measured.
* An 'aeroshell' provided a 20% drag reduction.[/QUOTE

I have a long bed. But is that 32" from the cab rearward (covering almost half the bed) or 32" from side to side?

I think I have come up with a simple solution for making a half tonneau that I can quickly convert to a full tonneau. It won't be exactly weatherproof but I never really carry anything of value anyhow.

The cab-wings were measured from the attachment point at the top/back of the cab, rearwards.

[hat_man]

Building the half cover will be much easier than the wing. Is there any advantage to only using the half cover while I am trying to fab up the wing? Or do they need to be in combination?

[hat_man]

Looks like the picture of the factory offering is for a Ford Wildtrak. I've only found the product for sale in the UK and Australia. I have a few other ideas though.

[kach22i]

Originally Posted by hat_man

Build the half cover will be much easier than the wing. Is there any advantage to only using the half cover while I am trying to fab up the wing? Or do they need to be in combination?

You need the bed cover or at least a half one for the roof wing to do much good - in my opinion.

There is some benefit to roof wing only, but more if half cover/cover only.

Combination working together is obviously best/optimal.

[hat_man]

I was thinking of the half cover and no wing for a short time. I should just install the half cover and record the results. I broke my foot three months ago and haven't driven anywhere since. My work commute gives a great test bed for mods. Depending on the job site it is usually 400-600 miles a week.

Once I can get behind the wheel again, ill give it a go.

[hat_man]

Looking through some of kach22i's threads and sketches I have come up with three different options for the wing/spoiler I would like to design. I will be using it in conjunction with the half tonneau. What I'm not sure of is how each design may or may not affect the low pressure created by the eye of the vortex that the half tonneau needs to be effective. Particularly, how the side profile of each design affects that vortex. Does the side profile move that eye rearward or lessen it's strength?

These are the three ideas I am considering.

[hat_man]

I really like the aesthetics of the Toyota wing arrangement.

[kach22i]

Originally Posted by hat_man

I really like the aesthetics of the Toyota wing arrangement.

Looks like it has similarities to the first generation Honda Ridgeline's profile, a shape claimed to be influenced by wind tunnel testing.

2005 Honda Ridgeline best image gallery #10/17 - share and download


As far as the study/development sketches posted (not final designs), they represent a single idea or concept. The reason none of them flute or flare out like the Toyota and Honda is my S-10's Sportside bed.

A standard fleetside bed would have more opportunity for elongation at the base.

This elongation might help prevent air on the sides from tumbling into the bed area.

Let me say that these concept sketches are untested and may induce some uplift.

The main idea running though them is going from the rectangular cabin to a half circle with fewer vortexes and more equal surface pressure.

https://appliances.knoji.com/how-to-...t-booster-fan/


https://forums.sketchup.com/t/drawin...to-round/18660


https://weldingweb.com/showthread.ph...quare-to-round





There is a small hovercraft in the UK that goes from round to square thrust duct so that reversing rudder deflectors can be used, the transition also expands the thrust area a bit. The sketches I did are sort of the opposite and reduce the drag area - in theory and if attachment of air is maintained.

Don't go too steep with the angles and you will be okay.

The question asked seemed to be; will this aft cabin hood funnel more or less air into the leading edge opening of a half bed cover.

More I would guess.

However once a static bubble of air pressure is established the rest of the air flow would just go around it I suspect.

I for one would fear some kind of buffeting with any half bed cover.

These could be unfounded fears, but personal experience with cross winds, passing large trucks and being passed tells me air does not always flow in polite uninterrupted smoothness they way I wish it to.

EDIT:

Found an older thread with great information and images in it.

How to improve fuel economy with a tonneau cover
https://ecomodder.com/forum/showthre...ver-124-5.html

7-pages long, got sidetracked with trailer towing and aircraft but it's all good.