Tonneau/half tonneau.....spoiler/half template - Page 2 - Fuel Economy, Hypermiling, EcoModding News and Forum

kach22i · 09-30-2018, 09:35 AM

I have a roof wing on my pick-up truck and a full full tonneau cover of coroplast.

My conclusion; roof wing with without a full tonneau cover is inferior a full tonneau cover alone.

This conclusion is based on drag and mpg, not on down force or road safety.

I like to keep my truck planted on the road, and the roof wing helps do that at speed. Sand bags held in place over the rear axle do it at low speed and off the line.

Freebeard posted this a while back, sure looks interesting.

https://ecomodder.com/forum/showthre...-19525-12.html

I have not yet had a chance to build follow up idea like aardvarcus has done, but I posted some concept sketches a while back.

Roof Spoiler on Pick-Up Truck Cab - Phase-2
https://ecomodder.com/forum/showthre...a-19525-9.html

More sketches in link above.

And other format studies.

hat_man · 10-01-2018, 04:51 PM

The sketches are what I was thinking of but with not so drastic an in board taper. Just as a guess, but if viewed from overhead I would guess about 30* outboard to in board. I was thinking about 7*-12* maybe.

kach22i · 10-01-2018, 06:26 PM

Quote:

Originally Posted by hat_man

The sketches are what I was thinking of but with not so drastic an in board taper. Just as a guess, but if viewed from overhead I would guess about 30* outboard to in board. I was thinking about 7*-12* maybe.

The angle I was showing is for a sportside bed, not a flat fleetside bed. Go to link to see plan detail.

The extreme angle would be an experiment for sure, the 7-12 degree you mentioned will have true attachment, and that is preferred.

What materials are you considering?

hat_man · 10-04-2018, 08:26 PM

I was going to start with an EMT skeleton. I might reuse and modify the one I started for my other Ranger in this thread.

https://ecomodder.com/forum/showthre...cap-26218.html

I'm not quite sure how I'm going to skin it. I was thinking about maybe a layer of chicken wire strategically snipped to follow the compound curves, then glass fabric and two part epoxy resin. Once the outer skin is done then maybe the same treatment on the inside for some extra strength.

kach22i · 10-04-2018, 08:40 PM

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

COcyclist · 10-10-2018, 07:59 AM

Quote:

Originally Posted by hat_man

I'm not quite sure how I'm going to skin it. I was thinking about maybe a layer of chicken wire strategically snipped to follow the compound curves, then glass fabric and two part epoxy resin. Once the outer skin is done then maybe the same treatment on the inside for some extra strength.

chicken wire is flexible enough you should be able to squeeze it together, instead of cutting and creating sharp little pointed loose wire ends to jab you.

hat_man · 10-16-2018, 04:40 PM

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.

hat_man · 10-16-2018, 05:05 PM

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?