Roof Spoiler on Pick-Up Truck Cab - Phase-1

[aerohead]

Originally Posted by kach22i

Nice find, thank you for posting it.

Here is a roof wing I've never seen before.

Random TRANSPORTATION pictures - Page 1712 - Pelican Parts Technical BBS


Looks large enough to work, and in undisturbed air stream too.

That wing position is what the aeronautical guys wanted to do with the Daytona Charger,placing the wing directly over the rear axle,but were out voted.
On the Lambo, they'd get the downforce without risking lifting the nose,as has happened on some cars.

[kach22i]

Looks more like someone took a ducktail from a VW Beetle hotrod and remounted it than a real roof wing, but perhaps worth a glancing look.

Only angle I was able to find.

Custom Paint Jobs On Trucks | Custom Paint Jobs

A black 1947 Studebaker Truck

[Ordnung]

This thread is making me wonder if the small wing on my Polo hatchback is a help or hinderance

[kach22i]

Originally Posted by Ordnung

This thread is making me wonder if the small wing on my Polo hatchback is a help or hinderance

If your car looks like this example below, then you already have a clean sharp edge for the air to release from (which reduces turbulence).

Polo Hatchback 3-door / 5th generation / Polo / Volkswagen / Database / Carlook


However, that said anything which makes the body longer ratio wise is usually good.

These retreating edge treatments (found on hatchbacks and SUV's) seem to get more common and larger every year (see image below).

2017 Mirage
Secor Mitsubishi | 2017 Mitsubishi Mirage in New London, CT


Several ecomodder threads on the topic:
http://ecomodder.com/forum/showthrea...hts-29383.html

I have begun sketching up a Phase-2 roof wing which includes cab side returns. Just have to figure out how to export the sketches from my phone to my computer, and then I will post them.

I currently do not make a big distinction between a roof spoiler and roof wing. However I do favor the leading edge air-slot approach of the semi-wing, just have to prove it works better than a flush sealed edge - somehow.

[freebeard]

When I saw that picture, I thought of this thread. What do you make of that cab? It looks like two Studey cabs back to back with the original rear wall moved back.


https://www.google.com/url?sa=i&rct=...74443054019968

[kach22i]

Roof Spoiler on Pick-Up Truck Cab - Phase-2

My thoughts on proceeding on a "Phase-2" started a few weeks ago when I read in Wikipedia about the first generation Honda Ridgeline's attention to aerodynamics accounting for it's somewhat unusual looks.

Reference Image:
2016 Honda Ridgeline Redesign - 2016 / 2017 Honda Ridgeline


The inspirational quote:
https://en.wikipedia.org/wiki/Honda_Ridgeline

Also, the design of the C-pillar, rear roof garnish, and tailgate were built to maintain good aerodynamics and reduce turbulence between the cab and the tailgate while maintaining driver visibility. This aerodynamic design allowed them to create a rear garnish that shields the rear glass window so when it's opened at speed there is no buffeting or rainwater intrusion.

Recently I've been doing some major rust repair on my old truck, cutting out the rust left some giant holes in the body, I filled them with expandable foam and currently in the process of glassing them up and epoxy micro-balloning the repair areas. All this activity has me thinking about going that next step.

One of my user related issues is that in the tonneau cover is removed most of the summer so my buddy and I can throw our bicycles in the back for weekend rides. The cover is easily removed/installed with a dozen screws, but not a task I want to do several times a week.

Posting a few sketches/thoughts done on my cell phone, using Sketchbook for a Samsung Galaxy Note 3.

S10 4x4 Pick Up by George Kachadoorian | Photobucket

















No actual design settled on, just exploring ideas.

I believe the NASA truck (truncated bluff body) gets away with extreme aft angles because the body is so long, but my pickup truck cab us not.

NASA Armstrong Fact Sheet: Aerodynamic Truck Studies | NASA

For subsequent tests, researchers installed a "boat tail" structure, shown in the photograph.

Question is; can one "boatail" the back of a pickup truck cabin?


One restraint perhaps not sketched up with proper accuracy is the sportside bed intersection to the cab.

There is this wedge shape to it which I'm convinced sets the side angle, so the longer teardrop sketches are now obsolete in my mind as they were done without actually looking at the truck.

I have Google images on several "Bed Bars" for further inspiration, although they are terrible aerodynamically. They just look cool.


Sample:
Go Industries Baja Rak Truck Bed Bars - FREE SHIPPING!


Just having fun at this point.

If anyone has seen something along these lines which is worth sharing please post it. The more ideas or solutions I see, the better.

I'm kind of looking to do something which has not been tried before for experimental reasons.

Perhaps a twist or an improvement on something which has done before.

[freebeard]

One restraint perhaps not sketched up with proper accuracy is the sportside bed intersection to the cab.

You did all that with your finger? Or do you have a stylus?

To respond to the question: One possibility I don't see would be a Trophenwagen-type boat tail to a vertical edge. It could extend past the bed wit the bottom half (of the extension) sliding up into the upper half for access to the tailgate.

The bed bar would make a good foundation for a 4-bar arrangement to alligator the whole aerocap open, if it had a 4" chop, or a 'visor' that lays over the top of the cab.

[gumby79]

my cap matches some of your drawings . V2 will compromise function for form . Shaped more like this Corvette, less the glass. Grew up driving trucks for Uhaul so driving by mirrors is second nature for me .

[gumby79]

Any open back with sides will have an eddy. Eddy=fuel economy reduction, you don't get to spin the air for free. I'll be it it would be a smaller eddy ,their for a smaller penalty.
Dreem big chisel down to reality

[kach22i]

Originally Posted by freebeard

You did all that with your finger? Or do you have a stylus?

The cell phone comes with a stylus (ink-less pen/pointer).

The program has several pen and eraser settings.

Originally Posted by gumby79

my cap matches some of your drawings .

I was thinking about your cap because I like it very much. However I believe yours is fairly true to the aero-template. This proposal is more like the rear of a Semi-Truck with those baffles.

The program used below came with a camera I bought over a dozen years ago, it is simple, but I can crudely draw straight lines using my mouse.

Below is that awkward transitional wedge between the cab and bed I talked about. Needless to say, the entire sportside bed is an aerodynamic mess, but I'm doing what I can.

S10 4x4 Pick Up by George Kachadoorian | Photobucket






I intend to keep the air gap between the cab and bed.

Think of a louver, the many steps are actually gaps, yet the air flow continues to follow the general form.

I also am operating on the premise that the air gap sucks in a small amount of high velocity, very low pressure air, practically a vacuum. This inner panel flow helps draw in the outer skin flow at the rear termination edge.

This is how I believe my current modestly sized roof wing performs at a scale much greater than it's size would indicate.

If any one knows the exact angle or optimum angle the rear baffles on a semi-truck are set at, please post this information.

If anyone knows the required body length or body ratio required in order to pull off using rear baffles, please post this information. I fear the upper part of the cab is simply too short to pull this concept off effectively, but I am willing to experiment and keep an open mind.