Boat tail back on T-100

[aerohead]

I wrestled the boat tail out of the shop and after 5-hours I finally had it back on the truck where she'll remain until after World of Speed in September.
I will be delivering a 'cab-wing' spoiler to Radium Springs,New Mexico which I'm constructing for John Gilkison's 4-RUNNER/APEX rig before his August 5 trip departure for the Denver,Colorado area.
This will give me a preview of the Bonneville trip as it will be the first time the new nose and boat tail have been on the truck together.
The tail is only 30" in length (762 mm) and gives a wake which is about 35% of the truck's frontal area.
I'll be constructing an extension which will take it back a little further.I might do that with an 'inflatable.'Not sure yet.
I've got some of the belly pan in the bed and will head for the car wash after Al closes here at Copy-Pro.I want to degrease it properly and prime and paint the interior portions for the first time.
Between now and September I'll be 'hardening' everything on the truck.The forces it will experience will be up to 8X the forces they experience at 65 mph.
The working conditions aren't the best right now,but it feels good to be fabricating again.

[Sven7]

Hey Phil, mind getting a picture? I might have a present for you

[Tango Charlie]

Yes, would love to see some pictures, please!

[aerohead]

There's is a photo of the boat tail undergoing tuft testing at the Aerodynamic Streamlining Template Part-C thread,page 4,#39 (permalink).
I'll get some additional shots when I can look up.
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*Also,I got the tail's diffuser skinned with aluminum sheet today,replacing the disintegrated luan mahagony door skin original.
*Also rinsed,dried,and primed the three T-100 forward belly pan sections that I degreased last night.I'll pick up paint tonight.
*Also,I've roughed in 4-add-on leading-edge sections for the front of the aero shell.I had some cedar and redwood and I bandsawed, belt-sanded to fit the shell perimeter,then ran them through a quarter-round bit on the router table for a uniform radius.I'll pull them,coat with polyester resin,re-attach,then Bondo and blend in.
It's crunch time!

[skyking]

Glad to you are up to the fabricating again. Sure wish I could make the journey.

[BamZipPow]

http://ecomodder.com/forum/showthrea...tml#post120277

[California98Civic]

Originally Posted by BamZipPow

http://ecomodder.com/forum/showthrea...tml#post120277

The tell-tales above the taillights and at the seam between your bed cap and the truck seem to indicate flow moving from the side to the top of the extension. Does that flow become turbulent as it intersects with flow from the roof?

[aerohead]

Originally Posted by California98Civic

The tell-tales above the taillights and at the seam between your bed cap and the truck seem to indicate flow moving from the side to the top of the extension. Does that flow become turbulent as it intersects with flow from the roof?

I'll give a 'long' answer and see if I can cover all the bases:
*The air on the aero shell is moving at a greater velocity than on the sides of the truck due to the way the greenhouse has divided the airstream at the front.
*Since the aero shell has plan taper and the truck bed does not,the aero shell can undergo a continuous increase in tumblehome,whereas the bed box is stuck with it's upright sides.
*From Daniel Bournoulli's research findings,the static pressure around the aero shell will be lower than on the sides of bed.
*This pressure differential causes the higher pressure air near the bed rails to migrate upwards into the lower pressure air above the rails alongside the shell.
*It's still laminar flow,but it is tranverse flow.
*If the aero shell had a 'steeper' curvature than it does,the shearing forces would be strong enough to whip up into attached longitudinal vortices,causing high drag.
*Since the curvature is gradual enough the flow remains attached.
*From the photo you can see that by the time the air makes it to the boat tail,all the air is flowing longitudinally with no perturbations.
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*Had the T-100 bed rails matched the plan taper of the aero shell it would be doubtful that any tranverse flow would occur.
*I was working on this issue in 2005 with the Dodge pickup,having created a mockup of a 'Template' truck bed when the T-100 showed up in my life.Perhaps before I die I'll be able to complete that project.This sort of bed would allow Cds which are half of the typical passenger car,Something pickup owners might appreciate at the gas pump.

[Sven7]

Very good description. Imagine a truck bed whose sides would fold in when not in use, creating the plan taper we need for low drag.

[aerohead]

Originally Posted by Sven7

Very good description. Imagine a truck bed whose sides would fold in when not in use, creating the plan taper we need for low drag.

ironically,'not in use' would describe most pickups in Texas at all times.