2011 Prius to get full boat tail w/ faired trailer

[MetroMPG]

This is the new thread.

Edited my post to hopefully prevent confusion...

[aerohead]

Originally Posted by dieselbeetle

wait. so is this the old thread or the new thread? if it's the old, please point me to the new!

thanks

I've been working on the 'Full-Boat-Tail Trailer with Gap-Fillers for T-100 Pickup.
Rather than embed the new Prius project within that thread we've determined to dedicate a thread expressly for this project.
If you like,you can check out the other thread to come up to speed on the premise for these projects.

[aerohead]

My friend Gary spent some time with the car.He got a couple helpers to sit inside while he measured.
* with 300-lbs ballast the height of the car is 58.2-inches ( 1455mm )
* point of maximum roof camber occurs @ 4.5-inches ( 112.5mm) aft of the B-pillar door joint.
* using the 'Template',the imaginary tail would strike the ground at 207-inches ( 5175mm ) behind the zero-point of the 'Template.'
* at 75% 'Template'( this will be my recommendation ) the back of the trailer will fall at 91.71-inches ( 2292.75mm ) behind the rear bumper fascia of the Prius.
* the elevation at the trailer body upper terminus is 24.5-inches ( 612.5mm ).
* in rear elevation view the body will mimic the Prius body tumblehome and evolve from there.
* Prius plan-view body camber and boat-tailing varies with position on the car.Very little at sill level,quite a bit as one moves up in elevation.The trailer body will pick up at these points and evolve.
* due to the original outside wheel width of 52.5-inches ( 1312.5mm ) I will recommend that the trailer tongue be shortened 5.82-inches ( 145.5mm ) to just maintain a 45-degree jack-knife swing,and go to a hyper-'Template' curvature in plan-view to allow enclosure of the wheels/tires within the footprint of the body.If done,the width of the trailer body rear will be 45.35-inches ( 1133.75mm ).Otherwise,to 'contain' the wheels with a on-'Template' plan-curvature,would require sectioning the frame and axle,a decision Gary will have to make.
* General Note:So far,cedar-strip canoe construction technology will be the fabrication path for the body construction.
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This is all preliminary,nothing is set in cement,and ideas will be bouncing back and forth between Sanger and Colorado Springs.
And so far,only the upper body is on the table.No bellypan,no wheel fairings.

[MetroMPG]

Originally Posted by aerohead

* General Note:So far,cedar-strip canoe construction technology will be the fabrication path for the body construction.

So, not only will it be functional, but possibly extra pretty too.

Any hints on how gap filling between the car & trailer will be tackled?

FYI, the diesel trike that's been to a few of the Green Grand Prix events at Watkins Glen is cedar strip construction:





From: http://ecomodder.com/forum/showthrea...-may-7961.html

[aerohead]

Originally Posted by MetroMPG

So, not only will it be functional, but possibly extra pretty too.

Any hints on how gap filling between the car & trailer will be tackled?

FYI, the diesel trike that's been to a few of the Green Grand Prix events at Watkins Glen is cedar strip construction:





From: http://ecomodder.com/forum/showthrea...-may-7961.html

Darin,Gary's pretty meticulous about stuff so I anticipate the bodywork to be really nice.
With respect to the gap-fillers,I think somebody will have to shoot me 'cause I keep re-inventing them in my head!
I hope to have some images to share before too long.Everything is pretty embrionic.Toughness is an issue with respect to road hazards and I want things simple and very strong for their weight.
Much of the panel system will be 'on' the trailer itself.Torsional coupling issues can be addressed this way.Less binding!
There will be an 'integrator' between tow vehicle and panel apparatus.
I'm close!
I'll show Gary and everyone what I've come up with and then 'ingenuity' can kick in.
That trike is rolling art work.Really sweet!

[Varn]

For your friend wanting more aero with a prius pulling a trailer. Design a one wheeled trailer. or a no wheeled trailer on a hitch. Stability issues aside more wheels = more significant drag.

I used to race hpv trikes and always took a big hit on drag from the extra wheel when compared to bikes. I did win the class 3 years in a row. I was over 50 then and raced against a lot of younger riders.

[ChazInMT]

Hi Phil,

I did a quick drawing of "The Template" over a web image of a 2011 Prius.



Some things to note:

The Prius back glass drops quicker than the plan taper.

In order to make up for it, I shrank the template a bit and lowered it to put it in a sort of compromise position that you see in the image.

I did this because it would seem to me that once the air starts moving along a given taper, it would be unwise to push it back up too much, I'd think a sort of go with it idea would keep the air moving as smoothly as possible.

The black line was used as a measuring device, it appears to me that a trailer would end at 82" or so if this line were followed.

Anyway, hope this helps.

Charlie

[aerohead]

Originally Posted by Varn

For your friend wanting more aero with a prius pulling a trailer. Design a one wheeled trailer. or a no wheeled trailer on a hitch. Stability issues aside more wheels = more significant drag.

I used to race hpv trikes and always took a big hit on drag from the extra wheel when compared to bikes. I did win the class 3 years in a row. I was over 50 then and raced against a lot of younger riders.

Varn,I hear what you're saying,but these designs are more ambitious than what Gary is willing to get into.
We're already looking at 800 man-hours just to get through a 'simple' design.And that does not include any metal chopping or welding other than the gap-filler mechanism which is not a mature technology at this point in time.
Of course,everyone else is perfectly free to go crazy with complexity.That's where I am.

[aerohead]

Originally Posted by ChazInMT

Hi Phil,

I did a quick drawing of "The Template" over a web image of a 2011 Prius.



Some things to note:

The Prius back glass drops quicker than the plan taper.

In order to make up for it, I shrank the template a bit and lowered it to put it in a sort of compromise position that you see in the image.

I did this because it would seem to me that once the air starts moving along a given taper, it would be unwise to push it back up too much, I'd think a sort of go with it idea would keep the air moving as smoothly as possible.

The black line was used as a measuring device, it appears to me that a trailer would end at 82" or so if this line were followed.

Anyway, hope this helps.

Charlie

Thanks Charlie,I've been working off photos Gary sent along with a Toyota factory shot of the 2nd-gen car in true-length.
I'm working @ 28-inch image scale ( car / trailer ) and have made allowances for differences between two cars.
I will follow the 'Template' in elevation which will produce a 'notch' behind the backlight,projecting straight back atop the spoiler 'til it hits the 'line'.There's nothing I can do about the roofline,so the trailer will just have to get back to the line on its own.There will be a locked-vortex captured in this area.
In plan-view,at the very base of the trailer we have issues.For the axle/tire width,@ 52.5-inches ( outside-to-outside ) the tires fall outside the 'Template' boundary.
Chopping the pull-bar a bit helps by moving the axle forward a smidge,but it still won't fit.Sectioning the spanwise frame rails and axle would fix this.
Gary will have to make the call on this one.
Leaving the standard width will force the trailer body to go hyper-'Template',widening the body significantly to allow enclosure of the wheels.
I've been working on the drawings this A.M. and will photo-reduce and scan
/post as time permits.
Right now,as things sit,the trailer body ends @ 75 % 'Template' in elevation.
Ground clearance,with projected Toyota diffuser angle is 14.66-inches.
Trailer body height,at terminus ( with the higher resolution drawings) is 22.25-inches.This will provide some area for the license plate and lights.
The small wake area should possess the 'phantom' tail phenomena.

[aerohead]

Talked with Gary last night.
I'd completed the work up in side elevation,that was okay.I told Gary about the hitch when considering the view in plan-taper.
He's elected to maintain the original pull-bar length and go ahead and section the trailer frame to get it narrow enough to fit under the 'Template' footprint,allowing full enclosure of the wheels/tires at normal length and axle position.
This will facilitate the smaller wake,as per 'Template' profile and best chance for lowest drag.
I made enlargements this morning here at Copy-Pro and will try and finish the layout by next weekend.If so,I can scan and post what we have so far if I'm in town.
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The trailer is a 40.5-inch/48-inch ( 1,012.5 X 1,200mm ) frame with 12-inch ( 300mm )wheels/tires.It was on sale at Harbor Freight Tools for $ 189.00 ( US ),same price I paid for mine in 1986.It weighs about 140-pounds ( 63.63 kg ).
With ABS thermo-formed body shell the complete trailer would way under 200-pounds ( 90.9 kg ).
Retail prototyping expense for the first rolling unit will be approx. $ 80,000 ( US ).Retail price for such a unit in mass production would be on the order of $409.00 ( US ).