2011 Prius to get full boat tail w/ faired trailer

[aerohead]

Originally Posted by NeilBlanchard

Yes, the single caster wheel meant that it was locked to the car and so it would drive like a long tailed car; backing up would be a breeze. This is precisely what I like about this idea. I would think that a design could be done with a larger wheel that went up into a cylinder in the underside of the floor. The bottom of the "papoose" would have to be flush with the floor of the car, anyway?

Neil,did you mean 'floor' as in where are feet are,or the bottom of the bellypan/diffuser ?

[aerohead]

Originally Posted by KamperBob

That's the same trailer I had years ago. Except mine had 8" wheels which spun welded a bearing at low miles, low load, and low speed. The upsized 12" wheels are a huge improvement.

The other problem I had was both fenders fatigue failed early. Maybe the enclosure will prevent that failure mode too.


Given the short wheel bases and relatively tall tail height of the Prius (and thus matching nose height of trailer) I'd suggest generous allowance for pitching angle (upwards of course) to prevent the trailer from tagging the car.

I'm particularly curious to see how this rig will look from above.

Rock on!

KB,the 'integrator' is hollow,shingling over slightly at the gap-filler package interface,allowing the rig to dip inside it when necessary.
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I completed the preliminary top/bottom plan-view drawings,plus rear elevation view last night.
I just now made enlargements and will darken the pencil lines with ink and scan/post asap.
Maybe Saturday by the latest.

[aerohead]

Originally Posted by dieselbeetle

This project is too interesting.

I'm curious, though, did your prius need a trailer to begin with for extra storage? Or is this exclusively to improve aerodynamics?

Have you considered making the "aero-trailer" have a "fifth wheel" electric motor as well?

all the best

Efficiency has always been a big deal with Gary.When he saw my trailer,he immediately made the connection and thought it would be interesting to see what he could squeeze out of the new car.
This project is for pure streamlining,as OTR rigs might one day use behind their semi's,so it,in itself will carry no load.
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A 'pusher' trailer has already been addressed here at EcoModder.I am personally opposed to the concept,but only for safety reasons.
Event-horizon vs human reaction time might create a regrettable situation in a worse-case-scenario.
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The trailer is intended to be used as an electric-vehicle range-extender,carrying a second set of batteries, or gen-set ( to create a serial-hybrid ).
I saw three EV trailers at the Solar-500 at Phoenix Int'l Raceway in the 1990s.I surmised back then,that all three vehicles could have extended their range had they seriously considered streamlining.
Alan Cocconi made an effort to soften the body of his trailer,but it would have been completely submerged within the turbulent wake of his CRX.

[aerohead]

Originally Posted by Vekke

You could put that trailer to use and add some extra batteries there. extra electric motor is a little bit more challenging to manufacture, but power feed to prius electric motors arent so difficult task.

In europe you are not allowed to tow anything on Prius is it allowed in the states?

Hauling extra batteries is one of the premises for the invention.
An extra 2,000-lbs ( 909 kg ) only costs 2.94 horsepower in additional road load from rolling resistance at 50 mph ( 80.5 km/h ).
At 55 mph ( 88.5 km/h ) Gary's trailer can add 11.3 mpg from drag reduction,with 3.77 mpg loss due to R-R ( radials ),4.1 mpg loss ( bias-ply ),for a net improvement,from 53 mpg,to 60.2-60.5 mpg at steady speed.
---------------------------------------------------------------------------- A Nissan Leaf,or plug-in EV,on a road trip,would extend the range of the initial battery pack,and carry the second pack with no penalty,only gain.

[aerohead]

The following predictions are made for the project if built to drawings:
NOTE: since this trailer carries zero 'load',it is by default,over-engineered.Consequently,approx. 21.5-lbs ( 9.77 kg ) can be removed selectively from the original trailer without sacrificing structural integrity
* 'shaved' weight,trailer kit = 118.5 lbs ( 53.86 kg )
* thermo-formed ABS plastic top = 32 lbs ( 14.54 kg )
* thermo-formed ABS plastic belly = 19 lbs ( 8.63 kg )
* thermo-formed ABS plastic wheel/leaf-spring/axle fairings = 20 lbs ( 9.09 kg )
* with steel out-rigger body supports and gap-filler mechanism,all-up weight of complete trailer = 225 lbs ( 102.27 kg )
* with 15 % tongue-weight = 191.25 lbs ( 86.93 kg ) on axle
* rolling-resistance penalty @ 55 mph ( 88.5 km/h )= 4.1 mpg ( bias-ply tires )
* ditto ------------------------------------------ = 3.777 mpg ( radials )
* modified wake area = 1.632 square-feet ( 0.151 square meters )
* modified drag coefficient = Cd 0.143
* aerodynamic drag benefit @ 55 mph = 11.3 mpg
* net gain from trailer based on tire type = 7.2-7.5 mpg
* predicted new fuel economy @ 55 mph = 60.2-60.5 mpg at steady speed,from a baseline of 53 mpg ( current tank mileage ).
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Many hundreds of hours from now we'll know something!

[NeilBlanchard]

Hi Phil,

Originally Posted by aerohead

Neil,did you mean 'floor' as in where are feet are,or the bottom of the bellypan/diffuser ?

I meant the underside / bellypan / diffuser.

[KamperBob]

Originally Posted by aerohead

KB,the 'integrator' is hollow,shingling over slightly at the gap-filler package interface,allowing the rig to dip inside it when necessary.
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I completed the preliminary top/bottom plan-view drawings,plus rear elevation view last night.
I just now made enlargements and will darken the pencil lines with ink and scan/post asap.
Maybe Saturday by the latest.

Understood, Phil. I was also thinking about interaction scenarios. Consider pulling out of a gas station through a gutter dip onto a crowned road. While executing such a turn rigs can experience yaw, pitch and roll at the same time. Once your trailer tags your tug (ask how I know) you get extra cautious...

[aerohead]

Originally Posted by NeilBlanchard

Hi Phil,



I meant the underside / bellypan / diffuser.

Hi Neil,
to have the bottom of the papoose projecting along the line of the tow vehicles diffuser angle seems to be the desired geometry so that would get you the lowest drag.

[aerohead]

Originally Posted by KamperBob

Understood, Phil. I was also thinking about interaction scenarios. Consider pulling out of a gas station through a gutter dip onto a crowned road. While executing such a turn rigs can experience yaw, pitch and roll at the same time. Once your trailer tags your tug (ask how I know) you get extra cautious...

KB,I've deceived myself before on projects,so until I actually test the silly thing I won't actually 'know' how it will perform in the real world.
The drawings will explain themselves best but they are time away.
I did a photo shoot of the wind tunnel,got it put away,and Viking is finally back in the shop,so I feel like I'm making a little progress.
So the drawings are on the burner,as Gary will need them too.
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Here is a description of where my thoughts are :
*the side gap-filler panel frames pivot from frames which themselves pivot from an axis above the ball-hitch.A link connects the side panel frame to the wedge face of the trailer to create a 3-bar linkage.
-------------------------------------------------------------------------- The top panels pivot vertically from a frame & post which receives into a tube above the swing points for the side panel frame support frame,which can displace from side to side like a lolly shaft on a windmill.
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All the panels are supported on the trailer itself and cannot bind against the trailer under any orientation,as they move with it.
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The integrator is designed to contact rollers mounted low and outboard on the swing-frames which support the panel frames.
*When the tug yaws,pitches,or rolls and the integrator contacts the swing frame,it will displace rearward.The link will force the trailing edge of the panel frame to displace outward,taking the panel with it for the clearance articulation,with a maximum yaw of 45-degrees.
As the yaw,pitch,or roll 'event' ends,and the tug straightens back out,the link forces the the panel frame to 'close',which in turn forces its supporting swing-frame to 'stowed' position under spring tension.
Nothing happens on the unaffected side.It will just remain in the 'stowed' position.
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If the rig goes over a high point,everything moves away from the integrator.
If the rig goes through a dip,the swing frames and upper frame can dip inside the upper void of the integrator.
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So far,the split lower panels are unresolved.I'm close but no cigar quite yet.Safety chains and landing gear issues must be thought out.
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The images will help a lot so I'll chip away at those.In the meantime,maybe the above explanation will help.

[SwamiSalami]

Thanks for answering back! I'm really looking forward to keeping up with your project.

sincerely