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Old 10-26-2010, 12:12 AM   #21 (permalink)
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Had a long drive and got some thinking done. Will.post it up once I scetch it out.

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Old 10-26-2010, 11:29 AM   #22 (permalink)
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The one problem with the swing-away hitch mount is that it has a long bar out to the side where the hinge has to be located - seems like that would be a big wind drag.

Thinking about it, I'd go one of two ways. One would be a completely hollow, ultra lightweight tail that clips on over the hatch. This would be the simplest to fab and hook up, but would also turn into a 5' sail when the hatch is open. However, it lets you use the car the same way as before.

The other way, which I would go prefer but would take longer, would be to remove the hatch altogether and replace it with a two-part tail. One part would mount to the upper hinge for stability, and into the trailer hitch below, and be semi-permanent. The second half would basically be a smaller version of the first option, but with the seam within the boat tail further back. Using the hitch for strength, you could extend the cargo space out about 2 feet, and not having the portion of the hatch nearest the car move, you could get a good tight seal to the car. The rear half of the hatch would have to be light and thus not cargo-equipped, but it's smaller anyways so less useful (although you could leave it open if you wanted to carry 10' long pipes).

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Old 10-26-2010, 11:37 AM   #23 (permalink)
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Will you have an alternative vehicle to tow your trailer with? If not, the temporary, lightweight way seems like the way to go.
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Old 10-26-2010, 12:38 PM   #24 (permalink)
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Niner: Good idea about making it a two part tail. I have put 8' lumber in my car before, and would like to be able to put 10' or 12' in

I was thinking that I could make it so the top part of the boat tail was lexan or Plexiglas and have that run on the top hinge (currently used for the glass part of the hatch). The rest would be attached to the other part of the hinge and to the trailer hitch.

If I do it right I might be able to just extend out the trailer hitch and still use it (not a good idea)

Yes I do have my dad's truck to pull the trailer with, or I could take the boat tail off.

Like I said before, all mods must be reversible

now if I could find some time to draw up what I was thinking...
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Old 10-26-2010, 02:29 PM   #25 (permalink)
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Quote:
Originally Posted by Weather Spotter View Post
I do not think there are any other good mount points- lots of plastic.
If you remove the rear bumper, you'll likely find some good extra mounting points - as with Jim's Insight boattail - but it makes it more complicated to install/remove.
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Old 10-26-2010, 02:41 PM   #26 (permalink)
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I might get there, but for now I want to try it without taking off the bumper.

here is an idea: make a metal ring that goes around the rough shape of the hatch. This would be the main base piece and would attach to the lower hatch hinges. off this I would send out 3 supports going back. One dead center that would attach to the hitch. The others would be at the widest points of the tail, all angled in. they would all be attached along the way back (every foot or so) to make the frame. I am not sure what I would cover this with but the top part would be see through and attach to the top hatch hinges in the front and have some other attachment in the back so that I can open and close it for cargo.

My student copy of CAD ran out so no drawings
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Old 10-26-2010, 07:18 PM   #27 (permalink)
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Maybe make something like this but out of plexiglass:



Use a 1"x1" fir cleat to screw the plexiglass to.

Fasten the plexiglass to the metal ring around the hatch perimeter

Can you buy another hatch from the junkyard and fasten the tail to the hatch? You could cut out the middle of the hatch and have your cabin open to the back of the tail. Then just reinstall the original to return it to no mod status.

Warning, the plexiglass tail seems somewhat dangerous to me, but if it were secured well enough, it should work.
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Old 10-26-2010, 08:59 PM   #28 (permalink)
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....My student copy of CAD ran out so no drawings
If I recall correctly, you can still get a free version of IntelliCAD. Just have to register with the manufacturer, but it is free.

We have a copy at work, and it does a really nice job. Just takes a while to get used to it.

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Old 10-26-2010, 09:18 PM   #29 (permalink)
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....Warning, the plexiglass tail seems somewhat dangerous to me, but if it were secured well enough, it should work.
I agree with your warning about the plexiglas being questionable...

We had 45 mph winds here today, and the foam/fiberglass held up fine, but I would NOT want to find out what a flimsy material would do in the same winds!!

The only way I can see making something this big and expansive, is to use a material with enough thickness to prevent buckling/bending/flopping in heavy winds.

If you study structural mechanics, you will quickly find out that thicker and/or stronger materials, are the only way to go for something this big.

Going from a 1" thick piece of foam to a 2" thick piece of foam, makes the bending moment four times stiffer just by doubling the thickness. That's not a typo; 4 times stiffer with 2 times the thickness.

Take a close look at Metro's tail extension with the cardboard. He employed the use of internal bulk heads to increase stiffness and stability of his design. If the cardboard could be sealed from the rain, it would definitely stand up to the abuse of these high winds we had today.

Jim.
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Old 10-26-2010, 11:49 PM   #30 (permalink)
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Good ideas guys. I was thinking about the scrap hatch idea it could work. I will look into that free cad program but I run mac so that might not work.

I will certainly go with a strong material, not sure if it will be foam or sheet steel. I will have to reread 3wheelers thread for a how to on foam.

What angle should the bottom come up at? What for the sides?

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