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Old 09-02-2015, 05:50 PM   #11 (permalink)
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I'm taking this semi-seriously. The biggest intellectual hurdle is figuring out where I would park the thing.

I want to put a hitch on my car and restore the Westy trailer anyway, and it has a steel frame supporting a plywood box. The tongue and axle bolt together and there is a 2x2" wooden joist supporting the back of the box. Deleting the box would make it a dolly. The tongue is 3' and the axle is 53" to the outside of the trailing arms. The wheels are 16x5".

Your wheels are smaller, and you plan on four, right? I was thinking of a towable model but to match your dimensions it would have to be trailerable.

My thought experiment is hang a flag on a long pole off the back of a short trailer. When the tow vehicle turns the trailer will follow, but the flag will be tangent to the curve and outside it. The steps would be:
  1. Add a trailer hitch (and take the chatter out of the clutch)
  2. Restore the Westy trailer frame (new elastomeric snubbers and bearings)
  3. An asymmetrical pyramid made out of angle iron from Hollywood bed frames
  4. A two frequency geodesic made of luan plywood and aluminum taped edges
  5. Over that—a removable thin 4v shell
  6. Bonus: finally a sock over that that could inflate to a compound curve.
If the front wheels were in blisters a 4x10ft model would be half-scale. A Vespa front fork would be a good match for the Westphalia wheel size.

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Old 09-02-2015, 06:57 PM   #12 (permalink)
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parking

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Originally Posted by freebeard View Post
I'm taking this semi-seriously. The biggest intellectual hurdle is figuring out where I would park the thing.

I want to put a hitch on my car and restore the Westy trailer anyway, and it has a steel frame supporting a plywood box. The tongue and axle bolt together and there is a 2x2" wooden joist supporting the back of the box. Deleting the box would make it a dolly. The tongue is 3' and the axle is 53" to the outside of the trailing arms. The wheels are 16x5".

Your wheels are smaller, and you plan on four, right? I was thinking of a towable model but to match your dimensions it would have to be trailerable.

My thought experiment is hang a flag on a long pole off the back of a short trailer. When the tow vehicle turns the trailer will follow, but the flag will be tangent to the curve and outside it. The steps would be:
  1. Add a trailer hitch (and take the chatter out of the clutch)
  2. Restore the Westy trailer frame (new elastomeric snubbers and bearings)
  3. An asymmetrical pyramid made out of angle iron from Hollywood bed frames
  4. A two frequency geodesic made of luan plywood and aluminum taped edges
  5. Over that—a removable thin 4v shell
  6. Bonus: finally a sock over that that could inflate to a compound curve.
If the front wheels were in blisters a 4x10ft model would be half-scale. A Vespa front fork would be a good match for the Westphalia wheel size.
Any Wal Mart will allow overnight 'camping' in their parking lots.
The larger LOVEs truck/car stations allow overnight stays.(if you park near the 18-wheelers,their engine noise drowns out distracting noises)
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Old 09-02-2015, 08:15 PM   #13 (permalink)
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Hold on. I need to start with a trailer hitch.

....or maybe do 1/3 scale and put it on a roof rack.
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Old 09-03-2015, 11:49 AM   #14 (permalink)
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How about lopping some of the tail off the template to simulate what is most often done with tails in the real world? Or is that well enough established?
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Old 09-03-2015, 12:56 PM   #15 (permalink)
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The question to be answered by my following aerohead's dimensions would be the difference between a pointed tail like The Template and a rounded tail like the Dymaxion.

Truncations are do-able. Or one could add a strap-on cone, while [re-]considering the fineness ratio.

The larger question is the effect of creases in the surface. A 3v sphere has a break angle of 360/20 or 18°. A prolated sphere will be sharper at the ends and smoother in the middle, with the limit case being a compound curve. I want to see if there's any 'dimple' effect with the lower frequency. A 2v would be about as angular as the F-117.

Last edited by freebeard; 09-03-2015 at 01:02 PM..
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Old 09-05-2015, 12:39 PM   #16 (permalink)
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lopping off

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Originally Posted by ennored View Post
How about lopping some of the tail off the template to simulate what is most often done with tails in the real world? Or is that well enough established?
I want to verify the shape exactly as drawn.If I can fit it into the schedule,I'll do removable tail sections,but that doubles the difficulty in fabrication at this scale of build.
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Old 09-05-2015, 12:44 PM   #17 (permalink)
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truncations

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Originally Posted by freebeard View Post
The question to be answered by my following aerohead's dimensions would be the difference between a pointed tail like The Template and a rounded tail like the Dymaxion.

Truncations are do-able. Or one could add a strap-on cone, while [re-]considering the fineness ratio.

The larger question is the effect of creases in the surface. A 3v sphere has a break angle of 360/20 or 18°. A prolated sphere will be sharper at the ends and smoother in the middle, with the limit case being a compound curve. I want to see if there's any 'dimple' effect with the lower frequency. A 2v would be about as angular as the F-117.
I've been struggling with an English translation of Kamm's research and what I can say is, 'don't do 'rounded' truncations.Make the cut as if you'd do it with a bread knife.Straight chop.
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Old 09-05-2015, 02:03 PM   #18 (permalink)
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Quote:
Originally Posted by aerohead View Post
I've been struggling with an English translation of Kamm's research and what I can say is, 'don't do 'rounded' truncations.Make the cut as if you'd do it with a bread knife.Straight chop.
One of the forum members once tried a rounded trailer rear - it made it rather unstable.

You get Coanda effect as air flows over the rounded surface, pulling at the surface trying to lift it.
As the air flow is never even L/R it pulls more on one end, then on the other ...
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Old 09-06-2015, 10:39 AM   #19 (permalink)
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Quote:
Originally Posted by aerohead View Post
I want to verify the shape exactly as drawn.If I can fit it into the schedule,I'll do removable tail sections,but that doubles the difficulty in fabrication at this scale of build.
Make the model full length and then cut a 20% truncation and tape it back together.
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Old 09-06-2015, 12:44 PM   #20 (permalink)
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Double bulkheads at the point of the slice, for strength.

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