User:Vincecate/Models

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Revision as of 04:07, 26 June 2008 by Vincecate (talk | contribs) (Problems)
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PVC models planned:

  • Tension Circle House
  • Versa Buoy - maybe a triangle - 3 pieces of 3.3 feet each
  • Pipe Spar
  • semisubmersible - can have square of pipes underwater and legs sticking up
  • catamaran
  • raft made by lashing pipes together - 5 pieces with 2 cross pieces underwater (120-(2*12)/5= ~19 inches for 5 pieces
  • beach ball half full of water - kind of the givens life raft design.

Idea is to use about the same amount of pipe in each model so they are sort of cost comparable and then test them all in the waves at the same time. Expect to have waterproof camera around July 10th.

I am going to assume migration makes 25 foot waves the largest we have to deal with because with a 1:25 scale model that makes for a nice round 1 foot wave.

A 75 meter pipe spar is about 250 feet, so scaled down we would use 10 feet of pipe.

If I use 2 inch pipe that is like 50 inches in the full scale version.

Force for Scale model speed testing

The force on a scale model should scale with the mass, which is with the cube of the scaling factor. So for a 1/25th scale model, the force should be 1/15625. So we have:

  8 ton kite -->  1 lb
  16 ton kite --> 2 lbs
  32 ton kite --> 4 lbs

Weights from a weight set or a gallon jug filled with the right amount of water could be a good weight. With a known weight being pulled down by gravity you can provide the same force to the model by connecting a rope between the model and the weight over a pulley. Just have to keep pulling the pulley forward at the right speed so that the weight stays between the pulley and the ground or water. With my Hobie pedal powered kayak I think this will be easy enough.

With speed results from this we can see how fast such a kite could pull a full sized seastead. This will tell us if the migration idea is plausible.

Problems

  • normal sched-40 fittings are heavy (elbows, Ts, etc) - try to find lighter ones
  • not clear 10 feet of pipe can make some of the designs clear 1 foot waves (or even 6 inches)
  • what to use for ballast - washers, cement, water