PICAVET  III

 This Picavet suspension is hung at 3 points, two of each are on a stabilising bow.

 

The damping is both longitudinal and transversal. The lateral freedom of a normal Picavet suspension which let a transversal balancing movement, or roll, is thus stopped.

 

The energy of any move of the cradle caused by crabbing of the kite being necessarily dissipated, it induces normally with a 3 points hanging a spin movement.

 

The cross of the Picavet III is H shaped with two spread braces designed such as this energy is not spent by spinning. There is a compromise between roll and pitch, the roll being almost entirely annihilated At the end, the cradle is following the final circular and slowed movement of the simple pendulum.

Rigging

 

The stays are constituted of two monofilament nylon  lines Ø1mm and 2 m long each. The ends are heated with a lighter to form a small ball which will act as a stopper.

Each line is set in A at its middle with a lark knot. The strands of the first line are running along ALY and ANZ while those of the second one are running along AKY and AMZ. The ends at Y and Z are tied with a running knot or a constrictor knot. Loose the knot to bring the strands from Y and Z to B when storing.

Note the lines AL and KY crossing at p and also AN and MZ crossing at q. For this, KY and MZ are running inner, AL and AN are running outer. Small rings can be added at p and q.

 The construction of this cradle is rather easy:

The main beam AB 400mm long is constituted with an aluminum U section 8x8x1mm and a U section 6x6x1. The cross bar YZ 300mm long is a tube Ø8. The hook and the guide are made of titanium rod Ø2,4mm. The junction of the main beam and tube is reinforced with wood inside and with a U outside 10x10x1 45mm long which are epoxy bonded. Then the tube is slided in the drilled hole and fixed with a screw. The ends of the tube are done with a pipe nock Ø6 and a plastic stop Ø10 also epoxy bonded.

 

This view shot underneath.

 

The cross comprises a transversal U section 10x10x1 100mm long and two tubes KL and MN Ø6mm 200mm long and bent. Distances are KM = 90mm and LN = 150mm. At the center of this bar  the axle of the cradle is a Ø4mm aluminum rod 30mm long, on which is set a Ø6x1 tube 40mm long and another Ø8 tube 10mm long. The whole is fit by riveting.

The two tubes KL and MN run through the U and are riveted. The guides are made of titanium rod Ø2,4mm 70mm long, bent, inserted in the ends of the flattened tubes which are then hammered down.

The stabilizing bow is made in two parts 500mm long each.see the page bow-stab for the details.