1/20th scale model CATAMARAN CONSTRUCTION

Aluminium space frame under construction - 1/20th model

The new 1/20th scale model of Solar Navigator is to be fitted with a aluminium spaceframe to replace the current plastic tubing.  This will save around 150 grams and it is hoped, reduce the drag coefficient.

Originally, stainless steel tubing was to be used, but this did not offer the same weight saving, although joining the material was much easier using jewelry grade silver solder and an ordinary plumbers blowlamp.

It was not quite so easy to join the aluminium rod.  However, Multicore came to the rescue with a 5% silver, tin/lead solder with a special flux.  This was supplied by RS.  Some alloys of aluminium do not wet easily, or not at all.  Fortunately Multicore's technical expert, Ian Williams, came to the rescue with tips to prepare the surface of the metal for joining.  We are pleased to say we have now managed to complete a test piece which gave a high strength joint.  The secret is not to apply heat directly to the join, which might then burn the flux.

A new drive train consists of 2 Swiss Maxon DC motors, a 2:1 reduction box.  This should provide a respectable performance from 40 solar panels generating close on 20 watts in fine conditions (peak summer).  The Sun Tracker system is to be incorporated in this model to ensure maximum energy collection.

It is hoped the combined technology will allow us to set model speed and endurance records (beat our own records) in the near future as part of our development of the full size vessel.