Fibre Glass Undercariages

[MIKE S]

Over the years I have used a number of ready made plastic undercarriages. Most are made from laminated glass fibre mat or Carbon Fibre sheet. The problem with these are a weakness at the bend. The strength of both carbon fibre and glass fibre is in the strands, when these are woven in to a sheet, they give strength in all directions, For an undercarriage you need the strength against bending. Also when a number of sheets are laminated , they often split apart at the bends. One can buy fibre glass strand, like rope. If you laminate this lengthwise in a mould, plus a few strands across, it makes a very strong assembly which should take a lot of hard landings.

 

Remember that when a plane lands on rough ground the undercarriage tries to bend backwards with considerable force and leverage. Think how much leverage you can apply to a 40cm spanner. Many ARTF models have a simple plate glued to the fuselage sides. It has no hope of resisting the bending force from a hard landing. Reinforce it with verticals up the inner sides or bend up a metal "U" to spread the load.