Build yourself
a cushion to land on! With simple materials you can make an undercarriage
that’s hard to break, and takes a lot of landing stress off
the rest of your airframe.
The classic charm of Golden Age and WWI aircraft has been recaptured
in many of the fine kits and plans available today. But the undercarriages
of these ships are highly stressed in landings – even good
landings - and breakage is a common problem. Unfortunately, many
commercial kits and plans have inadequate setups for undercarriages,
and builders are left to suffer the damage or find their own solutions.
But there’s no need to lose sleep over it anymore! In this
article you’ll learn how to build a springy, shock-absorbing
structure that works quite well for small models.
The sketch on the right illustrates the concept as it might be applied
to a WWI ship (some elements of the undercarriage are omitted for
clarity). The primary load bearing element is a piece of wire, bent
to shape as shown, and firmly attached to the fuselage. Sections of
balsa are epoxied to the wire to form the left and right forward struts.
A small gap is maintained between the balsa struts and the fuse longerons
to permit some flexing.
The rear struts are balsa only (no wire). These attach to the
forward struts with a rubber joiner, which allows considerable
flexing at the joint. The joiner can be cut from a thick rubber
band. The other end of each rear strut extends into the fuselage,
resting freely in built-in slots. These slots might be in the
wing or the fuselage, depending on the model, and will remain
uncovered when the model is finished.
