Much more attention is paid to designing the skids for model aeroplanes in America than abroad. Since the American model usually rises from the ground under its own power, this detail of construction naturally has come to be of vital importance. By attacking the problems faced by the designers of large aeroplanes, our work is helpful in developing the science of aviation as a whole.
Nothing has been found better for building skids than cane or bamboo. A chassis may be made of these materials which will weigh but a fraction of an ounce, so that even the most elaborate skids will add but little weight. They are, besides, exceedingly elastic, which makes them easy to work, while this quality enables them to take up the shock of a violent landing. The thinnest sizes are best for our purposes. The reed one-eighth of an inch in diameter will answer for all ordinary models. To prepare reed for working, soak it for an hour. Another plan is to heat it slightly over a flame, when it may be bent with little danger of breaking. In case of a bad smash during a meet such skids may be readily pieced out and repairs made so quickly that the model need not be kept long out of the contest.
A model with limited plane area built by R. Barry
An interesting experiment in metal frame building by R. Fisher
The simplest skid is made by splitting a section of reed, or splicing it, to form a Y, and attaching the upper ends to the bottom of your motor base. The lower end is then bent into a half circle. Wrap the reed tightly at the crotch to keep it from splitting, and touch the wrapping with glue. To make such a skid stable, join the two pieces by a cross brace. The skid should slant backward at a slight angle to reduce the friction on starting. Several methods of bracing such a skid are suggested in the accompanying photographs of models.
A stronger skid is formed by turning the reed to form ellipses and attaching them to the motor base. The curved parts will require bracing. Two diagonal braces will keep them in position. Some model builders prefer to shape the skids at the bottom, so that only a single point of the reed comes in contact with the floor. This plan makes it possible to shape the skids into several graceful forms which help to make the model attractive.
Still another plan, followed by some of the most successful model builders, is to shape the skids like the runners of a sleigh. In some of the Percy Pierce models this year, about six inches of the rear skids come in contact with the ground. It might be supposed that the friction in this case would be considerable, but this particular model is one of the quickest to rise. This design has the great advantage of being extremely elastic and letting the rear of the model down gently after a considerable fall.
Some model builders still retain the wheel skid in a much simpler and lighter form. The miniature bicycle wheels do very well for scale models, but since they are likely to add an ounce or two to the weight of the aeroplane, they are prohibitive. To avoid this weight, the wheels may be made of simple disks of wood cut very small. A wheel one-half an inch in diameter, cut from a board one-eighth of an inch thick, weighs practically nothing and affords sufficient support. These may be mounted very simply on axles made of bent wire attached to the feet of the skids. Sandpaper the rims to an edge in order to reduce the surface presented to the air. Since their surface is edgewise to the line of flight, they will offer very little resistance.