Construct RC Planes from a Wide Variety of Materials
RC airplanes built with balsa and foam are popular and fly well
World War I airplane frame made from balsa - an interesting airplane design challenge
There are numerous methods to construct an RC model airplane. The builder’s objective remains the same. Produce a lightweight aircraft structure that is strong enough to stay together when in flight. Model aircraft share the same general components, to include items such as ribs, formers and stringers. Various sized models require differing types of aircraft components. This is the fun and challenge of radio control model aircraft design and construction. The main point is to study and emulate success in other modeler’s aircraft and incorporate into your model plane designs.
Keep structures light
The central goal with RC model airplane construction is to keep all the structures as light weight as possible. Whether you are flying a micro indoor RC plane or a giant scale model, extra weight is the enemy of good performance. There is simply no downside to making your model aircraft as light as possible.
Demoiselle's lightweight balsa fuselage
The key to RC airplane construction is selecting the right building material and employing sound building methods. Balsa has historically been the model airplane building material of choice. Balsa is affordable, readily available, and comes in a variety of strengths (otherwise known as density). Balsa is very easy to work with and can be used for airplane structure (such as wing spars) as well as wing or fuselage covering (sheet balsa). Balsa is ideal for park flyer designs.
ParkZone Cessna 210 micro RC airplane
With the rapid introduction of ready to fly micro-sized indoor radio control model airplanes, foam is the building material for many RC modelers. Foam comes in a variety of styles and lends itself well for factory produced models. The ParkZone Cessna 210 is a superb example of a ready to fly lightweight foam model. Hobbyists can use foam to construct their own designs, whether from home insulation foam to thin Durobatic foam. Building techniques for foam differ from balsa. Foam requires specialized glues and paints. For smaller foam models, carbon rod reinforcement is often required to ensure strength in such areas as wing center joints and motor mounts. The rods can be used to reinforce the foam structure itself, or externally as support struts.
Electric motors for RC flight
Electric motors provide vibration free power. Much of the structure of an RC model aircraft in the past has been required to properly secure and support the gas motors used to power just about every RC aircraft flying. The smooth operation of an electric motor mandates significantly less aircraft structure. Less structure equals less aircraft weight. And the need for less model structure gives the RC model plane designer further options towards removing unnecessary weight from the typical electric RC plane.
Chickadee wing mount and fuselage tubes
A good example is the wing construction method I employed for the Chickadee and Finch. As these models are designed to fly at slow airspeeds with no stress inducing aerobatics, I used the wing leading and trailing edges as structural members. In effect, the wing’s leading and trailing edge balsa dowels function as spars.
For these two aircraft, there is no way that the 1/4” balsa dowels would provide sufficient strength where the wing plugs into the fuselage metal support tubes. The wing’s balsa dowels would quickly break under any sort of flight load. To prevent this from happening, I spliced in 1/16” plywood reinforcements to the balsa dowel. This approach has worked well, and is a good example of adapting the building materials available for your RC airplane production.
Observe modeling techniques
As you develop your model building techniques, keep track of the way other RC airplane designers have solved various construction challenges. For example, I followed the method used on the Sig Demoiselle for the wing construction (leading and trailing edge balsa dowels) for the Finch and Blackburn, to include the metal tubes used for mounting the wing to the fuselage.
Model airplane wing construction using diagonal ribs
I often take pictures at trade shows of how various model airplanes are made. Designers come up with some very original ideas for wing ribs and spar arrangements, mounting of wings and placement of radio equipment.
In this day and age of rapid advances in micro RC equipment, motor systems and RC airplane construction techniques, the way ahead is to learn all that you can from others and build on their success. Consider the use of free RC model airplane plans for your next project. Some of your model aircraft designs may not work out as planned, but you will gain knowledge with every attempt. RC Groups is a popular on-line forum which contains a vast source of knowledge for anyone trying to design and build RC model aircraft. The key thing is to experiment. Not every modeling attempt will meet with complete success. But I guarantee that you will learn something and benefit from the process. This is the sure method to move ahead towards modeling success.