Ray’s Rant #5 August 9, 2015
Some modelers are more builders than fliers, and are challenged to create history in model form. With the war on, and the Battle of Britain taking place that summer, many of us boys turned our eyes toward the sky, and longed to reproduce the airplanes we saw, in model form.
It was about the summer of 1940 that I discovered the world of rubber powered models. In a store window on main street were displayed a number of finished models, probably a contest and these were the ones modelers put in. It opened my eyes to the possibilities of not only making models, but ones that would fly.
I was introduced to a lot of new things; LePages model airplane cement, model plans, and how to read them; razor blades that were sharper than pocket knives; dope; and tissue paper, to name a few. It took awhile for us to learn to read plans, so we could reproduce the model we liked. I am attaching an insert placed in a model kit of the early 1940’s. Just about all you needed to know to build the model is on this instruction sheet. Besides this sheet, there were a set of plans to build the actual model from, plus the wood, prop, rubber, tissue, wheels and parts needed to complete the project. This was the beginning of a long learning curve, and this training proved its value years later when I took my airframe course in the Air Force, as many of the airplanes up to the mid-thirties were built this way, steel tubing taking the place of the balsa wood. This type of construction comes out light, strong, and flyable, and lent itself to modeling many airplanes of similar construction. We had to build two sides for the fuselage, one on top of the other, with wax paper in between them. You learned quickly that the wax paper was very necessary. Once this was done, we would pin the two sides to the top view of the plan, and put in the cross pieces, starting and the centre, where three or four would be the same length. Once the glue dried, we would bring the tail end together, then insert the rest of the cross pieces to the tail. Then we had to bring the nose section together, keeping it square, and put in the front formers, and bottom cross pieces. At this point we learned another valuable lesson. That lesson showed us the necessity of making sure the four longerons (the longitudinal member of an airplanes fuselage)were all of the same hardness and flexibility. If they weren’t, you ended up with a fuselage that looked like a banana, because even if you pinned them straight on the plans, once removed, the stronger longeron would go back to its straightness, as the softer one on the other side would bend easier. It is important to pick four pieces, usually 1/16th square for the small rubber powered models (1/4 square on larger models) that are very much the same to prevent this from happening. The sticks you pick also have to be straight, use the others for the short pieces. In using this type of construction in a RC model, it is equally important to pick out similar wood strips, so the fuse will come out straight. The weak points in this type of construction are the number of butt joints, because of the small gluing area. Also, we need to introduce triangulation to keep the fuse square, and not a parallelogram. By adding another piece to cut the square into two triangles, (drawing on the attachment) you significantly strength the structure. To overcome the weakness of the butt joint, we can add a triangle piece on each side of the joint, top & bottom (see attached drawing).
On larger radio controlled models, we can use 1/32 plywood caps, as illustrated, to strengthen the fuselage. These details are usually on the plan, to show you where they are needed. On some models I have, such as the Flybaby, and my Fox Moth, the sides of the box, and the bottom of the fuselage are sheeted with 1/16th balsa, which comes out light and strong, and the joints are strengthened in this way.
I like building models that are practical scale models of the planes I like, using this style of building. By substituting balsa for the planes style of construction, you can easily come up with a wood model, that resembles the full scale one you want to replicate. It may be a bit more work than other styles, but the result is a light, strong model that is a good flyer.
We will look at a different style of constructing, that will duplicate the metal structures of the planes that came along during the later part of the 1930’s and into the war years in the next blog.