Ray’s Rant # 9 November 1, 2015
THE TAIL OF A MODEL AIRPLANE
The Tail Feather’s, they are more than around for the ride.
In the early years of building model’s, I would build the fuselage first, then the wings, and lastly the tail feather’s. Most kits today have you build the tail feather’s first, then the wing, and then the fuse. And they have their reasons for that, I suppose. I find it hard to change habits I have had for years, so still usually follow my path for building a model.
In looking at the Wright Flyer that introduced heavier than air flying, we find that the elevator was on the front, and the rudders on the back. In looking at the setup, it may have had to do with the balance of the airplane. Even the pilot lay down to fly using his feet to operate the rudders. The engine was centred, and the props were run by a series of chains. Eventually the aircraft took on the form we are more familiar with today. The tractor engine was at the front, with propeller attached, and the Centre of gravity was about 25-30 % of the wing cord.
The tail feathers were grouped at the back of the fuselage. The tail feathers are a very important part of the total airplane. What we refer to as the fin and rudder are really called the vertical stabilizer, and what we usually call the stab is correctly called the horizontal stabilizer. They perform important functions in flight. The vertical stabilizer keeps the plane on a steady course straight ahead, and the horizontal stabilizer keeps the plane on a level flight course.
Because of the position of the tail feathers so far back on the fuselage, care must be taken during construction not to build them too heavy. They have to be strong enough to take all the vibration and forces on them, yet light enough so that little compensation is needed during balancing. Every ounce added at the tail, would need four ounces added to the front. If you are building a kit, follow the instructions carefully, and don’t use heavy wood.
The vertical stabilizer can have many shapes to divide up the fin area. Some planes like a Beech 18 have two small fin and rudders, one behind each engine.
The advantage of two small fins over one big one, is less drag as the area of two small ones is less than the area of one big one. Some planes have a large central fin, and a couple smaller ones on the outside, like the Lockheed Constellation. The DH Otter has quite a large fin and rudder, compared to the Beaver, and so does the CL 215/415, this is needed for stability while picking up water. Even some float planes required sub-fins to offset the side area of the floats.
Away back, you could tell the make of many airplanes by the shape of the fin. The De Havilland series of Moth biplanes are easily identified by the shape of their vertical stabilizers .The Norseman and the Stinson’s were easy to identify, and so was the Mooney’s.
This comes to an end of the series on building wooden models. During my years of building models, starting with rubber powered ones, I built mostly scale models, rubber powered, but in the early years not many of them would fly like my imagination thought they should. In fact, it was only a few years ago that I built a rubber powered model that did fly, I think it stayed up about 45 seconds and made many circles before the rubber motor ran down, and she landed. Maybe the fact that it wasn’t a scale model had a lot to do with it. I had a lot of pleasure out of that model over the last few years, without much building. I like working with wood, as I have become familiar with it, and how to build with it, and at my age am unlikely to change to something else.
There is nothing wrong with the new materials of themselves, it’s just that us oldsters find it hard to change from what we get our pleasure and enjoyment from. Hopefully, kits will soon return, along with the desire to build a certain favourite we may have. There are plenty of plans around from many of the old timers up to the modern age, and by learning how to make them will bring a lot of satisfaction in your following of this hobby. Building season is upon us, and soon the shops and basements will get busy, making a new model for the coming season.
I want to do a series on the theory of flight next, to bring up some of the basics we should know, to improve our skills.