Ray’s Rants #2

Ray’s Rant, #2

In the first rant, we looked at some problems we encounter in building models. The problem of weight and strength. We could make a strong model, carving one out of oak, even hollowing it out so the sides were quite thin. Even with a strong engine, it probably wouldn’t fly.

The size of a model becomes an important part in picking a project. Generally speaking, the smaller the model, the harder it is to fly it. Until we got the miniaturization of our radio gear, our radio control models had to be quite large, to be able to even get the receiver and servo’s into the fuselage. When I started in the late fifty’s and early sixties, the airplanes were really free flight models, with rudder only, then later elevator, then engine control. One of the favourites was called the Smog Hog. I had installed a control setup called “Galloping Ghost” system, and the plane sounded like a thrashing machine coming through the sky.

The elevator and rudder were in constant motion, in neutral, flapping the same up and down, and right and left. When you chose to climb, the elevator flapped more to the up side and less to the down side. It worked once in awhile, I can only remember one good flight with it. Getting everything to work at the same time was a chore, and a successful flight by anyone was a time to rejoice. Radios were rapidly improving, so much that this year’s radio would be obsolete the next, so those of us who could not afford new radio’s would try and get last year’s radio and give it a go. My second radio was a reed radio, and every time we flew we would have to tune it to get simultaneous control (getting the different channels to operate at the same time). They were a big improvement until the mid sixties when the proportional radios of today came along. Radio’s were expensive, costing almost two months wages.

The first really successful low wing model was the Astro Hog, and was still in production a few years ago. It was a six foot model, and a Veco 45 was the preferred power.

Radio’s were miniaturized, and so models could become smaller as time went on.

The problem of small models still lingered, as they were hard to see and control.

Models that could use 40 size engines became the popular ones, as their size made them more visible. I flew a radio-contolled model once with a .049 engine, and it could be flown in a small field, but it was tricky. One of the better trainers around today is the LT40 put out by Sig. It is a good model to use as a basis of the size a model should be. I hope to put in a couple of pictures this time, if I can get the system to work, both are of the same airplane, but of a different size. The larger plane is a Stinson SR5 often referred to as a Straight wing. The smaller one is a Stinson SR6, but they are essentially the same airplane. The smaller one has a wingspan of about 60”, the larger one has a wingspan of 84”. The larger one is a great flying airplane, while in four tries we were unable to get the smaller one to fly. Why? Scale models tend to be heavier, so size plays an important role. I figure the smaller one is too heavy for its wing loading. I built the plane from a kit, and followed the plans and built it accordingly. It used a lot of spruce which made it a heavy model for its size. It would go racing along the ground, and when lifted into the air would turn sharply to the left. It survived the attempt, so we checked to see there were no warps or twists, gave the engine side thrust to try and counter the sharp left turn, but no matter what we did, we never got the plane in the air. The larger size flies like a trainer, and is a joy to fly. So size can matter. You need the wing area to carry the load. Both planes used the clark Y airfoil, which is flat bottomed, and gives good lift, yet one flew and the other was uncontrollable. Given the same radio equipment, but different engines, the larger plane was able to carry the weight, when the smaller one couldn’t.

The small one
The small one
The larger Stinson
The larger Stinson

There is more to consider with this, and I will continue in the next rant. This is enough for now.