CONTROL LINE AEROBATICS
Frank McMillan — 12106 Gunter Grove, San Antonio, TX 78231
When I started writing this column almost 13 years ago, I had no idea how long my tenure would last. I thought I'd do it for a year or two, until the ideas stopped coming. But as time passed, I kept making mistakes and solving problems, so there was material of interest to share. By now, you're probably wondering where I'm going with this. As in all things, there is a beginning and an end. The time has come for me to conclude my stewardship. This will be my last column.
As I discussed this with Bob Hunt, he said it would be appropriate to survey where Stunt has gone in these years. It's amazing when you consider the breadth of change that is not so apparent in the short term.
Nationals and competition
One significant change has been the evolution of the Nationals (Nats) format for competition. I focus on competition because that is what fuels technological development, which is what provides everyone with the kits, engines, etc. that work so well.
The first change was the addition of the Advanced class, which allowed even competition among less-skilled fliers. At the time, I really didn't favor the additional class. However, I was wrong big time! From the start it has attracted more fliers. It has even evolved from the initial single day of competition to three days, paralleling the Open competition.
To flesh out the skill levels, there are Beginner and Intermediate classes. Beginner even has age categories. One neat experience was talking to a 65-year-old Beginner at his first Nats. Watching all the fliers on a cool Midwest morning, with the green grass and blue sky, is a picture I'll always remember.
- Advanced
- Intermediate
- Beginner (with age categories)
You cannot buy the winning model and you cannot wish the winning flight. There is a worthy group coming up to take the place of the current top competitors, if they are willing to "pay the price" and work.
Materials and construction
Technology, of course, has leaped forward. Certainly the models have progressed, but if you look at the airplanes you'll see that the aerodynamics are similar to the best of the classic-era models. The looks have changed, as have construction techniques. Composite materials have been integrated into construction, but not nearly to the extent most of us envisioned in the 1980s when the materials became available.
We have seen only one composite wing at the Nats thus far, although a commercial venture with a Nomex® honeycomb molding is under test. A molded carbon-cloth fuselage has been used in Nats competition, and an entire molded model has been offered for sale in England. The limiting factor to general use, aside from high cost of materials, is the technology to achieve comparable weights to balsa for an entire airframe. Individual parts have successfully been molded and used. Time will tell.
Engine development
Engine development is another story. When I started my column, most were flying the lightweight SuperTigre 60 in varying degrees of tune. It was, and is, reliable, with good characteristics. A few were pioneering tuned-pipe augmentation, much to many doubts. However, the technology was there and it did work. The equipment improved, and the word spread. It couldn't be denied. As good engines and newer pipes were developed, everyone was able to achieve good performance. It's not over; newer engines are under development and should be available soon.
The newest approach to engines is the four-stroke revolution. For many years they have been used successfully in Europe. Several were flown at the past Nats, with more to come this year—even by former National Champion Paul Walker. The typical comments I hear are that four-strokes have tremendous torque and run at a steady, comfortable speed. They are easy to fly, making converted airplanes easy to handle. Many have tried them and found they like the four-strokes better than anything they have used.
Be advised that, as with the SuperTigre 60, pipes, and any other engine setup, four-strokes have their own set of requirements. Again, time will tell.
Propellers
Another area in which there is still more magic to be gained is propellers. It seems that the more I know, the more I learn how much I don't know. Just because a particular propeller or pitch profile works doesn't mean you should stop there.
There are two things you have to please: the airplane and the engine. Some days it works, and other days you have to adjust—just a little more or less pitch, more blade, or larger diameter. Keep experimenting; you will be amply rewarded with increased performance and earned knowledge.
Acknowledgments
Through the years I've been so fortunate to have had many good friends and helpers. Without them, I would not have gained whatever knowledge and skill I have accumulated.
I must thank my wife Marilee for her unwavering support in this endeavor. My sincere thanks also to:
- Al Rabe
- Keith Trostle
- Bob Hunt
- Bill Werwage
- Randy Smith (for his superb equipment; I would be long retired if not for his engines)
- John Hill (my coach and good friend, for his endless patience)
Well, it's a spring morning in South Texas. I have airplanes to work on and painting to do. Hopefully the wind will allow some flying today. Fair winds and good flying to all.
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
