RC Flying Today
70 Froehlich Farm Road, Hicksville, NY 11801
Abstract
- 1. AMA, model design and sport fliers
- 2. AMA and youth
- 3. Model airplane design aids
AMA: Origins and Mission
AMA is an association of sport fliers, but it didn't start that way. AMA was launched as a scientific and educational organization. The aim was to teach boys and girls to design model aircraft scientifically. AMA competitions were designed to reveal which boys and girls best understood the science of aviation, as demonstrated by the performance of their creations.
Winning the Nats was evidence of academic achievement as well as of craftsmanship and flying skills. That's why AMA was named the Academy of Model Aeronautics. An academy is a place where scientific knowledge is exchanged.
Charles H. Grant was cofounder of the Academy of Model Aeronautics. For an idea of what the founders were thinking, examine a copy of Aero Science of Free Flight by Charles Hampson Grant (1983; first published as Model Airplane Design and Theory of Flight, 1941). You will find data, graphs and complex equations, all for the purpose of designing gasoline- and rubber-powered models. Available from: Charles H. Grant and Associates, 10 Cottage Street, Manchester Center, VT 05255.
That book was written when famous fliers (like Al Williams, Jimmy Doolittle and Amelia Earhart) were college educated. The pilots who survived did their best to understand everything. The media glorified the educated pilots. Today, commercial pilots have college degrees.
The AMA boys and girls grew up, found other interests (like fighting wars, working for a living and raising families). Very few of them went on to become engineers and scientists. Some returned to model aviation as a sport, using it to show off physical skills, like making a perfect touchdown.
As they aged, they talked about companionship (like football players). Middle-aged people now make up more than one-third of AMA membership. Many of them joined with an ARF (almost-ready-to-fly) for the sport of it. That's RC flying today: sport flying, kit-builts and ARFs that function like factory-made footballs.
Over its 50+ years of existence, AMA became a protective club composed largely of sport fliers. The AMA office has worked to keep government from interfering with model aviation. AMA promoted helpful things such as pull tests for control-line models, mufflers for engines, insurance and license-free channels for radio control of models. AMA kept lines of communication open with the FAI, FAA, FCC and other government offices so they'd know that we exist.
AMA and Youth
"Where are the youth?" is a song that has been sung since WWII. The simple fact is that the romance has gone out of aviation. Without romance, how can we expect to attract youth? With the exception of The Right Stuff, can you think of a movie glamorizing aviation as it is today? None of the Airport series did it.
When half of the current AMA membership was young, they could go to an airport where they could see and touch airplanes and talk to pilots. Today, an airport is a place where you only see airplanes overhead. Most of the time, you only know airplanes exist by their noise and by contrails in a blue sky. As far as kids are concerned, real airplanes burn kerosene and don't have propellers on the nose.
The Delta Dart program is a reminder of AMA's purpose to attract youth into the science of aviation. AMA has nothing to keep them there. Show me that unsubsidized teenagers can compete with adults' factory teams in the annual Nationals competition. I know about the AMA scholarships, but I don't think they are advertised well enough. Have you seen any article in Model Aviation that inspired youth to compete for the scholarship—to earn the academic recognition, rather than the money? Have you seen anything extolling the academic prowess of the winners?
Editor's note: See "AMA News" in this issue.
Compounding the problem, the Walsh-Healey Occupational Safety and Health Act of 1976 created OSHA and a whole new opportunity for lawyers. When a manufacturer chose to improve a light airplane, lawyers started grabbing for his money, based on the idea that "If you didn't build it wrong in the first place, it wouldn't need fixing now." The price of a light airplane doubled almost overnight and most of the increase was the cost of the manufacturer's liability insurance.
So many light-plane manufacturers went out of business. OSHA and the lawyers made the workplace safer by eliminating it. Exit another opportunity in aviation for the youth.
Never mind that all history records is development. Nothing is (or ever was) perfect. Nothing happens in a perfect world, because perfection prevents change. In the real world, hundreds of thousands of people have died from eating bad things. That's how the human race learned which of the earth's plants and animals were safe to eat. It is unfortunate that flower gardens are full of poisonous plants and that bee stings kill some people. Should we kill all the bees?
We have let the lawyers and media redefine our world. "Survival of the fittest" means survival of the quickest, smartest, best informed, healthiest and most physically perfect. I trace the United States' decline in the world to the fact that we have let them shift our attention away from those facts, despite all the evidence that stupidity is the unpardonable sin of our world. What human being intent on survival is stupid enough to "do drugs" or kill brain cells with alcohol?
Put the pen down! One of the people I most admire is Stephen Hawking (A Brief History of Time). The fact that he has done so much in science, in spite of his disability, is wonderful. I wish I had done as well. I feel angry about his disability. In a just world, Lou Gehrig's Disease wouldn't exist. But this is the real world.
Design and Mathematics
I try to educate with my little essays. They should use more math, because mathematics is one of the languages of science. If you can't speak math, you can't understand or be understood by scientists. I have avoided using mathematics in this column for years because so many AMA members are afraid of it. We must be entertaining and include pretty pictures in order to entice them to read the words. I've yet to learn how to write mathematics entertainingly.
Let's say you want to design a model Jump Jet. First problem: there's nothing you can copy. You've got to build a mathematical model first (wing area, weight, power, etc., in the correct equations), then see what it does. We won't jump into the math right here.
If you are interested in a modern version of Mr. Grant's book, you can buy Model Airplane Design and Performance by Howard L. Chevelier, P.E. (1993, $25, Challenge Engineering, Inc., P.O. Box 67, New Baden, TX 77870). It contains many drawings and explanations but very little math. Building a valid mathematical model takes work.
An alternate approach is to follow an expert through every step of the design process. Write down an "expert" computer program that does exactly the same things. To solve the problem, you run the program and fill in the blanks. What's lost from the design process are the underlying assumptions and simplifications, which can be critical in some situations. An expert program for a hammer will produce a poor screwdriver.
The real reason for writing expert programs is to help you do what the expert does. He or she will repeat the same calculations, exactly the same way, as many times as necessary to look at all ranges and combinations of variables. The purpose is to optimize the design. The process is called iteration. The expert program does the mathematical "dog work," time after time, without making mistakes. Computers excel at iteration.
Expert Programs and Software
If you'd like to try an expert program, look into Electro Flight Design by Kress Jets, Inc., 500 Ulster Road, Saugerties, NY 12477. It hides the math behind the menus. You could do worse than print out the glossary in the Help file. It will tell you what Bob Kress means when he uses a term like "drag bucket." Someone else, in another book or program, may have an entirely different concept.
Definitions are a universal problem because people apply different meanings to common terms. Look up "flat" in a dictionary; you may be surprised at the multitude of meanings people have given that three-letter word.
I work with words. My bookshelf holds several kinds of dictionaries (English, electronic, medical, scientific, foreign languages, etc.). My computer has several more built into the software. I usually know what I write, but I never know what you read.
Getting back to the Jump Jet design, you can use Electro Flight Design to investigate thrust available from various motors and propellers, varying (for instance) propeller diameter and pitch, rpm, gear ratios, battery pack composition, etc. This program wants to define an electric-powered, propeller-driven airplane. You'll have to make some assumptions to use it on the Jump Jet.
Since you know that you need a thrust-to-weight ratio greater than 1.0 to get off the ground, you can quickly find the best propeller and rpm for your estimated model weight without spending money on a cut-and-try method. If you want to use a glow engine instead of an electric motor, you can use 700 watts per horsepower to find the equivalent engine.
Once you have enough thrust to lift your assumed weight into the air, you can do another calculation (based on wing area, weight and power) to define the model and propulsion package for level flight. Experience will tell you whether you can build the model light enough and strong enough to fly, because none of the above references will help you with that.
Recommendations and Closing Thoughts
Getting back to AMA, I think it should place greater emphasis on its original purpose: to promote education. For example, AMA should obtain FCC permission for telemetry from RC airplanes and publish articles by people who have succeeded in doing that. The last scientific articles I recall were Maynard Hill's articles on the electrostatic stabilizer.
You may disagree; you may like AMA as it is. Write your District VP to let him know what you think. Before you jump out of AMA to protest something, think: who else will fight off the governments that are trying to eliminate model aviation? Who works with the FAA and FCC to preserve your ability to fly RC? Who's your friend?
Transcribed from original scans by AI. Minor OCR errors may remain.
