Letters To The Editor
All letters will be carefully considered; those of general interest will be used. Send to Model Aviation, 1810 Samuel Morse Dr., Reston, VA 22090.
Our Apologies
As a number of RC soaring enthusiasts may have noticed, there was an error in my Nats report which appeared in the November issue. The error indicated the winners in Standard class wrongly as: first Le Roy Stowers, second Clarence Nikkel, and third Troy Lawicki, with Kevin Webb placing fourth. I had used a printout from Nats News and was unaware I had somehow gotten the places and pages mixed up. My most humble apologies go out to the actual winners, who were: first Larry Jolly, second Orie Adcock, third Robert McGowan, and fourth Terry Edmonds. Le Roy Stowers was fifth, followed by Clarence Nikkel, Troy Lawicki, and then Kevin Webb.
Mistakes of this magnitude are not easy to accept, but hopefully this correction will be a bit of consolation.
Wil Byers Richland, WA
Fortunately the results shown in the "Competition Newsletter" were correct, and so were the photo captions for pictures of Larry Jolly and Terry Edmonds. Alas, Wil Byers had no pictures of Orie Adcock and Robert McGowan, so we asked each of them for a photo of his winning model and a bit of information about it.
O. L. Adcock, Oak Harbor, WA — Open Standard, second place: The photo was taken during the last round of the Standard class competition in which I placed second, 10 points behind Larry Jolly. The ship is a Dodgson Designs Camano with a Schuemann planform wing. It's stock except for that. It's the best-flying ship I've ever had, except possibly for my Lovesong. I also placed eighth in F3B with the Camano, having never flown nor seen F3B before. I'm a member of the Whidbey Island RC Society in Oak Harbor, WA.
Bob McGowan, Fremont, CA — Open Standard, third place: The model is a prototype kit from Flight Lite Composites called the Falcon 800. It is a smaller version of their popular Falcon 880 Unlimited-class sailplane. I used the Airtronics Vision 8SP computer radio for control. This radio has a three-position toggle switch that puts my Falcon into thermal, cruise, or penetration mode at preprogrammed settings. I also use the crow feature (both ailerons up and flaps down) for landing control. The Falcon is a very forgiving ship, and with the Vision radio it's nearly as easy to fly as a three-channel plane with polyhedral; this is very important when under competition pressure. This combination has been performing super for me. I'm looking forward to another great Nats next year.
It's a Skyraider
On page 63 of the November issue, you have Charlie Bauer on final approach in a Douglas Dauntless. The airplane actually is a Douglas Skyraider.
C. Little Baltimore, MD
dB Facts
Your October 1989 article entitled "dB Facts" has one tiny fact wrong. The article states decibel means 10 bels. This is backwards. Deci is a prefix meaning one-tenth; decibel means one-tenth of a bel. The bel is too large to be convenient, thus the use of the decibel.
The article "dB Facts" is so good otherwise that I'd hate to see it besmirched with an obviously wrong bit of information. Thanks to George F. Abbott for an excellent article.
Robert L. Harberson Biloxi, MS
I would also like to call your attention to a very common misuse of the Radio Shack dB meter as illustrated in the photograph on page 34 of the October 1989 issue ("dB Facts" by George F. Abbott). As you can see by the enclosed page copied from the owner's manual, you should not point the meter toward the source such that the instrument is between the observer and the source. The meter will pick up reflections from the observer's body and give a false reading. The meter should be held at a right angle to the direction of sound propagation.
I hope this will help standardize the way we measure sound levels of model airplane engines.
Since the exhaust outlets of mufflers can go in any direction, it seems to me they should be pointed toward the meter for a fair comparative reading (or at least in some fixed direction relative to the meter).
Hugh Harber West Chester, PA
We sent both of these letters to author Abbott for his information and possible comment. His response follows.
Reader Robert Harberson is perfectly correct, and I don't know how I made that error. I know perfectly well that the decibel is one-tenth of a bel; not only does the prefix deci mean one-tenth, if it were ten times the unit, the prefix would be deka, abbreviated da, and we would have to call it the dBa! Thanks otherwise for the kind comments.
With regard to Mr. Harber's letter, we have a little problem. First, while the Radio Shack instructions do in fact recommend against certain orientations, I have tried the meter both ways and have not observed any appreciable difference when readings were taken either behind or beside the meter. The Radio Shack manual also states that you should point the meter at the source. In point of fact, at frequencies below 1 kHz, which are of most interest to us, the electret-condenser microphone is essentially omnidirectional. Even at 5 kHz there is only about a 2 dB difference between zero and 90°. Consequently, for our purposes I doubt if the orientation is of any major importance.
Mr. Harber's comment about the relative position of the meter and the exhaust outlet is very germane. A related question involves taking the measurement over a hard surface, which will reflect sound, rather than over grass, which may not. I personally believe the measurement should be taken with the airplane held overhead over fairly tall grass (five to eight inches) to simulate the free-space situation which prevails when the plane is in flight.
George F. Abbott Raleigh, NC
Transcribed from original scans by AI. Minor OCR errors may remain.
