Sound & Model Aeronautics
Howard Crispin, Jr.
SOLUTIONS: This column has suggested where we need to go to get model aircraft operating with minimum sound levels. Active input from engine and muffler manufacturers is needed, but response has been limited.
A letter to the editor of Model Aviation from Ian MacLaughlin (Escondido, California) echoes this concern. Ian writes that manufacturers claiming quieting performance for engine/muffler systems should state the propeller size and manufacturer, engine rpm, and other key factors used during testing. He suggests beginning by asking manufacturers who advertise in Model Aviation to provide that data.
Irvine is one manufacturer that lists propeller diameter, pitch, and manufacturer for an engine/muffler combination (their Q40 unit). I checked that engine using the APC 10 x 8 propeller specified in their instructions and found the published figures valid. The Q40 is among the quietest engines on the market. Honest, documented testing procedures like these would be of great benefit.
Many other manufacturers advertise good mufflers but do not state how they attained the advertised sound levels. For example, several makers produce .40-size engines; a couple of these can operate in the mid-80 dBA range, but not when run at the high rpm figures sometimes listed (14,000-plus) with small propellers. The apparent lack of specific testing by some manufacturers creates problems for buyers. Those of us who have tested many muffler/engine combinations make a point of stating rpm, propeller size, and propeller manufacturer. Emphasizing maximum output is self-defeating when the goal is acceptable operation within sound-level limits.
Some engine/muffler units have been reviewed here strictly for their quieting capability; those reviews do not attempt to determine maximum torque or rpm. Operating at the very peak (unmuffled, small-propeller conditions) does not result in quiet operation.
K&B Sportster engines are good general-purpose R/C engines and are also used in some control-line applications; when operated under conditions conducive to quiet performance they are among the quietest series available. The quiet muffler available for the Fox .40/.45 is also effective, and several other mufflers have checked out acceptable. However, many products on the market cannot have their performance stated because of a lack of test data.
Most manufacturers either do not have the information needed or hesitate to provide it. The majority of modelers do not need maximum performance; they need flying sites, and quiet operation is increasingly a requirement nationwide. Some manufacturers, especially those producing very large engines, make no effort to offer a range of mufflers. There is a real need for multiple muffler designs to suit various installations.
Suggestions that Model Aviation require this information in advertisements are sensible but likely difficult to enforce. Advertisers place ads across many magazines, so the more practical step is to induce manufacturers to publish the data themselves. At minimum, instruction sheets that accompany engines should list:
- propeller size and propeller manufacturer used for sound measurements,
- engine rpm used during testing, and
- any other pertinent test data.
Another important area is aftermarket muffler manufacturers and distributors, since aftermarket sources are often the only way to obtain a quiet muffler for many engines. Problems in this area can affect product endorsements and overall usefulness to the consumer.
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AMA News
AMA Elections — Nominations Due
Nominations for the offices of Vice President and Districts V–IX are due at Academy of Model Aeronautics Headquarters Friday, July 15, 1995. Any AMA Open member may submit a nomination. The nominee must be a Leader Member of the Academy; a letter of acceptance from the nominee must be filed with AMA Headquarters. For Nats Headquarters the deadline is July 19, 1995.
The nominee must also submit a resume of professional qualifications and model aviation experience. The resume should include, but not be limited to, the following:
- A statement regarding Leader Member status, including date conferred.
- Background in the following areas, as applicable:
- a. management experience
- b. financial background
- c. insurance employment or expertise
- d. legal background
- e. technical background including areas of aeronautics, electronics (especially radio frequency propagation and usage), acoustics as relates to noise studies/analysis, and other areas of engineering
- The nominee's aeromodeling experience.
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Executive Director's View from HQ
Jerry Rouillard AMA Executive Director 5151 E. Memorial Dr. Muncie, IN 47302
Starting with this month's column, the "View from HQ" will introduce readers to members of our Headquarters staff—the administrative team that helps make AMA one of the largest air-sports organizations. These profiles will not appear in every issue, but we will feature staff often enough to introduce the team over the coming months.
This month we feature the AMA Membership Department. Membership is one of Headquarters' largest departments and has the most direct daily contact with our members. The team handles membership processing, Chartered Clubs, Chapters, and Leader Members. On a day-to-day basis they perform the data-entry functions that keep our computer records updated, and they respond to a wide variety of member inquiries, suggestions, and complaints. These are the people who put you on the membership rolls and answer your questions on our toll-free membership hotline: (800) 435-9262.
The Membership Department operates under the general management of Joyce Hager, Director of Operations and Administrative Assistant to the Executive Director. Joyce is one of the four remaining AMA employees from the Reston Headquarters staff and is AMA's longest-tenured employee, recently celebrating her 25th anniversary with the Academy. Joyce handles a number of important responsibilities for AMA; directing the Membership Department is a top priority.
Colleen Pierce is the Membership Department Supervisor, a position she assumed last October. Colleen has been with the Academy less than two years; she served as Club Secretary before her promotion and has earned broad respect at Headquarters for taking on a difficult job during our annual renewal surge. Colleen's duties include overall department management, maintaining consistent workflow, ensuring memberships are processed promptly, and that member questions are addressed as quickly as possible.
The Membership Department operates with three subdivisions: club processing, data entry, and customer service.
- Lois Pierce is the current Club Secretary. A Muncie native, she joined AMA in October 1993. As club secretary, Lois processes and files all Chartered Club and Chapter applications, corresponds with clubs and chapters, maintains their member and officer records, processes internal pilot records, and handles insurance and charter certificates. Twice each year she produces and mails an updated roster for all Chartered Clubs.
- Data entry is crucial to membership processing. Cliff McKee is the Lead Data Entry person. He balances operators' worksheets, processes credit card transactions, and prepares record batches for input to the membership database. Cliff has been with AMA in Muncie since April 1992.
- Other data entry operators are Debbie Briggs (joined April 1993) and Jeannie Hodge (started September 1993). They open membership mail, check renewing member records, and enter new data. They also back up customer service representatives on the telephone during peak periods.
- Katie Phillips and Randa Coats are our chief 1-800 hotline receptionists. They answer and redirect member inquiries and research and solve member problems whenever possible. Customer service is especially demanding during the peak renewal period between October and February. Katie, recently a new mom, has been with AMA since July 1993. Randa started in October 1993.
Of all AMA departments, Membership serves the most crucial function. Whatever happens in membership processing affects all other departments. The Membership personnel are the front line of Headquarters operations and the primary point of contact with the Academy's most important customers: our members.
Transcribed from original scans by AI. Minor OCR errors may remain.
