Safety Comes First

Safety Comes First

John Preston

Response to Reader Questionnaire

In the March 1986 issue, I included a questionnaire that might improve the safety of RC flight operations. These suggestions were made by Dave Abbe, a California modeler, in a letter he wrote to Bill Northrop, publisher of Model Builder magazine. Bill published Dave's letter in his "Workbench" column in the November 1985 issue of MB. Compared to other solicitations for readers' responses that I've had in previous columns, there has been an outstanding number of letters for this one. As I write this (February 28, 1986), they are still trickling in.

Since I wrote that March column, I've received both a letter and a telephone call from Dave Abbe. He has asked me to correct the impression that you may have received by reading the March column that made it seem his letter was critical of AMA. In my opening paragraph I had stated: "Dave cited a number of reasons for the criticism that he aimed at RC equipment manufacturers, the news media, and our national organization." These were my words and were coined from both Dave's letter and a statement by Bill Northrop. To set the record straight, Dave wants it known that he is pro- rather than anti-AMA. The point he was trying to get across in his letter to MB was that safety at the flying field is our concern and, since AMA is our organization, it seems logical that any effort to improve RC flight safety should be spearheaded by AMA. I happen to agree with this.

After I get this column into the mail, I intend to sit down and draft a letter to the AMA Safety Committee summarizing the results of the questionnaire and soliciting their views on the selection of Dave's suggestions that respondents clearly favored. More on that in a later column. Meanwhile, back to the results of the questionnaire.

Thirty-seven readers responded to the questionnaire, but not every respondent provided an answer to all of the questions. So, if you add up the yeas and nays to each question, you will see that, in all cases, the total number of votes cast is fewer than 37.

Many respondents provided comments to support their answers, and I'll pass some of these on to you. But first, a summary of the yes/no responses to the questions.

Analysis of reader response to the questionnaire in the March '86 issue. The RC industry should read this, too.

1. More uniform and informative operating instructions: 25 Yes; 5 No.

1. Should manufacturers standardize the following components for interchangeability:

• 2a) Servos: 24 Yes; 7 No.
• 2b) Batteries: 24 Yes; 7 No.
• 2c) Switch harness: 24 Yes; 7 No.
• 2d) RC format: 22 Yes; 7 No.
• 2e) Other: One response discussed later.

1. Should we require mandatory battery checks before flight at club flying fields: 8 Yes; 24 No.

1. Should we require mandatory checks of any of the following before flight at AMA-sanctioned contests:

• 4a) Radio range: 17 Yes; 6 No.
• 4b) Transmitter & receiver batteries: 16 Yes; 6 No.
• 4c) Control-surface flutter check: 20 Yes; 7 No.
• 4d) Should models over some specified weight have battery redundancy or a fail-safe throttle:
• Battery redundancy: 11 Yes; 5 No.
• Fail-safe throttle: 7 Yes; 17 No.

1. Should AMA-chartered clubs specify pilot locations at the club flying field: 13 Yes; 6 No.

1. Any other suggestions to improve RC flying safety: See discussion later.

AMA Policy Statement

The results of this poll are very interesting and helpful. However, because of the very small number of responses (37 out of a total of approximately 80,000 AMA members who are active in some aspect of RC flying), the AMA would need a greater input to act on any of the questionnaire-item responses. The points addressed in the questionnaire and the tabulated results of the reply will, however, be carefully considered along with all other factors by appropriate AMA officers, boards, and committees to see if further pursuit of these questions is warranted.

Before discussing the comments submitted by some respondents, let me thank Fred Van Keuren of Greenville, MS. Fred took the initiative to poll 15 club members, which is something I thought the March safety column would have suggested.

Discussion of questions and reader comments

Question No. 1. I hope some RC equipment manufacturers read this column and notice that respondents were 25–5 in favor of more informative instructions. From the comments that some respondents provided, it seems that there may be significant variation from brand to brand in the quality and completeness of operating instructions. For example, one reader (who voted No to No. 1) stated that his last radio (Kraft) was accompanied by "very complete" instructions. Having owned a recent model Kraft radio myself, I would agree with this. However, another respondent who voted "Heck Yes" said he vividly remembered being a beginner in this hobby and having all kinds of trouble learning about his first radio, engine, and plane. The radio was his major problem.

I don't believe Dave Abbe's suggestion for better instructions was aimed at modeling products other than radios. However, several respondents voiced displeasure with instructions that accompanied engines. I remember one engine I purchased several years ago that was not accompanied by any operating instructions. The only thing in the box besides the engine itself was a sheet of warnings that told you what not to do and what might happen if you ignored them. A necessary item, but no help in figuring out which is the best prop or what is the recommended fuel, etc.

Some respondents also stated that some model kits have poor instructions. One reader, John Hough (Platte City, MO), included with his letter the "Construction Guide" that accompanied an ARF kit. Although the guide does not say the model is intended to be a trainer, it certainly has the appearance of a typical trainer and may well appeal to a beginner. The construction guide consisted of only three pages, two of which contained a total of four drawings showing "exploded" views of portions of the model with a few captions. The last page illustrated suggested control-surface throws for elevator and rudder together with a picture of a transmitter which showed which stick should operate each of these control surfaces. Unfortunately, the illustrations were for a Mode 1 setup which is rarely used by U.S. RC fliers. John's comment was that the "drawings are sorely missing many real instructions." I agree. The construction guide contained absolutely nothing concerning radio installation.

In my opinion, based on reader response to Question No. 1, there is room for improvement in the instructions accompanying some radios and even some engines and kits. Manufacturers take note.

Question No. 2. As I anticipated, a majority of respondents (over 3:1) were in favor of standardizing components of RC equipment to assure interchangeability. Several stated that standardization is not related to safety. I had thought this myself when I wrote the March column. However, others pointed out that there are a lot of modelers who cannot make a decent soldered connection, a situation which could compromise the safety of their flying if they have changed the connectors on, say, the servos.

I have mixed emotions on standardizing components. I do feel it would be beneficial to the average modeler to be able to use any brand of servo with a specific receiver without having to change connecting plugs. However, manufacturers may have sound technical reasons for not wanting to standardize their equipment. Since none of the respondents identified themselves as manufacturers, I have no way of knowing how industry people feel about this issue.

One reason for having unique connectors was pointed out in a recent letter from Dave Abbe: incompatibility due to different pulse polarity or operating voltage. On the other hand, pulse polarity and battery voltage could also be standardized—I think. I'm not an electronics expert, so any comments would be welcome from readers who are knowledgeable on this subject.

Question No. 3. I anticipated that most respondents would be opposed to mandating battery checks at the club field. In all walks of life, people are generally opposed to mandatory rules and regulations. (Mandatory use of automobile seat belts is a good example.) Typical comments submitted by negative voters were, "It would be nearly impossible to enforce," and "Who would be the policeman at the AMA club's flying site?" One anonymous respondent, writing on notepaper from the Thai Hut Restaurant in Wheaton, MD, stated: "No, absolutely No More Rules." This respondent submitted a comment to Question No. 6 which stated: "It is not more rules that we need, but rather how much knowledge experienced RC'ers can pass on to newcomers to the hobby that will determine how safe our operations are."

In the March column I stated my belief that mandatory battery checks at club fields "might be difficult—or even impossible" to enforce. On the other hand, the Thai Hut Restaurant's suggestion that the experience of the experts needs to be conveyed to beginners to ensure safety is a good one. Many larger RC clubs have formal or semi-formal flight-training programs for new members who are beginners in the RC hobby. I'm going to suggest to such clubs that they recommend to beginners that they purchase an ESR or other battery-condition checking device and use it at least periodically throughout each day's flying session. As one respondent who was opposed to Question No. 3 stated: "Anybody who cares anything about their radio and aircraft will faithfully monitor the condition of their batteries throughout the flying day." I hope this can be said for all of us.

Question No. 4. This was another multi-part question with the first three parts suggesting mandatory checks of radio range, Tx & Rx batteries, and control-surface flutter prior to flying at AMA-sanctioned contests. Since it was again suggested many times in the questionnaire that a majority of respondents were in favor of them, could it be that most of the "Yes" answers came from modelers who generally do not participate in contests and would not, therefore, be affected by the adoption of such rules? The only respondent I recognized as a frequent (scale) contestant voted No to all three mandatory checks at contests. He stated that "The seasoned contest flier isn't likely to arrive at the scene with an unsafe airplane." He went on to state that "The fellow who needs to have his airplane checked for safety is the newcomer at the local flying field, someone who hasn't had long experience and would very likely welcome the check." To some extent, I agree with these statements, although I did witness the destruction of a scale racer (Cassutt, I believe) at a World Championships back in 1974 when it developed severe flutter in one or more of its control surfaces. Whether this could have been prevented by a third party doing a preflight check, I don't know.

I believe a control-surface flutter check is one of the preflight inspection requirements at IMAA-sanctioned events for "big birds." I would be interested to learn if IMAA inspectors have ever grounded a model because of sloppy control surfaces that could have caused flutter. One thing to bear in mind is that most (if not all) RC contest rules stipulate that models being entered must have been previously flown. It is safe to say that if you have not experienced a flutter on previous flights it is unlikely to occur at a contest—perhaps unless something undetected has worked loose in the control system over time.

Question 4(d) had two parts. Most respondents were in favor of battery redundancy in big models but were opposed to fail-safe throttle servos. The question also asked for readers' opinions on the model weight above which the extra requirements would apply. Responses to this latter part were, to say the least, diverse. The suggested weights varied from a low of four or five pounds to a high of 30 lb. The respondent who suggested the low weights and who favored the fail-safe insisted that it should be a requirement on "any plane over about four to five pounds that is expected to fly at about 60 mph or greater."

Several who were opposed to a fail-safe throttle were concerned about the cost of such a feature and that it might be "just another thing to go wrong" in the airborne system. One respondent who was opposed to redundant batteries felt that an automatic throttle cut-off with low battery power would be useful and could be built into the radio. Not having purchased a radio with all the "bells-and-whistles" features, I don't know if there are radios that currently feature a built-in fail-safe throttle. A number of years ago, some radios had this capability and would also neutralize the control surfaces.

As one respondent pointed out, neutralizing the control surfaces of a trainer-type model upon low battery power or loss of signal might save the model. However, it would be unlikely to prevent a crash of a more advanced model that did not possess inherent stability.

I have recommended the use of fail-safe devices to close the engine throttle on big models in previous Safety columns. I recall describing an incident in which a giant model had the airborne battery pack fall out shortly after takeoff. The model was inherently stable and flew 10 miles or so before landing in someone's back yard. A fail-safe throttle could have prevented this fly-away. Although most respondents were opposed to such a device, I would recommend a fail-safe throttle on a big model. As to redundant batteries, I favor these, too. However, if a battery-condition check is performed before each flight, battery failure should be minimized. Do we have as much control over a potential crash due to radio interference? That's the subject of the next question.

Question No. 5. In his "Radio Technique" column in the January 1986 MA, George Myers discussed tests he conducted to examine the likelihood of third-order intermodulation (3IM) interference when certain combinations of frequencies are used simultaneously. Spacing out pilots along the edge of the runway is one way to minimize this problem of "self-generated" interference. By this I mean that we may be creating our own interference rather than its coming from an outside source such as a pocket pager transmitter. It seems at least some respondents read George's columns, since there was an affirmative vote of about 2:1 in favor of pilot spacing. Mandatory pilot spacing seems to be more important in large clubs. Dave Abbe belongs to such a club.

Dave flies with the Pioneer Club in Santa Clara, CA, which has over 500 members. To reduce the possibility of self-generated (3IM) interference at the club field, there are procedures governing pilot locations, each of which is assigned certain frequencies. The club used a computer program to determine which frequencies are most likely to combine and cause 3IM interference. The result was that the worst offenders are spaced the farthest apart. I hope to have more on this in a future column.

One respondent, who was opposed to mandating pilot location at the club field, was nevertheless very concerned about our radios interfering with one another. He enclosed a letter that his club had sent to AMA President John C. Grigg which expressed the club's concern about the ability of radio manufacturers to manufacture equipment that will operate successfully when the frequency spacing between channels is reduced in the not-too-distant future. Perhaps mandatory pilot spacing may be the only way to operate after 1991!

Question No. 6. Ten readers submitted other suggestions concerning safety at RC flying fields. Briefly summarized, they are as follows:

• Get rid of the hotdoggers who are always on the edge (wrong side) of flying safety.
• Reduce interference by having good, clean, primary-channel output from transmitters. Good product review boards—everything in the magazines comes out good, but we have problems in the field.
• Radio manufacturers should provide connectors to accommodate EVSs for battery checks. Increased punishment for not following the already-set rules.
• Keep the needle valve away from the spinning prop. Each club should have safety officers.
• Experienced RC'ers should pass on their knowledge to newcomers.
• Enforce rule to keep spectators out of pits.
• Ground models with visual damage or poor/improper workmanship.
• Maybe some video tapes to scare guys who couldn't care less about safety.
• Have a first-aid kit and, if possible, a telephone at the field for emergencies.
• Classify "trainer models" into Primary, Basic, and Advanced.

By the time you read this column, my May Safety column will have addressed the subject of trainer models which really aren't trainers, a situation one respondent wrote about at some length. If you haven't already responded to my request in the May column for your thoughts on classifying trainers into Basic and Advanced categories, I'm still interested in hearing from you.

I want to thank all who responded to this reader questionnaire. I intend to pass on the results to the AMA Safety Committee and suggest that they review Dave Abbe's suggestions. With the exception of Question No. 3 and the fail-safe throttle part of Question No. 4(d), a majority of readers appears to agree with Dave. Have a safe month.

John Preston 12235 Tildenwood Dr., Rockville, MD 20852.

Transcribed from original scans by AI. Minor OCR errors may remain.