Radio Modeller Magazine, June 1969 Issue

THERE are three references in this issue to the noise problem created by models, either un-silenced, or equipped with inefficient silencers. The detailed letter from J. B. Hawkins puts the case well, and covers the points raised by the Sevenoaks club report; the comment in American Column shows that the problem is not now confined to Europe, as was the case when our silencer ruling was first introduced. We think that, broadly, modellers classify into four groups — 1: the grossly irresponsible, who fly without silencers when they think they can get away with it, in places where commonsense dictates otherwise; 2: the irresponsible who modify commercial silencers in an effort to give themselves more power, at the expense of an increase in noise; 3: the majority who use the silencers available, and, 4: those who, even with commercial silencers, are still making too much noise, to retain their flying fields. Of course the problem is that "standard" silencers reduce power and an efficient silencer, even if it only gives a comparable power drop, is of a bulk far greater than most modellers will contemplate. Because of this we do not think the manufacturers are at fault, in that no one can afford to market a device which will not sell. If the demand is there, either from the modellers because of their intention to keep the flying field they have, or by the insistence of the clubs, the S.M.A.E., and contest organisers, on greater silencing efficiency, then the manufacturers will meet the demand. The acceptance of more efficient silencers will necessitate a drastic re-think in model design to accommodate them neatly, and are modellers ready for this? Reluctantly we must say no but, as Mr Hawkins points out, unless this acceptance is made, it will mean giving up the hobby! Is there then a choice?

We are in entire agreement with Mr. Hawkins' views, but how can they, in practical terms, be met? Broadly we accept that the typical multi model, equipped with a silenced 61, is adequately powered; to reduce this power by better silencing, means the model becomes underpowered. Even with miniature gear, a smaller 61 model is a bit of a bomb, so what is needed is an even more powerful 61 adequately silenced, and providing as a result, the same power as now. How then do we cope with the number 1's and 2's on our list, who will seek to release the extra power? Perhaps the answer is to restrict the maximum engine size, but then, as is so often pointed out, small inefficiently silenced engines produce an even more irritating noise than a 61.

Where the necessity exists, a small full house model (like the Moonprobe) with effective silencer can be . flown almost anywhere without giving offence. Perhaps here lies one answer, although we are sure flying fields used with such models, will soon be lost by the irresponsible who seem to delight in noise for its own sake. No, the only answer is for engines to be made with an effective, built-in, silencing unit, and for those who try to modify it, to be banned from flying. Such a radical re-design will take time. How much time have we got? It won't take manufacturers too long to meet a demand (especially as the problem is no longer confined to G.B. and hence export sales are not in jeopardy), but how many more fields will be lost - before the demand is created?