From: ntaib@silver.ucs.indiana.edu (Iskandar Taib)
Subject: Re: New C/L (control-line) FAI rules 
Organization: Indiana University
Date: Wed, 23 Dec 1992 19:34:29 GMT

In article <1992Dec23.024644.7388@leeweyr.sccsi.com> bill@leeweyr.sccsi.com (Bill Lee) writes:
>In article <Bzo3AH.JzH@usenet.ucs.indiana.edu> ntaib@silver.ucs.indiana.edu (Iskandar Taib) writes:
>>In article <1992Dec18.182341.27111@bernina.ethz.ch>
>>>Kibo peny@ppc.lpc.ethz.ch writes: >Combat F2D >	Glow engines shall use
>>>a singel simple chamber silencer of min. internal>	length 40mm
>>>and max. int. length of 89mm; int. dia. min. 20mm and max. 40mm;
>>>	with tail pipe max. int. dia. 8mm. Any other shape of the same
>>>volume limits >	(4 to 32 pi cm#) is acceptable. Total length of the
>>>exhaust system from engine >	port (xylinder liner) to system outlet
>>>not to exceed 15cm.
>>
>>In the latest Model Builder magazine are some pictures of experimental 
>>mufflers attached to various Russian engines. The interesting ones 
>>seemed to be made of silicone rubber and were tiewrapped onto the motor.
>>Hmmm.. wonder if a cloth muffler would be within the rules... I'll bet
>>it'd even work at reducing the noise!
>>
>>
>
>Hey, Isky, I didn't see any smiley faces there. Were you serious?
>
>			I didn't think so!
>
>
>At the CL World Championships this summer, the Russians (well, all
>the guys from what used to be the Soviet Union) were there showing
>off all of their stuff for sale. The pictures in Model Builder were
>ones that Rich (I think) took. You'll see about the same pictures
>in Model Aviation when they publish the World Championships report.

Oops.. wrong magazine. Flying Models is what I meant 9-) I'd like
to experiment with some of the cheaper Russian motors myself - Lyman
Lew bought something called the Puma .15 from an outfit called the 
Hobby Club or similar. They were $50 or so.

>Yes, one of the "mufflers" was a white rubber-like. It conformed
>to the rules, it didn't do much for the sound level (it's not noise
>if you like the sport!), and it cut the performance some.

>The whole muffler thing in FAI Combat is a joke. Legislating the
>dimensions of the muffler doesn't say anything about the real
>question: how do we get the sound level down. Remember the 4mm
>venturi? It was supposed to slow things down AND reduce the sound
>level! (Oh, yes, less power = lower pitch props = higher rpm = just
>as much noise and damned near as much performance.) 

From what I've heard noise actually went _up_ - and the higher rpms
everyone is running makes the noise particularly irritating. FAI
Combat is a lot noisier than AMA Fast even.

I'd say the thing to do, as has often been stated, is legislate that
FAI meets be flown where the noise won't impact anyone. Noise should 
be measured at the edge of the field rather than near the airplane.

>And then you 
>throw in the new, provisional, FAI Combat event JUST FOR DIESELS and 
>which require NO (zero, zilch, nada) mufflers, and you have to wonder
>where the thinking is coming from. Diesels are not quiet when they are
>being run for high performance. A diesel at 22,000 rpm is just as loud as
>a glow.

Ah.. sounds like the Brits at work. Oh for the days of Oliver Tigers,
Warlords, Titans, Ironmongers and the like.

>Oh, well, whatever the rules, the good flyers will prevail. And,
>I guess, that is how it should be. I just hope the rules-makers
>don't legislate the event into oblivion.

Yeah.. right now FAI combat isn't something many people fly, simply 
because the rules are so ornery and the equipment so expensive.








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Iskandar Taib                          | The only thing worse than Peach ala
Internet: NTAIB@SILVER.UCS.INDIANA.EDU |    Frog is Frog ala Peach
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