Noise reduction for glow engines
 

Hi guys,
I'm looking for your thoughts on d.b. sound reductoin for large glow
engines. 95db or less.
thanks Lorn

How large?

Simple ground checks dont tell much about how loud a plane is in the air but it is a decent comparison. 98 dB, 3 meters away is a pretty quiet setup.

IF you're looking to hit 95 with a large glow engine, (assuming a 1.80 or 2.10), our sport mufflers will put you down around 88-90 or in that range. Our large volume pitts will sit around 95-98 depending on how you prop them. What motor are you running?

The engines are super tigers a 2500 & 3250 with bison pitts mufflers
the Reddeer club is trying to get all planes under 95db
mine are sitting at 98db at 9'.
the 2500 has a 17x8 prop the 3250 has a 18x10 prop
thanks Lorn

Hi Lorn

are you using Master Airscrew props? Even on a .46 we dropped >8db switching from MA to APC. Might be worth a try.

Bob

94 dB at 9' is the FAI pattern limit and by club standards seems very strict. With expensive exhaust systems and special setups we have a hard time making 94 at 9'. Can you not get the club to bump it to 98 which is actually still quite quiet?

Even the MAAC pattern committee does not follow FAI and has their limit set to 96 at 9'.

I dont know seems like the club is asking a lot of the average modeller.

As for reducing your noise more, the easiest way beyond different mufflers is dropping diameter and increasing the pitch on your prop.

Nuker
I'm useing APC props know.
as Chad said 95 db is onthe low side. But we have a few members
pushing to get the db's down.
They are electric flyers & don't like the noise
Lorn