rcbry

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Hi Guys, I want to be able to fly a 33% bird but we have some noise issues at the flying field. Can anyone help me out with some quiet muffler suggestions for the big twins. 100cc +

Thanks

KenLambert

My Feedback: (107)

canisters

Hooked-On-RC

My Feedback: (16)

DA100 KS Canisters
ZDZ....JMB Canisters
3W...3W Canisters

or if you dont want canister try a snuffler muffler.[link=http://www.jtecrc.com/snufflermufflers.htm]jtec[/link]

mmattockx

Your choices depend a bit on how much power loss you can tolerate. If you are flying a Cub and power is not an issue, the Snuffler will probably work well for you. If you are flying an Extra and want way too much power, then canisters or tuned pipes are your only practical choice. When you say you have some "noise issues" at your field, what exactly does that mean? You can't run open exhaust diverters? You can hardly run internal combustion engines there? Does your club have a sound check and decibel limits in place now?

There are 2 components you need to worry about: engine exhaust noise and prop noise. After a bit of work on the exhaust, your prop will be the loudest thing on the aircraft and then you need to start working on it.

1) Engine noise - there is only one way to make the exhaust note quieter and keep the power up. That is to add volume to your exhaust system. This lets the exhaust gases cool and expand, which lowers the energy in the gases and lowers the sound level. The easiest choice (from the tuning standpoint) is short headers and untuned canisters. Done properly, you can equal open stack power and can dramatically cut the noise levels. Easily to the point where glow engines are louder. Second easiest to tune is headers and tuned canisters. More power, same noise levels as untuned canisters. But you must match the length of the header to your prop choice, airframe and flying style. They have a pretty wide tuning range and should not be super tough to get right. Hardest to tune is a full tuned pipe set up. Also the most power and possibly the quietest sound level, as well. But you MUST do some experiementing and match your pipe/prop/airframe/flying style to get them to work properly. Not for the inexperienced or someone who wants a simple install it and fly type of set up.

2) Prop noise - to keep the prop noise low, you must use an efficient prop shape and keep the tip speed down. This is accomplished by either lowering rpm or using a smaller prop, or both. This is where the tuned exhaust setups come in, because it is possible to tune them to work well at lower rpm. This means you can run a high load prop and still make lots of power for good flight performance without the noise. A full tuned pipe set up can be extremely quiet and offer amazing performance at the same time. Just check out pattern planes sometime, they are super quiet (generally you can't hear them running in the air if any other engines are running at the same time) and the power and performance are incredible. This is the result of quiet tuned pipes, careful prop selection and tuning.


Mark