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Tower Hibbies .75 - too noisy

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Old 06-28-2003, 10:46 PM
  #26  
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Default Tower Hibbies .75 - too noisy

You might be able to braze a piece of thin sheet metal with holes drilled in it to the center through bolt to act as a baffle
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Old 08-04-2004, 02:09 AM
  #27  
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Default RE: Tower Hibbies .75 - too noisy

hi there i have 6 tower engines, i would try steel wool in the muffler, and or diffrent props. props can contribute to hi DB #

SGG
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Old 08-04-2004, 07:07 AM
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Default RE: Tower Hibbies .75 - too noisy

The Bisson muffler is specified to work with both the Tower 75 and the GMS 76. Makes sense because both engines are made by the same maker and both have the same backward muffler bolt attachment. So the exaust sizes must be the same.

http://www2.towerhobbies.com/cgi-bin...?&I=LXGBL0&P=0

Therefore it makes sense that the GMS standard muffler would fit the Tower 75 just fine and be quieter because it is of a more conventional design than the Tower.

http://www2.towerhobbies.com/cgi-bin...?&I=LXEHA2&P=Z

If you try this please post back as I have a Tower also and would like to know how it works out.
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Old 08-04-2004, 09:38 AM
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Default RE: Tower Hibbies .75 - too noisy

Is the Brison muffler actual quite? Thought those were almost useless as a muffler.
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Old 08-04-2004, 11:12 AM
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Default RE: Tower Hibbies .75 - too noisy

Hate to interrupt. But has anybody any ideas how to quieten my ***!!!! Tower .75 ....?

Interesting though the conversation is.

this thread just went completely off course fast!! anyway, try putting some fiberglass material inside the exhaust. (start small and work your way up.) Use the fiberous stuff, not the cloth like material.

also, if you aren't overly concerned about power, just set up your linkages to go a little below full throttle. you might not need it, and that might be enough to be at the noise level permitted by your field.


also, I wasn't aware that AMA had any noise restrictions? anyone have a document at modelaircraft.org that says it?
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Old 08-04-2004, 11:54 AM
  #31  
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Default RE: Tower Hibbies .75 - too noisy

When the pattern guys used 2-strokes, they used long tuned pipes and higher pitch props to keep the rpm below 10,000 and met 94db pretty easily. And they gained power. It's something to think about.
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Old 08-04-2004, 06:23 PM
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Default RE: Tower Hibbies .75 - too noisy

ORIGINAL: Sport_Pilot

Is the Brison muffler actual quite? Thought those were almost useless as a muffler.
Nobody cares if the Bisson is quiet. The web site says the size is the same. Use of the GMS standard muffler will lower the noise.
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Old 08-04-2004, 10:48 PM
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Default RE: Tower Hobbies .75 - too noisy

I'll bet my Fox-74 is louder than your TH-75 !! :-)

Put a steeper pitch prop (not a longer one), like try an 11x9 or even an 11x10 with rounded style tips, that is, not sharp corners. The idea is to reduce the tip speed, which is where a lot of noise comes from. Props get very noisy when the tips go supersonic.

Also, go to an automotive parts store or LHS and get a foot of silicone tubing. Zip tie it to the end of the muffler and attach the tubing to the underside of the fulelage. Not only will it be quiter, but it will get th oil/gunk away from most of the aircraft.

As a third step, make the after-muffler suggested in one of the previous steps and you'll have an airplane that will sound like a high performance electric!
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