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From: Frank Krygowski <frkrygow@sbcglobal.net>
Newsgroups: rec.bicycles.tech
Subject: Re: rec tech mower
Date: Wed, 16 Apr 2025 11:26:58 -0400
Organization: A noiseless patient Spider
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On 4/16/2025 5:28 AM, John B. wrote:
>
> Why all this worry about electric mowers? Get a liquid fuel mower and
> build a proper exhaust system so it's quit :-)

Long ago in some engineering forum one guy described modifying his 
mower's exhaust system, mostly by adapting a far larger muffler. But the 
engine exhaust is only part of the noise from a typical mower. Much of 
the noise is generated aerodynamically by the 21" or 22" blade whirling 
around in a sort of echo chamber beneath the engine.

Many electric mowers use much smaller blades, eliminating most of that 
noise. Mammotion's mowers https://us.mammotion.com/  use discs that 
carry little razor blades on their periphery.

-- 
- Frank Krygowski