chainsaw backpressure

For the price of the earplugs you'll have to buy the neighbours you can put a muffler on. A chainsaw without a muffler is AWFUL loud, and usually does not run very well.

Fire hazard, and so illegal to operate in many situations, too.

On 30 Apr 2004 21:45:56 GMT, snipped-for-privacy@aol.com (Wwj2110) vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

This advice is given without guarantees. I take no responsibility for the results should you choose to follow it. It is free and wirth what you paid for it.

Yes. Dunno for how long.

Yes. Remember to take firefighting gear.

How cheap is your hearing?

snipped-for-privacy@aol.com (Wwj2110) wrote in news: snipped-for-privacy@mb-m28.aol.com:

The muffler/pipe on a 2-cycle is 'tuned' and is an integral part of the overall flow path for the engine. Without it, you will be down on power considerably, get sh*tty fuel consumption, and as PM said, it's also a fire hazard.

My chainsaw never did have a muffler and I never had complaints from the neighbours, especially when I was using it for them; of course, it does have a 60 cycle motor. Gerry :-)} London, Canada

Your pre empted from further discussion then.

Well you can put a tuned muffler on a two stroke but that does not mean they all have them . I have had lots of chainsaw mufflers apart and they are nothing but a shell with one baffle plate inside . I have seen those same plates burned out and the only change was the noise level . On the other hand a loose plate can block outflow enough to stop the saw . A common failing on the old Husky 65R brush saws . Ken Cutt

"> Well you can put a tuned muffler on a two stroke but that does not mean

That has been my experience also. It's not a tuned expansion chamber on a chain saw. I've run mine for a couple years now with the baffle displaced from a branch hitting it. Runs fine, just noisy, and I'm too cheap to buy the parts.

Garrett Fulton

That may be true of some (many?) saws but compact tuned exhaust systems for chainsaws do exist and provide considerable performance improvement.

I've been helping my neighbour with an exhaust system for a homebuilt aircraft and found THE reference on two-strokes. In the process I ran across this:

Ted

Why? Isn't that thirty times better than the two-cycle one being discussed? :-)

Enjoy, DoN.

Yes.

But only till you get to the end of the extension cord.

Interesting type . I have seen the ones they put on competion saws and the remote control planes powered by saw motors but they are the typical expansion chamber design you would see on a Motor bike . Learn some thing new all the time . Ken Cutt

I have, from the same book, a drawing of tuned pipe such as you mention and an APL2 function to calculate the dimensions given: õ Thep is exhaust port open angle õ D0 is diameter equivalent to exhaust port area õ rpm is exhaust pulses per minute

Let me know if you can use this.

Ted

That's an UNTUNED exhaust system... nothing more than a silencer that does absolutely nothing to improve the performance of the engine. The tuned expansion-chamber exhaust systems that you mentioned are not typically found on industrial/commercial engines... except as you noted, for hi-performance use. The other guys were right on the money, unless you have an expansion chamber type exhaust system, the less back-pressure the better... with an expansion chamber it's a careful balancing act trying to get the pipe temperature to stabilize without overheating the piston. Blair's book is really not THE reference on two-strokes. Gordon Jennings did all the hard work back in 1969... Blair just re-wrote it so it would be harder to understand. When the pistons melt and the propeller stops... oh, never mind!

David

"Ken Cutt" wrote in message news: snipped-for-privacy@corp.supernews.com...

Glad you know more about it than Blair. What are your qualifications?

Blair's book is really not THE reference on two-strokes. Gordon Jennings did all the hard work back in 1969... Blair just re-wrote it

Who wrote the simulation stuff? Jennings is repeatedly quoted and credited.

Ted

You really didn't need to know more than Blair or the average English speaking 3rd grader to read and comprehend the word "UNTUNED" at the top of the page. My qualifications are sort of irrelevant, since I'm not working on anybody's airplane; but I can read... how's that for a start? David