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Author Topic: The sound of 4 strokes.  (Read 4421 times)

Offline Dennis Toth

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The sound of 4 strokes.
« on: July 17, 2017, 08:34:57 PM »
Guys,
Several years ago I flew small and medium size 4 Strokes. I kinda liked the engine run and won several contests with them. One thing that always bugged me was the sound note of the 4 Strokes. They always sounded flat. Has anyone worked with mufflers designs to get a different sound from them?

Best,   Dennis
« Last Edit: November 21, 2018, 07:33:54 PM by Dennis Toth »

Offline Dennis Toth

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Re: The sound of 4 strokes.
« Reply #1 on: July 26, 2017, 05:39:01 PM »
So everyone is happy with the sound? I've heard it described as a Pig farting into a barrel. I did see some information on changing the exhaust note by using a disc type diffuser, this might be a lot of work but maybe some creative muffler internals would work.

Best,        DennisT

Offline Chris Wilson

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Re: The sound of 4 strokes.
« Reply #2 on: July 26, 2017, 05:43:12 PM »
Bolt another cylinder on at 45 degrees for that American sound!
MAAA AUS 73427

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Offline Dane Martin

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Re: The sound of 4 strokes.
« Reply #3 on: July 26, 2017, 06:48:16 PM »
So everyone is happy with the sound? I've heard it described as a Pig farting into a barrel. I did see some information on changing the exhaust note by using a disc type diffuser, this might be a lot of work but maybe some creative muffler internals would work.

Best,        DennisT

I grew up on a feed lot in bakersfield. I like pigs. Lol

Offline Chris Wilson

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Re: The sound of 4 strokes.
« Reply #4 on: July 27, 2017, 07:39:09 PM »
Seriously here, what is with an engine that has the exhaust length about the same as the intake?
Run a decent length pipe and put a muffler at least 6X the engine capacity on it and see how that goes.
And try and pick up the bass notes with an absorption type muffler.
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline Dennis Toth

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Re: The sound of 4 strokes.
« Reply #5 on: July 28, 2017, 04:51:53 PM »
Chris,
Interesting idea, so are you suggesting that we us a longer exhaust pipe and something like a glass pack muffler?

Best,     DennisT

Offline Chris Wilson

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Re: The sound of 4 strokes.
« Reply #6 on: July 28, 2017, 05:35:51 PM »
Chris,
Interesting idea, so are you suggesting that we us a longer exhaust pipe and something like a glass pack muffler?

Best,     DennisT
Yes to all except the glass pack as it will get oil soaked eventually.
An interesting idea is to use perforated pipe, glass wrap that section and jam open ended tubing over that.
That way you can simply slide the tubing off to replace the glass packing.
Hope that makes sense.

P.S. thinking about this again, perhaps a simple perforated tube wrapped with glass tape exhaust wrap just wired on may work well enough. All you need would offcuts of alloy pipe and a few inches of tape to test it out.
« Last Edit: July 28, 2017, 08:35:29 PM by Chris Wilson »
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline Dennis Toth

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Re: The sound of 4 strokes.
« Reply #7 on: July 30, 2017, 07:29:01 PM »
Ok, do you think we could use a tube within a tube (a small one inside a larger one) that would allow a sliding length to tune the note? I'm wondering if the inner tube can be perforated with the end closed then slide the length to get the desired note?

Best,    DennisT

Offline Chris Wilson

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Re: The sound of 4 strokes.
« Reply #8 on: July 30, 2017, 09:37:44 PM »
Ok, do you think we could use a tube within a tube (a small one inside a larger one) that would allow a sliding length to tune the note? I'm wondering if the inner tube can be perforated with the end closed then slide the length to get the desired note?

Best,    DennisT
Like a trombone?
Give it a go!
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline Jim Carter

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Re: The sound of 4 strokes.
« Reply #9 on: July 31, 2017, 10:18:29 AM »
I grew up on a feed lot in bakersfield. I like pigs. Lol
:) I like'm too .... boiled, fried, baked, roasted ......  LL~ LL~ LL~

Offline Steve Helmick

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Re: The sound of 4 strokes.
« Reply #10 on: August 11, 2017, 10:29:53 PM »
"Pig farting in a barrel" is a perfect description. Try a megaphone and see how that sounds? I've read of folks running without the muffler, only using the tube between the pig and barrel. They said it didn't sound much louder, but then there's no muffler pressure to the tank, which some said was important.  D>K Steve

 
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In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Steve Helmick

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Re: The sound of 4 strokes.
« Reply #11 on: August 11, 2017, 10:33:54 PM »
:) I like'm too .... boiled, fried, baked, roasted ......  LL~ LL~ LL~

SMOKED!!!  y1 Steve
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Offline Dennis Toth

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Re: The sound of 4 strokes.
« Reply #12 on: January 26, 2020, 07:15:03 PM »
I wonder if changing the fuel mix say add a bit of gasoline will give a different exhaust note?

Best,  DennisT

Offline Robert Zambelli

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Re: The sound of 4 strokes.
« Reply #13 on: January 27, 2020, 01:34:21 PM »
Hi, Dennis - don't know for sure but the next time I run a 4S, I'll try a bit of gasoline.   ~^  ~^

Bob Z.

Offline Dennis Toth

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Re: The sound of 4 strokes.
« Reply #14 on: January 27, 2020, 06:00:15 PM »
Bob,
I know that the ignition engines running gasoline are louder then when they run them on glow fuel. Maybe a few % gasoline will give them a bit sharper growl.

Best,   DennisT

Offline Robert Zambelli

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Re: The sound of 4 strokes.
« Reply #15 on: January 30, 2020, 02:22:00 PM »
Allow me to quote the mantra of R&D (and test engineering)

"One test is worth a thousand EXPERT OPINIONS".   y1  y1  y1


Bob Z.


Offline Joe Gilbert

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Re: The sound of 4 strokes.
« Reply #16 on: May 11, 2020, 05:12:03 PM »
I have been very successful with a saito 40. I like the sound it makes if it is winning it is really sounding good to me if you want noise get a Anderson Spitfire and have fun.
Joe Gilbert

Offline Dennis Toth

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Re: The sound of 4 strokes.
« Reply #17 on: May 11, 2020, 05:20:45 PM »
Joe,
What model Saito 40 do you have, do you use the carb or have you changed it to a straight venturi? What %Nitro do you run? What ship do you have it in, weight and prop? Just interested in what has worked.

Looking at the engine reviews the Saito 40 FA Golden Knight is listed at 10.75oz, about 3oz lighter than the OS FS40. WOW, that is really lots of power for the weight, easily matches any of the modern two stroke 40's if you add the fuel load for each.

Best,   DennisT
« Last Edit: May 11, 2020, 06:34:51 PM by Dennis Toth »

Offline Dennis Saydak

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Re: The sound of 4 strokes.
« Reply #18 on: August 04, 2020, 04:54:52 PM »
You need to buy yourself a set of Bagpipes. An adapter is all the extras you would need. :)! :##
Just when you think you're getting ahead in the rat race.....you find the rats just get faster! MAAC 13120L

Offline proparc

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Re: The sound of 4 strokes.
« Reply #19 on: August 05, 2020, 05:29:31 AM »
So everyone is happy with the sound? I've heard it described as a Pig farting into a barrel.

Best,        DennisT

Saito 72. A REALLY big angry pig farting into a VERY large steel reinforced barrel.
Milton "Proparc" Graham


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