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JS-40-TT muffler on OS46SF

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Old 10-03-2009, 01:04 AM
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Bone
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Default JS-40-TT muffler on OS46SF

Hi Bob,

Currently have my trusty (but old) OS46SF with standard muffler on a Blackhorse Twister ARF. Fuel used is 10% red Klotz, 10% Castrol M, 10% nitro & balance being methanol.

Horizontal performance is pretty good but there is no way the OS will climb the Twister vertical OOS - not even with an APC 10 x 6.

Anyway......bolt on power - how much of a power / RPM increase can I expect with the JS-40-TT muffler?

Alternatively, the Jett SJ46 is really tugging my "must have list" [8D]

regards,

Greg from Oz
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Old 10-03-2009, 12:29 PM
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Default RE: JS-40-TT muffler on OS46SF

Thanks for writing......

Power increase with the jett-stream muffler tends to produce about 1000-1500 more rpm than the stock muffler. On that same 10x6, you would see a notable power gain. Out of sight well, that depends on how much the plane weighs, and what sort of shape the engine is in. But I think you get the idea.
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Old 04-05-2010, 11:26 AM
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Default RE: JS-40-TT muffler on OS46SF

if you use the jett muffler and the os 46 is in good health, it will climb out of sight vertically at less than full throttle, i have one with magnum 52 with same muffler and its got unlimited vertical, mine weighs 4 pounds eight ounces, 10 percent powermaster fuel, merlin 2003 plug
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Old 08-07-2011, 01:57 PM
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Default RE: JS-40-TT muffler on OS46SF


ORIGINAL: bob27s

Thanks for writing......

Power increase with the jett-stream muffler tends to produce about 1000-1500 more rpm than the stock muffler. On that same 10x6, you would see a notable power gain. Out of sight well, that depends on how much the plane weighs, and what sort of shape the engine is in. But I think you get the idea.

Bob,

it looks as if this is still available. I have a Don Muddiman Flying Machine with an O/S .46 AX on it, I generally run a 10X7 on this.

I currently have a open Max Pipe I want to replace.....i hated the power box (Stock) muffler but I think I even took a 300RPM hit using the Max pipe and now I want to switch this out with something better.....I looked at the Max "Tuned Pipe" but I like the looks of the jet pipe 10 times better!

Do you thiink I can really gain 1000RPM? If so it is DEFINETLY worth the $60 man, and I will be ordering one soon.
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Old 08-08-2011, 09:12 AM
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Default RE: JS-40-TT muffler on OS46SF

Hi Tom,

Thanks for writing and sorry for the delay. Was on vacation

The Mac's tuned pipes, properly configured, will give you more boost than the Jett-Stream. We sell the full size pipes as well, configured with the Jett engines, for those seeking flexability in the setup the long pipe can be specifically tuned to the prop/rpm target desired.

The black Mac's muffler is just that a muffler. Very good product, light weight, but it is not tuned at all. If that is what you are running now, yes, the Jett-Stream will give you better performance.

The Jett-stream will give you hassle-free performance. You get about 80% of the boost as available from a full size pipe - just a lot easier to install, no tuning, and a fairly broad range of operation. Difference from the stock muffler is easily 1000+ rpm with the correct prop choice.

On the .46AX, a standard Jett-Stream TT-40 works great. Prop with a 9x8, 10x6 or 10x7. Target ground peak rpm is 15,000 rpm or higher.... select a prop that gets you above that rpm at peak on the ground. Back off rich slightly 600-800 rpm down from peak, and fly it there.

Bob
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Old 08-08-2011, 09:23 AM
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Default RE: JS-40-TT muffler on OS46SF


ORIGINAL: bob27s

Hi Tom,

Thanks for writing and sorry for the delay. Was on vacation

The Mac's tuned pipes, properly configured, will give you more boost than the Jett-Stream. We sell the full size pipes as well, configured with the Jett engines, for those seeking flexability in the setup the long pipe can be specifically tuned to the prop/rpm target desired.

The black Mac's muffler is just that a muffler. Very good product, light weight, but it is not tuned at all. If that is what you are running now, yes, the Jett-Stream will give you better performance.

The Jett-stream will give you hassle-free performance. You get about 80% of the boost as available from a full size pipe - just a lot easier to install, no tuning, and a fairly broad range of operation. Difference from the stock muffler is easily 1000+ rpm with the correct prop choice.

On the .46AX, a standard Jett-Stream TT-40 works great. Prop with a 9x8, 10x6 or 10x7. Target ground peak rpm is 15,000 rpm or higher.... select a prop that gets you above that rpm at peak on the ground. Back off rich slightly 600-800 rpm down from peak, and fly it there.

Bob
Awesome news! Let me ask you one more question....in my Application (Flying Machine with O/S .46) the pipe will hit the frame of the plane (As best I can tell from dimensions available on Rossi site and your site)

Will the use of a 1/2" X 37MM exhaust "Extender" affect the tune of the pipe and any idea how? (Good, Bad, Etc)?

Here is an example of the extension, for that matter I could use a Jet Part number.......

http://shop.vendio.com/RossiEnginesU...320/index.html

Thanks again for the help!










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Old 08-08-2011, 09:33 AM
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Default RE: JS-40-TT muffler on OS46SF

Jett does offer .12" and .25" extensions. No more than .25" is recommended.

But avoid using them if possible. Slight hit on top-end rpm, but it trades off for a little torque... most people never notice the difference.

1/2" extension would not be a good idea. Reconfigure the engine and muffler installation on the airframe.

My suggestion is rotating the engine so the muffler can clear the fuselage, or releave the fuselage in that area to clear the muffler.
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Old 08-08-2011, 11:17 AM
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Default RE: JS-40-TT muffler on OS46SF


ORIGINAL: bob27s

Jett does offer .12'' and .25'' extensions. No more than .25'' is recommended.

But avoid using them if possible. Slight hit on top-end rpm, but it trades off for a little torque... most people never notice the difference.

1/2'' extension would not be a good idea. Reconfigure the engine and muffler installation on the airframe.

My suggestion is rotating the engine so the muffler can clear the fuselage, or releave the fuselage in that area to clear the muffler.

Good advice and that's why I ask!

Thanks for the help.....off to see what I can do about rotating the engine......hard to do with the cowl I have on it........[:@]
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