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Turbo-Jett noise levels

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Old 06-05-2008, 05:22 PM
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CustomPC
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Default Turbo-Jett noise levels

Hi,

A clubmate is entering in the Rare Bare class at this years national air races (Australia).

The class is restricted to Thunder Tiger ARF models (Rare Bare, Sea Fury and September Fury) and allows only .91 2-strokes from OS, TT, Magnum or Super Tigre with a minumum prop diameter of 13" and max pitch of 12"

There is also a noise limitation of 98dB when measured from 3 metres (10') over grass 1 metre (3.3') above the ground and up wind.

The rules also stipulate that tuned pipes are not allowed but there must be an expansion type muffler that is fully enclosed in the cowl.

Will the Turbo-Jett meet these criteria?

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Old 06-05-2008, 07:27 PM
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Default RE: Turbo-Jett noise levels


Difficult to tell if it would qualify.

Other racing organizations and aerobatic organizations recongize the jett-stream and turbo-jett mufflers as mufflers.

As for sound..... I have no sound level data I can share. Sound is entirely dependant on the airframe/prop/engine combination. There are many variables.

Yes, the turbo-jett is fairly quite. A different sound/note than most mufflers. My Jett BSE-100 with a 15x6 prop, turbo-jett installed on an Aeroworks Edge check around 10,000 rpm and a bit below 90db.

That is just an example.

Your combinations are likely looking at 11,000-12,000 rpm range, smaller props... glass fuselage.

In general, hitting 98db on grass at 3 meters is probably achievable based on what you said.

Soft mount the engine and its probably easy to hit.

But I can not guarantee that. Has to be tried, measured... then optimized.
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