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Old Jun 30, 2002, 09:02 AM
Registered User
Southern Spain
Joined May 2002
15 Posts
Ehaust extension

Hi all,

I have fitted a silicone 3" exhaust extension to my 61 engine to keep oil
away from plane. A friend says that this is cutting down performance
considerably. If this is right by how much ? I don't have a tacho.


Mike L
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Old Jul 01, 2002, 02:58 AM
Registered User
Vandergrift Pennsylvania
Joined Jun 2002
35 Posts

It will cut back some; How much? What I would do is run the plane with it on and with it off. Remember that back pressure IS a factor the engineers work with when designing a engine/exhuast.
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Old Jul 01, 2002, 05:03 AM
Registered User
N. Staffs, UK
Joined Jan 1997
5,654 Posts
It depends on the particular engine and what muffler is fitted. I've tried one on an Irvine .46 and got no measurable change in rpm. On a SC .53 it dropped only 100 rpm. Some engines might lose a lot of power but those 2 didn't. If you really want to know what yours does I suggest investing in a tacho (or find a friend who has one you can borrow).

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Old Jul 10, 2002, 07:13 AM
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Mike C's Avatar
Roxboro, NC U.S.A.
Joined Sep 2000
714 Posts
A guy at our field had a piece of silicone tubing about 8" long attached to his Something Extra last weekend. It appeared to be a good bit larger than the ones I have seen sold for this purpose. He attached it to the muffler with a cable tie and another cable tie to the LG. Plane was clean at the end of the day! I could see no change in performance from this setup vs. no extension at all. Of course that is measured with my eyes and ears not tach.
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Old Jul 11, 2002, 04:33 PM
Got my ears on
Beige's Avatar
England (oxfordshire)
Joined Sep 2001
303 Posts
i have nearly 10inchs on my ol' trainer, didn't notice any change, that with an irvine 40 and 1/5inch ID silicone tube

keeps all the goop from thoes hard to reach places, but it sure looks ugly

IMO, if it's not doing any damabe, you like the way it flys, then fly it
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