Today's Message Index:
----------------------
1. 05:03 AM - Re: Re: My Firestar 2 Build (Gary Aman)
2. 05:58 AM - Re: My Firestar 2 Build (Richard Pike)
3. 06:20 AM - Re: Re: My Firestar 2 Build (John Hauck)
Message 1
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| Subject: | Re: My Firestar 2 Build |
I dont recommend isolating the exhaust system from the engine. I think it should
be one with the engine,as tight and secure as you can make it.
Sent from my iPhone
> On Mar 24, 2019, at 8:35 PM, william sullivan <williamtsullivan@att.net> wrote:
>
>
> Funny how often that happens. Somebody discussing things that have just happened
to somebody in a group, and not knowing about it.
>
> Bill Sullivan
>
> do not archive
> --------------------------------------------
> On Sun, 3/24/19, west1m <west1m@hotmail.com> wrote:
>
> Subject: Kolb-List: Re: My Firestar 2 Build
> To: kolb-list@matronics.com
> Date: Sunday, March 24, 2019, 6:30 PM
>
> <west1m@hotmail.com>
>
> Interesting talk about muffler
> brackets. This is what happened to me yesterday on a short
> flight to Amery airport. I was already in my seat when the
> the guy I was chatting with asked what was wrong with my
> muffler. It was kind of angled a bit funny.He then helped me
> wire it together so it wouldn't fall off and scratch up my
> prop..
>
> --------
> West1m
> Hastings, MN
>
>
>
>
>
>
>
>
>
> Attachments:
>
> http://forums.matronics.com//files/broken_muffler_176.jpg
>
>
>
>
>
>
>
>
>
>
>
Message 2
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| Subject: | Re: My Firestar 2 Build |
zeprep251(at)aol.com wrote:
> I dont recommend isolating the exhaust system from the engine. I think it should
be one with the engine,as tight and secure as you can make it.
>
Unless your secondary goal is to get rid of vibration. Then you isolate it from
the engine, keep it tight at the connections, and flexible at the mounts. Then
(IMO) you have the best solution: reliability and less vibration.
The original muffler mounting on the 277 on the Firefly was set up to be tight,
and it shook worse than you could imagine. We assumed it was because it was a
single. Wrong. it was because the muffler was too tight.
A single cylinder engine waving that muffler back and forth 5,000 times a minute
was a disaster waiting to happen. And it very nearly did: during the 45 minute
ferry flight from the test field to David's hangar it broke 3 out of 4 new
muffler hangars.
The first picture shows that setup with the original curlyque muffler.
The current setup is in the later pictures, there is no stress on the muffler hangars
and vibration is about 90% less, and at 5500 rpm (the sweet spot for this
engine) there is literally no vibration now.
The goal was to let the engine move without it also moving the muffler - or at
least moving it as little as possible. So far it seems like a good plan.
Addendum: test flew the Firefly Saturday with the fan cooled 277, (the pictures
show the original engine) first flight since the blackberry patch adventure last
year, and it flew as nice as ever, engine ran good, but wouldn't idle right.
Will be swapping the carb out today for a new one that we just happened to
have. When you have a partner who has had even more U/L type airplanes over the
last 30 years than you have, there seems to be no lack of spare parts...
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kolb Firefly Part 103 legal (Ready for a test flight on the new 277)
Kingsport, TN 3TN0
Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=488251#488251
Attachments:
http://forums.matronics.com//files/p1060084_medium_210.jpeg
http://forums.matronics.com//files/p1060450_medium_158.jpg
http://forums.matronics.com//files/p1060451_medium_132.jpg
Message 3
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| Subject: | Re: My Firestar 2 Build |
I use rubber hanger straps, scrounged from my local muffler shop, look like they
are made from conveyor belt material, for vibration isolation for other applications,
but would probably work well for an exhaust hanger.
I remember many years ago when I discovered the problem of over soft Lord Mounts
on my FS/447. Thrust and torque was causing the engine to get way out of line.
While down at Brother Jim's in Tallahassee, Florida, one flight, I got the
bright idea of using shock absorber donuts to make up some engine mounts. Jim
zipped them up with the TIG welder and I flew back to Titus, Alabama. Before
I got home the entire exhaust system was disintegrating from vibration. Reckon
the airframe would have been next had I had a longer flight.
Vibration is some bad stuff.
john h
mkIII
Titus, Alabama
-----Original Message-----
From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Richard Pike
Sent: Monday, March 25, 2019 7:58 AM
Subject: Kolb-List: Re: My Firestar 2 Build
zeprep251(at)aol.com wrote:
> I dont recommend isolating the exhaust system from the engine. I think it should
be one with the engine,as tight and secure as you can make it.
>
Unless your secondary goal is to get rid of vibration. Then you isolate it from
the engine, keep it tight at the connections, and flexible at the mounts. Then
(IMO) you have the best solution: reliability and less vibration.
The original muffler mounting on the 277 on the Firefly was set up to be tight,
and it shook worse than you could imagine. We assumed it was because it was a
single. Wrong. it was because the muffler was too tight.
A single cylinder engine waving that muffler back and forth 5,000 times a minute
was a disaster waiting to happen. And it very nearly did: during the 45 minute
ferry flight from the test field to David's hangar it broke 3 out of 4 new
muffler hangars.
The first picture shows that setup with the original curlyque muffler.
The current setup is in the later pictures, there is no stress on the muffler hangars
and vibration is about 90% less, and at 5500 rpm (the sweet spot for this
engine) there is literally no vibration now.
The goal was to let the engine move without it also moving the muffler - or at
least moving it as little as possible. So far it seems like a good plan.
Addendum: test flew the Firefly Saturday with the fan cooled 277, (the pictures
show the original engine) first flight since the blackberry patch adventure last
year, and it flew as nice as ever, engine ran good, but wouldn't idle right.
Will be swapping the carb out today for a new one that we just happened to
have. When you have a partner who has had even more U/L type airplanes over the
last 30 years than you have, there seems to be no lack of spare parts...
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kolb Firefly Part 103 legal (Ready for a test flight on the new 277)
Kingsport, TN 3TN0
Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=488251#488251
Attachments:
http://forums.matronics.com//files/p1060084_medium_210.jpeg
http://forums.matronics.com//files/p1060450_medium_158.jpg
http://forums.matronics.com//files/p1060451_medium_132.jpg
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