Today's Message Index:
----------------------
1. 11:43 AM - Securing Muffler Springs (KIRBY, DENNIS T GS-13 USAF AFMC AFNWC/EZS)
2. 12:20 PM - Re: Securing Muffler Springs (Stuart Harner)
3. 12:46 PM - exhaust springs (B Young)
4. 01:19 PM - Re: Securing Muffler Springs (John Hauck)
5. 06:46 PM - Re: Securing Muffler Springs (Richard Pike)
Message 1
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Subject: | Securing Muffler Springs |
Kolb Friends -
I'm sharing with you a tip that may prevent you some grief that I encountered recently
on my Mark-3. One of my muffler springs broke on a recent flight and
departed the engine. Went thru my Powerfin prop and it took a bite-sized chunk
out of the leading edge of one prop blade. Damage was beyond repair - cost
of a new blade was $250.
All 8 springs on my Rotax-912 muffler are safety-wired, per common practice intended
at securing the spring when (not if) they break. I always check the safety
wire on each muffler spring as part of my preflight. Apparently on this day,
one of these safety wires was worn partially through and still appeared secure
when I checked it. When the spring broke in flight, the instantaneous energy
must have been sufficient to break the already-weakened safety wire, resulting
in the spring's departure from the engine. Double failure.
So, here's the tip: I will no longer rely on ordinary safety wire to secure my
Rotax muffler springs. I've upgraded to 1/16" braided cable to secure these
springs. This is bicycle brake cable, available at any bike shop. I use one
piece (about 10 inches long) for each pair of springs. The cable ends are joined
and secured using a swaged ferrule. Cheap, easy to install, and most of all,
WAY more secure than a single strand of .032 safety wire! Constant engine
vibration will not wear thru it, as it does on safety wire.
Fly safely ...
Dennis Kirby
Mark-3 / 912ul
Sandia Park, NM
Message 2
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Subject: | Securing Muffler Springs |
Dennis,
Very interesting. Thanks for sharing. Makes me want to use the flange/bolt
method.
Did you use RTV to keep the safety wire from bouncing around and wearing
out? I have always done this, but don't like not being able to see the wire
and judge its condition.
Do you have any pictures of your new method?
Question for the group.
Do you think the stainless steel springs are better, and would it be a good
idea to just replace the springs at say spark plug replacement intervals?
Thanks,
Stuart
-----Original Message-----
From: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of KIRBY, DENNIS T
GS-13 USAF AFMC AFNWC/EZS
Sent: Monday, April 25, 2016 1:38 PM
Subject: Kolb-List: Securing Muffler Springs
--> AFNWC/EZS" <dennis.kirby.3@us.af.mil>
Kolb Friends -
I'm sharing with you a tip that may prevent you some grief that I
encountered recently on my Mark-3. One of my muffler springs broke on a
recent flight and departed the engine. Went thru my Powerfin prop and it
took a bite-sized chunk out of the leading edge of one prop blade. Damage
was beyond repair - cost of a new blade was $250.
All 8 springs on my Rotax-912 muffler are safety-wired, per common practice
intended at securing the spring when (not if) they break. I always check
the safety wire on each muffler spring as part of my preflight. Apparently
on this day, one of these safety wires was worn partially through and still
appeared secure when I checked it. When the spring broke in flight, the
instantaneous energy must have been sufficient to break the already-weakened
safety wire, resulting in the spring's departure from the engine. Double
failure.
So, here's the tip: I will no longer rely on ordinary safety wire to secure
my Rotax muffler springs. I've upgraded to 1/16" braided cable to secure
these springs. This is bicycle brake cable, available at any bike shop. I
use one piece (about 10 inches long) for each pair of springs. The cable
ends are joined and secured using a swaged ferrule. Cheap, easy to install,
and most of all, WAY more secure than a single strand of .032 safety wire!
Constant engine vibration will not wear thru it, as it does on safety wire.
Fly safely ...
Dennis Kirby
Mark-3 / 912ul
Sandia Park, NM
Message 3
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Dennis
fyi... the safety wire on my Springs do not have to be tight, that is
the springs job... after putting the springs on, I run the safety wire
through the spring. then run a bead of silicone rubber in the spring to
encapsulate the wire. the silicone keeps things from vibrating. that is
the belt, and for the suspenders.... I install a second piece of safety
wire from the center point of one spring to the center point of the next.
also silicone on the ends. the second wire is tight enough to pull the
two springs very slightly out of column. this out of column should keep
things from excessive vibration movement.. should one spring fail, the
through ( belt safety) wire should keep it close... should that also
fail the ( suspenders) should keep things out of the prop.
Boyd Young
Message 4
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Subject: | Securing Muffler Springs |
Dennis K/Kolbers:
Until I went the expensive SS spring route, I had problems with breaking
springs. They didn't go through the prop because I use a lot of silicone
seal to encapsulate the entire spring from one end to the other, including
the hooks. No need for safety wire.
I bought a set of SS springs to go with my new Titan exhaust system, some
800 hours ago. The springs are pricey, but they work. Well worth the
money.
As far as props go. The reason I use WARP Drive props is because I can't
find a better one for performance and for durability/reliability. You could
have put that spring through a WARP Drive blade and kept on flying.
Probably take a little cosmetic work, but not a new blade.
Here is the url for the springs:
http://jbmindustries.com/SOCKET.html
john h
mkIII
Titus, Alabama
-----Original Message-----
From: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of KIRBY, DENNIS T
GS-13 USAF AFMC AFNWC/EZS
Sent: Monday, April 25, 2016 1:38 PM
Subject: Kolb-List: Securing Muffler Springs
--> AFNWC/EZS" <dennis.kirby.3@us.af.mil>
Kolb Friends -
I'm sharing with you a tip that may prevent you some grief that I
encountered recently on my Mark-3. One of my muffler springs broke on a
recent flight and departed the engine. Went thru my Powerfin prop and it
took a bite-sized chunk out of the leading edge of one prop blade. Damage
was beyond repair - cost of a new blade was $250.
All 8 springs on my Rotax-912 muffler are safety-wired, per common practice
intended at securing the spring when (not if) they break. I always check
the safety wire on each muffler spring as part of my preflight. Apparently
on this day, one of these safety wires was worn partially through and still
appeared secure when I checked it. When the spring broke in flight, the
instantaneous energy must have been sufficient to break the already-weakened
safety wire, resulting in the spring's departure from the engine. Double
failure.
So, here's the tip: I will no longer rely on ordinary safety wire to secure
my Rotax muffler springs. I've upgraded to 1/16" braided cable to secure
these springs. This is bicycle brake cable, available at any bike shop. I
use one piece (about 10 inches long) for each pair of springs. The cable
ends are joined and secured using a swaged ferrule. Cheap, easy to install,
and most of all, WAY more secure than a single strand of .032 safety wire!
Constant engine vibration will not wear thru it, as it does on safety wire.
Fly safely ...
Dennis Kirby
Mark-3 / 912ul
Sandia Park, NM
Message 5
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Subject: | Re: Securing Muffler Springs |
Silicon? Safety wire? Um - no. How about some 5/16" bolts and springs from Ace
hardware? The lugs that the bolts go through are cut off the ends of some big
muffler clamps and welded to the pipes. Drill a hole in the end of the bolts and
put a cotter pin through them. Replace them every year during condition inspection.
Don't know how a 912 exhaust is configured, so it might not work for that application.
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Would you consider yourself to be a good person?
https://www.youtube.com/watch?v=VWcDXT6pH7A
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