Today's Message Index:
----------------------
1. 01:34 AM - Re: Air system lubrication CJ (Harv)
2. 02:06 AM - Re: Yak-List Digest: 1 Msgs - 04/24/13 (Peter Shaw)
3. 06:50 AM - Re: Air system lubrication CJ (bipolar)
4. 07:31 AM - Re: Air system lubrication CJ (jetjockey)
5. 10:32 AM - Re: Hydraulic lock (Jill Gernetzke)
6. 12:00 PM - Re: Air system lubrication CJ (Harv)
7. 12:02 PM - Re: Re: Hydraulic lock (Bitterlich, Mark G CIV NAVAIR, WD)
Message 1
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| Subject: | Re: Air system lubrication CJ |
The CJ6 manual mentions 'Castor Oil' quite alot for lubricating seals in the air
valves, etc. so as Doug says
Methylated spirits and glycerin mixed 50/50% works too for other people I've spoken
too.
I'd break the pipe joint where the air compressor line joins into the system on
the engine firewall and put a small amount in there.
You need to be very careful what fluids you inject into these systems, if the seals
are old and decide they don't like what you use the impending reaction can
degrade them and you'll be rebuilding gear actuators etc etc (Not nice)!
Rgs
Harv :D
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399411#399411
Message 2
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| Subject: | Re: Yak-List Digest: 1 Msgs - 04/24/13 |
Having seen a Yak 50 land wheels up I can guarantee that the theoretical
loss of "a tenth of an inch per rotation" does not occur.
Because the flare is at a normal height (unintentional wheels up) the
aircraft then drops the undercarriage length stalled, and in this case
snapped all three blades off in one revolution, all at the thick part of
the chord.
Check out the remains of a prop strike, it will not consist of several
slivers of tenth of an inch long pieces of prop, rather foot long chunks
snapped off!
So, check out properly for engine damage after a prop strike, it is not a
benign event that gently machines the prop length down.
Regards,
Pete
On 25 April 2013 11:02, Yak-List Digest Server <yak-list@matronics.com>wrote:
> *
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> Today's Message Index:
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>
> 1. 08:24 AM - Re: Re: Re: Hydraulic Lock (Bitterlich, Mark G CIV
> NAVAIR, WD)
>
>
> ________________________________ Message 1
> _____________________________________
>
>
> Time: 08:24:17 AM PST US
> Subject: RE: Yak-List: Re: Re: Hydraulic Lock
> From: "Bitterlich, Mark G CIV NAVAIR, WD" <mark.bitterlich@navy.mil>
>
>
> Actually this is very good information to keep in mind, and I am going
> to chew on the physics of that answer for a day or two. It poses a very
> interesting study in the stresses involved and should make for a rather
> intense dinner table debate! :-) (Not you, my engineering friends!)
> Thanks for writing back Jill.
>
> So given this information, what is the advice of M14P.com regarding prop
> strikes and what should be done to the engine afterwards?
>
> Mark
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Jill Gernetzke
> Sent: Tuesday, April 23, 2013 16:56
> Subject: Yak-List: Re: Re: Hydraulic Lock
>
>
> Good feedback, Mark.
>
> Most prop strikes occur with wood composite or carbon fiber blades. (We
> haven't had a prop strike teardown with a metal prop, yet.) The inertia
> of
> energy is absorbed by the blades disintegrating or being shaved off.
>
> I agree with your assessment of a hydraulic lock on startup, but not
> when
> the engine fires and it pulls fuel or oil in from the intake tubes. If
> it
> fires, there is a good likelihood that the accessory shaft will twist.
>
>
> At landing speed, the aircraft travels 3.5 feet for each blade in
> contact
> with the ground at initial point of contact. As the engine slows, this
> increases. Consequently, the rearward deflection of a very thin blade
> exceeds the rotational shearing. Additionally, the reduction of blade
> length per rotation with a normal flare landing is less than a tenth of
> an
> inch. In other words, the wood fails well before any engine parts are
> stressed to the +400 foot/lbs of torque design load.
>
> Jill
>
>
Message 3
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| Subject: | Re: Air system lubrication CJ |
Basically a stock system with the SS mods added
Thanks guys
Bipolar
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399429#399429
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| Subject: | Re: Air system lubrication CJ |
Article 105 from the CJ6 Maintenance Manual clearly states: "Replenish 5-10 gr.
of castor oil or No. 8 aviation lubricating oil into each retraction cylinder
THROUGH THE NIPPLES OF THE CYLINDER RETRACTION AND EXTENSION PIPES AND 3-5 grams
of castor oil or No. 8 aviation lubricating oil into each of the uplock hook
cylinders THROUGH ITS NIPPLE."
Adding lubricant at a point right after the compressor will have little or no effect
on the landing gear and uplock release actuators and will actually have
a VERY NEGATIVE effect on your pneumatic system as it will unnecessarily contaminate
your system filter by saturating the felt filters with lubricant and coating
the desiccant with oil, rendering it ineffective.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399432#399432
Message 5
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| Subject: | RE: Hydraulic lock |
Additionally, the calculations for torque at full power are 641 ft/lbs on
the crankshaft and 936 ft/lbs on the prop shaft. (Double-check of the
calculations are welcome.)
The numbers in the previous post were for a typical prop strike which is at
near idle on an "Oh, %*&$!" gear up landing. We have had some sudden
stoppage prop strikes where we fully expected damage to the accessory shaft
and there was no damage. This comes back to design limit loads on the
individual components and how much over those limits the parts are
engineered to. I do not have that engineering data.
Mark, the prop strike teardown boils down to the insurance companies and
also, the ultimate peace of mind of the owner and subsequent buyers of the
aircraft. This is a judgment call; which we handle on a case by case basis.
For practical discussion, much of what dictates the prop strike teardown -
in the U.S. - is liability.
Jill
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Yak-List Digest
Server
Sent: Thursday, April 25, 2013 12:02 AM
Subject: Yak-List Digest: 1 Msgs - 04/24/13
*
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=================================================
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Links listed below. The .html file includes the Digest formatted in HTML
for viewing with a web browser and features Hyperlinked Indexes and Message
Navigation. The .txt file includes the plain ASCII version of the Yak-List
Digest and can be viewed with a generic text editor such as Notepad or with
a web browser.
HTML Version:
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13-04-24&Archive=Yak
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2013-04-24&Archive=Yak
===============================================
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===============================================
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Total Messages Posted Wed 04/24/13: 1
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Today's Message Index:
----------------------
1. 08:24 AM - Re: Re: Re: Hydraulic Lock (Bitterlich, Mark G CIV
NAVAIR, WD)
________________________________ Message 1
_____________________________________
Time: 08:24:17 AM PST US
Subject: RE: Yak-List: Re: Re: Hydraulic Lock
From: "Bitterlich, Mark G CIV NAVAIR, WD" <mark.bitterlich@navy.mil>
Actually this is very good information to keep in mind, and I am going to
chew on the physics of that answer for a day or two. It poses a very
interesting study in the stresses involved and should make for a rather
intense dinner table debate! :-) (Not you, my engineering friends!)
Thanks for writing back Jill.
So given this information, what is the advice of M14P.com regarding prop
strikes and what should be done to the engine afterwards?
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jill Gernetzke
Sent: Tuesday, April 23, 2013 16:56
Subject: Yak-List: Re: Re: Hydraulic Lock
Good feedback, Mark.
Most prop strikes occur with wood composite or carbon fiber blades. (We
haven't had a prop strike teardown with a metal prop, yet.) The inertia of
energy is absorbed by the blades disintegrating or being shaved off.
I agree with your assessment of a hydraulic lock on startup, but not when
the engine fires and it pulls fuel or oil in from the intake tubes. If it
fires, there is a good likelihood that the accessory shaft will twist.
At landing speed, the aircraft travels 3.5 feet for each blade in contact
with the ground at initial point of contact. As the engine slows, this
increases. Consequently, the rearward deflection of a very thin blade
exceeds the rotational shearing. Additionally, the reduction of blade
length per rotation with a normal flare landing is less than a tenth of an
inch. In other words, the wood fails well before any engine parts are
stressed to the +400 foot/lbs of torque design load.
Jill
Message 6
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| Subject: | Re: Air system lubrication CJ |
Guys
Sorry misunderstood what your trying to lubricate, so be careful what you inject
and where you inject it!
Been having issues with my firewall check valves (worn seals and rusty springs).
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399457#399457
Message 7
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| Subject: | RE: Hydraulic lock |
Good answer again Jill. Thank you.
I wrote a separate message about an engine that had a prop strike when
the left gear collapsed after touch-down. It took off after about a
foot on either end of the stock prop was ground off, then flew around
the pattern and landed. The engine was at idle, and the pilot stated
that he never even knew it happened until after he finally landed. I.E.
No sudden stop.
The engine has since had about 300 hours put on it with no problem
what-so-ever. Which is not to say it was not inspected, it was.
However, it was not totally torn down, only partially. Some of the
decisions were based on what your company published some time ago
concerning prop strikes based on the training they had received in
Russia. It seems it turned out to be the proper decision based on good
information.
The problem with replacing the engine is that you really don't know what
you're going to end up with there either. Hope for the best, but train
for the worst as they say.
In the end, my opinion is that there is a term called "PROP STRIKE!"
that we try to quantify into something that requires an exact action, no
matter what. This is what the FAA leans towards and if specific
information on the engine is unknown, they will also tend to apply
information made for other engines that they consider similar. This is
of course in many cases totally incorrect. Is the engine geared? What
about specific weak points (Accessory Shaft for instance)? These are
not the same from engine type to engine type even if they do both happen
to be "Radials". So EVERY case is unique and the actions taken can
vary within a fairly large margin, insurance companies and liabilities
excepted.
The other take-away from discussions like this is to realize that the
FAA reads the YAK LIST. This is not a guess. I know it for a fact. I
was confronted by an FAA Inspector for what I said on this list one time
and while some may say "so what, FREE SPEECH!", the fact is that when
confronted by these guys, it is not a fun experience no matter how much
"in the right" you might happen to be. Giving credit where credit is
due, I've eventually seen them make some good decisions, but the time
span in the interim is not something anyone wants to experience.
So while sharing good information is what this list is all about, I
would offer this one tiny suggestion: "WALLS HAVE EARS" Be careful
not to make arguments in public that could turn around and bite you in
the tail later on. Of course this is the "Pot calling the Kettle
Black", but hey, I'm learning.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jill Gernetzke
Sent: Friday, April 26, 2013 13:29
Subject: Yak-List: RE: Hydraulic lock
Additionally, the calculations for torque at full power are 641 ft/lbs
on
the crankshaft and 936 ft/lbs on the prop shaft. (Double-check of the
calculations are welcome.)
The numbers in the previous post were for a typical prop strike which is
at
near idle on an "Oh, %*&$!" gear up landing. We have had some sudden
stoppage prop strikes where we fully expected damage to the accessory
shaft
and there was no damage. This comes back to design limit loads on the
individual components and how much over those limits the parts are
engineered to. I do not have that engineering data.
Mark, the prop strike teardown boils down to the insurance companies and
also, the ultimate peace of mind of the owner and subsequent buyers of
the
aircraft. This is a judgment call; which we handle on a case by case
basis.
For practical discussion, much of what dictates the prop strike teardown
-
in the U.S. - is liability.
Jill
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Yak-List
Digest
Server
Sent: Thursday, April 25, 2013 12:02 AM
Subject: Yak-List Digest: 1 Msgs - 04/24/13
*
=================================================
Online Versions of Today's List Digest Archive
=================================================
Today's complete Yak-List Digest can also be found in either of the two
Web
Links listed below. The .html file includes the Digest formatted in
HTML
for viewing with a web browser and features Hyperlinked Indexes and
Message
Navigation. The .txt file includes the plain ASCII version of the
Yak-List
Digest and can be viewed with a generic text editor such as Notepad or
with
a web browser.
HTML Version:
http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Cha
pter
13-04-24&Archive=Yak
Text Version:
http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chap
ter
2013-04-24&Archive=Yak
===============================================
EMail Version of Today's List Digest Archive
===============================================
----------------------------------------------------------
Yak-List Digest Archive
---
Total Messages Posted Wed 04/24/13: 1
----------------------------------------------------------
Today's Message Index:
----------------------
1. 08:24 AM - Re: Re: Re: Hydraulic Lock (Bitterlich, Mark G CIV
NAVAIR, WD)
________________________________ Message 1
_____________________________________
Time: 08:24:17 AM PST US
Subject: RE: Yak-List: Re: Re: Hydraulic Lock
From: "Bitterlich, Mark G CIV NAVAIR, WD" <mark.bitterlich@navy.mil>
Actually this is very good information to keep in mind, and I am going
to
chew on the physics of that answer for a day or two. It poses a very
interesting study in the stresses involved and should make for a rather
intense dinner table debate! :-) (Not you, my engineering friends!)
Thanks for writing back Jill.
So given this information, what is the advice of M14P.com regarding prop
strikes and what should be done to the engine afterwards?
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jill Gernetzke
Sent: Tuesday, April 23, 2013 16:56
Subject: Yak-List: Re: Re: Hydraulic Lock
Good feedback, Mark.
Most prop strikes occur with wood composite or carbon fiber blades. (We
haven't had a prop strike teardown with a metal prop, yet.) The inertia
of
energy is absorbed by the blades disintegrating or being shaved off.
I agree with your assessment of a hydraulic lock on startup, but not
when
the engine fires and it pulls fuel or oil in from the intake tubes. If
it
fires, there is a good likelihood that the accessory shaft will twist.
At landing speed, the aircraft travels 3.5 feet for each blade in
contact
with the ground at initial point of contact. As the engine slows, this
increases. Consequently, the rearward deflection of a very thin blade
exceeds the rotational shearing. Additionally, the reduction of blade
length per rotation with a normal flare landing is less than a tenth of
an
inch. In other words, the wood fails well before any engine parts are
stressed to the +400 foot/lbs of torque design load.
Jill
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