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1. 01:48 AM - Re: Nose gear collapse (Mark Pennington)
2. 05:36 AM - Re: Nose gear collapse (bill wade)
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| Subject: | Re: Nose gear collapse |
Mr Graves. I did not recognize you as Flibob.
It does sound like your nose gear actuator did fail to lock and hold up the
plane for some reason.
There is a message in the thread from Tom Elliot.
He offered to share his procedure for testing etc.
He has shared that with me and I use that information to check my landing
gear each year at condition inspection. He is a good resource
Mark
On Thu, May 7, 2020 at 9:32 PM Robert Graves <flibob@att.net> wrote:
> Mark, Thanks for all your help. My original message said I left out the
> landing gear selector a better terminology would=99ve been the valv
e at the
> gear handle. The actuator was in the airplane at the time.
>
> Sent from my iPhone
>
> On May 7, 2020, at 7:50 PM, Mark Pennington <
> pennington.construction.inc.1@gmail.com> wrote:
>
> =EF=BB
> Mr Graves
>
> From reading the original post from Flibob. He was trouble shooting his
> air leak and determined the NLG actuator needed to be replaced. He order
ed
> one from Doug and left the old one out of the plane. Leaving the NLG on
> the ground with no actuator and only the upper and lower jack stay holdin
g
> the nose gear in place.
>
> The upper and lower jack stays when installed correctly and the actuator
> fully extended do settle into place over center. But this does not ensur
e
> the front nose gear will not collapse with the upper and lower jack stays
> only. If you are moving the airplane while the actuator is out and you h
it
> a bump or jog the airplane while moving it the upper and lower jack stay
> could reverse and allow the nose gear to collapse.
>
> Based on the original post I think the gear collapsed because the actuato
r
> was not installed and the gentlemen moved the airplane. If this is
> incorrect Flibob could give us more info.
>
> Based on a guy I know named Doug. He told me anytime your working on the
> landing gear. Have the plane on Jacks. The plane could collapse onto th
e
> floor of the hangar and onto the person under it in the right conditions.
> The only way the gear can not collapse while on the ground is to have ful
l
> pressure on the gear. And the other way is to ensure the 5 balls are
> engaged with zero pressure on the landing gear system. To do this, in th
e
> words of another CJ owner "whack the crap out of the incline brace struts
> on the main gear and the upper and lower jack stays on the nose gear at
> their pivot point using a 4x4".
> It should not collapse. Do the "whack test" while on Jacks...
>
> If I am incorrect in any of this please feel free to lend a hand and help
> out with more information.
>
> Mark Pennington
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm
_campaign=sig-email&utm_content=webmail&utm_term=icon> Virus-free.
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>
> On Thu, May 7, 2020 at 7:17 PM Robert Graves <flibob@att.net> wrote:
>
>> So in the case we are talking about it would indicate a defective nose
>> gear actuator. Am I reading this correctly?
>>
>> Sent from my iPhone
>>
>> On May 7, 2020, at 5:58 PM, Mark Pennington <
>> pennington.construction.inc.1@gmail.com> wrote:
>>
>> =EF=BB
>> Doug
>>
>> Will the balls in the locked position hold the aircraft up during a
>> normal landing with zero air. ?
>>
>> Mark
>>
>>
>>
>> On Thu, May 7, 2020 at 5:49 PM doug sapp <dougsappllc@gmail.com> wrote:
>>
>>> The locking balls will hold the aircraft in a 0 air situation if they
>>> are in the locked position.
>>> Mark is correct except there are 5 balls not 3. There is a joke here
>>> some where................
>>>
>>> Better every day.
>>> Doug
>>>
>>> On Thu, May 7, 2020 at 1:14 PM Mark Pennington <
>>> pennington.construction.inc.1@gmail.com> wrote:
>>>
>>>> Flibob
>>>>
>>>> I am assuming that when you refer to the nose gear selector you are
>>>> talking about the nose gear actuator the extends and contracts the gea
r
>>>> with air pressure.
>>>>
>>>> That actuator will hold the nose gear in the down position two ways.
>>>>
>>>> One is with air pressure on the cylinder.
>>>>
>>>> The second way is the locking balls in the actuator in the down
>>>> position. When the actuator is extended fully there are three balls t
hat
>>>> lock the gear in the down position. I think it is three if I remember
what
>>>> Doug taught me.
>>>>
>>>> With no air on the actuator the gear will stay down with the balls in
>>>> the locked position. If for some reason the actuator was not fully
>>>> extended the balls did not lock, the upper and lower jack stays can
>>>> collapse in the absence of air pressure.
>>>>
>>>> This is true of the main gear as well.
>>>> This is not true for the flap actuator. There are no balls in the fla
p
>>>> actuator.
>>>>
>>>> The locking balls is what enables you to move the plane with the air
>>>> off and no pressure in the system.
>>>>
>>>> I=99m not sure if the locking balls would hold the airplane up d
uring a
>>>> landing and no air pressure.
>>>>
>>>> Doug would be able tell us that.
>>>>
>>>> If I have mis quoted the system Doug let us know.
>>>>
>>>> Mark Pennington
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, May 7, 2020 at 3:41 PM Flibob <Flibob@att.net> wrote:
>>>>
>>>>>
>>>>> Nose gear collapse
>>>>> So last Saturday working on a minor air leak at the nose gear
>>>>> selector. Decided to do it outside in the warm spring sunshine. Ended
up
>>>>> having to replace the selector so emailed doug to get a new one and l
eft
>>>>> the old selector out. When I push the airplane back in the hanger as
I=99ve
>>>>> done hundreds of times same hanger the nose gear slowly collapsed ont
o the
>>>>> tug.
>>>>>
>>>>> Why did this happen? My theory is that the open circuit on the gear
>>>>> circuit provided no back pressure for the nose down side. But, I real
ly
>>>>> don=99t know. I know it=99s over center to lock down. I
would like to hear any
>>>>> ideas or theories.
>>>>>
>>>>> Luckily just minor damage to the cowling and the fiberglass on the
>>>>> tug. But I don=99t want to move the airplane again until I fig
ure out why it
>>>>> happened.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Read this topic online here:
>>>>>
>>>>> http://forums.matronics.com/viewtopic.php?p=496246#496246
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ==========
>>>>> List" rel="noreferrer" target="_blank">
>>>>> http://www.matronics.com/Navigator?Yak-List
>>>>> ==========
>>>>> FORUMS -
>>>>> eferrer" target="_blank">http://forums.matronics.com
>>>>> ==========
>>>>> WIKI -
>>>>> errer" target="_blank">http://wiki.matronics.com
>>>>> ==========
>>>>> b Site -
>>>>> -Matt Dralle, List Admin.
>>>>> rel="noreferrer" target="_blank">http://www.matronics.com/contrib
ution
>>>>> ==========
>>>>>
>>>>>
>>>>>
>>>>>
>
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Message 2
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| Subject: | Re: Nose gear collapse |
There is one other thing that could have happened and that is the original
equipment had steel balls and steel in a hi moisture environment will rust
and could rust to the point of not being able to lock the piston in place,
might want to replace the balls in that actuator with stainless steel, unle
ss it is recorded in the logs somewhere that it has been done. One of the f
irst maintenance items I did on my Yak 52 and it had rusty steel ball's.
On Thursday, May 7, 2020, 11:27:06 PM EDT, Robert Graves <flibob@att.ne
t> wrote:
Mark, =C2-Thanks for all your help. My original message said I left out
the landing gear selector a better terminology would=99ve been the va
lve at the gear handle. The actuator was in the airplane at the time.
Sent from my iPhone
On May 7, 2020, at 7:50 PM, Mark Pennington <pennington.construction.inc.1@
gmail.com> wrote:
=EF=BBMr Graves
>From reading the original post from Flibob.=C2- He was trouble shooting h
is air leak and determined the NLG actuator needed to be replaced.=C2- He
ordered one from Doug and left the old one out of the plane.=C2- Leaving
the NLG on the ground with no actuator and only the upper and lower jack s
tay holding the nose gear in place.
The upper and lower jack stays when installed correctly and the actuator fu
lly extended do settle into place over center.=C2- But this does not ensu
re the front nose gear will not collapse with the upper and lower jack stay
s only.=C2- If you are moving the airplane while the actuator is out and
you hit a bump or jog the airplane while moving it the upper and lower jack
stay could reverse and allow the nose gear to collapse.
Based on the original post I think the gear collapsed because the actuator
was not installed and the gentlemen moved the airplane.=C2- =C2-If this
is incorrect Flibob could give us more info.
Based on a guy I know named Doug.=C2- He told me anytime your working on
the landing gear.=C2- Have the plane on Jacks.=C2- The plane could coll
apse onto the floor of the hangar and onto the person under it in the right
conditions.=C2- The only way the gear can not collapse while on the grou
nd is to have full pressure on the gear.=C2- =C2-And the other way is t
o ensure the 5 balls are engaged with zero pressure on the landing gear sys
tem.=C2- To do this, in the words of another CJ owner "whack the crap out
of the incline brace struts on the main gear and the upper and lower jack
stays on the nose gear at their pivot point using a 4x4".=C2- =C2- =C2
-It should not collapse.=C2- Do the "whack test" while on Jacks...
If I am incorrect in any of this please feel free to lend a hand and help o
ut with more information.
Mark Pennington
| | Virus-free. www.avast.com |
On Thu, May 7, 2020 at 7:17 PM Robert Graves <flibob@att.net> wrote:
So in the case we are talking about it would indicate a defective nose gear
actuator. Am I reading this correctly?=C2-
Sent from my iPhone
On May 7, 2020, at 5:58 PM, Mark Pennington <pennington.construction.inc.1@
gmail.com> wrote:
=EF=BBDoug
Will the balls in the locked position hold the aircraft up during a normal
landing with zero air. ?
Mark
On Thu, May 7, 2020 at 5:49 PM doug sapp <dougsappllc@gmail.com> wrote:
The locking balls will=C2-hold the aircraft in a 0 air situation if they
are in the locked=C2-position.Mark is correct except there are 5 balls no
t 3.=C2- There is a joke here some where................
Better every day.Doug
On Thu, May 7, 2020 at 1:14 PM Mark Pennington <pennington.construction.inc
.1@gmail.com> wrote:
Flibob
I am assuming that when you refer to the nose gear selector you are talking
about the nose gear actuator the extends and contracts the gear with air p
ressure. =C2-
That actuator will hold the nose gear in the down position two ways. =C2-
One is with air pressure on the cylinder. =C2-
The second way is the locking balls in the actuator in the down position.
=C2- When the actuator is extended fully there are three balls that lock
the gear in the down position.=C2- I think it is three if I remember what
Doug taught me. =C2-
With no air on the actuator the gear will stay down with the balls in the l
ocked position.=C2- If for some reason the actuator was not fully extende
d the balls did not lock, =C2-the upper and lower jack stays can collapse
in the absence of air pressure. =C2-
This is true of the main gear as well.=C2-This is not true for the flap a
ctuator.=C2- There are no balls in the flap actuator. =C2-
The locking balls is what enables you to move the plane with the air off an
d no pressure in the system. =C2-
I=99m not sure if the locking balls would hold the airplane up during
a landing and no air pressure. =C2-
Doug would be able tell us that.=C2-
If I have mis quoted the system Doug let us know. =C2-
Mark Pennington
On Thu, May 7, 2020 at 3:41 PM Flibob <Flibob@att.net> wrote:
Nose gear collapse
So last Saturday working on a minor air leak at the nose gear selector. Dec
ided to do it outside in the warm spring sunshine. Ended up having to repla
ce the selector so emailed doug to get a new one and left the old selector
=C2- out. When I push the airplane back in the hanger as I=99ve don
e hundreds of times same hanger the nose gear slowly collapsed onto the tug
.=C2-
Why did this happen? My theory is that the open circuit on the gear circuit
provided no back pressure for the nose down side. But, I really don
=99t know. I know it=99s over center to lock down.=C2- I would like
to hear any ideas or theories.
Luckily just minor damage to the cowling and the fiberglass on the tug.=C2
- But I don=99t want to move the airplane again until I figure out
why it happened.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496246#496246
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigat
or?Yak-List
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
WIKI -
errer" target="_blank">http://wiki.matronics.com
b Site -
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
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