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gord(at)thedampub.ca
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 Posted: Mon Aug 24, 2015 5:47 am Post subject: Landing Gear actuators |
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A little over a month a go I posted an note on the experience I had with no green light on gear down selection. It all worked out ok with no damage.
We took the landing gear actuator cylinders out and sent them to M14P inc for overhaul. When they applied 200 psi shop air to the left actuator to retract the piston and blew the end off the cap when the piston contacted the end cap. You can see from the picture that the end face of the cap is quite corroded where the actuator cylinder end was probably resting on the cap while on the ground and moisture collected. There are also dents in the cap where the piston was contacting it.
I had a slight air leak in the gear system and I think this was it. You can see discolouration where there was a slight crack for some time. I would turn the air off after a flight and then when I turned it back on before a flight the gear actuators would load up and reduce the air pressure. This does not happen now.
We installed the overhauled actuators and did some gear swings. Then we discovered that there were no restrictors in the normal air lines. No where in the manuals are restrictors shown.
We ordered the restrictors and drilled them out to .8mm.
I asked Jill at M14P if the other 3 end caps were checked for cracks and the answer was yes they were visually inspected and there was no problem. However I couldn’t be so sure and worry every time I put the gear down, so we removed the actuators again and I had the end caps x-rayed for cracks. The tests turned out fine and there are no cracks.
We installed the gear with the restrictors in the lines. It now takes 3 seconds to retract and 5 to extend instead of 1 and 2 seconds.
We were very careful to measure the amount of piston protruding from the actuator in the gear down position to make sure that end of the piston does not contact the end cap. We had to adjust the fork end 1 thread. The restrictors will also help that problem.
I will be removing the actuators for overhaul again sooner rather later.
[img]cid:859C8DD6-112F-44F9-B400-6D17C198E4FF[/img][img]cid:E611C6FD-B684-4465-BB69-5C3151E4F820[/img]
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1992 Time(s) |
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1992 Time(s) |
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jan.mevis(at)informavia.b
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| Posted: Mon Aug 24, 2015 6:26 am Post subject: Landing Gear actuators |
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Thanks for sharing!
Jan
From: <owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)> on behalf of Gordon Price <gord(at)thedampub.ca (gord(at)thedampub.ca)>
Reply-To: "yak-list(at)matronics.com (yak-list(at)matronics.com)" <yak-list(at)matronics.com (yak-list(at)matronics.com)>
Date: Monday 24 August 2015 15:43
To: "yak-list(at)matronics.com (yak-list(at)matronics.com)" <yak-list(at)matronics.com (yak-list(at)matronics.com)>
Subject: Landing Gear actuators
A little over a month a go I posted an note on the experience I had with no green light on gear down selection. It all worked out ok with no damage.
We took the landing gear actuator cylinders out and sent them to M14P inc for overhaul. When they applied 200 psi shop air to the left actuator to retract the piston and blew the end off the cap when the piston contacted the end cap. You can see from the picture that the end face of the cap is quite corroded where the actuator cylinder end was probably resting on the cap while on the ground and moisture collected. There are also dents in the cap where the piston was contacting it.
I had a slight air leak in the gear system and I think this was it. You can see discolouration where there was a slight crack for some time. I would turn the air off after a flight and then when I turned it back on before a flight the gear actuators would load up and reduce the air pressure. This does not happen now.
We installed the overhauled actuators and did some gear swings. Then we discovered that there were no restrictors in the normal air lines. No where in the manuals are restrictors shown.
We ordered the restrictors and drilled them out to .8mm.
I asked Jill at M14P if the other 3 end caps were checked for cracks and the answer was yes they were visually inspected and there was no problem. However I couldn’t be so sure and worry every time I put the gear down, so we removed the actuators again and I had the end caps x-rayed for cracks. The tests turned out fine and there are no cracks.
We installed the gear with the restrictors in the lines. It now takes 3 seconds to retract and 5 to extend instead of 1 and 2 seconds.
We were very careful to measure the amount of piston protruding from the actuator in the gear down position to make sure that end of the piston does not contact the end cap. We had to adjust the fork end 1 thread. The restrictors will also help that problem.
I will be removing the actuators for overhaul again sooner rather later.
[img]cid:859C8DD6-112F-44F9-B400-6D17C198E4FF[/img][img]cid:E611C6FD-B684-4465-BB69-5C3151E4F820[/img]
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
| Description: |
|
| Filesize: |
1.26 MB |
| Viewed: |
1989 Time(s) |
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| Description: |
|
| Filesize: |
134.98 KB |
| Viewed: |
1989 Time(s) |
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draftsjust417(at)gmail.co
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| Posted: Mon Aug 24, 2015 10:02 am Post subject: Landing Gear actuators |
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Good info, thanks-
Justin
N280NC
On Aug 24, 2015 5:58 AM, "Gordon Price" <gord(at)thedampub.ca> wrote:
[quote] A little over a month a go I posted an note on the experience I had with
no green light on gear down selection. It all worked out ok with no damage.
We took the landing gear actuator cylinders out and sent them to M14P inc
for overhaul. When they applied 200 psi shop air to the left actuator to
retract the piston and blew the end off the cap when the piston contacted
the end cap. You can see from the picture that the end face of the cap is
quite corroded where the actuator cylinder end was probably resting on the
cap while on the ground and moisture collected. There are also dents in
the cap where the piston was contacting it.
I had a slight air leak in the gear system and I think this was it. You
can see discolouration where there was a slight crack for some time. I
would turn the air off after a flight and then when I turned it back on
before a flight the gear actuators would load up and reduce the air
pressure. This does not happen now.
We installed the overhauled actuators and did some gear swings. Then we
discovered that there were no restrictors in the normal air lines. No
where in the manuals are restrictors shown.
We ordered the restrictors and drilled them out to .8mm.
I asked Jill at M14P if the other 3 end caps were checked for cracks and
the answer was yes they were visually inspected and there was no problem.
However I couldn’t be so sure and worry every time I put the gear down, so
we removed the actuators again and I had the end caps x-rayed for cracks
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
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