Do L'Hotellier Ball Fittings Wear?

In Australia AD177 covers L'hotellier couplings. 1000hr replacement for shanks under 6mm, 3000hr for others on flap and dive brake circuits. 0.1mm max difference between different axes of ball at 90 degrees to each other - like an X through the cross section (best to look at the diagram!). Lubrication each rigging, 50hrs and 6 months. There's a bunch of other stuff in there too, but not sure how much is Oz specific vs out of manufacturer ADs.

Cheers Ben

Reply to myself - most of that is in the previously linked L'hotellier maintenance instructions. My post was incorrect, replace all balls at 10yrs/3000hrs.

Cheers Ben

On Thursday, 14 April 2016 09:22:43 UTC+10, Ben Coleman wrote:
In Australia AD177 covers L'hotellier couplings. 1000hr replacement for shanks under 6mm, 3000hr for others on flap and dive brake circuits. 0.1mm max difference between different axes of ball at 90 degrees to each other - like an X through the cross section (best to look at the diagram!). Lubrication each rigging, 50hrs and 6 months. There's a bunch of other stuff in there too, but not sure how much is Oz specific vs out of manufacturer ADs.

Cheers Ben

Ben, it was probably the 10 year thing that Camden Sailplanes flagged my Nimbus on.
Jim

I have never heard of anyone replacing l'Hotelliers after 10 years (or any other interval). The annual check with measurements tells you when to replace them, if ever. That's condition-based maintenance, or CBM for those who love TLAs.

On Thursday, 14 April 2016 17:43:19 UTC+10, krasw wrote:
I have never heard of anyone replacing l'Hotelliers after 10 years (or any other interval). The annual check with measurements tells you when to replace them, if ever. That's condition-based maintenance, or CBM for those who love TLAs.

RBM down here.

Cheers Ben

In the maintenance instructions from l'Hotellier (attached in
http://www2.lba.de/dokumente/lta/1993-001.pdf pages 11 and 12)

At 20:47 13 April 2016, Casey wrote:


The interval recommended by L'Hotellier (and taken over by several
national
authorities as mandatory) is ten years or 3000 hours (whichever comes
first). Most manufacturers of aircraft who use L'Hotellier balls have
specified their replacement during the 3,000 and 6,000 hours and so
intervals. IIRC Schempp-Hirth has closer intervals (500 hours?) due to
them
being fitted in a different way and they have had threaded ends fail.

Erik,
Where do see that L'Hotellier recommends ten yrs or 3000 hrs? Also my
glider manufacturer has no mention of this in the life extensions.
I emailed them this morning and all they sent me was the maintenance
instruction and there is no mention in that of this recommendation.

At 07:43 14 April 2016, krasw wrote:
I have never heard of anyone replacing l'Hotelliers after 10 years (or
any
other interval). The annual check with measurements tells you when to
replace them, if ever. That's condition-based maintenance, or CBM for
those
who love TLAs.


Measuring them will indicate wear, not fatigue. On some types of gliders
fatigue has been an issue, especially when not properly lubricated, with
threaded ends breaking off from the control rod. Typically gliders where
the ball is on a 90-dgree angle to the socket and not in line with it.

National interpretations of the factory recommended replacement vary from
country to country.

On Thursday, 14 April 2016 14:00:09 UTC+3, Eric Munk wrote:
Measuring them will indicate wear, not fatigue. On some types of gliders
fatigue has been an issue, especially when not properly lubricated, with
threaded ends breaking off from the control rod. Typically gliders where
the ball is on a 90-dgree angle to the socket and not in line with it.

National interpretations of the factory recommended replacement vary from
country to country.


Which types are these? I have a glider that has only 90 degree joints.

If national authorities turn expression "recommended" into "mandatory", I would call that something else than interpretation.

no spray grease. huge mess. gentlemen never use it.

On Wednesday, April 13, 2016 at 9:06:58 AM UTC-4, Casey wrote:
Thanks for the comments.

I'm wonder what the dimensions of the balls are new.

My aileron balls on both wings are 0.02 mm smaller than the spoiler balls on both wings. Dimensions are same on each wing.

What is best lubricant? Thicker grease or thiner spray? I know the pro and cons of each but just wonder others thoughts.

Casey

At 12:18 14 April 2016, krasw wrote:

If national authorities turn expression "recommended" into "mandatory", I
would call that something else than interpretation.

Welcome to Europe, where this is how EASA-rules are interpreted by most
national authorities' legal experts. Australia too, and I believe New
Zealand.