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Hartzell HC12x20 diaphragm leaks

Posted: Sun Apr 08, 2007 4:40 pm
by danMichael
'Hartzell fliers:

Its time to replace the diaphragm on my Hartzell HC12x20-8 prop. It
works well but has been seeping oil since a few weeks after its last
replacement which makes for a dirty airplane (although rust-free!).
Does anyone flying behind the Hartzell have any good advice on
keeping it dry? Ive contacted Hartzell and they werent able to offer
any advice other than to avoid over-tightening the clamp bolts (which
cracks off the ears). Last time we used a light coat of sealant but
Im not sure if that helped or hurt. It seems that the rubber
compresses over time and the clamp bolts lose torque; I am going to
leave the prop off for a few days and re-torque before finishing
reassembly to see if that helps.

Thanks,

:Dan Michael
:NC81323'

Re: Hartzell HC12x20 diaphragm leaks

Posted: Sun Apr 08, 2007 5:03 pm
by Jamie Treat
'Dan,

Expect very little help from Hartzell. All the folks that knew the prop have died or retired. You can give Tom Goodlett a call in Texas. He has about 20 years experience with the Hydro. Has been inside and replaced items over the years.

Tom Goodlett
817-790-3190


Jamie

Jamie S. Treat
Aircraft Restoration & Repair
Kelly Airpark (CO15)
24201 David C. Johnson Loop
Elbert, CO 80106

Hm/Hgr 303-648-0130

Never fly anything that doesn't have the paint worn off the Rudder Pedals.

----- Original Message -----
From: danMichael
To: fairchildclub@yahoogroups.com
Sent: Sunday, April 08, 2007 3:39 PM
Subject: [fairchildclub] Hartzell HC12x20 diaphragm leaks


Hartzell fliers:

Its time to replace the diaphragm on my Hartzell HC12x20-8 prop. It
works well but has been seeping oil since a few weeks after its last
replacement which makes for a dirty airplane (although rust-free!).
Does anyone flying behind the Hartzell have any good advice on
keeping it dry? Ive contacted Hartzell and they werent able to offer
any advice other than to avoid over-tightening the clamp bolts (which
cracks off the ears). Last time we used a light coat of sealant but
Im not sure if that helped or hurt. It seems that the rubber
compresses over time and the clamp bolts lose torque; I am going to
leave the prop off for a few days and re-torque before finishing
reassembly to see if that helps.

Thanks,

:Dan Michael
:NC81323




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