REFLECTOR:MT 540 Prop
reflector@tvbf.org
reflector@tvbf.org
Fri, 31 Oct 2003 10:39:34 EST
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In a message dated 10/31/03 6:14:34 AM Pacific Standard Time,
cjensen@dts9000.com writes:
> However, their insistence
> of overhauling the hub ($1,400) to install a new seal design was less
> palatable.
I have the mentioned electric mt on a STD-RG that has been a headache mostly
due to the electric option. Definitely hydraulic is the way to go. I was
also caught up in the harmonic cracking of a blade and was responsible for
bringing out of the closet the rpm restriction on non-counterweighted 360s (sorry).
While my prop was in for the 3 month blade repair (warranty, after much
reluctance by mt) it was also noted that I had the "old" seal configuration. The
seals have nothing to do with it. The problem was, the hub being aluminum, the
bores where the blade "O" rings rest are also aluminum. The vibration of the
blade will cause this "O" ring to slightly move across the sealing area,
causing wear of the aluminum and particles becoming impregnated in the "O" ring,
compounding the problem. This will cause scoring of the sealing area and
eventually a leak. MT first tried changing elastomers to fix the wear problem but
this did not solve the problem. The correct fix is nothing special, counter
bore the sealing area (first 3/8" of each bore), and press in a stainless steel
ring for the seal to rest on. MT was overwhelmed with leaking seals so much
that mt will not provide seals to any repair station unless the hub has been
modified.
Now, if you mention the lack if proper engineering regarding seal design
(really pisses off the Germans) and that you understand this is a recognized
problem as mt now installs SS inserts in all new hubs, they should pay for it as
they did mine.
Sorry if this is to late for you Chuck.
TEC
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<HTML><FONT FACE=3Darial,helvetica><FONT SIZE=3D2 FAMILY=3D"SANSSERIF" FACE=
=3D"Arial" LANG=3D"0">In a message dated 10/31/03 6:14:34 AM Pacific Standar=
d Time, cjensen@dts9000.com writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">However, their insistence<BR>
of overhauling the hub ($1,400) to install a new seal design was less<BR>
palatable. </BLOCKQUOTE><BR>
<BR>
I have the mentioned electric mt on a STD-RG that has been a headache mostly=
due to the electric option. Definitely hydraulic is the way to go.&nb=
sp; I was also caught up in the harmonic cracking of a blade and was respons=
ible for bringing out of the closet the rpm restriction on non-counterweight=
ed 360s (sorry). While my prop was in for the 3 month blade repair (wa=
rranty, after much reluctance by mt) it was also noted that I had the "old"=20=
seal configuration. The seals have nothing to do with it. The pr=
oblem was, the hub being aluminum, the bores where the blade "O" rings rest=20=
are also aluminum. The vibration of the blade will cause this "O" ring=
to slightly move across the sealing area, causing wear of the aluminum and=20=
particles becoming impregnated in the "O" ring, compounding the problem.&nbs=
p; This will cause scoring of the sealing area and eventually a leak. =20=
MT first tried changing elastomers to fix the wear problem but this did not=20=
solve the problem. The correct fix is nothing special, counter bore th=
e sealing area (first 3/8" of each bore), and press in a stainless steel rin=
g for the seal to rest on. MT was overwhelmed with leaking seals so mu=
ch that mt will not provide seals to any repair station unless the hub has b=
een modified.<BR>
<BR>
Now, if you mention the lack if proper engineering regarding seal design (re=
ally pisses off the Germans) and that you understand this is a recognized pr=
oblem as mt now installs SS inserts in all new hubs, they should pay for it=20=
as they did mine.<BR>
<BR>
Sorry if this is to late for you Chuck.<BR>
<BR>
TEC </FONT></HTML>
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