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number of rotor blades



 
 
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  #41  
Old December 16th 03, 11:29 PM
Bill Chernoff
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Can anyone identify which helos use elastomeric
bearings in the rotor hub.

As a bonus, can anyone post an exploded view?

Thanks
Bill


  #42  
Old December 17th 03, 01:45 AM
Helimech
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Your right, pictures are great. The problem is with the head assembled you
can't see the TT strap. I'll e-mail you some pictures from the BK117
(semi-rigid) head scanned from the Maintenance Manual and the Part Catalog
and also the same for the A109A/AII (fully articulated) head. JC

wrote in message
...

Having a picture certainly helps, but I'm still confused as to where
exactly that they go. First, are we talking about a semi-rigid or
fully articulated or other hub?

Essentially, it looks a lot like a box end wrench. However, in
function, it sounds a lot like an elastomeric bearing.

Do you know of any closeup photos with TT straps installed on the hub?

Dennis.


"Helimech" wrote:

The Tension-Torsion (TT) straps are basically 2 bushings a certain

distance
apart connected together by thousands of turns (I've heard something

like
12,000 turns) of stainless steel wire (around .020" dia.), sealed in a
plastic like covering. These straps (one for each blade) are what hold

the
main rotor blades to the rotor hub. The straps have to handle the huge
centrifugal loads (tension) of the blade but still allow for pitch

(torsion)
control inputs from the pilot. Here is a link to Lord Corporation and a
picture of some TT straps. Lord is the present manufacture of the

straps
for the BK117 and BO105. The strap that failed in Houston was made by
Bendix. http://www.lordmpd.com/aerospace/rot...ion_straps.asp

Hope this helps, I'm sure someone could describe a TT strap better but

this
is the best I can do this early in the morning. JC




Dennis Hawkins
n4mwd AT amsat DOT org (humans know what to do)

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm



  #43  
Old December 17th 03, 02:25 AM
Helimech
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Well I'm going to miss some but the ones I can think of a
Eurocopters-AS350, AS355, AS365, EC120, EC130. Agusta-A109E, A119 and the
AB139. Bell-407, 427 and maybe Bells big aircraft, I don't know.
Sikorsky-S76. That's all I can think of right now. JC


"Bill Chernoff" wrote in message
news:5HLDb.732201$9l5.488178@pd7tw2no...
Can anyone identify which helos use elastomeric
bearings in the rotor hub.

As a bonus, can anyone post an exploded view?

Thanks
Bill




  #44  
Old December 17th 03, 05:49 AM
Stan Gosnell
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"Helimech" wrote in
news:kgODb.410428$ao4.1341495@attbi_s51:

Well I'm going to miss some but the ones I can think of
a Eurocopters-AS350, AS355, AS365, EC120, EC130.
Agusta-A109E, A119 and the AB139. Bell-407, 427 and maybe
Bells big aircraft, I don't know.


The 412 uses elastomeric bearings.

--
Regards,

Stan
  #45  
Old December 17th 03, 06:11 AM
Helimech
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I was a "small" ship mech back in the early 70's at PHI and have always
tried to steer clear of the heavy metal stuff so don't know too much about
them. Always felt it too far to slip and fall from the deck. Had a feeling
the 412 used elastomeric but wasn't sure. What does the 430 have?

JC

"Stan Gosnell" me@work wrote in message
...
"Helimech" wrote in
news:kgODb.410428$ao4.1341495@attbi_s51:

Well I'm going to miss some but the ones I can think of
a Eurocopters-AS350, AS355, AS365, EC120, EC130.
Agusta-A109E, A119 and the AB139. Bell-407, 427 and maybe
Bells big aircraft, I don't know.


The 412 uses elastomeric bearings.

--
Regards,

Stan



  #46  
Old December 17th 03, 06:24 AM
Stan Gosnell
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Default

"Helimech" wrote in
news:fARDb.374117$Dw6.1220465@attbi_s02:

I was a "small" ship mech back in the early 70's at PHI and
have always tried to steer clear of the heavy metal stuff
so don't know too much about them. Always felt it too far
to slip and fall from the deck. Had a feeling the 412 used
elastomeric but wasn't sure. What does the 430 have?


No idea. I think they're mechanical, but I've never seen one up
close.

--
Regards,

Stan
  #47  
Old December 17th 03, 06:26 AM
Stan Gosnell
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Posts: n/a
Default

Stan Gosnell me@work wrote in
:

"Helimech" wrote in
news:fARDb.374117$Dw6.1220465@attbi_s02:

I was a "small" ship mech back in the early 70's at PHI
and have always tried to steer clear of the heavy metal
stuff so don't know too much about them. Always felt it
too far to slip and fall from the deck. Had a feeling the
412 used elastomeric but wasn't sure. What does the 430
have?


No idea. I think they're mechanical, but I've never seen
one up close.


Wait, you said 430, not 230. Probably elastomeric, but I've
never seen one up close. ;-)

--
Regards,

Stan
  #48  
Old December 17th 03, 07:17 AM
Dave Jackson
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Default


As a bonus, can anyone post an exploded view?


This web page has some exploded views. Click on the 3 small pictures, which
are located 1/4 of the way down the page.
http://www.UniCopter.com/0798.html

Dave J


  #49  
Old December 18th 03, 03:29 AM
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The diagram posted here was a lot better. I can see how it fits
inside the cones. I didn't know that they did it that way. I thought
the cones just had a big bolt down the center of them like the one on
the R22. I guess this just prooves that there is more than one way to
skin a cat.

Dennis.

"Helimech" wrote:

Your right, pictures are great. The problem is with the head assembled you
can't see the TT strap. I'll e-mail you some pictures from the BK117
(semi-rigid) head scanned from the Maintenance Manual and the Part Catalog
and also the same for the A109A/AII (fully articulated) head. JC


Dennis Hawkins
n4mwd AT amsat DOT org (humans know what to do)

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm

 




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