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#41
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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
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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
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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$9l5.488178@pd7tw2no... Can anyone identify which helos use elastomeric bearings in the rotor hub. As a bonus, can anyone post an exploded view? Thanks Bill |
#44
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"Helimech" wrote in
news:kgODb.410428$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
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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$ao4.1341495@attbi_s51: Well I'm going to miss some but the ones I can think of a Eurocopters-AS350, AS355, AS365, EC120, EC130. Agusta-A109E, A119 and the AB139. Bell-407, 427 and maybe Bells big aircraft, I don't know. The 412 uses elastomeric bearings. -- Regards, Stan |
#46
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"Helimech" wrote in
news:fARDb.374117$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
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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
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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
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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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