Tail rotor blade to pitch change link rod ends

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Tail rotor blade to pitch change link rod ends

Postby seneca2e » Thu Mar 28, 2013 6:24 am

The book p/n is a 2975 and they’re a little unusual because they have a 3/16” bore and are a 1/4-28 male thread on the other end. Some have been changed to REM4T rod ends(1/4” hole) with reducer bushings to make them work. The brantly book specifically allows this on some rod ends(noting for example that Brantly p/n ##### is just a REM4T or whatever with reducer bushings). However I found a comment(from memory I think this was in SI/SL #9) that the teflon rod ends (which the R designates) can be used everywhere BUT the tail rotor pitch links. What is your opinion on the tolerances and possible speculation on why the teflon ones would not be allowed there? My tail rotor has the new style longer pitch change links(2.87 inches or so from memory) which take the 2975 not the 325-20 rod ends. Obviously the 2975 must be shorter since the pitch change link is longer. Any equivalent numbers? Does anyone have a opinion why teflon rod ends were approved as replacements everywhere but the tail rotor pitch change links? Perhaps that has been superceded but not published since but with an orphan machine it's hard to find such stuff out. Some of the former Brantly factory guys might know but I've been unable to make contact with them. This is not as trivial as it sounds since there are so many different rod ends with alignment specs as well as radial and axial load specs. Somewhere someone probably knows what a 2975 is in Heim or Aurora numbers. Spruce has a Heim p/n M34-14M that is close(not sure if the threaded shank would have to be trimed slightly due to the longer pitch link) but can't get a definitive answer.


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Last edited by seneca2e on Thu Mar 28, 2013 10:18 pm, edited 1 time in total.
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Re: Tail rotor blade to pitch change link rod ends

Postby 9121u » Thu Mar 28, 2013 5:04 pm

HI ED I have found that using teflon rod ends especially on any pitch links the teflon gets beat out in time i no on the main blades any how.. i like to use the original brass race type.there.. still available new.. all the bearings for the brantly are available new.. the original tail blade pitch ends were sealed mini roller typ bearings.. just make sure you use the correct ones because some wont let you get the pitch you need 17 to 18 on your blades with out binding. what ever you use...when all done check for freedom in all directions and.. minimum 17 degree on full left pedal b...safe have fun...
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Re: Tail rotor blade to pitch change link rod ends

Postby seneca2e » Thu Mar 28, 2013 10:13 pm

Thanks Tom. Do you know of any cross reference part numbers that you've seen successfully used either Heim or Aurora or any other for that matter?
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Re: Tail rotor blade to pitch change link rod ends

Postby 9121u » Fri Mar 29, 2013 2:28 pm

ED I do not have a alt # .try calling RADIAL BEARING..they might have what your looking for or the can make for you ..the make rod ends.....hope this helps yea out...or bill might have some..
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Re: Tail rotor blade to pitch change link rod ends

Postby seneca2e » Sat Mar 30, 2013 12:19 pm

Okay Tom thanks.
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Re: Tail rotor blade to pitch change link rod ends

Postby seneca2e » Wed Apr 03, 2013 8:03 am

Okay after considerable time and effort I've come up to the answer to my own question. Many thanks to those that helped! I obtained a actual Brantly drawing of the Brantly part number 2975 rod end! It superceded to a REM-4T with reducer bushings to take it from a 1/4 hole to a .190 hole. In addition it must be trimmed to 1.312" center of hole to end of male thread and the end chamfered .030/.060x45 degrees. It then says that it goes to a Rem3T-3 which does not require the reducer bushing. However you will still have to trim the male thread as above as Radial Bearing who makes that rod end says the stock length is 2" on that rod end. Note that the Rem3t-3 is a teflon lined bearing which according to service bulletin #9 should not be used. Sometime after that came out they obviously decided it was okay(and in fact teflon lined bearings are used in some Bell and other helicopters tail rotors according to people I talked to). If you want to go with a non teflon lined bearing Radial p/n Rem3-4m is exactly the same rod end except it is not teflon lined. It also will require trimming as it is about 1.5" long(only other difference) so trim as above and you have the same thing just not teflon lined.

To review a p/n 2975 can be replace with a Rem4t with reducer bushings and trimmed to 1.312"
A Rem3t-3 can be used without reducer bushings and trimmed to 1.312"
A Rem3-4m can be used without reducer bushings and trimmed to 1.312".

As Paul Harvey used to say "That's the rest of the story!"
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