Tail Rotor Question for Eng TPs
Thread Starter
Joined: May 2003
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From: OS SX2063
Tail Rotor Question for Eng TPs
Is there any connection between Tail Rotor Teeter Friction and pedal sensitivity or Yaw instability.
We operate a 109E and it has 0 teeter friction in the tail rotor, when I picked it up I found it more difficult to keep in balance than the 109E I flew the day before, and any other 109 I'd ever flown. I got used to it, and just thought it was a bit sensitive. I've got another pilot doing my job for two weeks while I am off and he mentioned to me earlier that he had experienced the same thing as I have.
I questioned the friction values when went for a 100hr and was told zero is acceptable, they even left me a photocopy of the maintenance manual page in the aircraft to prove it.
Any ideas ?
We operate a 109E and it has 0 teeter friction in the tail rotor, when I picked it up I found it more difficult to keep in balance than the 109E I flew the day before, and any other 109 I'd ever flown. I got used to it, and just thought it was a bit sensitive. I've got another pilot doing my job for two weeks while I am off and he mentioned to me earlier that he had experienced the same thing as I have.
I questioned the friction values when went for a 100hr and was told zero is acceptable, they even left me a photocopy of the maintenance manual page in the aircraft to prove it.
Any ideas ?
Last edited by VeeAny; 15th December 2007 at 11:45.
Joined: Nov 2004
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From: Cambridgeshire, UK
Just a humble engineer, i'm afraid. By teeter friction you mean friction in the teetering assembly in the tail rotor hub itself? I would have though low friction the norm, since the teetering is there to allow sharing of lift on advancing and retreating sides. Perhaps they are meant to be sensitive, but the friction normally reduces tail rotor efficiency. You are discussing forward flight, and not hover?
Avoid imitations
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From: Wandering the FIR and cyberspace often at highly unsociable times
I would have thought that "zero" friction (wow!) is good! Surely, too much friction will cause difficulty if the control system linkage suddenly "gives" when that friction is overcome by a pilot yaw input.
Are you sure this isn't a SAS problem?
Are you sure this isn't a SAS problem?
Thread Starter
Joined: May 2003
Posts: 1,032
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From: OS SX2063
I do indeed mean the friction in the hub teetering assembly. The maintenance manual gives values of something like 0-1.6Kgs (units seem wrong but from memory this is what they quote) for acceptable 'pull off''.
If I am right about the units, its probably because its done with a spring balance, and they seem to be calibrated in Kgs.
I am talking about forward flight, and by balance I mean ball centred straight and level flight.
It may be a Yaw SAS problem, but I don't think it is. [Edited to Add Shytorque and I crossed posts, so I am not arguing with him]. The SAS APIs are pretty still during all of this and it seems to be worse on turbulent days, it reacts worse to turbulence than other same Spec 109s.
I am still interested if any Test Pilots can shed light on this as a general case, and not neccesarily the 109 specifically.
Cheers
Gary
If I am right about the units, its probably because its done with a spring balance, and they seem to be calibrated in Kgs.
I am talking about forward flight, and by balance I mean ball centred straight and level flight.
It may be a Yaw SAS problem, but I don't think it is. [Edited to Add Shytorque and I crossed posts, so I am not arguing with him]. The SAS APIs are pretty still during all of this and it seems to be worse on turbulent days, it reacts worse to turbulence than other same Spec 109s.
I am still interested if any Test Pilots can shed light on this as a general case, and not neccesarily the 109 specifically.
Cheers
Gary
