j.huey Posted June 9 Report Share Posted June 9 Hello all, I had been flying this b-212 helis for long. I encountered a peculiar problem that never eseen before. The heli develops a violent and uncontrolled vibration on short finals at ht of 10 ft, when i eased back the cyclic and come up with collective for a moment. The vibration kept on increasing. I had to go round. On the next approach, the same thing happened. However, this time i could land. This heli had an issue of violent on ground vibration and it was corrected by some work on pitch link. Quote Link to comment Share on other sites More sharing options...
iChris Posted June 12 Report Share Posted June 12 (edited) On 6/9/2024 at 6:23 AM, j.huey said: Hello all, I had been flying this b-212 helis for long. I encountered a peculiar problem that never eseen before. The heli develops a violent and uncontrolled vibration on short finals at ht of 10 ft, when i eased back the cyclic and come up with collective for a moment. The vibration kept on increasing. I had to go round. On the next approach, the same thing happened. However, this time i could land. This heli had an issue of violent on ground vibration and it was corrected by some work on pitch link. Have an A&P check the bearings on the lift-link and elastomeric isolator mounts; I think there are five. The transmission is connected to the airframe by three different devices. The main attachment, the lift-link, is a forged steel connector incorporating self-aligning bearings at each end. The lift-link connects directly between the airframe and the transmission case and is designed to absorb all airframe/rotor loads. Four elastomeric vibration isolator mounts position the transmission properly on the pylon and isolate rotor/transmission vibrations from the airframe. A fifth mount is bolted to the center of a support fitting which is bolted to the airframe structure. Also confusing sometime SCAS issues induced oscillations in the 212 at low speeds, particularly in out of trim conditions. Transmission Mounting BELL_212 Edited June 12 by iChris Add link... Quote Link to comment Share on other sites More sharing options...
j.huey Posted August 9 Author Report Share Posted August 9 Thanks a lot @iChris Quote Link to comment Share on other sites More sharing options...
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