Twos In
I am not looking for an argument so I will trust what you say on the Tow Fit causing Much of the vibration.
I never fitted a "bonk' but memory says that when fitted you had to 'Strike it Hard' with you fist to assist setting up the first reading , hence the Bonk name.
I stand to be corrected on that.
The Curse of Lynx from early on was the 4 R Vib.
We, 9 Regt shared a hangar with 4 Regt who where the first unit in BAOR to be equipped with the Lynx.
Our new cabs where up and running and the Mechs from 4 Regt, where consistently busy trying to sort out the 4 R which had come from nowhere.
Much ribbing and friendly rivalry as we shared same Seniors Mess.
I cannot remember the figure of Flying Hrs when the 4 R appeared but will suggest 300 Hrs a Honest estimate.
Memory says we did our First Lynx Op Banner tour before we started to have 4 R problems.
The cab would be OK pass the electronic monitored Vib runs, Then Bang pilot would come in an complain about a 4 R from nowhere.
4 Regt where already up to their necks in this matter and could offer little serious advice.
The arguments in the maintenance side soon got nasty.
One side said 4 R so must be something that affects All 4 Mr Blades.
However expireance from the men at 4 SUGGESTED that by checking the complete system from Collective to Head you often found a worn linkage and by replace this you reduced or even brought the Vibs in limits.
The Falklands had finished and Lynx deployed down there, taking a unbelievable amount of stores out of the system, That is another story.
4 & 9 amalgamated to form a new 4 Regt with 3 line Sqns.
Blood letting then occurred in Maintenance organization which split the unit down the middle.
The other Regts in BAOR had similar problems on 4 R but someone else will have to make there contribution.
I could never get rid of the 4 R and I will suggest neither could anyone I knew UNLESS they managed to Change, The Main Rotor Gearbox and with all the items in the Falklands supply chain MRGB changes where few and far between.
Start of 86 I went to NI and saw out the 4 1/2 years I had left there.
Same problem but higher priority and availability for spares, especially after Lynx where withdrawn from Falklands and in NI, MRGB where change overnight. Cab in by 18.00 and back 'S' for 08.00 following morning, weather permitting airtest.
I was not involved in the solution but to the best of my knowledge,
SOMEONE at 71 Workshops in German finally put all the reports together and notice that the 4 R only developed over a certain number of Flying Hrs. About lets say 300 Hrs.
Further investigation I assume with Wastelands, led to the discovery that a large diameter spacer in the MRGB was 'Wearing' and then permitting vertical movement.
Replacement of this 'Spacer' cured the Vib.
In NI the OC Wksp arraigned with an engineering company down in Belfast to machine a new spacer to correct dimension after it had been determined on a strip down. This took place overnight and the 18.00 in 08.00 out procedure was accepted policy.
I was not involved in the matter having other duties at the time so all Hearsay, but I understand correct.
john
I have been told by a Little bird that the Lynx supplied to a friendly Mid East power now suffer the dreaded 4 R at 300 + Hrs.