Elevator control rod

[Stevec]

Hi all
Just googling away the evening I came across a technical built in from the UK CAA talking about mandatory replacement of an elevator control rod on all T66 aircraft. The instruction given was that part number T66-c/512 must be replaced with part number T66-C/5009. It is dated 1995 so is quite old but I would be interested to know if anyone has any information on this and what the changes were. I have looked at my plans and see they mention this part as the rod that runs back from the control column.
Rgds Steve

[JimCrawford]

This came up in a conversation I had with Dave GARBG a while ago. If I remember correctly the original push rod joining the bottom of the control column to the bellcrank arrangement at the rear of the seat had made up plain bearings which were prone to cracking. Replacing them with spherical bearings solved the problem. I believe all Slingsby Nippers had the AD incorporated at manufacture but it would be easy to tell by inspection.

On my Nipper this rod has spherical bearings rivetted in so the operating length is fixed. I shall be applying to the LAA for a mod to use a rod with a threaded bush welded in the end so that a spherical bearing with a thread can be used, this will make that operating length variable. The reason for this plan is that, at full aft stick, the stick hits the harness buckle (and I am not a particularly porky shape). I find this unacceptable*. All the cable tensions and stops are aft of this rod so changing the length doesn't alter any of that geometry. It does however move the position of the top of the stick, lengthening the rod by 10mm moves the handgrip forward by 50mm. so it is quite a powerful adjustment. My Nipper does not have the seat rake mod and those that do probably do not experience this problem.

I'll dig out and post some photos I took for the mod papers.

*as does the instructor at Bicester recently when Bloggs, demonstrating a spin entry, brought the stick fully back and released the instructor's seat harness. - bet that got his attention!


Jim

[Stevec]

Hi Jim

Thanks for the reply. I suspected it may be something like that. I like the idea of the adjustable end on the rod it is far better to be able to make small adjustments like that. I have incorporated a similar idea on the flap rods on my Menestrel as it was just about impossible to get the flaps exactly where you want them with fixed length rods.
Any photos would be appreciated.

Rgds Steve