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Calling any B747 mechs... please help


I've attached a schematic - what are the purposes of the aileron yoke load limiter (big centering cam and serious spring) and the 6° lost motion tang?  The manual says nothing about the function of these devices.  Need to know if I should use any portion of these functions or just let them be and do nothing. 

A rod and heim joints will replace the cables on the lower spool for the yoke linkage, and there's a pulley on the FO yoke to provide positioning to a pot or transducer using an o-ring as the belt.



These are failsafe devices to allow for aileron operation in the event of one yoke becoming jammed, or a cable snapping etc.

A word of advice, don't use an O-ring to drive your position sensor!
You need something indexed and repeatable.  O-rings will move on the pulleys constantly, and you will be forever calibrating your yokes.
Use a toothed belt or similar instead.

Also when replacing the aileron cables between the yokes with the rods, be careful to keep the full range of motion, which can be difficult with solid linkages.   Im not a 747 expert, but i know on the 737 the yokes can move 107 degrees each way, but a lot of replicas and conversions only move 45-60 degrees.

Hi, Mick. I couldn't find  aileron drums for my 737, so I bought 747 drums as a lot of the parts are the same.

There are hard stops on the drums, and this gives me about a hundred and five degrees total motion for the yokes.

Thank you for the good advice on the drives for the encoder. It's always good to know of potential problems before you create one.

I should be able to use a mechanical linkage and modify the drum pulleys accordingly. But I will keep an eye on it and if I have to I'll use cables.



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