Check your fly lead plugs and sockets.......a lesson learned!

[Mike.K 60]

I learned the hard way!

Two low level prangs in less than a week......I`m quite diligent with my air frame maintenance but I missed a vital point. Having flown my Ultra Stick for over a year now, I failed to note advanced wear on the Rx fly lead to the aileron Y-lead. Each time the wing was removed for LiPo changing, wear on this connection accelerated with increased use and accumulated air time.

I`d completed three successful flights out of the Falcon field last week before an issue became apparent just as I was completing a landing. The Ultra Stick failed to respond to an aileron command and the model ploughed into the rough vegetation around the landing strip. This broke the fuselage in half aft of the wing trailing edge and ripped the centre section out of the wing. The model is currently border line as regards repairs.

Close examination of the wreckage revealed a worn plug and socket connection between a fly lead and a Y-lead.  I often debate whether to use security keepers in such locations wondering if it is better to have connections that part easily in the event of a crash or to put security keepers in place and risk tearing leads to pieces if there isn`t an easy break point. What do you do? Please tell me.

Having the heavily damaged Stick on the bench for post-prang evaluation, I compared the near two hundred flight fly lead and Y-lead against two unused equivalents. The used part connections were certainly worn. The new parts plugged together with an audible "click". Its obvious which parts would be more reliable. For the sake of just £3 worth of new leads, I lost an almost new air frame and the LiPo suffered a single cracked cell. Whilst it still held full 6S charged voltage of 25.2v in total and all cells read around 4v individually after a two minute flight.  The pack is now considered as scrap. Why? Whilst the pack holds its voltage, it will not provide sufficient current to run the 360Kv motor. It is a dead unit.

The defective £3 worth of cable and Y-lead cost the demise of a £206 Ultra Stick and the £100 LiPo pack. A lesson learned. Please check your own model cables and Y-leads for similar faults on a regular basis. I`ll be applying an inspection of this high wear point now after each and every flying session.

Yip, I missed this fault when checking the model over prior to flight. It won`t happen again. My model, my responsibility.

Mike

Edited July 16, 2020 by Mike.K
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