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A very near miss


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Elsewhere I've related how I succumbed to a model shop bargain in the shape of a seagull i sport 10cc, lovely flier but I needed to spend a little time just tidying things up, throttle cable run, fastening servo leads out of harm's way etc.

Flew her last week and noticed a tendency for overcontrol, which I put down to insufficient exponential.

Flying her today with usual exponential and she is a REAL hand full. Landed her but not before I noticed random control inputs that I have not put in eg full up elevator full left rudder and engine speed changing.

Landed and changed the receiver (both futaba 617 faast jobs) started take off run violent turn to left so aborted and, taxying back noticed the elevator going to full up.

Called it a day and decided to change both the switch (which came with the plane) and the battery which was a new 1600 mAh LiFe unit.

When I got the battery out (after changing the switch) decided to check the voltage which was 6.62V. Whilst I was doing this noticed that the leads from the battery to the plug were showing bare metal and that the wee plastic barbs on the plug weren't snugged down into the crimped on terminal.

I then got a paper clip and cut two pieces off each about 25 mm in length pushed one into the live pin on the plug and clipped each of the DVM terminals to a piece of paper clip, Discovered that the pins on the female socket were only 0.5 mm longer than the distance from the end of the plastic of the male plug to where voltage began to show, ie the connectors were only inserted about half a millimetre metal to metal, whereas they should be nearer 5 mm in. I had used those hobbyking anti fall apart clips for the connecting plug and socket and believe that without this fitted it would have been a binbag job.

Quite pleased to have survived this and can't begin to think how this defect occurred.

Answers on a post card please

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When making up my plugs and sockets I need to watch the pins carefully. I always push home the plastic tabs. The pins need to sit in the plastic housing a certain way to get them to lock in correctly. I also use a desk light with a magnifying lens....helps no end ! cool

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I also had a very close call recently, also battery related, but a different cause.

Was charging up my trusty Great Planes PT19 mode using a Reaktor charger with separate power supply. l noticed that the battery seemed to be "full" faster than usual. So I waited a bit and put it back on charge. Same result.

Went flying and had 2 perfectly normal flights. The landing after the 2nd flight was a real smoothy and as I was happily taxiing back I realised there no rudder and no elevator either, but throttle still was working - thank goodness.

Reason - rx battery almost flat. It had just enough for the 2.4G rx to keep going and the analogue throttle servo, but not enough for the digitals on rudd, elevator and ailerons!

Cause -faulty power supply giving a fluctuating supply to the charger so it was cutting out early and hadn't charged the battery. The ps in question has now been taken out of service.

So that was far too close a call. If I had attempted just 1 more circuit there would have been nasty consequences. Obviously I should have investigated further when the charging didn't seem right. But its so easy to miss a warning isn't it?

Edited By David Ovenden on 29/08/2017 13:59:31

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