Tricopter V1.5 arm retaining pin system

Have been working on this project since March this year –  finally it flies!  The breakthrough for me was getting some HK KKV2.0 boards.  Got my new flamewheel style 450 quad and the tricopter flying on the same weekend.  Haven’t had much luck with the old KK boards,  but I have a few so will eventually try to get to grips with them.

I just wanted to share something relating to the 1.5 Tricopter, but it may be useful for other versions.  I’ve had the unfortunate problem of the forward arms swinging back on the craft under accelleration and destabilising the copter causing a crash.  I’ve installed a lightweight pin retainer system using 1.5mm piano wire and zip ties that will prevent this happening in future, but still allow the arms to fold in event of a crash  (though that bit is untested as yet!).

notes:
– When bending the wire don’t do a full 90 degree bend – this allows the wire to spring-lock against the hole and retaining zip tie.

– Two small holes are drilled – one through the frame plates and spar to lock the arms in position and one just through the spar clear of the frame for securing the locking wires when the tricopter is folded.  Hopefully the photos should make it clear.

– You don’t need to cinch down the yellow zip tie – it remains loose for reuse as the spring of the locking pin pushes against it.


Locking pins to the side of the copter showing the degree of bend and also the location of the two holes in the arms.


Locking pins inserted in locking holes, but not yet retained by zip ties


Here the locking pins are installed, retained by zip ties & ready for flight.


Retaining pins stored on the arms in secondary holes and retained by zip tie.

Here’s a video of the flight where I experienced the problem at the end and resulting crash

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