Mailing List flyrotary@lancaironline.net Message #64230
From: Neil Unger 12348ung@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] wiring
Date: Sun, 12 Aug 2018 12:18:36 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Andrew,   Electrics -- I hate them as all looks the same if it works or not.  At least with mechanics you get a half gear missing which is obvious, not so with electrics.  I wired my fuses with a 30 amp fuse so that without a solid short it should never trip.  Redundancy is the never ending discussion --- just where do you stop?  LIke Dick Smith said, we need "affordable" safety, not a full second plane towed behind.  Only time I have trouble starting is if batteries get below 11 volts, otherwise second turn every time -- noise.

Question to all, just what sort of connection can I put in my electrical circuit to take jumper leads??  My baron had a female plug on the outside for those occasions.  I want something similar on the inside that I can plug into without having to dismantle the seats to get to the batteries.  Bad enough having to find another battery let alone a full tool kit as well.  Suggestions??

Neil Unger.


On 8/12/2018 11:41 AM, Andrew Martin andrew@martinag.com.au wrote:

Just found the cause of an intermittent problem I've been having. Seems over the last couple of weeks I thought I had been flooding the engine on startup, Well, I had but not from what I thought. For absolute years I've never really had any issue getting the engine to start. but then just as I'm about to start flying again occasionally it would be impossible to start. turns out the ignition fuse was acting like a resistor.
Was hard to diagnose as just touching the fuse made it work so every time I put the multimeter on it it would show as ok, and volts at the coils was only ever slightly lower but obvious now at very low amps. and if by luck when the engine did start it would continue to run( guess due to extra couple of volts from alternator) so no inflight failure, but would only have been a matter of time.

Anyway now when I should be right in my test phase, I'm back trying to figure out if I need a redundant power supply for the engine. hard because of the type of failure and there are so many single point failures possible its kind of pointless trying to mitigate them all.

The problem area was the contact surface between fuse & fuse holder, Not sure if I got a dodgy fuse block or if its just the environment.
So do I duplicate the engine power bus, switches & wiring with diodes where the systems join at each component( lots a work) or just put it down as a totally random failure & just check & clean fuse panel connections as part of the annual inspection?

Andrew




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