From: "Andrew Martin andrew@martinag.com.au" <flyrotary@lancaironline.net>
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Date: Sun, 12 Aug 2018 09:41:01 +0800
Message-ID: <CAJxaVD2Zr145OA4BLGGHz1jde6nzFBYuQGTKFag8LMDs=p-szw@mail.gmail.com>
Subject: wiring
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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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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<div dir=3D"ltr"><br><div><div class=3D"gmail_signature" data-smartmail=3D"=
gmail_signature"><div dir=3D"ltr"><div>Just found the cause of an intermitt=
ent problem I&#39;ve been having. Seems over the last couple of weeks I tho=
ught I had been flooding the engine on startup, Well, I had but not from wh=
at I thought. For absolute years I&#39;ve never really had any issue gettin=
g the engine to start. but then just as I&#39;m about to start flying again=
 occasionally it would be impossible to start. turns out the ignition fuse =
was acting like a resistor.</div><div>Was hard to diagnose as just touching=
 the fuse made it work so every time I put the multimeter on it it would sh=
ow as ok, and volts at the coils was only ever slightly lower but obvious n=
ow at very low amps. and if by luck when the engine did start it would cont=
inue to run( guess due to extra couple of volts from alternator) so no infl=
ight failure, but would only have been a matter of time.</div><div><br></di=
v><div>Anyway now when I should be right in my test phase, I&#39;m back try=
ing to figure out if I need a redundant power supply for the engine. hard b=
ecause of the type of failure and there are so many single point failures p=
ossible its kind of pointless trying to mitigate them all.</div><div><br></=
div><div>The problem area was the contact surface between fuse &amp; fuse h=
older, Not sure if I got a dodgy fuse block or if its just the environment.=
 <br></div><div>So do I duplicate the engine power bus, switches &amp; wiri=
ng with diodes where the systems join at each component( lots a work) or ju=
st put it down as a totally random failure &amp; just check &amp; clean fus=
e panel connections as part of the annual inspection?</div><div><br></div><=
div>Andrew<br></div><div><br></div><div><br><br></div></div></div></div>
</div>

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