Do you run a master switch, or are the Circuit breakers the switch. I
   have a master switch, but its bothering me that if that if ONE switch
   fails, it all fails. I I think I'll skip the master switch for flight
   critical.

   Bob Mears
   Supermarine Spitfire

   That has happened Bob. A Power Sport RV8 crashed and was destroyed
   when the master switch failed.

   Not a problem with mags in cert airplanes.  Only in these all electric
   airplanes.

   Paul Lamar ...No rotor no motor.

It sounds like you are considering what might be known as a battery
bus.  A good idea.  A battery bus powers flight critical items like fuel
injection systems and electronic ignition.  The general guideline for a
battery bus is that its feed is short (less than 1ft) between the
battery and the circuit protection devices (fuses - preferable or
breakers).  This makes it more robust from a standpoint of power
interruption and minimizes the length of unprotected wire (lacking a
fuse - unprotected wire might be a fire hazard should the wire's
unsulation become damaged for some reason).

Also be sure to use flexible wire (fine strand - like welding wire) for
connections to the battery.  Normal 2g or 4g wire is quite stiff because
each strand is rather heavy.  Fine strand wire puts much lower
mechanical loads on battery terminals (which are generally relatively
weak compared to other electrical connections).  For smaller wire
elsewhere in the plane, the strand size isn't critical - just for the
main feeds connecting to the battery (power and ground).

For aircraft that have engines that are electrically dependent, pay
close attention to the small details in the electrical system.


Regards,

Matt-

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2007 All world wide rights reserved.