Increasing current only burns out fuel touching the glo plug.  Increasing current only shortens glo plug life, and can burn it out.  Best solution for flooded engine is to turn the cylinder upright and crank it in reverse, or wait a few seconds for fuel to fall away.

Increasing current only burns out fuel touching the glo plug.  Increasing current only shortens glo plug life, and can burn it out.  Best solution for flooded engine is to turn the cylinder upright and crank it in reverse, or wait a few seconds for fuel to fall away.

I'm more interested because people are asking me about current meters that the can mount on their forearm-mounted racing kits.  Knowing the meter current lets me keep my eye open for something better than disassembling a metered glow starter (which, so far and in the absence of any real experience, seems to me to be the best bet).

An ammeter is a handy device used on a flight box/battery.  You can instantly see the health of the glo plug and battery.  When the engine doesn't want to start, a meter helps in isolating the problem.

Any passive device for measuring current necessarily causes a voltage drop in the circuit.  An ammeter causes a voltage drop.  A sensing resistor (producing a voltage which can be measured in many ways) also drops the voltage.

An active current sensor would require a  magnetic field detector for the weak magnetic field surrounding a straight wire carrying current.  This would require an amplifying circuit because the resulting signal would be too weak to indicate directly.

Any meter using a D'Arsenval movement is a delicate instrument, easily damaged unless protected.  Iron Vane type meters are more rugged.

I think I'd be happy with a 0.01 ohm sense resistor.  That works out to a 50mV drop, which is considerably smaller than the drop in the battery, and probably less than in the wiring in a typical glow plug setup.  I checked on what's available on the market today -- I think it would be doable, maybe even easy, to make a meter with an LED bar graph that wouldn't light up until there was glow plug current, and that would take a couple of years to suck the charge out of a single D cell, much less a few in parallel.

   This one seems small enough and you can change the shunts to get it in the right range:

https://www.ebay.com/itm/Dual-LED-Digital-Voltmeter-Ammeter-Panel-Tester-0-28-DC-100V-10A-Red-Blue-Shunt/183188976926?hash=item2aa6e9f51e:m:mG1OmsQ3VVYTF0nQaufeHyQ

     This will be much more durable than an electromechanical meter.

     Brett