Originally Posted by Brutus1967
OK? a glow plug cannot break?
Anyway, that is not how reliability assessments are made.
That would be: parts present combined with their respective mean faillure rate.
Personally, I think glowplugs in general show a significantly higher faillure rate than the combined chain of battery, sensor, electronics and sparkplug.
I understand . Actually I was just breaking it down a bit . Still , there is very little that breaks down with a basic glow system . (Abuse aside) Even if you add on board glow (An extreme practice, far from mandatory) In the unlikely event of an onboard glow failure , the engine usually just purrs along without notice . In 50 years of flying , I have used on board glow with one plane . That plane is a loaner / trainer Kadet Senior . The on board glow is a convenience/ saftey addition to eliminate the need for a glow plug driver for starting . The engine idles and runs perfectly without the glow addition .
In the air , the main link is a simple glow plug . Many ,if not most
glow plug failures are discovered and fixed on the ground .
The typical CDI has a myriad of components that can fail , any one of them can stop the engine at that point . Spark plugs foul , just as glow plugs fail . Hall effect sensors can come loose/fail , heavy on board batteries can fail , shielded plug wires can fail , CDI boxes etc . Shielding inadequacies can cause radio interference as well .
Parts that are not there cannot break still holds true .
Glow may have some drawbacks but the reliability and simplicity factor is pretty high with glow systems . I have seen very ...VERY few problems with glow systems . That won't keep me using CDI ..just sayin !
I whole heartedly doubt the potential glow failures in the air exceed the rate for spark ignition systems .
Diesel anyone ?