Glow Plugs

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 Checking a glow plug
OS #8
Enya #3
Fox #8
Fox R/C Long
OS A3
K&B 4520
Checking a glow plug
Of course the easiest way to check a plug is to replace it and see if your engine performance improves. But some things to look for on the plug are:
a)frosted coil - the coil will have a white frosted type of look to it instead of the shiny metallic look. This is a sign of running too lean.
b)leaning coil - the coil is no longer centered and is close, if not touching, the side of the glow plug. The side of the plug acts like a heat sink to the coil and does not allow the coil to get as hot as it should. This also is a sign of the engine having been run lean.
c)dark color - the coil will have a brownish look. This is a sign of either running too rich or contaminents in the fuel. Usually just running too rich.
d)weak glow - put the glow plug driver on it and watch the coil. If only half the length of the coil glows, then it is bad (make sure your glow driver is charged up). Some plugs light up the whole coils while others like the OS #8 light up all but the last section of the coil. If you're not sure how much of the coil should light up, put the glow driver on a new plug and compare it.
OS #8
This is the plug everyone told me to use. It is very good. It's a hot plug which is necessary if you run a rich low end. The durability is better then any plug I have used. Durability of a plug means how well it will withstand a brief lean run. I have had over a hundred flights on this plug.
Enya #3
It's equivalent to the OS #8 in durability and is just a little hotter. I have heard more and more people prefer this plug over any other.
Fox #8
The performance is equivalent to the OS #8 and Enya #3, but the durability is not as good. The good thing about this plug is the cost. It typically sells for $3.50 as compared to the $7-9 price of the above plugs
Fox R/C Long w/ idle bar
I used this plug for a long time before switching to the OS #8. It doesn't cost much (~$2.50) and it works, its just that durability is very low on this plug. I consistently only got around 30 flights on each plug.
OS A3
I have only used one of these. It did not seem as hot and because my engines typically need a rich low end, this made starting the helicopter up and carrying to the flight line a tough job.
K&B 4520 (RC long reach)
I have not tried these but have heard they are good, last a long time, equivalent temperature of the Enya #3 (maybe just a hair cooler on idle), and cheap ~$2. I was also told Curtis Youngblood uses these.