Wondering how critical the glow plug position is (have a P80). I know the manual notes that it should be upright ... but the engine hatch is on the bottom of the aircraft and if I mount the engine so that the plug is upright I will have to remove the engine whenever the plug needs replacing. Would mounting the engine so that the plug is at the 4 O'clock or 8 'O'clock position be acceptable ? ? Thanks. Bob

Bob, I have a similar situation with my P70 in the R-54. I only have access to the plug if it's in the bottom quadrant of the engine. I asked Jet Cat about this, relating that the manual states the plug should be within the upper quadrant. They told me that it would be OK near the bottom but I might see shortened plug life because the plug will tend to accumulate more combustion debris in this area. To date I have the original plug installed and have had no problems with starting.

John and Bob

Dave Wiltshire of Motors and Rotors has said in one of his articles in RCJI that the most problems he encounters is with the plug in the 1600hrs too 2000hrs position, this seems to be less ciritical with the Kero start, but still he advises if possible to get the plug as near to the top as possible.

Mike

Dave if you read this forgive me for quoting you, but I wanted to show it was from an informed source.

I have two Flash with P-120s and both have the plug at 4 oclock and there has been no problem in two years.
One plug went south after 21 flights.
About average.
It was changed in 5 miniutes.

According to "Mr. Matt JetCat" the orientation of the Keroplug can be at all 360 degrees:
http://www.rcuniverse.com/forum/m_8357027/tm.htm

you can in theorie

but dont ask me why :

gas start plug mounted on 9-12 will ignite faster then on 12-15.

kero plug works best on 12
small flames can be seen on : 15 and 17
wont work to good on 6.
and seem to perform ok on 8 and 16.