I hope this is not a stuped quetion. but if it is then I gess that is just the way it is. lol


I got a spark plug with my ignition. It is a NGK BPMR6F. On the box is has a big X on a pic of a air plane. Now This came with my cdi ignition so I know that it is good plug for the ignition but I would like to know why is there a X and a pic of a plane?

Can some one give me some info on this plug..
thanks
Paul

Not approved for full scale aircraft. Quite a few homebuilts use engines not specifically designed for aircraft.

It's not for FULL scale planes

Beat ya by seconds!

I've gotta ask, why does it not qualify for a full size airplane? What is special about a spark plug for an aircraft engine?

The governments involved... So because they cost 10 to 20 times the regular price they must be better. LMAO

I got out of full scale a little over a year ago and now that I don't have the expense of Annuals, Flight reviews, inspections, maintenance, hanger space, etc., ect., my model fleet is growing tremendously, (faster than my skill...LOL). But I'm having a blast...wife's ready to kill me but I'm having a time....

Ok I see.. the pic on the box looked like a rc plane.. Hard to look at...

I had a frind die last year from haveing a plug blow out of his engine in his plane... So I gess I can see why they do not want you to run them in one.
Paul

I have a dozen NGK plugs here and none of then have a plane on the box. Only things I see and can say about the plugs in my fathers full scale plane is there is a metal jacket over the plug. They appear a bit larger and the plug wire is screwed on and is spring loaded somehow.

You oughtta take a look at the electrodes. They're called "massive electrodes" in many cases and in no way resemble what we normally use. To qualify for use in full scale the plug has to be FAA/PMA/STC.

You can't believe how much that adds ot the cost of parts. In my old C-150 a legal replacement generator cost about $450.00 at the time. You could take one out of a Chevy and run for years for $55.00. It was essentially the same generator. Don't ask how I know...

Close Pat...

While the majority of the full scale piston stuff does use the massive electrode style plugs, there are fine wire versions available which usually have nearly twice the service life but also cost about twice as much. Also there are two electrodes on nearly every full scale plug I've ever seen with the exception of some AC plugs that actually had three electrodes, but the biggest requirement is indeed that they be FAA/PMA approved. While I've never played with the stuff that does not use an engine actually designed for A/C use, an STC would cover that as well.

As for running a regular automotive type AC Delco generators/regulators/parts etc. on full scale A/C, I have no recollection of having done that...

I'm not certain, but I think the fine wire plugs became more prominant after I left full scale stuff about 16 years ago, They were probably there but all the planes I was working on at the time had the massive electrode plugs.