Hello, I have a Hobbico Trainer with an O.S. 40 LA engine. The glow plug that came with it was an A3. When I asked my LHS for A3 glow plugs they said that I Shouldent use those and I should use thunderbolt standard w/ an idle bar. Should I use those glow plugs or return them and get some A3's?

Your local hobby store told you not to use the manufacturer's recommended glow plug?

Most Medium Hot to Hot glow plugs in standard or long length and with or without idle bar should work in your .40 LA

Your LHS gave you very suspect advice, although Thunderbolt plugs are supposed to be good plugs.

There shouldn't be anything wrong with the A3 plug. In fact, that's the plug I use in all of my 2-stroke engines (ranging from .25 to 1.6 size) and it's a great plug. Go ahead and use it, you'll be just fine

Hope this helps

Ken

Sounds like the LHS is over stocked on those plugs and is trying to find someone to unload them on. I have an la40 and have never had a problem with the A3. In fact I put in a new plug in the spring, and fly all season never having to change it. They are almost indestructable. {now watch, I'll fry 1 every time out this year LOL}

Just because someone works in a LHS doesn't mean they know what they're talking about. The manufacturer's recommendations don't always work well in every application, either. For your LA in a trainer, a standard Fox or K&B plug will work well. Since some LAs tend to run a little rich at idle, get a plug with an idle bar.

Dr.1

I use the A3 in my LA 46, and it runs perfectly. No need for an idle bar. If you think its running too rich at idle, lean the low end a little. You don't have the overheating problems with a lean run at the low end.

Brad

I would take them back and tell the LHS to sell you what you ask for and to save their opinions for when you ask for one. Use an A3 or OS #8, either is fine in that engine.

Yup I was wondering too why they said A3's wouldent work. If they work then Ill just keep them.

A3 is pretty much the standard "regular" glow plug... i use them alot, and they are pretty good..
it seems like the Hanger 9 plugs last a bit longer,,, but cost more,,
and ENYA 3's are a club favorite,, but again, cost more,,

like alot of things in this hobby, you get what you pay for..

tower hobbies plugs work, but wear out pretty quick...

A3 will do just fine. The LA series engines are rather low compression and very tolerant. I don't run them but instruct many that do.
In addition those Thunderbolt Idle Bars will also give you good service, however not for a long time.
Like many standard plugs today the platinum is in short supply in these plugs and after 20-25 flights, even though they glow well to the eye, they allow a thin glaze to occur which tends to insulate the low platinum amount from the methanol thus reducing catalytic action between platinum and methanol with resulting poor ignition, especially at throttle-up and idle.
Some years ago TBs were the choice of many fliers, especially me. However for the past 10+/- years the specialty heat ranges of the McCoy line has won me over.