Hello all,

I have been around RC planes for almost 6 years, and still havent really understood the glow plug fuss. What is the best glow plug for a 2 stroke motor. Does it really matter what brand that you use with certain motors? And long/short, hot/cold? I have a OS 46SF, OS 46FX and a Webra 40. And I am pretty sure that I have the same plugs in them all. Any help,advice or explainations would be great!! [8D][8D]

Thanks,
Chris

"Keep Em Flyin"

I have had good luck using the Tower Power plug in all my 2 cycle engines. There are other plugs that some people have used in all their engines though.

Enjoy,

Jim

Jim,

I didnt think that it mattered what name brand plug you used, but what is the diffrence between long/short, hot/cold, or plugs with and idle bar? I am sure that I could eventually figure all of this out but it would help.

Thanks,
Chris

"Keep Em Flyin"

Hi Chris,
From what I'm lead to believe, the 'bar' in the idle bar plug was to stop the element becoming 'saturated' at idle and thus flaming out. I'm sure someone will correct me if I'm wrong there.

The hot/cold thing is where it gets interesting though.

The different heat designations are 'supposed' to be an indicator of what type of fuel they're suitable for (specifically the methanol content of the fuel). Unfortunately, the 'cold/hot' designations aren't always the same between brands. A much better way of identifying different plugs would be by element thickness. This way, they can't be confused. Thicker element for low methanol content fuels (more platinum available for the catalytic reaction), thinner element for higher methanol content fuels.

The thicker the element, the more platinum surface area is available for the chemical reaction that keeps it glowing. Lower methanol content fuels require proportionally higher platinum in order for the reaction to be sustained. However, if you look at the element in, say, an Enya#3, it's actually quite thick, even though it's called a 'hot' plug

As for the long or short plugs, well, the difference there should be obvious No idea of the virtues of either though......I assume some engines prefer having the element further down in the head (or visa versa), thus requiring a 'long' (or 'short') plug.

Mr. Bonk,

Thanks for the information. All of that explains a lot of my questions. I never really paid much attention to what glow plugs I had or bought, usually when I went to the local hobby shop I told them I needed a glow plug for a certain engine and never gave it much thought as to what type it was. Really just knew that the name of the plug meant more or less money in my pocket! And to be honest I never really saw any difference in plugs.

Thanks again,
Chris

The short plugs are for .15 size engines and smaller. The long are for anything over that. A short will work in a large engine, at reduced compression in a pinch. A long plug in a small engine will sometimes hit the top of the piston. Idle bar plugs were designed for cross flow engines to keep the element from cooling when the bypass fresh mixture came in. These days with schnuerle porting on just about every engine, they are not really needed although for many it is a hard habit to break. As to hot or cold, If you remove power to the glow plug and notice a drop in rpm, you either need a hotter plug or more nitro. If no drop is noticed, you are probably right on. If on the other hand, you hear a frying egg type noise, your plug is too hot or you are running too much nitro. Hope this helps. To be quite honest, most engines aren't too picky!

Max

Bonk's explanation is right on. It couldn't have been said better.

There's some other kinds of plugs. There's the 4 cycle plugs that tend to be rather hot and to have a extended end on them that protects the element from the cold fuel charge.

There's the Turbo plug that is realatively new. It is rounded on the end. There are certain engines that are made for Turbo plugs only. There's nothing more than just the element part of the plug that sticks into the combustion chamber.

Generally, the short plugs are used on the .15 and smaller engines and the longs are used in the bigger engines.

But the OS #8 and Tower Power plugs will confuse you because they are half way between short and long. They are to be used in 'long' engines and they work just fine.

Sometimes a person will use a 4 cycle plug in a two cycle engine.

You will see on here people declaring that only a certain plug works in a certain engine. Or that they use the same plug brand and type in all their 2 cycle engines. But there are a lot of variables and this combination may not work for you.

The best thing is to try it and see.

Enjoy RCU

Jim

Thank you to all of you for the information. It will be very helpful! In fact I did what you guys said and changed my plug today with a OS #8 and the engine ran perfect. I am not sure what was in the engine before it was old looking though, should ask the previous owner. But I got the motor running really well and thas all that I wanted to do. Maybe down the road I will experiment with other plugs but for now it seems that the OS #8 does the trick for my OS 46 SF!!

Thanks again everyone,
Chris

Jim & Mr. Bonk,

Thanks for all the great information. I never really looked at glow plugs that way. They just seemed like dpark plugs for a car. I never really messed with them either. Just bought new ones took them out of the box and put them in. And up until a few years ago learned that its best to set them to the right guage or what ever the mecanical term is for that. So I guess hot and cold, long and short is almost like a automobile spark plug in a certain perspective. Anyway, after reading your replies I wll think or know to ask questions the next time that I am at the LHS buying parts and plugs. I just wish that my LHS was like RC Universe. Very informative and helpful. I havent had bad experience here yet. And as for the "New RC Universe" the new look and changes scared me a little at first, but after a few hours and days looking and surfing the site is bascially like the old one and better. I think that everyone that complained or left just wasnt ready for "change". And that comes in everyday life so we will just have to get over it and deal with it. And I know of a few people that I told about this site and they now use it more than the others and really like it. So change is good. I hope everyone that is new and has been around for awhile begins to enjoy and love it as much as me. Its helped me in many ways and answered a lot of questions that I have had.

Thanks RC Universe and all of the members that are stll here and to come![sm=cool.gif]

Chris

Chris,

Bonk, Max, and I appreciate the applause and kudus. It makes us feel good. I think I'll go out to the flying field?

I could share a lot more glow plug info with you if you would like it?

Hope you have a nice day also.

Enjoy RCU

Jim

Edited to add MAX

Enjoy RCU

And I suppose I have no idea what I'm talking about. thanks W8ye

Max

Max,

I meant thanks to everyone, sorry that I left you out. But I meant everyone that posted a reply. W8ye could really use a lot of help with tuning glow engines. Something is always coming up and I have one good friend that helps me out all the time but he has his own thing going on and me being disabeled it makes it very hard to try and get to the field every weekend to just ask for help or find someone who is willing. But as I said before in my last post here on RC Universe everyone has been great and even reading on other subjects posted in other forums has helped and answered a lot of my questions. "RC Universe" is a 24 hour help hotline!!!! Thanks again guys! If any of you dont mind I could use the email or pm feature to email you direct because I could ask or post a page or more here!! Ha ........[sm=biggrin.gif]

Thanks again,

Chris

Here is my email if you would like let me know if I can email direct!!
[email protected]

Hey, no worries......glad you found the info useful!

Hello again,

Thanks again for all of the useful information. It came in handy and explained a lot of wuestions that I had. Also everyones websites were also very full of information. So thanks again guys!!!


Chris
P.S. You can close this thread.