Author Topic: Idle bar vs. non-idle bar plug heat (Read 7016 times)

Clint Ormosen · « **on:** November 24, 2024, 06:31:02 PM »

I’m having a FB dispute so maybe someone here can clear it up. Does the idle bar simply protect the plug element from raw fuel splash, or does it help the plug retain and/or distribute heat?

Dan McEntee · « **Reply #1 on:** November 24, 2024, 06:57:55 PM »

I have always thought of it as a guard, so to speak, in the way we use them. I have seen numerous examples where carbon would grow on the idle bar and once scraped off, the coils was still nice and centered, and glowed bright and evenly. i learned from reading I think , that it got it's name from keeping the on rush of extra cold fuel from over whelming the element when throttle was moved to idle. That acts as a choke, so to speak, when the throttle barrel closes and draws extra fuel, and it tended to drown out plugs. That's my take on it.
What group is that on?
Type at you later,
Dan McEntee

PS to Ad: The answer is mostly in it's name, it is an IDLE BAR plug!! Something that small isn't going to retain and spread much heat. It's the element that does all the work, so it's meant to protect that at idle throttle settings.

GERALD WIMMER · « **Reply #2 on:** November 25, 2024, 02:33:01 AM »

Quote from: Clint Ormosen on November 24, 2024, 06:31:02 PM

I’m having a FB dispute

Oh no another of those, on there!
I'm sure the idle bar protects the glow from going out when running really rich on an old style engine that's doing the two /four thing.
If it just retained the heat better a Four Stoke plug would be just as good.
I think a lot of us have found a 4stoke plug and idle bar plug behave differently.

Regards Gerald

Motorman · « **Reply #3 on:** November 25, 2024, 05:53:01 PM »

I don't think the idle bar distributes heat in any significant way. Probable warmer than the aluminum walls but, it certainly wouldn't light fuel off if the glow element wasn't there.

MM

Clint Ormosen · « **Reply #4 on:** November 27, 2024, 11:09:21 AM »

Thanks all for the input

Lauri Malila · « **Reply #5 on:** November 27, 2024, 11:30:38 PM »

Brett Buck · « **Reply #6 on:** December 02, 2024, 11:04:18 AM »

Quote from: Clint Ormosen on November 24, 2024, 06:31:02 PM

I’m having a FB dispute so maybe someone here can clear it up. Does the idle bar simply protect the plug element from raw fuel splash, or does it help the plug retain and/or distribute heat?

I haven't noticed a consistent difference, other things about it seem to matter more.

For reference, I have only used "standard" plugs for about the last 25 years, either Thunderbolt "Big Bore and 4-Cycle" or S&H Type F.

Brett

Jim Oliver · « **Reply #7 on:** December 03, 2024, 07:55:05 PM »

Interesting comments.

bill bischoff · « **Reply #8 on:** December 03, 2024, 09:06:34 PM »

Early RC carbs weren't very good at metering fuel at lower power settings, so idle bar plugs helped. Consider that OS RC engines typically include the #8 glow plug, which doesn't have an idle bar. It just isn't necessary any more.

Dan McEntee · « **Reply #9 on:** December 05, 2024, 08:46:11 AM »

I got started using the Glow Devil R/C Long way back when after it was suggested to me and they always seem to perform better than K&B, and most certainly Fox plugs at the time and they lasted much longer. I have seen many examples of where carbon attaches itself to the bar and can grow until it interferes with the flow of fuel and it affects the engine run. It can be cleaned off, and the performance level returns. The thing I have always been hesitant about in trying the newer OS glow plugs is that they seem to be too short. The examples that come with new OS engines appear to be something in between a short reach and a long reach. Whether an idle bar is necessary any more or not, I want the element and the end of the plug where it should be in the combustion chamber. I think cost may be the driving force behind both the elimination of the idle bar ( along with the great improvements in model engine carbs ) and this odd ball length of the OS plugs.

Type at you later,
Dan McEntee

Brett Buck · « **Reply #10 on:** December 05, 2024, 12:38:03 PM »

Quote from: Dan McEntee on December 05, 2024, 08:46:11 AM

I got started using the Glow Devil R/C Long way back when after it was suggested to me and they always seem to perform better than K&B, and most certainly Fox plugs at the time and they lasted much longer. I have seen many examples of where carbon attaches itself to the bar and can grow until it interferes with the flow of fuel and it affects the engine run. It can be cleaned off, and the performance level returns. The thing I have always been hesitant about in trying the newer OS glow plugs is that they seem to be too short. The examples that come with new OS engines appear to be something in between a short reach and a long reach. Whether an idle bar is necessary any more or not, I want the element and the end of the plug where it should be in the combustion chamber. I think cost may be the driving force behind both the elimination of the idle bar ( along with the great improvements in model engine carbs ) and this odd ball length of the OS plugs.

Glow plugs are like props, you just have to try various types and find out whether it works or not. But always be very careful on the first few flights with a different glow plug, because one of the possible outcomes is that the engine just suddenly quits like you flipped a switch. We don't have a plausible mechanism for this, and it doesn't happen that often, but when it does do this you had better be prepared to recover. If it's a Rossi plug, be doubly cautious.

We have wound up with the plugs we have because of testing, and more-or-less, how much "power" they provide. The Thunderbolt RC was pretty good and worked OK, the Thunderbolt 4-Cycle let you run just a big richer for the same power, so we used that. The S&H type F gives about the same "power" but is much steadier in flight, essentially it removes some boost/brake which seemed to be really good on the 75, and is a mixed bag on the Jett 61 (since it was far steadier to begin with).

Brett

Reptoid · « **Reply #11 on:** December 05, 2024, 01:40:15 PM »

Quote from: Dan McEntee on December 05, 2024, 08:46:11 AM

"The thing I have always been hesitant about in trying the newer OS glow plugs is that they seem to be too short. The examples that come with new OS engines appear to be something in between a short reach and a long reach. Whether an idle bar is necessary any more or not, I want the element and the end of the plug where it should be in the combustion chamber."

Type at you later,
Dan McEntee

OS makes a plug that is actually a "long Reach" plug. It is the "LC3" and it works pretty well in most modern engines for stunt. I have no explanation for why OS makes their other plugs in weird lengths, as does Enya, and yet makes a normal long reach plug with a "hot" designation.

Brian Hampton · « **Reply #12 on:** December 05, 2024, 03:05:38 PM »

Quote from: Dan McEntee on December 05, 2024, 08:46:11 AM

The examples that come with new OS engines appear to be something in between a short reach and a long reach.

OS and Enya plugs have always been a medium length which no other manufacturer has ever used. Enya have never made any idle bar plugs either.

Brett Buck · « **Reply #13 on:** December 05, 2024, 04:23:47 PM »

Quote from: Brian Hampton on December 05, 2024, 03:05:38 PM

OS and Enya plugs have always been a medium length which no other manufacturer has ever used. Enya have never made any idle bar plugs either.

I have used Enya and OS plugs in regular engines with no particular problem. I don't think the difference in the length makes much if any difference. Slightly lowers the compression on a very low compression engine.

Brett

Dave_Trible · « **Reply #14 on:** December 05, 2024, 06:25:31 PM »

Quote from: Dan McEntee on December 05, 2024, 08:46:11 AM

I got started using the Glow Devil R/C Long way back when after it was suggested to me and they always seem to perform better than K&B, and most certainly Fox plugs at the time and they lasted much longer. I have seen many examples of where carbon attaches itself to the bar and can grow until it interferes with the flow of fuel and it affects the engine run. It can be cleaned off, and the performance level returns. The thing I have always been hesitant about in trying the newer OS glow plugs is that they seem to be too short. The examples that come with new OS engines appear to be something in between a short reach and a long reach. Whether an idle bar is necessary any more or not, I want the element and the end of the plug where it should be in the combustion chamber. I think cost may be the driving force behind both the elimination of the idle bar ( along with the great improvements in model engine carbs ) and this odd ball length of the OS plugs.

Type at you later,
Dan McEntee

I have a few OS 35S engines. It was suggested to me to use the OS plugs or add one or two additional plug washers to standard length plugs to pull them back a little. The engines do seem to behave better with a smoother needle range so it does seem to have a purpose at least in these particular engines.
I have long used the GloDevils, RC /bar in the past and now the standard since the RC plug has been out of stock for over a year (maybe forever?). I can't say I can tell too much difference although I think I am changing them a little more often.
BTW Sonic Tronics has the standard long on sale this week for cyber week -25% off. We ordered a few. Looks like S&H is about done with very little available at Mike's.

Dave

Lauri Malila · « **Reply #15 on:** December 06, 2024, 01:13:48 AM »

The best plug for Retro Discovery is the old Soviet KC-2. Sometimes they come with odle bar, sometimes without. Without it the engine runs better and at least the bar in KC was easily removable, making them usable.
There is 2 problems with idle bar, at first there is no access to the filament for centering and pulling/pushing it to correct depth in bore, and secondly, the orientation of idle bar is not always the same in combustion chamber. So, if some sort of a shield is needed, it’s better to make it integral with the head, not the plug.
I think Idle bar does what the name says, helps when the engine is idling. Not important for us. L

Author Topic: Idle bar vs. non-idle bar plug heat (Read 7016 times)

Clint Ormosen

Idle bar vs. non-idle bar plug heat

Dan McEntee

Re: Idle bar vs. non-idle bar plug heat

GERALD WIMMER

Re: Idle bar vs. non-idle bar plug heat

Motorman

Re: Idle bar vs. non-idle bar plug heat

Clint Ormosen

Re: Idle bar vs. non-idle bar plug heat

Lauri Malila

Re: Idle bar vs. non-idle bar plug heat

Brett Buck

Re: Idle bar vs. non-idle bar plug heat

Jim Oliver

Re: Idle bar vs. non-idle bar plug heat

bill bischoff

Re: Idle bar vs. non-idle bar plug heat

Dan McEntee

Re: Idle bar vs. non-idle bar plug heat

Brett Buck

Re: Idle bar vs. non-idle bar plug heat

Reptoid

Re: Idle bar vs. non-idle bar plug heat

Brian Hampton

Re: Idle bar vs. non-idle bar plug heat

Brett Buck

Re: Idle bar vs. non-idle bar plug heat

Dave_Trible

Re: Idle bar vs. non-idle bar plug heat

Lauri Malila

Re: Idle bar vs. non-idle bar plug heat