What is the deal with a idle bar on the glow plug? what is the purpose???????????????

I have some older OS engines one os46 sf that will when tuned on the high end will studder full throttle give her 2 clicks lean and shes perfect , then she leans out after half a tank and cuts, off the tank is installed center level with carb. Never had these problems for yrs the low end is fine.

Do you think an idle bar will stop the sputter so I can run her a little rich without sputter ???????????????????

Idle bars are old school and came about due to the flow of air/fuel into the cylinder of engines with baffled pistons.

How about a little more info on your setup? What fuel are you running, what plug, what prop. Did the engine ever run properly or has it always behaved like this? Have you checked for any leaks around the needle valve, barrel, carb throat, back plate or head?

John

Idle bar plugs were used with cross flow scavenged two-stroke engines. Not the schnuerle ported engines of today, although I have seen a few rare applications where an idle bar plug saved the day.

I doubt that an idle bar plug is the cure, for your OS .46SF, which is a modern schnuerle ported engine. My guess would be fuel foaming. Make sure your fuel tank, or the brass feed lines of the fuel tank, are not touching any part of the fuselage. Especially do not use a fuel tank with its neck passing through the firewall. The ARF makers know better than to do this. They simply do not care about their customers.

They are also used for zero nitro applications to help keep heat in the plug, I have used them in engines that required a rich Idol setting in order to run good at full throttle. Simply helps protect the element from fuel splatter.

I still use Fox Gold Post idle bar plugs in several two strokes. One of them cured my Moki .61 LS of a quitting problem during transition at about 3/4 throttle. If you opened the throttle very slowly it would never quit, with the Fox in it, you can throw the throttle open and transition is instant. And they are a must in Webra SilverLines and Mercos.

Didn't know this was bad. Care to elaborate?

Those tanks that stick through the firewall have never been a problem, just something for people who worry too much to fret about.

I've had to straighten out the fuel tank neck through the firewall problem more times than I care to remember, Dave.

Having been a club instructor for many, many years, I always try to get to the student pilot before they assemble their trainer. The reason is to discourage them from using those through the firewall tank installations and have them switch to what a real R/C'er knows to do - isolate the fuel tank completely from any and all solid parts of the model.

Fuel foaming is one of those things that ruins engines and engine makers' reputations unnecessarily. You have the right to disagree, that is for sure, but I know that you are dead wrong on this one. I have solved too many problems with "junk engines" by isolating the fuel tank to change my mind.

I just finished a Telemaster 40 and put an RCV .58 CD on it, I placed the fuel tank in the bottom of the fuse on cg and, glued a piece of 1/8 ply across the former with a 1 inch hole in it for the exact purpose of anchoring the front of the tank. It will not be a problem as it's not a problem on any other plane I have.

Sounds like fret to me. I have a through the wall tank on my Cap and Avistar. Used some silicone all around and have 1/8" or more isolated by the silicone, which will dampen vibration.

No fuel foaming issues.

This is my perfered method for mounting tanks if at all possible since it gives very easy access to replacing the fuel lines should the need present it self. I've done this on countless pattern and sport models without a single foaming issue.

John

If you put one cartridge in a six shooter and play Russian Roulette, the odds are five to one that you won't have a discharge when you pull the trigger. I'd rather do something right the first time and not have to worry about it.

What's really funny is when the model flies okay for a while with the tank through the firewall and then one day, after many flights, the engine begins acting funny.

I've seen people chase their tails and end up rebuilding engines a couple of times because of fuel foaming and eventually end up replacing several different "bad" engines.

After all, it couldn't be caused by the model that has flown flawlessly for a year or so, could it? Models change over time and resonance points move around the model as they age and wear. What once worked well, is now causing problems, but sometimes people just refuse to see it. Habit, I guess.

To each his own.

....went out with "high button shoes". I had this proven
to me over 25 years ago....back in the old days....idle
bar plugs were considered r/c plugs (with throttles) and
non idle bar plugs were used in control line planes....
(full throttle)....I had a friend who started competing in
c/l "carrier" events....where the planes had to run several
laps at high speed....and then real slow (throttled down)
for landing.

He found out that the non idle bar plugs were far better
than the ones with the bars. He asked me "why would
you want to block the fuel....from the fire" ? Made sense
to me....and I switched. Yes, exposing the fire to the
fuel....without a barrier is a good idea....

Dave.

I'm with Artisan on the Fuel Tank issue. As dear ol' Dad use to say. "Never time to do it right, but there's always time to do it over."

So when ever possible, I do isolate the fuel tank and that in turn virtually eliminates fuel foaming as a problem should the engine start acting up.

I do have models where the tank has an interference fit in the formers to retain it and if I should have engines problems I do keep this in mind before starting to needlessly tear down an engine.

Neoprene weatherstripping works excellent here. Inexpensive, comes in a variety of widths and thickness.

Happy Fly'n....

Shoot, almost all planes have a center of the engine
mount hole cut in them for the tank to stick through.
I'm kinda' a vibration nut myself....and always make a
foam rubber donut....for the front of the tank.

Here's a rear tank mount I made for the Arresti....
I know.....a little overdone, I guess....but it's fun

....I could have used a popsickle stick, and a piece of
foam....but, what fun would that be....

Dude, you could have built a kit with less effort than you put into that ARF.

John