Hi Fellas,

Just been doing some reading and it appears 'cold medium hot' glow plugs control the glows ignition timing. Basically, if you want to advance the ignition timing then use a hotter plug and conversely if you want to retard your ignition timing use a colder plug.

Another way of advancing your timing is to increase the fuel nitro %, so for a maximum ignition advance use 25% nitro and a hot plug.

I was experimenting with a Force 46 aero engine and was using 5% nitro and a medium os plug and I found that the idle wouldn't go below 3k rpm without cutting out so today I changed the plug to hot and now it idles nicely at lower rpm.

I notice cars/buggy/truggy idle at 6~7k rpm, this is an unfortunate consequence of high performance race nitro engines. Aero's are lazy by comparison.

Or change the mixture
Of change the compression ratio
Or use switched on board glow
Or combine a colder plug with switched, on board glow
Or ditch the glow plug and switch precisely settable spark ignition.

Yeah, Jesse, thanks for your reply, you are indeed correct. But..., using a medium plug and leaning out the idle mixture I still couldn't get satisfactory results until I changed to a hotter plug.

Or, use a cold plug and add battery power at idle to add heat. That way you retain the desireable colder heat range at higher speeds.

Or, use a cold plug and add battery power at idle to add heat. That way you retain the desireable colder heat range at higher speeds.

Not saying the solution, laying out a viable option.


Actually sounds like you are trying to retard, not advance firing angle.

I tried a hotter plug and found the engine idles at lower rpm than with the medium plug, this makes sense to me because I am only running on 5% nitro and actually I would like to go down to zero nitro and see how she runs.

Due to bad weather I haven't tried the top end yet but it was pretty darn good with a medium plug but idling was a a problem, I'll try again tomorrow.

Jesse, having put some thought into what you said I maybe getting mixed up between advance and retard or early detonation with a hot plug, but then I am a learner so the reason for raising the thread in the first place.

try a larger muffler but not too big. yet you can go even bigger if you rase your nitro percentage.

Jim

and the Hotter plug will help with a larger prop because the Hotter plug will burn more fuel when at slower RPM.

Edit: the OS plugs are numbered 6, 7, 8. the #6 is a rather hot plug. most 46 engines today run well with the OS 8 even with 5% fuel.
to go with all the info in this thread above, prop size has can have effect on what plug range you need when burning 0%-5%. just know that the longer your prop is the more momentum it has/so the more flywheel effect it greats. your engine will work harder with that big prop, it will accelerate slower. so a Hot plug will stay lit longer and start the flam front sooner all helping to burn more fuel.
more pitch only loads an engine more, it doesn't great more momentum. nevertheless with more pitch you still "may" need a hotter plug because your engine is working harder so it is turning slower, so again the hotter plug will help burn more fuel.

Jim

Well, well, well been playing the whole afternoon with running my engine, there is not much difference between a medium and a hot plug. The slight difference I did see was the every now and again the engine would cut out when using the medium plug. With both plugs the lowest rpm I can get is between 3~4k. I can get it lower but the engine is prone to cutting out and the vibrations are severe(mechanical harmonics).

You have quite a bit to do .

yee-up, that's typical. and that gets worse with the small engines. 35, 25, 21, 19, 12 all need to run a higher and higher Idle.
but then again, you may just find that one guy that has learned to get his engine to run a lower Idle than all others. that's the blood of the hobby.

but to add, if an engine has a "Higher Port Timing" most likely it needs to have a bit higher Idle. but all factors come in to play. fuel type, oil, and Nitro %, air density, prop size, muffler/pipe.
if you ask me I would guess your Force 46 has a bit higher port timing than other engines. it doesn't cost more to make and it's a good way to get people to buy. some Chinese 46 engines come with an oversize muffler. my friend has a Chinese Tower Hobbies 46 and it's a screamer. it may have a loose connecting rod but it's a screamer.

they say "if your engine has been running OK, yet when you start it and it's Idle/RPM drops a bit when you remove the Igniter from the plug you may need a new plug or a hotter plug".

Jim

I'm happy with the results, practical manufactures rpm range is 2~16k rpm that is a a no no I doubt these figures, top end I'd be happy with 12k rpm whilst bottom end 3k5 rpm. Although aero engines are lazy compared to surface nitro engines, they are still high performance engines, what 7.45cc producing 1.6 hp@16k rpm that's good going if you ask me.

Well, actually Jim, I'm finding the opposite, I'm using an os no8 medium glo plug and a fastrax hot and I notice, whilst running the hot plug and removing the glo starter, the rpm drops a little? This is not noticeable with the os medium plug?

If you are a beginner reading this, don't use a integrated rechargeable battery glow starter, get yourself a 12V 7Ah lead acid battery and charger, use a 12 V glo start current source glo adapter and a Hangar 9 12V starter motor, it works well. With this equipment, I can start my engine when ever on demand.

Looks to me like more room for improvement.Hang in there!


Why should a beginner tether himself to lossy, corded equipment?

I sure wouldn't

I'd be mighty interested in your alternative?

But you didn't say why a cord-free starter should be avoided?

Okay, what is a cord free starter then?

A starter that has the battery directly attached.
Like this Syllivan starter powered by a DeWalt power tool lithium battery, mounted on the rear cover.

Or this LiPo mounted to a Kavan geared starter.

The single cell glow ignitor is also a viable, reliable glow lighter.


No cord, low power loss at the loaded end.

I started with an integrated rechargeable glo starter 1800mAh. works but lasts about 10 minutes of use. Then recharge takes 16 hours.

Then buy a more beefy one 2100mAh, after 16 hours charging produces a dull red glow for a hot plug so it's duff and I'm -£18 down.

Then buy a more beefy 3Ah with built in battery indicator meter use for 20 minutes then flat requires 16 hours for recharge.

Now, there are two ways to start a glow engine either you can try turn the engine over with a chicken stick until hell freezes over or you can use a 12 v starter, there are 3 to choose from JP, Hangar 9 or Align. for the former 2 you need a 12 V 7Ah lead acid battery and the align requires a 2s lipo 7.2V+ charger.

Now the JP burnt out in couple of days total crap £30 down the drain, next up is Hanger 9(£50) which I recommend-it works. next we need to sort out the glow starter, since we are using a 12V 7Ah lead acid battery already we need a glow start system to be powered of the 12V 7Ah these specialist 12 V starters are available for £13.50, just connect them across your 12V 7Ah battery and you are good to go.

the OS 8 is a medium-hot plug. different brands are not rated the same. your Fastrax plug may be colder than the OS8 ? or bad ? I don't know. look at the coils and see if they are bent. the coil in a plug can bend if the engine was run too lean or too hot, or too much compression or too much Nitro. the coils in a cheaper plug don't hold up to a lean run as good as a better plug would. (I'm NOT saying Fastrax plugs are cheap, I don't know). you can take both plugs and lite them both in the dark to see what one is hotter. but nevertheless, a cheaper plug can look good in that kind of test. but on a running engine it's a different kind of test

Jim

To each his own.
My field can usually remains in my car between flying sessions. The internal battery is tapped to the vehicle and maintained on charge, always ready. Planes and transmitters are charged during the drive to the field. As is the glow driver battery. I arrive at the field with all batteries topped off and ready for a day of flying.
Once at the field l generally have no problem at all getting a day of flying in with a single glow driver. For the exceptions, there is a "backup" in the car that sees very little use, except when flying twin cylinder engines. An average start takes less than thirty seconds of glow power. One or two flips with powered glow plug.
Most starts are hand flipped, still have not used a cord connected starter or glow driver in years. Would never go back to full time use of them either. The electric tool battery produces far more starting power. Will crank much larger engines than a cord connected lead-acid battery.


The above field can is all I usually take to the flight line. This is my field support for a very active day of flying. The starter sees very little use, usually sits in the car, with a spare glow driver, also rarely used. Also in the car, seldom visited,a few spare props, a couple spare glow plugs and the tools needed to change them.


The other side of the fuel can, 12 volt Lithium Ion battery below.

Fast charging option for field charging, seldom used but available.


Regarding plug heat:
There is also the on board glow option. An often neglected side benefit of on board glow is the ability to run a colder glow plug. This minimizes the need for a compromise plug.
Run a cold plug best suited for top end. Switch the glow power on at idle, hot plug.



Again, to each his own but I would surely not rule out the cordless option when giving advice to a beginner.

I did not rule out the cordless starters but at the same time I did not mention them due to expense, I merely put forward a viable cost effective option because I had a poor experience up until I tried the Hangar 9 12 V starter.

I actually did buy an Align cordless starter which cost me about £200(with batteries and mains charger) total just for backup however the low cost arrangement I'm currently using (Hangar 9) works great and I'm quite impressed with it.

Sure looked to me like you told the beginner not to consider anything but corded options:

The piggy back battery uses most any starter. The piggy back adapter costs about $12 on Amazon and most folks already have a cordless drill to "borrorow " a battery from. You now have a far more powerful starter and lose the sloppy, tangly cord and the bulky, weak battery at the other end.
A lot less money than the Align thing too.



After fifty plus years in the hobby there isn't much I have not tried or seen.
Settled on what I have shown for good need and solid experience.


You asked to see my alternatives and I have shown you, along with the supportive comparisons.
Starter or glow driver, cordless works very well.

Nuff said.

I thought you were referring to the corded Hangar 9 starter only, however, I still stand by my guns the integrated rechargeable glow stick which come complete with a mains based charger are in my opinion crap and given I am myself a beginner I bought 3 of them before I gave up, they are inferior to my corded current source glow stick, I now have certainty that the glow is working without having to worry about a whether I have a flat glo stick battery or not.

But hey, if you find them useful then as you say everyone to their own.