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Quote from: sushil_anand on December 27, 2010, 11:42:57 AM
Hey! The glow plug, by itself, does not make the engine run hotter or cooler. "Hot" plugs are used with low/zero nitro mixtures and 4 stroke engines, "cold" for high nitro mixes. The reference is to the PLUG temperature and NOT the engine!

Have you ever tried running your car for 15 mins flat out ?.. Do you have temp gun to see what is your constant temp?. With 15% nitro on a hot plug (OS A3) the temp was 280 to 320.. With the same setting i ran a Medium plug (OS A8), the temp was 240 to 260.. With same setting on a cold plug (Enya 6) the temp was between 180 to 220.. Please let me know if you had you own experience.. If you are answering these questions based on research, pls note that most the guys who share the exp come from a not so hot country like ours.. Engine temp is directly connected to the Glow plug... You can run with A3 on a 20% nitro and still run in less that 220 deg f by making it extremely rich.. You rather not drive this rich, since the max performance you can get out by this is only 50% or below..
My suggestions are based on gettin the best performance out of your car with less damage..

BTW glow is not used just to start the car but also to make sure the car performs consistently. Please read an article about what the glow plug on your rc car tells you about your engine after a couple of tanks on it.. I can paste the article. if you can't find it..

I have a small question. What voltage does a glow plug requires? Also can i use a AA size Nimh battery instead of a duracell in a non rechargable igniter?

Please see the topic 'Glow plug igniter from scratch' in related topics below.

Quote from: traxxrc1 on December 28, 2010, 07:01:36 AM
I have a small question. What voltage does a glow plug requires? Also can i use a AA size Nimh battery instead of a duracell in a non rechargable igniter?

1.2v.. An AA battery will help but it wont last more than couple of minutes.. I have seen people use it..

It will depend on the capacity of the NiMh cell. A glow plug typically draws around 4A. A 2700 mAH cell would last a flying session, unless your engine is a sluggish starter, or, of course, if your sessions are very long drawn out! Anyway certailnly more than "a couple of minutes".

so how many starts can i make out with a 2000mah nimh?

BTW a duracell dosent even lasts 4 starts...!

A 500 Mah single cell Pananica (the white ones which at one time were the only cells available in India)  used to last pretty long for me.
 

Quote from: traxxrc1 on December 28, 2010, 02:46:10 PM
so how many starts can i make out with a 2000mah nimh?

Capt. Manish (flyingboxcar) found a 500 mAh cell to last "pretty long". 2000mAh should last "pretty much longer"!!

Quote from: above the limt on December 27, 2010, 04:47:14 PM
Have you ever tried running your car for 15 mins flat out ?.. Do you have temp gun to see what is your constant temp?. With 15% nitro on a hot plug (OS A3) the temp was 280 to 320.. With the same setting i ran a Medium plug (OS A8), the temp was 240 to 260..
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BTW glow is not used just to start the car but also to make sure the car performs consistently.

My answer is not based on research but on long time practical experience, albeit with aeroplane engines. With due consideration with your readings, have you checked performance with the different plugs? The plug type will afffect timing which may or not be critical depending on the application. I am in full agreement that you would need the "right" plug for optimising this. At the same time the fuel mixture, ambient temperature, etc. would also be of significance if you wanted to tweak to "maximum". This, in no way negates what I have said, so far.

For whatever it's worth, my little "research" has not shown up ANY reference to a direct co-relation with type of plug and engine temperature. Please do send  me any pertinent info on this. It's never too late to learn something new and of interest!

anyone has any idea how much is the mah rating of a standard 1.5V AA duracell,,,?

Check this out:

http://www.powerstream.com/AA-tests.htm

Note how the effective AH rate changes dramatically at high current draw.

What I had found was that, the normal dry cells were of no use for starting the glow engines, where as  the humble 500 MAh Pananica Nicad always did the job. Never used a Duracell as these were not even availble then
Those were the days when a imported booster was a luxury and standard way to start was with a single cell. You had a short piece of single strand cooper wire attached to the plug. Hold the cell with one end of wire to any pole and touch the other pole to anywhere handy on the engine and go flipping the prop 

So i guess my kodak 2100mah AA Nimh wil do the job. Plus point--i have 7 of them...heheheh

Quote from: flyingboxcar on December 28, 2010, 07:38:03 PM
What I had found was that, the normal dry cells were of no use for starting the glow engines

I have, at least once, seen our member Prakkat starting engines with normal dry cells.  

i tried but i never worked for me at least

Eveready used to make big 2V dry cells which was very much suited to our use. A normal 1.5 dry cell will not last even few starts.
Another way is to use a 3V or even 6 V with a resistance in line to give the required volatge at the plug. This was one of the recommended practice by engine makers. If you have an old OS manual lying you can this recommendation.

What ohm resistance do we need for this purpose with a 3V supply...?

Quote from: traxxrc1 on December 29, 2010, 07:40:04 AM
What ohm resistance do we need for this purpose with a 3V supply...?

A 3V supply would work with a 1 ohm resistor in series. It should be rated at a minimum of 5 watts. Do note that this will get quite warm, if not hot, in operation. I would opt for a single NiCd/NiMh option.

i tried a Nimh 2100mah AA size, the glow plug lighted but the first two rings were not glowing, rest was gowing in bright orange(not dim orange). BTW glow plug is brand new.
What reason can explain this query?

Is it battery insufficiency?
pls help

Hard to imagine only a part of the plug glowing brightly. Try another plug of a different make/type and observe the result.

Ok its like whole plug is glowing except the last turn...its a usual sign for a low battery of igniter