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glow plug idea

Posted: Mon Dec 15, 2008 11:46 pm
by jon_89
Okay I know the idea of using a glow plug has been thrown around and I think it has actually been done but that was with a car glow plug and a big 12v battery. I was thinking why not use a glow plug from an rc car. They are small, heat up almost instantly, and only require a 1.5v battery.

Posted: Tue Dec 16, 2008 12:23 am
by Xxplosive42o
Your asking if a glowplug would work or not?

Well draw up an idea of how it would be implimented then we can say whether or not it will.

Remember that the glow plug is heated by an external power source. A glow plug igniter. So you will need to incorporate this item as well. The igniter heats the element in the plug, causing it to glow. This starts the chain reaction of igniting the fuel on the compression stroke and starting the internal-combustion cycle (in an RC Car).

Which kind of glow plug would you use by the way? medium, medium-cold, medium-hot, or hot? Each plug is designed for different fuel mixtures.

Just take that all into mind when concidering this project. Make sure to keep me informed if you attempt to design.

Posted: Tue Dec 16, 2008 12:27 am
by jon_89
Well it would be super simple. Just a glow plug or two screwed into the chamber wired to a switch and a "d" battery. What would you reccommend for temp ratings?

Posted: Tue Dec 16, 2008 12:37 am
by CasinoVanart
I think you wouls be better served using other methods of ignition to be honest. I am not even sure that a glow plug would work, the temperature of a spark from a normal bbq sparker is far hotter than a glow plug cpould ever reach.

Add to this the constant need for fresh batteries, new glow plugs and the fact that even if it did work you would have no chance of telling when it was going to fire plus threading holes.
Turning into a rant!!

Why o why do you want to use a glowplug? Use a sparkplug and a piezo electric sparker dude. :)

Posted: Tue Dec 16, 2008 12:50 am
by jon_89
no stun gun and would like to have remote ignition.

Posted: Tue Dec 16, 2008 12:56 am
by CasinoVanart
jon_89 wrote:no stun gun and would like to have remote ignition.
A piezo will still work with remote ignition :P

Posted: Tue Dec 16, 2008 12:59 am
by jon_89
sorry well i figured it would be better than steel wool.

Posted: Tue Dec 16, 2008 1:05 am
by CasinoVanart
Sorry for what mate? No harm talking things through. :P
I have no tests results but a piezo should be able to do a good couple of metres through the right king of wire, you might just have to adjust the spark gap a little.

Posted: Tue Dec 16, 2008 1:10 am
by jon_89
what kind of wire? i have tried regular 14 gauge copper wire with a small gap and it only worked for about 2 feet.

Posted: Tue Dec 16, 2008 1:18 am
by SpudBlaster15
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Posted: Tue Dec 16, 2008 1:40 am
by CasinoVanart
jon_89 wrote:what kind of wire? i have tried regular 14 gauge copper wire with a small gap and it only worked for about 2 feet.
IDK! What am i, a wire expert? :lol: Seriously though i am sure that there is wire of a suitable guage to obtain the required results.
Maybe a google would help :)

Posted: Tue Dec 16, 2008 1:42 am
by Xxplosive42o
SpudBlaster15 wrote:However, I'm not sure if a glow plug would ignite a propane/air mixture. They work in glow engines due to a catalytic reaction between the methanol in the fuel and the platinum/iridium plug element. Heating the plug helps initiate the reaction, but I don't know if it would be sufficient to ignite more traditional spudgun fuels. Worth a try though.


This is true, it all has to do with the catalytic reaction platinum has with fuel. The ingitor is only a heater per-say to start the process. I found one study that investigated platinums reaction with propane. It goes as follows:

Results are presented for propane oxidation on platinum at 6 and 10 atmospheres, at temperatures from 800K to 1050K, and at equivalence ratios from 0.5 to 4.0. For turbulent transport rates as much as 20% of the fuel was found to react on the catalyst before the onset of the gas-phase ignition would begin.

I can't quite interpret that per say, but hopefully somebody can explore this notion.

Posted: Tue Dec 16, 2008 6:56 am
by FishBoy
jon_89 wrote:what kind of wire? i have tried regular 14 gauge copper wire with a small gap and it only worked for about 2 feet.
I have used 16 guage I think; just make your gap as small as possible, the size of the spark is not very important.

Posted: Tue Dec 16, 2008 11:45 am
by jimmy101
jon_89 wrote:what kind of wire? i have tried regular 14 gauge copper wire with a small gap and it only worked for about 2 feet.
The gauge of the wire really doesn't matter too much. 14G, 20G, 30G, they'll all work. It is much more important that the wires are kept well separated. Typical wire insulation is only good to about 300V. At the 5KV to 10 KV of a piezo the spark will jump through the insulation. The longer the wires the more likely that is. To make up for using a much higher voltage than the wire is rated for (actually, it's the wires insulation that is rated) you should basically treat the wire like it is uninsulated. If you spark gap is 1/8" then the wires should never get any closer than perhaps 1/2".

I'm not sure if anyone has ever tried the small glowplug from a model plane. I would have thought it had been tried. Easy enough to test, will the glowplug ignite a butane lighter or propane torch?

Posted: Tue Dec 16, 2008 12:35 pm
by mark.f
I know nichrome has been used to ignite launchers before. I would think a glow plug would work, but there's only one way to find out.