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Old Feb 13, 2013, 01:35 PM
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USA, TX, Grapevine
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Originally Posted by 600Bob View Post
Are those 180 glow engines 4 stroke? That would make a difference. Does anyone make a 180 2S glow?
There are quite a few "big" two and four stroke glow engines out there.

Now there are twins and other multicylinder engines that are glow but here are some of the single cylinder engines.
ASP has a 1.80 (30cc)
OS makes the BGX-3500 (35cc)
Mark and Moki have big ones too in 1.80 and 2.10 sizes.
MVVS also has a 26cc and currently it is a 30cc I think. Both glow and gas.
Saito has a 1.50 and 1.80 too.
Enya makes a big 1.80 two stroke and a 1.55 four stroke.
You can still find some out of production engines like the OPS 30cc Maxi too.
SuperTigre still makes a G3250 engine (32.5cc), they used to make the G4500 (45cc) and G3000 engines (30cc).
Quite a few fellows including myself used to convert trimmer or blower engines over to glow airplane engines too.

Here is a ASP 1.80 on my huge Aeroworks Profile Extra with a 80 inch wingspan.


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Old Feb 14, 2013, 03:01 AM
TigreJohn
United States, CA, Corona
Joined Aug 2008
980 Posts
I just love reading some of these discussions: castor vs. synthetic, 2 stroke vs. 4 stroke, gasoline vs. methanol. In this particular discussion, in any engine size, gas is more economical to operate for the same sized engine. In terms of power, methanol provides more power in the same sized engine. If you adjust engines sizes in order to match power, gasoline (larger but initially more expensive) is still cheaper than methanol to operate. Take your pick; simplicity with a glow plug and more operating cost; or gasoline with an ignition system and more initial and less operating cost.

Why? Basically, our engines are air pumps. Given two engines of the same size and style: they will both pump (intake) the same amount of air. The difference between them in this example is the amount of fuel needed to burn efficiency and the amount of power in the fuel. Gasoline has 125,000 Btu/gl energy, methanol has 64,600: a 93% advantage. But then factor in air/fuel combustion ratios of 14.7:1 for gasoline; 6.47:1 for methanol: methanol now gains a 17% advantage. Adjust downward for oil content: 5% for gasoline, 17% for methanol. Methanol still has a 3% advantage. Add nitromethane to the mix: all bets are off as to power advantage, but then at the expense of cost.

Jetmech05: FYI, I have a 11# Katana, 71" wingspan, rated for up to a 1.6 ci engine. It has a Super Tigre 2500 (1.5 ci), 16x8 prop, 5% fuel, and it will do what you say it can't do. I have an IMAC pilot who maidened it to verify it.
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Old Feb 14, 2013, 06:42 AM
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United States, CT, Plainville
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[QUOTE=jjkupinski;24130957]I just love reading some of these discussions: castor vs. synthetic, 2 stroke vs. 4 stroke, gasoline vs. methanol. In this particular discussion, in any engine size, gas is more economical to operate for the same sized engine. In terms of power, methanol provides more power in the same sized engine. If you adjust engines sizes in order to match power, gasoline (larger but initially more expensive) is still cheaper than methanol to operate. Take your pick; simplicity with a glow plug and more operating cost; or gasoline with an ignition system and more initial and less operating cost.

Why? Basically, our engines are air pumps. Given two engines of the same size and style: they will both pump (intake) the same amount of air. The difference between them in this example is the amount of fuel needed to burn efficiency and the amount of power in the fuel. Gasoline has 125,000 Btu/gl energy, methanol has 64,600: a 93% advantage. But then factor in air/fuel combustion ratios of 14.7:1 for gasoline; 6.47:1 for methanol: methanol now gains a 17% advantage. Adjust downward for oil content: 5% for gasoline, 17% for methanol. Methanol still has a 3% advantage. Add nitromethane to the mix: all bets are off as to power advantage, but then at the expense of cost.

Well put!!
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Old Feb 14, 2013, 10:59 AM
Jim in the Desert
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Quote:
Originally Posted by jjkupinski View Post
I just love reading some of these discussions: castor vs. synthetic, 2 stroke vs. 4 stroke, gasoline vs. methanol. In this particular discussion, in any engine size, gas is more economical to operate for the same sized engine. In terms of power, methanol provides more power in the same sized engine. If you adjust engines sizes in order to match power, gasoline (larger but initially more expensive) is still cheaper than methanol to operate. Take your pick; simplicity with a glow plug and more operating cost; or gasoline with an ignition system and more initial and less operating cost.

Why? Basically, our engines are air pumps. Given two engines of the same size and style: they will both pump (intake) the same amount of air. The difference between them in this example is the amount of fuel needed to burn efficiency and the amount of power in the fuel. Gasoline has 125,000 Btu/gl energy, methanol has 64,600: a 93% advantage. But then factor in air/fuel combustion ratios of 14.7:1 for gasoline; 6.47:1 for methanol: methanol now gains a 17% advantage. Adjust downward for oil content: 5% for gasoline, 17% for methanol. Methanol still has a 3% advantage. Add nitromethane to the mix: all bets are off as to power advantage, but then at the expense of cost.

Jetmech05: FYI, I have a 11# Katana, 71" wingspan, rated for up to a 1.6 ci engine. It has a Super Tigre 2500 (1.5 ci), 16x8 prop, 5% fuel, and it will do what you say it can't do. I have an IMAC pilot who maidened it to verify it.
This confuses me, because I am not experienced.

Is methanol = nitro?


" Gasoline has 125,000 Btu/gl energy, methanol has 64,600: "

" But then factor in air/fuel combustion ratios of 14.7:1 for gasoline; 6.47:1 for methanol: methanol now gains a 17% advantage. "

Can you define what "advantage" means in this sentence? More power for same sized engines? I think what you are trying to say may be obvious to some but it's not clear to me. Because same sized gas / nitro engines are passing through the same amount of air/fuel, and there is 3 times as much nitro as gas passing through (air fuel ratios), and that nitro has half the power of gas inherently, the power of the air/fuel is 1.5 times greater for the nitro engine?

I don't see how you get the 17% or the 3%. Sorry for the elementary questions.

I don't think I recall seeing anybody say a gas motor has more power than a nitro motor. I think the advantages have more to do with fuel economy and flight time, since the motor will use less fuel to fly. At least that's what I have gleaned so far.

Also, there is the issue of engine weight. If you go up in size to equal the power of a glow (methanol?), now you have a heavier engine and all the issues that causes, plus the extra battery possibly.

Thanks for any clarification.
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Old Feb 14, 2013, 11:44 AM
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cloud_9, gasoline is petrol in some countries. Now then the glow fuel engines use methanol and oil primarily for fuel. They add nitromethane to the glow fuel to give it some extra power. But it can be confusing as some people call the engines that use glow fuel things like nitro engines, glow engines, methanol engines, and so on. Some people even still call the glow engines gas engines too. The RC car people have a tendency to refer to the glow engines as "nitro engines" because it sounds better.

Most countries outside of the USA tend to use glow fuel that does not contain nitromethane (sometimes referred to as FAI fuel). Here in the USA nitromethane was more readily available and more inexpensive so the Americans tend to use nitromethane in their glow fuels more often.

The advantages to using glow engines is that it is more simple, no spark ignition system or the extra weight involved. Plus glow fuel provides some extra power over gasoline as well as the methanol in the fuel helps to cool the engine more. Gasoline doesn't help cool the engine much if any. The glow plug is very simple and easy to use as well. Another plus is the carburetor can be made much more simple in comparison to a gasoline engine carburetor. Methanol based fuel has a more rich air to fuel ratio and the ignition or combustion ratio is much more wide or varying. Gasoline on the other hand only works at a more lean very narrow air fuel ratio range which is why the carburetors are more complicated. Some people just like the simplicity of it all.

But glow fuel may be quite expensive in some locales. I have seen some hobby shops wanting high prices for glow fuel. So using gasoline would tend to be more attractive then.
But conversely there are some locales where methanol is much easier to get and much more inexpensive too. There are some people that have found that in their respective country, making their own glow fuel with methanol and oil is cheaper than using gasoline and oil. So it really depends on your locale and what the fuel costs are.

Now our modern gasolines stink a lot more than the gasolines of the past and the gasoline smell or odor can be a big turnoff for some people. But the glow fuels tend to be quite a bit less smelly. Gasoline has a shelf life where it goes bad over time but glow fuel has a indefinite shelf life. I have used glow fuel over 20 years old and it worked just fine.
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Old Feb 15, 2013, 03:18 AM
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Gas

OK once more : in Europe gas is what you put into a balloon
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Old Feb 15, 2013, 04:45 AM
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Originally Posted by Reginald View Post
OK once more : in Europe gas is what you put into a balloon
Than, these are from the controlroom of a balloon!
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Old Feb 15, 2013, 04:50 AM
Jim in the Desert
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United States, NM, Las Cruces
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Originally Posted by earlwb View Post
cloud_9, gasoline is petrol in some countries. .....I have used glow fuel over 20 years old and it worked just fine.

earlwb, thanks so much for the message, that was golden. I appreciate you taking the time to explain it so well. That really clears a lot of questions up for me.

If I am understanding correctly, from your answer and jjkupinski's, for a given amount of engine displacement, glow engines provide more power than gasoline (petrol) engines. For a given amount of fuel, gasoline provides more power than glow fuel, even with nitromethane added to the glow fuel. Glow engines burn fuel faster because they have a much richer air:fuel ratio. So the greater power in a given quantity of gasoline is distributed over a greater time span than that in which an equal amount of glow fuel is burned and at a given instant the glow engine is producing more power than an equal displacement gasoline engine. The greater amount of fuel burned in the glow engine allows it to cool the engine more.

Am I close?

Thanks again
Jim
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Old Feb 15, 2013, 10:10 AM
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Jacksonville Fla.
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Something I need to say. IMHO gas has more power than glow, Never see a glow stand on its tail and accelrate in the verticle until power is pulled off. running 1 battery for ignition and system is risky. flying a gasser without an optic kill is also risky.
I know I know, I've been doing it this way or that way for years and never had a problem never needed this or that.
Try and make your airplanes as safe as possible You can't fly an airplane in the pattern where you don't turn to the pits or people standing around.
Gasser are heavier than glow airplanes generally.
Redundancy is safety 2 batteries are better than 1. Optic kill switches reduce the possibillity of interference and give you an additional way to shut off the motor from the transmitter. It also kills the ignition if you loose power to the system preventing a runway airplane.
When's the last time I saw a runaway 2 aiplanes about 2 weeks apart a few weeks ago one glow just went to fail safe last see headed for the beach and climbing with power on. and a gasser that flew well above the pits crashed in a tree the other side of everyones cars.
Ok I'll get off my soap box...thanx for reading this
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Old Feb 15, 2013, 10:55 AM
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Originally Posted by Reginald View Post
OK once more : in Europe gas is what you put into a balloon
You put gasoline in balloons? In the States we put Helium in ballons.
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Old Feb 15, 2013, 08:52 PM
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Yes, gasoline (gasolene, cazeline, gazeline) is known by many different names depending on the country: gasoline, gas, petrol, pétrole, benzin, benzine, benzina, bencina, and nafta too.
There is also "mogas". "autogas", and "avgas" as well. In the UK gasoline could have meant it was lamp oil as it is referred to here in the USA.
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Old Feb 15, 2013, 09:50 PM
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United States, NM, Clovis
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Size at which gas becomes practical

OK guys,

If you want to think even harder on this subject, look at the current issue of the UK magazine RCM&E. Their engine specialist has been running his gas engines on a glow plug with the regular gas fuel. He says that it takes a hot glow plug. He also claims that the top RPM and dthe idle RPM stay the same.

Interesting eh?

Jamesf
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Old Feb 16, 2013, 05:09 AM
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Originally Posted by jamesf View Post
OK guys,

If you want to think even harder on this subject, look at the current issue of the UK magazine RCM&E. Their engine specialist has been running his gas engines on a glow plug with the regular gas fuel. He says that it takes a hot glow plug. He also claims that the top RPM and dthe idle RPM stay the same.

Interesting eh?

Jamesf

Welcome James.
(James' first post after more than four years of membership!)
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Old Feb 18, 2013, 03:19 PM
Karpinski4137
Philadelphia, Pa.
Joined Oct 2007
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Originally Posted by MikeCr View Post
It's generally not recommended because of possible interference problems.


Mike
I flew my Maxford giant Jenny using a DLE-55 and had a BEC and was powering both ignition and receiver off one battery for two years. Had no problems.
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Old Feb 18, 2013, 10:15 PM
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In some countries they have M85 fuel, which is gasoline mixed with methanol. Here in the USA they have E85 fuel which is gasoline mixed with ethanol. I think there are a couple of places or locales in the USA where they do sell M85 fuel too. So if you have M85 fuel in your area, you should be able to have good success using it in a glow engine with glow plugs. The glow plug's platinum element works good with methanol.
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