Water in glow fuel may be good?

Water in glow fuel may be good?
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Water in glow fuel may be good? - 11/22/2003 2:39:26 AM

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I presume you have all read Joe Wagner's engine column in the January 2004 Model Aviation. He tried running glow fuel with 20% water and upped his engine's performance by 100RPM. He had to richen the engine considerably, it did not start as well, and took 30 seconds or so before he could remove the glowplug battery. Joe is not what you would call an incrementalist!

Jim

RE: Water in glow fuel may be good? - 11/22/2003 3:59:18 AM

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I tried to tell people that some time ago and got flamed for it. Lots of BS about the condensation in your fuel jug being water going around also. This is an old drag racer trick. If you are having problems with detonation in you alky engines and don't have a convenient way of lowering compression, you can add water to the fuel.

(in reply to Jim Thomerson)

RE: Water in glow fuel may be good? - 11/22/2003 7:11:44 AM

AMB

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I think this was done 50 or 60 years ago with some aircraft engines using water injection as
a power boost am I right??

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RE: Water in glow fuel may be good? - 11/23/2003 2:30:05 AM

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Correct! It was called WEP, or War Emergency Power. It was usually a water or water/methanol mix!

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RE: Water in glow fuel may be good? - 11/23/2003 5:03:41 PM

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Actually the boost was an increase in the supercharger boost, the water or water alcohol mix was used to prevent detonation at such a high boost. When alcohol in any form is used a the primary fuel, all you have to do is add water to the fuel and richen up the mixture. This has the same effect as rasing the octane, makes the mix burn slower.

< Message edited by Sport_Pilot -- 11/23/2003 5:07:07 PM >

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RE: Water in glow fuel may be good? - 11/24/2003 4:15:56 AM

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Spraying or injecting water or water/methanol mix into an engine is a totally different thing to trying to mix water in with a methanol/oil mixture. On a mild day about the most water you can mix in glow fuel is 3%...any more than that and the water drives the oil out of suspension and it falls to the bottom of the tank. The warmer the fuel is then the more water is needed before the oil seperates but you're still only talking 4-5% water.

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RE: Water in glow fuel may be good? - 11/24/2003 5:06:00 PM

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I wondered how Joe Wagner got the 20% water to mix. He did not say.

Jim

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RE: Water in glow fuel may be good? - 11/24/2003 6:06:18 PM

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Oh, I can see it now...a certain fuel manufacturer...."we used only the highest quality proprietary 99.999% pure water additive in our fuel......"

< Message edited by Homebrewer -- 11/24/2003 6:06:56 PM >

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RE: Water in glow fuel may be good? - 11/24/2003 8:35:00 PM

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I am sure that the fuel manufacturers are rubbing their hands in glee over the increased fuel sales Mr Wagner's article will generate. Fuel sales to replace the good fuel ruined by the addition of water that is. Also the engine manufacturers may get some additional sales.

After dunking my seaplane one year, I decided to run the OS 61 four stroke on the fuel that remained in the tank in order to dry out the interior of the engine. I ran it at high power for about 5 minutes. When I got home I decided to pull the head to have a look. The interior of the head, valves and top of the piston had a very even coating of shiny black carbon that looked as if it had been spray painted. It was very difficult to remove. I do not know the chemistry involved but I am sure that it was the result of water mixed with the fuel.

Let the experimenter beware!

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RE: Water in glow fuel may be good? - 11/24/2003 8:50:25 PM

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Its not surprising. Its a trick college physical chemistry test question.

Its a well known fact of chemistry that water increases the efficiency of combustion once an engine is up to "operating temperatures" by providing free oxygen and hydrogen scavenging in the vapor phase.

If water was the end all to end to combustion, then I suggest next time your flying at 15,000 feet in a rainstorm, you think about the amount of rain going into the jet engine on your plane.

Oh, I would not go adding water to your fuel...the trick is that the combustion efficiency increases with temperature. If the engine is cold, it squelches the combustion. You need fuel with no water at first and then switch over to water-laced fuel when the engine is at temperature.

< Message edited by 2MuchThrow -- 11/24/2003 8:56:17 PM >

(in reply to Jim Thomerson)

RE: Water in glow fuel may be good? - 11/24/2003 8:59:58 PM

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quote:

ORIGINAL: Jim Thomerson

... upped his engine's performance by 100RPM.
Jim

100.00 RPM? Gosh that has to be within experimental error and insignificant.

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RE: Water in glow fuel may be good? - 11/25/2003 1:06:09 AM

Hobbsy

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Joe Wagoner couldn't get an RCV .58 to fit in a PSP engine test stand either and yet my .58 fits right in there.

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RE: Water in glow fuel may be good? - 11/25/2003 2:07:21 AM

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Hey 2Much,
Two reasons water really wont affect a jet engine in a typical rainstorm. First is most engines now are medium to Hi-bypas which means very little thrust is generated by the engine itself. Very hard to describe in words. About 70% is generated by the Fan, or N1. So 70%, if not more of that rain passes on the outside of the engine case and never sees a flame or combustion. I would suspect more than 70% due to centrifugal force. The second reason is these engines burn so hot, its not even funny. When I start a Lear 60, the start limit on the ITT (Interstage Turbine Temp) is about 960* C, or roughly 1700* F. That is the start limit and we usually never see it this high. Usually 860*C or so on start. These engines I would guess operate at cruise at about 500*C or roughly 900*F+. Now with a few rain drops which are obliterated by the fan disk and compressor stages into a mist, they are virtually non existent by the time they get to mix with fuel. Remember air is heated by compression alone. See if you can locate the engine testing video they did for the 777. They forced a virtual waterfall into the intake and she kept on chugging. Sometimes it is on TLC or discovery!! Totally freaking amazing!!

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RE: Water in glow fuel may be good? - 11/25/2003 3:13:26 AM

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Yes, I've seen that Discovery show...it is amazing. I like the part where they fire the frozen turkeys out of the cannon into the running engine.

Happy Thanksgiving...

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RE: Water in glow fuel may be good? - 11/25/2003 1:20:20 PM

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I once designed a wash to clean salt water off of low flying A-10's. A lot of the water nozzles were directed at the engines. They would park where the water was sprayed straight up in front of the wing leading edge. The engine suction would pull the water into the engine when they throttled up. They ran this way for a minute or so to rinse out the engine. A 1000 GPM or so of water going in, nothing but steam and mist going out.

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RE: Water in glow fuel may be good? - 11/25/2003 1:29:28 PM

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Also the engine manufacturers may get some additional sales. [/i]

How so?

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RE: Water in glow fuel may be good? - 11/25/2003 1:32:14 PM

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On a mild day about the most water you can mix in glow fuel is 3%...

Do you know how much water was in the fuel when you started? Also could differant oils asorb more or less water?

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RE: How so? - 11/25/2003 1:38:47 PM

Hobbsy

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Fuel Companies are going to sell more fuel when guys pour water into their fuel to get more power and find out the engine won't idle and runs hot if they get it to run above idle.

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RE: How so? - 11/25/2003 3:02:11 PM

Ragtop

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Call me crazy but the point of a jet motor is to accelerate mass out the back. The more the mass, the more thrust. Water (8 #/gal) weighs more than air so..... . Internal combustion doesn't work on the "accelerated mass" idea so water don't do much.

(in reply to Hobbsy)