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Model Forum / Radio Controlled / Air Models / June 2004water in fuel
This has been discussed before, but I just read it in Joe Wagner's column in Model Aviation (July 04). He claims a small gain in performance with fuel containing 20% water. All these years we have been warned about moisture in our fuel. When we can't find the problem for a bad engine run we are advised, "Try some fresh fuel, you may have gotten some water in the stuff you are using." I note Joe is from Ozark Alabama . . . . maybe the streams coming down from the mountains have some stuff that just looks like water - run off from the local still. :-) Or the revenuers are told that those jugs under the straw in the back of the pickup are only just water . . . and that's their story and they are sticking to it. :-0 Engines mentioned were a Johnson .29 and Cox reed valve 0.049. Red S. Johnson .29??? Now there is a relevant engine. A small amount of water may help with detonation on four strokes but having water mixed with fuel long term doesn't seem like a good idea. All of the oils and other additives surely must suffer under these conditions. -- Paul McIntosh http://www.rc-bearings.com > This has been discussed before, but I just read it in Joe Wagner's column in > Model Aviation (July 04). He claims a small gain in performance with fuel [quoted text clipped - 15 lines] > > Red S. >This has been discussed before, but I just read it in Joe Wagner's column in >Model Aviation (July 04). He claims a small gain in performance with fuel >containing 20% water. Spend a minute and do a google search on this group to get a pant load of stuff on this subject by many different experts... Have fun with it! FredD Would that come from the increase in compression due to the water not being able to be compressed? David - who has heard of the hassles that water in the fuel can create for diesel engines - ie bent conrods etc > This has been discussed before, but I just read it in Joe Wagner's column in > Model Aviation (July 04). He claims a small gain in performance with fuel > containing 20% water. I doubt that any of the liquids in fuel can be compressed. The fuel that goes in the combustion chamber is in vapor form (including any water). -- Paul McIntosh http://www.rc-bearings.com > Would that come from the increase in compression due to the water not being > able to be compressed? [quoted text clipped - 5 lines] > > Model Aviation (July 04). He claims a small gain in performance with fuel > > containing 20% water. With water in the fuel, as the fuel mixture vaporizes the water turns into water vapor and takes heat out of the mixture and thereby increases the density. In effect it acts as a mini supercharger. Some of the high performance piston engine aircraft, like the WWII Corsair, used water injection to boost power for short periods of time. I met some guys in Atlanta in the mid-1950s who used water in their fuel for competition UC team and rat racing. They claimed that about 10% water gave a noticeable performance improvement with acceptable fuel economy. > This has been discussed before, but I just read it in Joe Wagner's column in > Model Aviation (July 04). He claims a small gain in performance with fuel [quoted text clipped - 15 lines] > > Red S. Though slightly OT, water injection is a trick sometimes used to suppress detonation in high compression engines or engines running high boost pressures (high effective compression ratio), though no mention of it increasing horsepower except by virtue of the fact that it allows the higher compression ratios. I remember an article quite some years back by, I think, Road and Track, where they built their idea of the ultimate "sleeper" car - a Trans Am looking quite stock on the outside with a Keith Black 427 on twin turbochargers and adjustable waste gate. They claimed 1350 HP on max boost. IIRC the waste gate could be set between 8 and 35 psi. The comment was made that if you sneezed with your foot on the gas pedal you'd be doing warp 9 when your eyes opened again. Anyhow, they used water injection for detonation control at the higher boost settings. Mike D. > With water in the fuel, as the fuel mixture vaporizes the water turns into > water vapor and takes heat out of the mixture and thereby increases the [quoted text clipped - 4 lines] > team and rat racing. They claimed that about 10% water gave a noticeable > performance improvement with acceptable fuel economy. >I think, >Road and Track, where they built their idea of the ultimate "sleeper" car - All the posts I've seen so far are for large, powerful, 4 stroke engines. Does it really do anything for a small 2 strokes? Personally, I'll stick with stock glow fuel. If I need more horses, I'll buy higher nitro content or install a larger engine. Dr.1 Driver "There's a Hun in the sun!" That's my feeling as well. BTW, ADI used in Reno racers is a mixture of alcohol and water. -- Paul McIntosh http://www.rc-bearings.com > >I think, > >Road and Track, where they built their idea of the ultimate "sleeper" car - [quoted text clipped - 5 lines] > Dr.1 Driver > "There's a Hun in the sun!" Let's not confuses the issue here. The concept of water injection has been around since WWII or before. What we are talking about here is the addition of water (up to 20%) to glo fuel. Has anyone any experience with this other than the original author Bill Wagner in Model Aviation? > I met some guys in > Atlanta in the mid-1950s who used water in their fuel for competition UC > team and rat racing. They claimed that about 10% water gave a noticeable > performance improvement with acceptable fuel economy." And the guys trying to beat them bought it and then couldn't figure out why their engines wouldn't start. :-) This gag has been played on a lot wannabe competitors in a lot of venues. Red S. > With water in the fuel, as the fuel mixture vaporizes the water turns into > water vapor and takes heat out of the mixture and thereby increases the [quoted text clipped - 29 lines] > > > > Red S. > Let's not confuses the issue here. The concept of water injection has been > around since WWII or before. What we are talking about here is the addition > of water (up to 20%) to glo fuel. Has anyone any experience with this other > than the original author Bill Wagner in Model Aviation? Yes, I did some tests a few years ago by adding measured amounts of water to fresh fuel then flying the model if the engine (an SC 1.08) seemed to run OK. Starting at 0.5% water and up to 3% there was absolutely no change in how it started and ran compared to the fresh fuel. At 4% the engine wouldn't even pop let alone start. What I found was that at 4% the water drove all the oil from solution and it settled at the bottom of the tank so the engine was drawing raw oil instead of fuel. Back at home I found that the % of water needed to drive the oil out of solution was temperature dependent in that the cooler the fuel the less water could be tolerated. I had similar results with both all castor and all synthetics and got a virtually straight line graph of water%/temperature. Both fuels were zero nitro so I can't say what affect nitro might have on allowable water content. Brian Hampton Adelaide, South Oz Maybe you just thought it was a gag and didn't bother trying it. Adding water will allow a higher percentage of nitro on the same compression ratio. If the engine is detonating just enough you can't hear it then adding water will indeed improve the power. Also it may cause the engine to peak with a leaner mixture without overheating, this may also increase power. > Let's not confuses the issue here. The concept of water injection has been > around since WWII or before. What we are talking about here is the addition [quoted text clipped - 47 lines] > > > > > > Red S. Then why don't any of the fuel makers or hot competitors do it? I have been at this a while and I know a few competitors. None of them have done it. -- Paul McIntosh http://www.rc-bearings.com > Maybe you just thought it was a gag and didn't bother trying it. > Adding water will allow a higher percentage of nitro on the same [quoted text clipped - 54 lines] > > > > > > > > Red S. >Then why don't any of the fuel makers or hot competitors do it? I have been >at this a while and I know a few competitors. None of them have done it. -- >Paul McIntosh Exactly,look how much more profit they would make substituting 20% of the methenol with 20% water. DOUG Even if everybody understood that you can add up to x% water with no problems and possibly even a power increase, would they pay the same price for fuel with water premixed in? I would guess not. If you read the article closely you will note that there was some issue with starting. Also there is the fact many do not believe the article, well that means that almost no one will buy fuel with water, even if discounted. > Then why don't any of the fuel makers or hot competitors do it? I have been > at this a while and I know a few competitors. None of them have done it. [quoted text clipped - 78 lines] > > > > > > > > > > Red S. There is one other consideration. When water is heated to above the boiling point (as it is in the cylinder) its gas expands to many times its liquid volume. This characteristic has been used in some early jet airliners. (I think that some early Boeing 707 had water tank and injected water to increase thrust on take-off) Yes, this might work for a tirbine engine. The offsetting factor is that when water evaporates, it absorbs, which could have a downside in an internal combustion engine. > This has been discussed before, but I just read it in Joe Wagner's column in > Model Aviation (July 04). He claims a small gain in performance with fuel [quoted text clipped - 15 lines] > > Red S. When my dad was in the Air Force in the 60's he guarded B52's and he often talked about there being ground personnel whom were responsible for keeping the water in the water tanks hot while on the B52's where on the ground. Appearently water and/or steam was injected into the engines during takeoff. >There is one other consideration. When water is heated to above the boiling >point (as it is in the cylinder) its gas expands to many times its liquid [quoted text clipped - 6 lines] >The offsetting factor is that when water evaporates, it absorbs, which could >have a downside in an internal combustion engine. True, but it was kept separate from the fuel and injected AFTER the fuel was burned. -- Paul McIntosh http://www.rc-bearings.com > When my dad was in the Air Force in the 60's he guarded B52's and he > often talked about there being ground personnel whom were responsible [quoted text clipped - 12 lines] > >The offsetting factor is that when water evaporates, it absorbs, which could > >have a downside in an internal combustion engine. Somebody try it with a tank of fuel,add 20% water to it and see how it runs. courseyauto@aol.com (Courseyauto) posted message ID<20040607152033.22653.00000365@mb-m23.aol.com>on 07 Jun 2004 19:20:33 GMT >Somebody try it with a tank of fuel,add 20% water to it and see how it runs. Feel free. courseyauto@aol.com (Courseyauto) posted message ID<20040607152033.22653.00000365@mb-m23.aol.com>on 07 Jun 2004 19:20:33 GMT >Somebody try it with a tank of fuel,add 20% water to it and see how it runs. Todd spued forth: >Feel free. I dont have any junk motors,and besides i know what the outcome will be. courseyauto@aol.com (Courseyauto) posted message ID<20040607185507.15665.00000397@mb-m24.aol.com>on 07 Jun 2004 22:55:07 GMT >courseyauto@aol.com (Courseyauto) posted message >ID<20040607152033.22653.00000365@mb-m23.aol.com>on 07 Jun 2004 >19:20:33 GMT >>Somebody try it with a tank of fuel,add 20% water to it and see how it runs. > > Todd spued forth: Spellchecker on the blink? >>Feel free. > > I dont have any junk motors,and besides i know what the outcome will be. Well, then how aboot a nice STFU? courseyauto@aol.com (Courseyauto) posted message ID<20040607185507.15665.00000397@mb-m24.aol.com>on 07 Jun 2004 22:55:07 GMT >courseyauto@aol.com (Courseyauto) posted message >ID<20040607152033.22653.00000365@mb-m23.aol.com>on 07 Jun 2004 >19:20:33 GMT >>Somebody try it with a tank of fuel,add 20% water to it and see how it runs. > > Todd spued forth: Spellchecker on the blink? >>Feel free. > > I dont have any junk motors,and besides i know what the outcome will be. >Well, then how aboot a nice STFU? well how about a nice SIUYA I don't think anyone is saying it won't work like that. What I am saying is that what does the water do if left to sit in the fuel for a month or more? -- Paul McIntosh http://www.rc-bearings.com > Somebody try it with a tank of fuel,add 20% water to it and see how it runs. Paul spued forth: I don't think anyone is saying it won't work like that. What I am saying is that what does the water do if left to sit in the fuel for a month or more? -- Paul McIntosh http://www.rc-bearings.com > Somebody try it with a tank of fuel,add 20% water to it and see how it runs. Well then let it sit for a month....Then try it You won't be able to add more than about 3-4% on a warm day or the oil will come out of solution. > Somebody try it with a tank of fuel,add 20% water to it and see how it runs. Water injection is added in the intake manifold or directly into the cylinders BEFORE the fuel is burned. > True, but it was kept separate from the fuel and injected AFTER the fuel was > burned. [quoted text clipped - 22 lines] > could > > >have a downside in an internal combustion engine. Gee, I wonder how bit the cylinders are in a B-52!!!! -- Paul McIntosh http://www.rc-bearings.com > Water injection is added in the intake manifold or directly into the > cylinders BEFORE the fuel is burned. [quoted text clipped - 25 lines] > > could > > > >have a downside in an internal combustion engine. LOL! I was wondering if anyone else noticed that one!. > Gee, I wonder how bit the cylinders are in a B-52!!!! > -- [quoted text clipped - 35 lines] > > > could > > > > >have a downside in an internal combustion engine. About 5 or 6 feet diameter? > Gee, I wonder how bit the cylinders are in a B-52!!!! > -- [quoted text clipped - 35 lines] > could > > > > >have a downside in an internal combustion engine. How many and at what RPMs? ;^) -- Paul McIntosh http://www.rc-bearings.com > About 5 or 6 feet diameter? > [quoted text clipped - 37 lines] > > could > > > > > >have a downside in an internal combustion engine. Eight and at 100% for Takeoff :-) Cheers -- \__________Lyman Slack_________/ \______AMA6430 IMAA1564___/ \____Flying Gators R/C______/ \__Gainesville FL _________/ Visit my Web Site at: http://www.LymanSlack.com > How many and at what RPMs? ;^) So I guess the theory is something like: Water was injected into the exhaust side of the turbine engines where it turns to steam and expands increasing the volume of expelled gases from the engine. Thus increasing overall thrust of the engine. I guess they wanted the water boiling before takeoff so it would turn to steam more easily, and to prevent the exhaust gases from being cooled excessively, thus less expansion, less thrust. >True, but it was kept separate from the fuel and injected AFTER the fuel was >burned. Not quite -- The B-52G used 10,000 pounds of water in approximately 90 seconds during takeoff roll and initial climb out. It was injected just aft of the burner cans and before the turbine section as I recall. It's purpose was to keep the EGT (exhaust gas temperature) within limits. By keeping the EGT down, more fuel could be burned thus allowing more thrust to be developed while still maintaining limits.  SignatureCheers -- Lyman Slack B-52G A/C 1963~66 Visit my Web Site at: http://www.LymanSlack.com > So I guess the theory is something like: > [quoted text clipped - 8 lines] > >True, but it was kept separate from the fuel and injected AFTER the fuel was > >burned. Ok, the main purpose was cooling. Thanks, >Not quite -- > [quoted text clipped - 4 lines] >down, more fuel could be burned thus allowing more thrust to be developed >while still maintaining limits. Go back and read the article again. What he was saying in the article was not that you should add water in fuel. He was saying that the main cause of fuel degradation is not due to presence of water but from degradation of alcohol. Alcohol has a definite degration path in order of increasing oxidation states( from methanol to formaldehyde to formic acid), and having oxidizer such as notromethane did not really help the matter. He proved his point by adding huge amount of water to his fuel. He pointed out the engine ran like crap on tat 20% water laced fuel,but it ran, and that was his point. OK, I read it again. Are you talking about the same article I am, on page 83 of the July 04 issue of Model Aviation? Quoting from Wagner's column, starting at the bottom of page 82. "Another topic I recently mentioned in this column was my successfully hand-starting and running a glow engine - with a small actual gain in performance - on fuel containing 20% water." Perhaps we are talking about different articles. Red SO. > Go back and read the article again. > What he was saying in the article was not that you should add water in [quoted text clipped - 7 lines] > pointed out the engine ran like crap on tat 20% water laced fuel,but > it ran, and that was his point. The guy doing the article got a slight RPM increase on a non-throttled control line engine. The test does not seem relevant to RC engines. He didn't have to idle, run at part throttle, or transition from one extreme to the other. Seriously, did anyone read the article as a RECOMMENDATION to add water to your fuel? I got the impression he was just trying to demonstrate that some of the myths about fuel going bad almost instantly when exposed to the atmosphere are overblown. The problem with getting water in your fuel is that it usually doesn't happen instantly. It occurrs over an extended time during storage. This gives the water time to work its evil on the other additives to the fuel. If he REALLY wanted to do a test, he would let that same fuel sit for a month or two and try it again. -- Paul McIntosh http://www.rc-bearings.com > The guy doing the article got a slight RPM increase on a non-throttled > control line engine. The test does not seem relevant to RC engines. He [quoted text clipped - 7 lines] > myths about fuel going bad almost instantly when exposed to the atmosphere > are overblown. I know that a small amount of water won't hurt. I left a cap off of a fuel jug in the rain for about 15 minutes, I'm sure it was at least an ounce of water. Ran just fine. If you cap your fuel tightly water won't get in it no matter how long you store it. I don't think the methanol degrades very fast, in fact Wagner only stated it would degrade in the presence of brass. Obviously our engines won't run on water, most of us realize that our engines will run with very small amounts of water in the fuel. Perhaps the suprising part is just how much water. Actually I am more suprised that the oil doesn't seperate out, maybe he was constantly shaking the tank? > The problem with getting water in your fuel is that it usually doesn't > happen instantly. It occurrs over an extended time during storage. This [quoted text clipped - 17 lines] > > myths about fuel going bad almost instantly when exposed to the atmosphere > > are overblown. > I know that a small amount of water won't hurt. I left a cap off of a > fuel jug in the rain for about 15 minutes, I'm sure it was at least an [quoted text clipped - 8 lines] > suprised that the oil doesn't seperate out, maybe he was constantly > shaking the tank? Ever HOLD a C/L model until the fuel ran out? > > The problem with getting water in your fuel is that it usually doesn't > > happen instantly. It occurrs over an extended time during storage. This [quoted text clipped - 17 lines] > > > myths about fuel going bad almost instantly when exposed to the atmosphere > > > are overblown. > I know that a small amount of water won't hurt. I left a cap off of a > fuel jug in the rain for about 15 minutes, I'm sure it was at least an > ounce of water. Ran just fine. If you cap your fuel tightly water > won't get in it no matter how long you store it. I don't think the > methanol degrades very fast, in fact Wagner only stated it would > degrade in the presence of brass. Water in fuel will react with the oil even if it doesn't hurt the methanol. The hydrogen and oxygen of the water molecule form acids with chlorine and sulfur compounds from the oil. Those acids are what destroy automobile and aircraft engines when they're run infrequently and for short periods; small amounts of water vapour from combustion get past the rings into the crankcase and condense there because the engine isn't hot enough to boil them off and out the breather. I suspect the water in glow fuel would form similar reactions with the methanol over time and form undesirable compounds. > Obviously our engines won't run on water, most of us realize that our > engines will run with very small amounts of water in the fuel. > Perhaps the suprising part is just how much water. Actually I am more > suprised that the oil doesn't seperate out, maybe he was constantly > shaking the tank? Water in fuel comes in three forms: free water, which can be seen at the bottom of the container; as entrained water, which can sometimes be seen as tiny droplets, or as "snow" in cold fuel; and as dissolved water, which cannot be seen at all. Entrained or dissolved water in fuel can cause carburetor icing as the airflow accelerates through the venturi, lowering its pressure and therefore its temperature, and as fuel is sprayed into the airflow. Evaporating fuel absorbs heat and chills the carb further. Ice forms on the carb walls and on the throttle butterfly, if there is one. Carb icing has been noted at temperatures as high as 100 degrees fahrenheit in some engines. Icing in glow engines should be rather rare, seeing that the carb is usually part of the crankcase and should get warm enough to prevent it, but I imagine some modelers have run into it at lower power settings. It would be a bigger problem on gas engines. Carb ice can also form on humid days from atmospheric moisture. Dan That's mostly true only with petroleum oils. Since most petroleum oils are not compatible with our fuels, it isn't much of a problem in that respect. -- Paul McIntosh http://www.rc-bearings.com > > I know that a small amount of water won't hurt. I left a cap off of a > > fuel jug in the rain for about 15 minutes, I'm sure it was at least an [quoted text clipped - 37 lines] > > Dan > That's mostly true only with petroleum oils. Since most petroleum oils are > not compatible with our fuels, it isn't much of a problem in that respect. > > -- > Paul McIntosh > http://www.rc-bearings.com I see that glow fuels are still using mineral oils, which are petroleum-based. Fuels using synthetics would be no problem. Dan > > hppilot001@cs.com (Sport_Pilot) wrote in message > news:<3b550ea2.0406030718.1db88ef7@posting.google.com>... [quoted text clipped - 39 lines] > > > > Dan What glow fuels are using mineral ols? I don't know of any. All of the main ones use either castor oil or various synthetics. -- Paul McIntosh http://www.rc-bearings.com > > That's mostly true only with petroleum oils. Since most petroleum oils are > > not compatible with our fuels, it isn't much of a problem in that respect. [quoted text clipped - 51 lines] > > > > > > Dan |
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