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Engine basics => Engine set up tips => Topic started by: Bryan Higgins on July 17, 2010, 02:34:29 PM
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Hello Pilots I really need a little help here...
I have ordered some 18% Powermaster Fuel and would like to add enough Sig AA Castor Oil
to bring the total oil content upto 22%
Containers are gallon cans. How many onces of castor would i have to add ??? HB~> HB~> HB~>
Im new at this so i need a little help. I have alot of new engines to break in and there
is no GMA 10/22 out there yet. Terra at Texas Allied Chemicals said it would be a month
or two before they had some more GMA 10/22 made for sale.
Thank You Bryan
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Bryan, I don't have my formula right handy, but my rough chart shows that 8 oz will bring it up mighty close. It will also reduce your nitro percentage to 9.4%. What engines are you breaking in?
Come to our contest the 7th and 8th of august. Stunt is on the 8th as is carried. Racing and Combat is on Sat. Wichita KS.
Bigiron
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Hi Bryan,
You will need to add 6.7 Oz of oil to one full gallon of 10-18 to make it with 22% Oil.
We have this spreadsheet that computes several ways to mix fuel, but it is in Portuguese and uses metric system
http://www.hobbylink.com.br/fuelmix.xls
Oleo : Oil
Nitro : Nitro
Rícino : Castor
Acool : Alcohol
I am sure there should be a spreadsheet in English out there.
good luck,
Martin
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I've attached a .doc file that has a formula (assuming you can do the math....I can).
I have a spreadsheet (.xls file), but can't post that file type on this forum. It is in Englander's Units (which they abandoned for the French system, but we're stuck with). The person that created it can't spell "alcohol" without adding an extra 'h'....must be some type of alcohol with and extra hydrogen molecule? LL~ LL~ LL~ LL~ Steve
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Thanks Marvin,Martin and Steve
Thanks for all the information i will add it to my files. And thanks for the invite
Marvin i would like to attend that contest. I have familly coming out this August
but i'll write it down for next year.
Thanks Again - Bryan H^^
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Isn't the rule of thumb 1.3 ounces of castor added to a gallon of fuel will increase lube amount by 1%? At least that is what I use. If correct you would add 5.2 ounces of lube to you 18% powermaster to bring it up to 22%. 8)
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Check the Fuel Mixture Workshop at www.NitroRC.com and you'll find what you need to do.
Joe
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One percent of 128 onces is 1.28 ounces,, so roughtly you can raise the oil one percent by adding one and a quarter ounces of oil, so to raise it 4 percent, you need to add about 5 ounces
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I went through the formula and got 6.56 oz., for changing 18% to 22%. With Pete's 1.3 oz rule of thumb, it comes out to 5.2 oz. The math isn't that tough, but either is a step in the right direction for most (but not all) engines. #^ Steve
Edit: The difference between calculating it out and adding 1.28 or 1.3 oz is that you're ignoring the fact that you have more fuel when you're done adding more oil. Even the calculator thingy at NitroUC.com doesn't get it exactly the same, but closer (6.2 oz). My 6.56 is actually rounded down (from 6.564102564 oz), and most of us will be able to measure the added oil to no better than .5 fluid oz. at best. Bottom line is add 6 or 7 oz to the 18% mix.
One of my questions about fuel using Klotz is that some Klotz has castor in the blend, but not all. How do you know which Klotz your fuel uses?
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Hello Pilots I really need a little help here...
I have ordered some 18% Powermaster Fuel and would like to add enough Sig AA Castor Oil
to bring the total oil content upto 22% . . .
I made up a spreadsheet for my own use, but anyone can have a copy. My mathematical model is up to three "fuels" (a "fuel" can also be straight castor, straight nitro, or straight methanol, depending on what you're doing)
The results show, no matter what you mix, the percentage of total oil, ( + individual percentages of castor and synthetic), percentage of nitro, and percentage of alcohol. On some pages, I've added ml, depending on quantities.
Yes, adding castor changes nitro, and vice versa, which I why I chose to recalc everything in the "Results" side of the sheet.
One trick is to plan ahead, ya know, as you can't add castor to a full jug! And nobody is going to dump fuel on the ground to make room for the castor.
Figure out your container strategy before starting; e. g., measure out one half gallon of raw fuel, measure half the castor, and you have two identical jugs of fuel, each a tad more than half full. Other methods work, just figure it out before overflowing a jug.
Larry Fulwider
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Ok so I finally gave in and built an excell spreadsheet myself,, lol, guess I shoulda kept my mouth shut while I was ahead,, Steve, ya got me this time,, I came up with the same,, 6.5 ounces,, leading to a final mix that is a total of 134.6 ounces, 9.51 % nitro, and 22% oil,, sigh,,
ah well, its always been what I do, just add and ounce and a quarter per percent, in a gallon, always worked for me, besides then I tweak to taste. when I was Running my FP 40's, I would generally end up adding just a couple more ounces on top of that or they would start to go over at the end of the run. especially here when its 90 degrees at 2700 foot altitude!
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Ok so I finally gave in and built an excell spreadsheet myself . . .
. . . I came up with the same,, 6.5 ounces,, leading to a final mix that is a total of 134.6 ounces, 9.51 % nitro, and 22% oil . . .
Mark --
Looks like all of our sheets / methods agree. You said 6.5 castor above, but the results (and your words) say you used Steve's 6.56, correct? Checks out 9.51% nitro and 22.00% oil. (Well, we aren't measuring accurately enough, either ourselves or at the manufacturer to justify two decimal percentages, but it's nice to have the arithmetic confirmed)
. . . when I was Running my FP 40's, I would generally end up adding just a couple more ounces on top of that or they would start to go over at the end of the run. especially here when its 90 degrees at 2700 foot altitude!
Yes, 23% or so seems better on FP 35s and 40s.
Larry Fulwider
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Larry, as you say, measuring past one decimal place is pretty much overkill in this situation, but it was actually 6.56 , but I figure that if I get within 6.5 in there, well thats dang close,,
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One thing I'd like to add about adding oil is that, although the calculations (because of the way it's done) seem to indicate that nitro will be reduced, this isn't actually true because methanol will also appear to be reduced and the relative proportions of methanol/nitro stay exactly the same and that's all the engine itself needs to know.
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Sorry Brian, that isnt really true, if you run 4 ounces of fuel through your motor, it will contain less volume of nitro, and less volume of methanol,,true, but it will be a lower percentage of nitro, the math bears that out. If for example there is 15 ounces of nitro in a gallon ( 128 ounces) and you add 6 ounces to bring the total volume of fuel to 134, then there is still the same amount of nitro in a greater quantity of fuel, hence less nitro per ounce of fuel.
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. . . the relative proportions of methanol/nitro stay exactly the same . . .
So far, so good. Both methanol and nitro are diluted with additional oil.
. . . and that's all the engine itself needs to know. . . .
Not exactly. If your point is that the additional oil (and nitro% reduction) does not imply a performance drop, you are correct. y1 Opening the needle a tad more, you can give the engine the same amount of fuel (nitro and methanol) per revolution as you had with the 18% oil blend.
The difference is in the mileage, not the performance. The additional volume of "fuel and oil blend" needed to get the same amount of fuel to the engine is measurable, and as significant as the percentages would predict.
Larry Fulwider