Fuel Mixing Question

Guys,

Since I'm definitely not a fuel mixing guru, I have a slightly more advanced question to ask of y'all. Given: 1 Gallon of 20% oil content fuel that is 5% nitro. I wish to raise the oil content to 24%, I know add 5 oz castor, but here's the kicker, I want to raise the nitro content to 7% and the only other ingredient I can use is some 20% oil content 10% nitro fuel. O.K. mathmaticians to your calculators!

Thanks in advance guys!

Jim (Mathmatically Challenged) Pollock

LAST EDITED ON Jun-16-02 AT 09:15 PM (CST)

>Guys,
>
>Since I'm definitely not a fuel
>mixing guru, I have a
>slightly more advanced question to
>ask of y'all. Given:
>1 Gallon of 20% oil
>content fuel that is 5%
>nitro. I wish to
>raise the oil content to
>24%, I know add 5
>oz castor, but here's the
>kicker, I want to raise
>the nitro content to 7%
> and the only other
>ingredient I can use is
>some 20% oil content 10%
>nitro fuel. O.K.
>mathmaticians to your calculators!
>

Jim;

I think I can get you in the ballpark pretty quickly.

If you take a gallon (128 ounces) of 5%/20% (nitro/lube) and mix it with a gallon of 10%/20% (nitro/lube), you will have a two gallons of 7.5%/20% and a total of 256 ounces. Add your 10 ounces of lube and you are at 24% lube and a hair less than 7.5% nitro.

Is that .5% delta between 7% and 7.5% nitro all that critical? If it is, then only add 85 ounces of the 10% nitro fuel and 8.8 ounces of lube to the gallon of 5%, and you will be VERY close to 7% nitro 24% lube fuel.

We need to know how much of the 20% oil 10% nitro fuel you have. Because that is where you need to start.

For example, if you started (as you wished) with the 20% oil, 5% nitro and made it 24% oil (half your goal), then you would need to pour out 6.4 ounces of this fuel mix, and add an equal amount (6.4 ounces) of oil. This gets you to your 24% oil, but drops your nitro % to 4.75%.

So if you want to mix the 20% oil-10% nitro with your above mix you just made to get 7% nitro, you would need a full 54.8 ounces of the 20-10! And this takes you down to 22.3 % oil, too.

This is what the math shows.

So Kruger is right. But take your two gallons of fuel that Bob made up, put half in a gallon container (it's still the same mix), subtract 6.4 ounces of the mix, and add pure oil. Now you're up to 24% oil, and just a touch under 7.5% nitro.

Moral of the story: it is hard to make chicken salad out of chicken sh.. Unless you you understand a form of alchemy that is beyond my ken.

LAST EDITED ON Jun-17-02 AT 04:27 AM (CST)

Sorry!

>
>
>So Kruger is right. But take
>your two gallons of fuel
>that Bob made up, put
>half in a gallon container
>(it's still the same mix),
>subtract 6.4 ounces of the
>mix, and add pure oil.
>Now you're up to 24%
>oil, and just a touch
>under 7.5% nitro.

Actually, this morning I realized a couple of errors that I made.

Based on that, and the fact that we don't have raw methanol and nitro to add, my recommendation is:

Mix a gallon of the 5% and the 10% together. This gives you two gallons of 7.5% nitro fuel and a total of 256 ounces. 20% lube fuel has 25.6 ounces of lube in it per gallon. Two gallons will have 51.2 ounces of lube in it. Add 14 ounces of straight lubricant to the mix. This will give you a total of 270 ounces of fuel. 24% of 270 is 64.8. 51.2 ounces of base lube + 14 ounces new lube equals 65.2 ounces of total lube. That is just a hair above 24%. Base nitro content is 256 * .075 = 19.2 ounces. 19.2 / 270 = .071111, or 7.1%.

That is as close as I can get it without resorting to some difficult algebraic equations.

Of course, we call call professor Brett in. Any guy who can figure out how to put a satellite on an asteroid moving in space can easily crack this one.

Thanks Bob,

I figured the simple answer would probably include combining a gallon of each and then adjusting the oil content. Since I only have 1 spare gallon jug, what about combining 64 oz of each and then adjusting for oil content? I guess that might make the nitro content slightly higher? That's not a large problem so I think that's what I will do.

Yes, professor Brett did a nice job landing the space vehicle on the astroid. Did you notice who took all the credit for that in the press? It sure wasn't Brett. Typical Government Bureaucrats.

>Thanks Bob,
>

>gallon jug, what about combining
>64 oz of each and
>then adjusting for oil content?
> I guess that might
>make the nitro content slightly
>higher? That's not a large
>problem so I think that's
>what I will do.

Sounds like a plan to me. Just add 7 ounces of lube rather than 14 for the gallon. Hopefully your container will hold it. If not, then draw off 6 ounces of fuel and add six ounces of lube, and you will be very close as well.

>
>Yes, professor Brett did a nice
>job landing the space vehicle
>on the astroid. Did
>you notice who took all
>the credit for that in
>the press? It sure
>wasn't Brett. Typical Government
>Bureaucrats.

With typical modesty, he (Brett) gave credit to the folks who did the hard, hard number crunching and ultra precision calculations. And, some bureaucrats still took credit.

Ah, well.

Ah, but just let us accidently mix up or metric and English units for Mars atmospheric entry calculations, and see who the bureacrats blame!

L.

>Ah, but just let us accidently
>mix up or metric and
>English units for Mars atmospheric
>entry calculations, and see who
>the bureacrats blame!

It is like dealing with my wife....

What is mine is mine.

What is yours is negotioable.

My usual down home solution actually more or less explained above. Take your empty jug, half fill with the 10% nitro fuel. Then Fill to within the usual fill line with the 5% fuel. Add your 5 oz of castor(actually make it 6 for luck)-it should fit. Voila! it's done. A little under 7.5% nitro, around 24% total oil(castor ratio depends on original fuel however), no muss, no fuss, no measuring and again, all close enough for govenment work.

How about this solution - E-Mailed to me by a nameless engineer who just happens to have something? to do with rocket boosters.

Mix 61 ounces each of 5% and 10%, mix together 6 ounces of Klotz and Castor in a 50/50 mix - add to the 122 ounces and viola. You then have 128 ounces of 50/50 mix Klotz/Castor with 7.1 percent nitro and 23.8 percent oil content that is still a 50/50 mix of Klotz and Castor. That's close enought for good old government work, isn't it?

Thanks Rollin

LAST EDITED ON Jun-17-02 AT 12:13 PM (CST)

>and viola. You then
>have 128 ounces of 50/50
>mix Klotz/Castor with 7.1 percent
>nitro and 23.8 percent oil
>content that is still a
>50/50 mix of Klotz and
>Castor. That's close enought
>for good old government work,
>isn't it?
>

That will work. My premise was that you wanted to use all of the 5% nitro fuel.

Personally, I've run fuel at 7% nitro and 7.5 % nitro, and could not discern the difference. I usually see it at the 5% increment level.

Of course, all of this is predicated on the assumption that the fuel used as the components for the final mix was accurately mixed in the first place? .