"1/2 A" & "1/8 A" airplanes These are the small ones...more popular now than ever.

1/2A fuel mixed from RC Car Fuel

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Old 06-30-2014, 04:31 AM
  #1
049flyer
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Default 1/2A fuel mixed from RC Car Fuel

It took over a year but my 2 flying buddies (plus one who doesn't fly 1/2a as much) and I have burned through 12 quarts of 1/2A fuel and now it's time to find more! We decided to visit the hobby shop in Dallas, about 100 miles West, and bought 2 gallons of Powermaster 30% RC car fuel for $21.00 ea. I already had plenty of castor oil and we saved all of our quart size cans so now we are ready to mix fuel and consume adult beverages!

A little internet research reveals the car fuel to be 9% oil. So 9% oil and 30% nitro should mean that the remaining 61% should be methanol. Therefore 1 gallon of car fuel consists of:
38.4 oz of nitro
11.52 oz of oil (synthetic)
78.08 oz of methanol

Our target blend is 25% nitro, 20% oil (at least 1/2 of that castor), and the remainder (55%) methanol.

We will be mixing into quart (32 oz) containers. Here is the proposed procedure: We will first add 4 oz of castor oil to a quart size can and then add 28 oz of the 30% car fuel. The 28 oz of car fuel should consist of:
8.4 oz of nitro
2.52 oz of oil
17.08 oz of methanol

So adding 4 more oz of castor oil will bring the total package up to 32 oz in the following quantities:
8.4 oz of nitro
6.52 oz of oil - 2.52 synthetic and 4 of castor oil
17.08 oz of methanol

This mix should result in the following percentage:

26.25% nitro
20.375% oil - 7.875% synthetic and 12.5% castor
53.375% methanol

Close enough! Good for another year!

What did it cost us?

Total castor added to 2 gallons of car fuel is 40 oz (20 oz ea).
Net quarts of fuel made is 9.25
Cost of castor oil - 1 quart plus 1 pint = $20 with 8oz left over for next time.
Net cost of castor $16.40 ($.41 per oz)
Cost to mix up the fuel was $58.40 - 2 gallons car fuel plus the 40 oz of castor
Net cost for each quart of fuel - $6.31 per quart.
Each flyer gets 3 quarts with a bit left over the guy that ran to get the fuel.

In other words less than $20.00 per year fuel expense per person to fly 1/2A.

What's all this talk on RCU about the high cost of flying glow?

Last edited by 049flyer; 06-30-2014 at 04:43 AM.
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Old 06-30-2014, 05:03 AM
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Yes, and the $20 in gasoline to go to the field in the big pickup with the trailer never bothers anyone. But they run gas in the big planes to cut expenses. I like the little guys too. I can remember (faintly) driving to the school yard with a 1/2A combat plane under my arm and the toolbox in the rack/rat? trap on the back of the bicycle as a kid. A quart would last about 1/2 the summer. 25% nitro isn't really a big deal when so little is needed.
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Old 06-30-2014, 05:37 AM
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aspeed

Also ignored is the $10,000 trailer, $1500 airplane powered by a $1000 engine, 8 each $100 servos, and $50 prop but just think how much you'll save on glow fuel!
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Old 06-30-2014, 06:39 AM
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$20 a year for fuel works! I just buy SIG Champion 25 by the quart and add castor to bring it up to about 23% total oil.

With the big stuff it's funny how the cost of consumables gets so much attention when the cost of the hardware gets waved off as inconsequential. I guess it's cool to spend lots on the aircraft and radio, but also cool to boast about saving a few bucks on fuel cost.

There was a Motor Trend article many years ago that I loved so much, wish I could find the copy I stuck away somewhere. The writer talked about the pressure he was under from his wife to buy a new VW Golf because of the advertised fuel economy. He decided to do the math, comparing purchase of the Golf to his preferred choice which was some older Buick with a V6. Lousy mileage his wife said, bad choice.

Turns out if they drove the Golf for 311 years, they would have made up the difference in purchase price through fuel economy savings. He bought the Buick.
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Old 06-30-2014, 08:11 AM
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I've been mixing from car fuel for several years now. The low oil content car fuels really give you a lot of latitude for customizing your blends. I use a combination of 20/10 and 30/10 Sidewinder Pro plus Klotz BeNol to get my final mix.

andrew

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Old 07-01-2014, 04:46 AM
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Sig Champion 25 with some added castor has worked well for my Cox .049's. May not be racing fuel, but a good all around blend for 1/2 A's.

When the discussion comes to size of planes, fly and enjoy what you got. I love them small to large.
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Old 07-01-2014, 09:37 AM
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I'd prefer higher castor:syn ratio for Coxes than the SIG syn/cas 25% + castor gives, but it will have to do. Wish the full line of SIG fuels was available up here.

I need some 10% nitro 22-23% oil with minimum 70% castor, don't think I can even do that with car fuel as basestock unless I find 10% oil syn/cas blend. Hmm, any ST2000/2500 fuel left on the shelves?
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Old 07-01-2014, 09:46 AM
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70% Castor?
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Old 07-01-2014, 10:34 AM
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I mean 70% of the oil content needs to be castor - not 70% castor on total. Only Foxes need that much oil. This is for an F2A speed .15, the manufacturer says no more than 30% synthetic content.
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Old 07-02-2014, 05:34 PM
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About 2 years ago I started using Wildcat 30% Heli fuel spiked with 6 oz/gal Sig castor. My Norvel .074's love it.
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Old 07-25-2014, 11:22 PM
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Hi all!

I have a stock of fuel from GloPlugBoy, purchased on Ebay. It is all castor, a real plus for the Cox stuff. Any comments on this formula?

The Sig Champion has been used, but the Cox engines prefer that old Castor fuel 25% nitro mix, IMO.
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