Fuel advice

[cory colquhoun]

Hi all,
      Decided to mix my own fuel, I have some older engines where I use a mix of 75% methanol ,25% castor, 5% nitro, just wondering what’s best for the more modern  eg LA 46 , evo 36   ,flying stunt ,should I use a 50/50 castor synthetic

 Cory

[Gary Dowler]

Others might have a better idea on the newer engines, but I would say your 50/50 synthetic/castor is right, and 18-20% seems common today.
Many of the older engines, such as the Fox 35, etc, required higher oil content. If you run a Fox 35 with 20% oil it will likely act up about 1/2 way through a tank, and then probably quit before fuel starvation.  Then it's not likely to restart either, as they simply overheat. Those engines need the extra castor to cool them and run great with 30% oil.
Modern engines are much better with regard to the materials, design and tolerances which allow them to run well on much lower oil percentages.

[Brett Buck]

Hi all,
      Decided to mix my own fuel, I have some older engines where I use a mix of 75% methanol ,25% castor, 5% nitro, just wondering what’s best for the more modern  eg LA 46 , evo 36   ,flying stunt ,should I use a 50/50 castor synthetic

 Cory

    For general use woth modern engines, I would suggest 10% nitro, 20% oil with 75% of it synthetic and 25% castor. Use the synthetic with the lowest viscosity you can find .

    Brett

[Bootlegger]

  Brett, what synthetic fuel has the lowest viscosity, and why do you suggest the lower viscosity oil?  Thanks...

[Bootlegger]

  That should read which syn oil is the lowest viscosity, not fuel..  Again thanks..

[Brad LaPointe]

For the EVO go with straight synthetic oil , 18 % - 20 % . I’ve had good results using this formula.

Brad

[Brett Buck]

  Brett, what synthetic fuel has the lowest viscosity, and why do you suggest the lower viscosity oil?  Thanks...

  The lowest viscosity fuel I have run is the old Texas Allied Chemicals (pre--VP) Powermaster 10 Heli. Oil,  I don't know, because I don't mix my own fuel (although if you are going to mix fuel, you should probably be able to find out).

   You care because getting the fuel through the lines effectively in all conditions makes a far bigger difference in the run than you would be inclined to believe. As we have changed the plumbing to reduce restrictions we have had all sorts of "funny" things just go away. It's particularly true on larger engines. All the standard plumbing and fuel easily passes enough fuel - on average - to keep the engine running. Like 8.5 ounces into a PA75. But apparently the fact that the fuel suction varies through a rev and  in different load conditions apparently makes a difference.

    We discovered this back when people were attempting to run 4-Strokes like the Saito, changing the plumbing and fuel had almost unbelieveable effects on the way the engine runs. Its not nearly as touchy on a 2-stroke, but we hadn't even considered the issue until then.

    Brett

[cory colquhoun]

Thanks guys , as always more than helpful, just after a standard mix to use all round

 Thanks cory

[Fredvon4]

Cory

I am very rural and have to mix my own and YES
It IS aggravating to have 3 or 4 blends...but required...there is NO universal blend for all engines of differing designs and metallurgy

I keep on hand:
Torco sourced Nitro and Methanol
Sig Castor
Sig Benol
Sig techniplate
Sig Klotz 100% synth
Rices Brew UCON LB 625
Randy Smith Aero 1 additive
a variety of Metal ---quart, Half gallon, and 1 gallon clean cans

a spread sheet with my preferred blends....many formulas from here at SH
A graduated beaker set where I blend by ML vs Oz....base 10 system so much easier to deal with math wise

thus 1000 Ml or 1 liter...slightly more than a Quart

works for me OS LA 25 mix----
15% Nitro   = 150 Ml
20% oil  (15% Synth 5% Castor)  = 200 Ml  (150 Ml synth and 50 Ml Castor)
65% Methanol  = 650 Ml

Fox 35 mix-----
10% Vitamin N = 100 Ml
25% oil ( 20% Castor 5% synth) = 200 Ml castor and 50 Ml synth
65% methanol = 650 Ml

Each get a short shot of aero 1 additive

The nelson N36 combat blend is:

10% Nitro
20 % Uncon LB 625 per Henry Nelson advice
70% Methanol
and a short shot of Aero 1 additive....makes me feel good

Johnson 35 slightly diferent
Enya 35 yet again different
Veco 35 again a bit different

BUT truth is I am graduating to more and more OS, ASP, and Magnum powered planes    so this dorking around with different blends will eventually be 5, 10, or 15 % blends they all like

I expect a few will question the different blends for Johnson, Veco, Fox combat, Enya and K&B engines.... and true enough they all will run just fine on a standard heavy oil blend... I like to tinker and play with my Tach and props.....Most are on combat planes

[cory colquhoun]

Cory

I am very rural and have to mix my own and YES
It IS aggravating to have 3 or 4 blends...but required...there is NO universal blend for all engines of differing designs and metallurgy

I keep on hand:
Torco sourced Nitro and Methanol
Sig Castor



Sig Benol
Sig techniplate
Sig Klotz 100% synth
Rices Brew UCON LB 625
Randy Smith Aero 1 additive
a variety of Metal ---quart, Half gallon, and 1 gallon clean cans

a spread sheet with my preferred blends....many formulas from here at SH
A graduated beaker set where I blend by ML vs Oz....base 10 system so much easier to deal with math wise

thus 1000 Ml or 1 liter...slightly more than a Quart

works for me OS LA 25 mix----
15% Nitro   = 150 Ml
20% oil  (15% Synth 5% Castor)  = 200 Ml  (150 Ml synth and 50 Ml Castor)
65% Methanol  = 650 Ml

Fox 35 mix-----
10% Vitamin N = 100 Ml
25% oil ( 20% Castor 5% synth) = 200 Ml castor and 50 Ml synth
65% methanol = 650 Ml

Each get a short shot of aero 1 additive

The nelson N36 combat blend is:

10% Nitro
20 % Uncon LB 625 per Henry Nelson advice
70% Methanol
and a short shot of Aero 1 additive....makes me feel good

Johnson 35 slightly diferent
Enya 35 yet again different
Veco 35 again a bit different

BUT truth is I am graduating to more and more OS, ASP, and Magnum powered planes    so this dorking around with different blends will eventually be 5, 10, or 15 % blends they all like

I expect a few will question the different blends for Johnson, Veco, Fox combat, Enya and K&B engines.... and true enough they all will run just fine on a standard heavy oil blend... I like to tinker and play with my Tach and props.....Most are on combat planes

.  Thanks Fred,

                  The older engines I have run so much better since I’ve been mixing,  merco ,os max, tt all seem to love the castor with consistent runs, just wasn’t sure about synthetic/ castor ratio on the modern engines for stunt flying , was using a premix fuel for the La’s with 20 % oil but did not have oil ratios on the bottle ,so I think it was full synthetic

 Cory