Author Topic: Fuel Formula for General CL Flying (Read 1539 times)

Hoss Cain · « **on:** April 30, 2013, 10:03:05 AM »

In another post there is a request about fuel and all synthetic and some castor oil.

I thought I would post this old formula that I use and it works well, plus easy to obtain the basics.

Here is that fuel formula that works with all my OLD engines, that I fly every so often. Fox 19, Fox 29, and Fox 35s - 36, and .40, included along with even some .049, 074, and .15. Regardless of the other opinions, a good friend now gone, but once was an engine man for a magazine, FM I seem to recall, told me this and he was RIGHT!

Small engines need lot of oil vice nitro. My Cox .049s fly sport very easy to start and needle with the formula below. I always had trouble with my 1/2 A speed and FF engines by using high nitro as it was said one must do. When I learned it was all about OIL, I never had anymore problems.

No problem getting the fuel basics and just some Castor needed as the only extra.

64 Oz. (1/2 Gal.) of 10% nitro, 18% oil (Standard 80-20 syn-castor)

32 Oz. (qt) 5% Nitro 16% oil (Std 80-20 syn/castor)

Add 14 Oz. Castor Oil

RESULT: 110 Oz. fuel: 7.8% nitro, 27.8% oil at 56% Castor and 44% Syn.

It works fine for me.

Brett Buck · « **Reply #1 on:** April 30, 2013, 10:28:25 AM »

Quote from: Hoss Cain on April 30, 2013, 10:03:05 AM

In another post there is a request about fuel and all synthetic and some castor oil.

I thought I would post this old formula that I use and it works well, plus easy to obtain the basics.

Here is that fuel formula that works with all my OLD engines, that I fly every so often. Fox 19, Fox 29, and Fox 35s - 36, and .40, included along with even some .049, 074, and .15. Regardless of the other opinions, a good friend now gone, but once was an engine man for a magazine, FM I seem to recall, told me this and he was RIGHT!

Small engines need lot of oil vice nitro. My Cox .049s fly sport very easy to start and needle with the formula below. I always had trouble with my 1/2 A speed and FF engines by using high nitro as it was said one must do. When I learned it was all about OIL, I never had anymore problems.

No problem getting the fuel basics and just some Castor needed as the only extra.

64 Oz. (1/2 Gal.) of 10% nitro, 18% oil (Standard 80-20 syn-castor)

32 Oz. (qt) 5% Nitro 16% oil (Std 80-20 syn/castor)

Add 14 Oz. Castor Oil

RESULT: 110 Oz. fuel: 7.8% nitro, 27.8% oil at 56% Castor and 44% Syn.

It works fine for me.

This will will work well for older iron-liner engines like McCoys and Foxes. On any modern AAC/ABC/ABN engine this formula will run OK, but you will lose a lot of "power" and engine responsiveness, and will varnish it up in pretty short order. The squeak at TDC will go away and it will tend to fade off in "power" as the outside temperature goes up. It will also cause gradual loss of compression and "power" over the period of about 50 flights with a vintage ringed engine like an ST46.

If it does get like that, crock-potting it will get rid of the varnish, or you can run appropriate fuel like 18% 50/50 castor/synthetic, 15/85 castor/synthetic, or straight 18-20% synthetic for maybe 50 flights or so, which will tend to clean it out. You will hear and feel the engine responsiveness come back as you run it.

Brett

RandySmith · « **Reply #2 on:** April 30, 2013, 01:40:34 PM »

"This will will work well for older iron-liner engines like McCoys and Foxes. On any modern AAC/ABC/ABN engine this formula will run OK, but you will lose a lot of "power" and engine responsiveness, and will varnish it up in pretty short order. The squeak at TDC will go away and it will tend to fade off in "power" as the outside temperature goes up. It will also cause gradual loss of compression and "power" over the period of about 50 flights with a vintage ringed engine like an ST46. "

Hi

Pay special attention to what Brett wrote above, Too much castor and you can ruin an engine, modern engines especially, and when you do gum them up, or stick rings most times, even cleaned, they are not as good as before.
ON older motors like the FOX and McCoys the 1/2 castor 1/2 synth mix ,is normally good and enough to keep them from all the baked on castor that gums them up so badly

Randy

Steve Fitton · « **Reply #3 on:** April 30, 2013, 06:11:03 PM »

My experience was that even Fox 35s didn't like that much castor. My 40th anniversary Fox 35 would gunk up with castor varnish in as few as 100 flights on 29% castor Fox Superfuel. If I had had a clue back then (15 years ago) I would have run Powermaster 10/22 like the Philly guys were and never looked back. I even tried to run Superfuel in FPs ("ya have to run lots of castor to get a stunt run, kid!"). I gunked up every engine I had in short order, and ruined a number of planes in the process.

Jim Thomerson · « **Reply #4 on:** May 04, 2013, 10:42:14 AM »

For some years I have been running Sig Champion 10% nitro, 20% oil, half castor, half synthetic in everything but diesels. Works to suit me for TD 09, Tower 40, K&B 4011, Fox 35, and McCoy 19. Those are engines I have flown for hundreds of flights, and pretty well covers the waterfront. I have flown a flight on a couple of other brands of fuel, said to be the same composition, and had to make drastic needle changes to get less satisfactory results. The Sig fuel is also working to suit in a WenMac 049 on a sport FF.

Author Topic: Fuel Formula for General CL Flying (Read 1539 times)

Hoss Cain

Fuel Formula for General CL Flying

Brett Buck

Re: Fuel Formula for General CL Flying

RandySmith

Re: Fuel Formula for General CL Flying

Steve Fitton

Re: Fuel Formula for General CL Flying

Jim Thomerson

Re: Fuel Formula for General CL Flying