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Engine basics => Engine set up tips => Topic started by: Chris Wellington on October 26, 2007, 11:40:39 AM

Title: ST 46 Fuel
Post by: Chris Wellington on October 26, 2007, 11:40:39 AM
I'm sure this has been covered before but I'm too lazy to search....

I've been given an ST46 and test flew it on 10% nitro 20% castor : started really easily and seemed to run well enough for the couple of flights in a "hack" profile model. I'm quite impressed thus far but what should I be using?
Title: Re: ST 46 Fuel
Post by: Jim Morris on October 26, 2007, 12:13:19 PM
I might be slapped down by someone,but I will bet you cant go wrong using 10% nitro with 20% oil 1/2 synth 1/2 castor,or Powermaster 22% oil 1/2 and 1/2.
Title: Re: ST 46 Fuel
Post by: Bill Little on October 26, 2007, 01:23:44 PM
5%-10% nitro, 20-22% oil.  Pretty much what Jim said.  I run mine on Sig Champion 20% {??} 1/2-1/2, 5% nitro with no problems.  I DO add Aero 1 at the rate of about 1 oz to a gallon.
Title: Re: ST 46 Fuel
Post by: Bob Zambelli on October 26, 2007, 01:52:58 PM
Jim wrote: "I might be slapped down by someone, but I will bet you can't go wrong using 10% nitro with 20% oil 1/2 synth 1/2 castor,or Powermaster 22% oil 1/2 and 1/2."

No slap down - I run that mix in ALL my engine except my sparkers. Actually, I run Brodak fuel which is 23% but close enough.

Dan Banjock and I run it in our Fox .35s and it's PERFECT. I also use it in my 4 stroke engines.
I have a Stunt Rocket powered with a 1950 Atwood Triumph .49 and use the same fuel - no problems.

Bob Z.
Title: Re: ST 46 Fuel
Post by: Jim Morris on October 26, 2007, 05:38:44 PM
yea I run the Sig in everything I have fro Stalkers to Doublestars,but my personal opinion is not to go castor crazy.
Title: Re: ST 46 Fuel
Post by: Bill Little on October 26, 2007, 06:26:00 PM
yea I run the Sig in everything I have fro Stalkers to Doublestars,but my personal opinion is not to go castor crazy.

Hi Jim,

The "OLD" engines HAD to have castor, and lots of it, or they would go south REAL quick.  A ST 46 is a "tweener".  Ball bearings, but still not ABC construction w/sleeve-piston.  That's why the castor helps a touch in them.  The new ABC/ABN/AAC that have ball bearings need almost no castor really.  Just enough to help if the run goes lean and too much heat builds up.  Too much castor in the ST 46 with its ring can cause it to stick, I'm told.
Title: Re: ST 46 Fuel
Post by: Chris Wellington on October 27, 2007, 12:29:52 PM
As ever, thanks for the advice chaps : a "sticky ring" is to be avoided in life generally...