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Engine basics => Engine set up tips => Topic started by: Robin_Holden on June 23, 2020, 02:14:56 PM
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Hi from North Yorkshire , England.
Advice please regarding the best fuel for my (original Italian ) Super Tigre G51 Stunt , which was transformed by Mr Tom Dickson
Into the best stunt engine in my possession.
I’ve been laid up for 18 months or so , ailments , and have just got back into the groove
My G51 was carefully run in , but hasn’t been used for a while. It’s currently lodged in a profile Cardinal.
So , what fuel would you recommend ?
What proportion of synthetic to castor ?
It does like a Graupner 12 x 5.
Any help would be much appreciated,
Regards ,
Robin.
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50/50 . though all castors fine . Tom Dixon regards castor as doubling the ring life .
Generall concensus is 18 % total , or a stutter / stagger from residue in the backplate peripharyacumulates and clears causeing this .
fine on no nitro , maybe even best . Though a prime of ' nitro fuel ' in cold weather will wake it up easier .
5 or 10 % Nitro . or 3 to 10 % . Maybe extra gasket or two . But Dixon'd be a Hemi'd head , so likely unnessesary .
Theyre actually vary durable . Ran a good ten gallons of all sorts through one . Including one of stale sig ' F A I juice . Maybe double that.
Recent strip & clean , the ring was at a tight 5 thou. gap . An Italian version .
ADDED : ( see next post ) needs a few gallons through it before its ' loosened off ' a bit . !
They run good on the silent muffler ( as does a Merco 49 ) if youve the room & need noseweight . lots of power .
For setting , theres 3/4 turn , solid 4 to solid 2 . Wind it into the solid 2 slowly , then back 1/4 turn , usually gets ' the good ' setting .
Just going in from the 4 , your usually cautious and end up short / rich . Too Far .Get it into a steady clean two stroke, then back it off into a even gnarly 1/2 n 1/2 run.
a good tank 7&itll just switch through at 45 degrees , opening it out a tad and you can get it just into the switch across the top of the circle .Of if its a gale , in till
its pulling say halfway up the loops . Should cut in & out dead on the same hight. or try another tank . Usually use baffled wedge corner uniflow .
Maybe Enya 3 for cold fuel . ST plugs seems good for all fuel . maybe enya 4 with nitro .
The little std 46 muffler , with the tailpipe cut off is a good muffler for them . You can butcher the fins and nose a bit for streamlining .
Further to . . . Here in Aus, Prefered cool power , Syn & Castor . 50/50 , maybe 18 % winter , 20 % summer . Nitro accoring to taste , unnessesary , really . But likely a small syringe
to meter ' nitro fuel ' prime , if cold weather or competition . Sometimes hot weather needs it, you see Urtnowski hitting them with lighter fluid instead , for the same reason .
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My (Italian) G51 was horrible at first using 20% all castor and no nitro by going from a 4 stroke to a screaming 2 stroke if the nose lifted more than 1 degree (a slight exaggeration :) ) and took 2 level laps to come back to a 4 stroke. After a month of head scratching and much experimenting it dawned on me that it was extremely economical so not enough oil flow to control the temperature. I switched to 25% all castor and it was suddenly a brilliant engine. Rock steady 4 stroke from start to finish with a Zinger 12x5 prop and 80cc of fuel for a 6 minute flight.
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Hi Use 23 % oil with half synthetic, The ring will last longer on that brew than with 18% or all castor Hint 18% is not enough oil for that to cycle correctly,
100s of people use this brew in their ST51s and many other ST ring engines
Randy
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Robin,
I ran pretty much what Randy suggested. Mine was set up by George Aldrich , ran an Eather Flat back , wide , 11.7- 4.5 prop at 9,900 rpm Gary Nelson's were set up by Tom Lay, I believe ( 30 years ago) Gary used 24% all Castor with a Graupner 12-5 his were maybe the strongest, best running Italian Tigers I've seen. Better than mine. Later I dabbled with fuels , props & on a pipe. Mine wouldn't run on all castor.
John L.