stunthanger.com
Engine basics => Engine set up tips => Topic started by: Dennis Saydak on June 16, 2015, 12:59:35 PM
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I know the Super TigreV.60 is a real thumper and many people believe it benefits from a crutch style motor mount with 1/2" bearers, for consistent runs. It the same type of mount required for the newer square head .51?
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Hi Dennis,
The G.51 is much smoother running engine than the .60. I have used the usual 3/8 X 1/2 maple for engine bearers. I always build a crutch for the engine but I have had great engine runs with out 1/2 X 1/2. My best models with the G.51 were a 64 oz. SV 11 and a 53 oz. USA-1.
Bill
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Thanks Bill, that's what I was hoping for. I built a crutch for my Silver Fox .51 and I used 1/2" sq. bearers. They look a little over robust to me so I'll likely shave a little off each side. I'm working on a few "filler" projects for next building season while I finish up a few long over due projects. I'm thinking a Freeman Spitfire.
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Some people (me included) have had terrible results from genuine Italian ST51s. I and others suffer from totally inconsistent runs and believe me I have tried every suggestion here on Stunthanger, to make them run correctly (there are a lot of suggestions to, if you do a search).
The ST60s I have run totally consistently, although they do vibrate! Strangely, the recently available ABC piston / cylinders from Australia do not seem to vibrate as much, something that I did not expect!
Andrew.
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Andrew...you're saying you've got the BG ABC piston/cylinder for the G.51 already? I haven't heard a peep from Brian. I've got two sets and one head ordered, and should be able to pay for them! How were you notified??? #^ #^ #^ Steve
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OK, let me put on my English major hat and read the second to last post again...yup, just what I thought, Andrew is referring to the recently available ST-60 ABC P&L liner sets, not the ST-51 parts...patience Steve, patience, they will get here. FWIW: the 60 P&L ABC P&L really transform a ST-60 into a smooth modern engine, mine is slated for a Shark 45. 8)
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Well, I did figure out that Saydak's Fox .51 was a Lew Woolard G.51! LL~ I have an excuse...it was almost dinner time, and the panic was setting in.... ;) Steve
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You could try 1/2" bearers on the outboard side and 3/8" the inboard.
This nicely allows for 1/8" engine offset that is centred around the prop driver as it gives room for the engine to cant.
I have seen it on 60 sized models.
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Hello Steve,
Sorry I got you confused, I was referring to Brian's ST60 ABC conversion kit. I did not know he was thinking of doing one for the ST51, if so I will be first in the queue! I did not weigh the new or old piston. Maybe the new one is lighter, I am not tearing down my ST60s to find out. But as said above, the transformation is quite startling. It is as good as anything I have and that includes the recent Enya 61 and that is saying something!
Andrew.
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The general concensus on the G 51 is , after run in , 18 % OIlL . probly 50/50 castor / synthetic .
As to BEARERS . :-X some think 3/8 x 1/2 is A BIT LIGHT for a G-15 , to get max. revs .
Henry Nelson comented on the yukey alloy combat Eng. Mounts , when they first came out ,
as inadequate .
The general idea is to have a ENGINE BED . as in a sound secure mass to damp ' ossilations '
( vibes man ) , the mass & ' natural frequency ' of the nose nullifying attempts by the engine
to dictate matters there .
Thus secuely adheared aligned mounts to ply doublers secured to the sides & LE / Spar area of the wing,
making the whole affair homogenous .
The G 51 will haul a ton , ( Er 2 kilo ) on STRAIGHT FUEL ( No Nitro ) on 70 ft. of 18 thou seven strand .
IN 20 mph winds . If you glue your shoes to the tarmac .
Ended up with golf shoes in the wet field . Still needed two hands at times for security .
The Engine ( G51 ) is happyest & ; bounceyest ' ( change rpm/ gear - 4-2 ) on a smallish prop .
Going to do a 11 x 5 three blade tornado copy , One Day .Got a pile of 11 x 5 Zingers for FOUR BLADE
props , just set another up . these are with 2 3/4 and 3 inch spinners , so maybe it likes a bit of FLYWHEEL .
( horrible plastic Goldberg & Du Bro things . they weigh 5 ton . ACTUALLY I havnt weighed them .Over a Oz.
ANYWAY . )
So theres No Harm in nailing 1/2 x 5/8 ( or 1/2 x 3/4 ) Bearers in there ,with adequate epoxy , and 4 mm
8 ply formers . As it saves Nose weight . :## . Damn thing did the schedule on 80 cc of no nitro in the 71
Oz Spitfire .
Give this , I think they like a bit of aerodynamic load ( a big plane ) to get there juices flowing .
So if youve a horrenous overweight old dunger , or theres one up for grabs , Nail a G 51 in with
a 11 x 6 or 12 x 5 prop ( Zinger ) and let it SNARL .
I dont actually think a 55 Oz thing loads them up enough to ' get in there stride ' .
P.S. , They make a funny noise on a 10 x 4 Three Blade , but go like stink . ( " Thatll Be DETONATION . ~! " )
Er , " Yes " .
VD~