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

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.

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.  

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.

The general concensus on the G 51 is , after run in , 18 % OIlL . probly 50/50 castor / synthetic .

As to BEARERS . 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 " .