so I have this OS Hyper 50 with the stock 60L Carb set up for a plane with an APC 11x8, and a GMS .47 oversize muffler, this muffler is about 1mm longer and 1mm wider than an OS 61FX stock muffler, see the muffler in the photo, sorry, but it's the only ohoto I have..
the engine had 2 gallons run threw it and I replaced the bearing and the ring, then I set it up for a plane, it has only had to flights on it and one take full running on the ground.

the Numbers
Prop APC 11X8,
fuel, mixed, 15% Nitro 18% oil,
Idle 3,200
Peak RPM,, 12,200
Tuned for flight,, 11,600

I have it in a World Models P-40, I plan to lean it out another 200 RPM after a few more flights, but as for now the guys at the field say the plane does about 100 MPH.. the thing is, when I order new fuel I will be ordering 20%, but the question is, what am I going to do with the 3 gallons of 30% I have




Jim

Mix the 30% with some lower nitro fuel. Got some 30% at a good price from someone in the club that had stoped useing glow and that's what I did.

A J, I never knew you replied till today.
once I got the plane to the field and ran it a 2nd time the RPM came up another 300 to 12.500 peaked, and 11,900 tuned for flight (APC 11x8). I still think I can lean it a click or 2 more. I will keep it checked by the plug. the better pilots at the field say she does 100 mph LOL
and with that big Heli carb the engine runs and idles beautifully with a prop.

if you click on my link below you will see the stock OS 50sx is the same engine, same liner and same piston, but a smaller plane carb of course, the review says the SX with the smaller plane carb and stock muffler turns the APC 11x8 at 11.000 peaked (5% nitro), so I am 900 over that

BTW, once this 15% is gone I have 3 gallons of 30% Heli fuel

OS Max 50SX

Jim

Good to hear it's working out for you. The hyper 50 will like the 30% fuel.