RE: PBY-5A Catalina
Hi!
Using .30 fourstrokes certainly will overpower the Kyosho Catalina.
2,5cc (.15) OS LA engines is the perfect choice as they provide ample power and are very reliable and throttle very good. I fly mine with APC 8x5 props (scale size) and it cruises along nicely at under half throttle.
.30 fourstrokes are perfect in little larger twins like the Marutaka or Top-Flite DC-3...but not in the Kyosho PBY Catalina.(I got OS .26 fourstrokes in my Marutaka DC-3)
Regards!
Jan K