Y'all,
I have been away from the hobby for many years, and am now comming back. Four strokes were just comming on as a viable replacement for the 2 stroke for their higher torque at a lower RPM and quiteness. The general rule at that time was 2s .40, 4s .60, 2s 60, 4s .90 and so on. My question is all of this still the same? I am hearing now that the 4s are a lot closer to the 2s in the power department. Is this true? Inquiring Minds Need to Know! I am looking to put a 4s into a .40 Sig Rascal ARFand I need to know about what size.
Thanks, Parham

Saito 56 would be perfect.....

10-4 on the Saito 56. It is a sweetheart

OK, How does the Saito .56 run inverted?

The do about as well as any inverted model engine

The main problem with inverted engines is proper location of fuel tank in respect to spray bar of throttle. When inverting an engine often the fuel tank will be too high, thereby causing fuel siphoning. Get the tank in proper relation to spray bar and get engine tuned and it run fine. If it runs too rich, due to siphoning or improper tuning it may kill glow plug. other than those 2 things engine doesn't know it's inverted and will run fine. At times it may be necassary to use a glow plug lighter.

The 56 is nice but a 62a will make bark.I have a 1400mm wingspan midget mustang and the standard factory engine is an os 46.If you want to turn it into a real pocket rocket you can fit an os55 or 75.I've squeezed a saito115 in and if you look at the specs for both the 115 and the os75 they are not far apart.