What is the difference between a FX, AX, or whatever X they may have? Also what does the number in front of it mean? is it the power or the size? or a little bit of both? for example: .20 .40 .60 .90.??

I can seem to find a thread on engine basics

Thanx

The letters are manufacturer designations. Some have ball bearing, some are ringed where others are ABC (aluminum, brass, chrome) construction.

The number is the displacement in cubic inches. a .50 or 50 is 1/2 cubic inch cylinder displacement.

Try this http://www.masportaviator.com

Click PRI FLY which is primary flight training.

There you should see lots of beginner articles including Engines 101 and Engines 101 part 2.

Excellent site, Thank you.

My pleasure. Where are you in Jersey? I grew up in Philly and spent most summers in Ocean City NJ.

hey, Union City NJ.. 10 min from NYC.. Not too far from philly.

I've only seen AX, FX, and SX on the OS engines...

The AX and FX seem to be their high quality "ABL" (Advanced Bi-Metallic Liner) engines with ball bearings. The SX engines appear to be bored & stroked versions that have higher displacement in the same size engine (.50 SX is same size as a .46 AX/FX, .32 SX is same size as .25 FX), and the .50 SX is actually a ringed engine, instead of an ABL engine like the .46 AX/FX. OS also makes an LA series, which I believe are lapped engines (no liner) with bushings (instead of ball bearings).

The LA series are ABN, bushing engines.