ORIGINAL: combatpigg
The main difference between 2 stroke and 4 stroke engines when comparing them side by side with cubic inch size is 2 strokes are generally less cost, more powerful, fewer moving parts, more crash damage resistant, lighter, better selection of sizes to fit more models........
4 stroke model engines are engineering marvels, most brands and sizes can be matched up with a corresponding airframe to deliver either stupendous or "scale like" performance....whatever you want.
Right.
All too often we see the "Four Strokes have more power & use less fuel" statements here.
In a direct comparison of identical displacement TWO STROKE engines produce more power, but they need to rev higher than four strokers to do so.
To equate power output, you most purchase a larger displacement four stroke engine. However since the four stroke engine produces more torque at a lower RPM, larger props CAN be swung with the larger sized engines. At equal displacements this is not necessarily true and is marketing hype.
By the time you move up to the larger four stroke size, fuel utilization is only marginally less for an equally performing four stroke engine.
However the four stroke engines sound so nice, and some are SO tolerant of mis-tuning ( Saitos ) that we tend to like them a lot.
Ultimately you can use whatever you wish to use for your plane.