Four Stroke (Four Cycle): Although a 4-stroke engine has less power than a 2-stroke engine of comparable size, there are advantages to 4-stroke engines. They do not require a muffler and are often quieter than most 2- strokes are with a muffler. They can swing a bigger prop than the same size 2- stroke engine. This is an asset in the large, slow-flying aerobatic and scale models where 4- stroke engines are usually mounted. Lastly, the fuel economy is better.