The engine PC4 - the most protected at falling on the ground. Course of 16 mm, the piston of 14 mm. The combination of the big course and short (23.5 mm) a rod has given good start-up. Very easy. It is recommended for beginning. Resource speed of 24-25 seconds on 10 circles. Very economic. Structure of fuel: 20% of castor oil and 80% metanol.