The F33 A/AS is an air cooled, reed valve controlled 1-cylinder-2-stroke engine with slide carburetor and Nikasil coated cylinder. It has one of the highest power to weight ratio available on the 30 HP engine market. Ideally suited for powered parachutes, light experimental aircrafts and ultralights and all applications where weight is an issue. This engine is available in several versions. an overview is given in the Hirth-information 0069/1N.
Description from the website http://www.hirth-motoren.de/en/engine-f33-a-as.html on 2014-05-18.