Saito Fg-90R3

According to Saito, the FG 90R3, like the FG 60, can also be traced back to the FA-220 glow igniter. Among other things, a gasoline-compatible carburetor was installed and the cylinders and cylinder heads are made from one piece. The crankshaft has double ball bearings. As with the FG84 R3, large heat sinks are mounted on the housing, which should be located in the airflow of the propeller to ensure optimum heat dissipation from the crankshaft housing. The magnetic sensor appears to be of the same type as the FG60 and is mounted at an angle to the side. The exhaust outlet is routed to the rear, so the type CM6 spark plug is well protected at an angle. Almost a little too hidden, because when a ring silencer is fitted, which has to be purchased separately, it gets quite tight when attaching and locking the spark plug connector. The carburetor is again behind the mounting plate, but this time the throttle lever has been moved to the left-hand side. However, Saito seems to have learned from the “nagging” of the carburetor of the FG 60 radial engine: This time, it is possible to choke the engine from the outside. When installed, it was more than awkward to suck in fuel with the engine on the 60 and also on the 84.
Saito has also come up with a practical solution for the latest model, the FG90 R3 being tested here: In the middle of the throttle lever there is a connection to the internal choke flap, which can be operated using the enclosed “choke stick”. For this purpose, a 4 mm hole must be provided in the hood and possibly the front end of the engine bulkhead when installed. In order to be able to prime the carburetor without a second person holding the choke stick in position, an adjusting ring or similar should be installed in the hood so that the stick remains in the required position. After suction, the chock stick can be removed again. Unfortunately, servo-controlled suction is not provided. The main jet needle is located at the top right of the throttle lever and the idle needle in the throttle lever. Chocking does not, of course, adjust the idle needle, because the screw connection for the choke stick is a thread directly on the throttle lever. Therefore, when readjusting the needle, the stick must be unscrewed so that the carburetor adjusting stick can be used.
In addition to the aforementioned stick for choking, the engine also comes with the carburetor setting stick. Due to the large amount of information on engine design on the aero-naut website, it is not necessary to explain it again at this point.