RCGF 21CC-Twin Operator's Manual page 7

9. Install the spark plug into the engine cylinder (7-8lbs torque).
Installing the RCGF 21cc twin cylinder engine
on Your Airplane
Note: The RCGF 21CC twin must be installed on at least a 9.5 mm thick 5-phy plywood
firewall.The firewall must be securely glued to the airplane. Use triangle stock and pin the
firewall with hardwood dowels to reinforce the firewall glue joints. Never install the RCGF
21cc twin onto a firewall thinner than specified because it may fail due to the power of the
engine.
Note: The length of the engine from the back on the engine mount to the face of the
propeller washer is 139 mm
Note : Please remember to remove the prop washer and the small blind nut, when
you mount the adapter nut in your 21cc twin engine.
1. Please check engine size chart (on the back cover of this manual) to drill the engine
mounting bolt holes.
2. Install (4) 5mm blind nuts (not included) into the back side (non-engine side) of the
firewall. Install the engine to the firewall using(4) 5x45mm SHCS with 5mm lock washers
and flat washers with the included standoffs. Use threadlocking compound, such as
Threadlocker on the screws where they thread into the blind nuts.
3. Install the fuel tank in the airframe. Use only gasoline approved fuel tank and fuel lines
and a gasoline approved stopper. One line should go to the carburetor and the other is to
be used as a vent (a vent line is simply an open ended fuel line from the fuel tank which
exits the engine compartment or the fuselage; most vent lines exit at the bottom of the
firewall).You can fill the tank by using the carburetor line as fill line if you have access to
it or install a third line to be used as fill line. Installing a third line is the cleanest and
easiest way to add fuel. An alternative fueling set up is a 2-line system with a T-fitting
approved for gasoline use. Be sure to use a filler plug with either a 2 line or 3 line set-up.
It's a good idea to add an extension to the vent line as shown, that goes up and to the
rear of the tank. This helps to avoid draining fuel from the tank when the model is pointed
down.