ENGLISH
17
FUEL SELECTION
Break-in Fuel
Normal Flying Fuel
Gasoline : 2-Strok Oil
40 : 1
45 : 1
A good break-in process is essential to the longevity and performance of your Tomahawk radial
engine. You can complete the break-in process by either mounting the engine on a test stand or on
an airframe. If you choose to mount the engine on an airframe, remove the cowl during break-in to
ensure adequate cooling.
Specific fuel is required for the break-in process. Please refer to the chart above for the proper
fuel. Break-in fuel contains additional oil compared to fuel you will use for everyday flying. The
additional oil is critical for cooling and removing break-in debris from the engine.
Run the engine through four tanks of fuel (32 oz/1000mL) for 3—4 minutes at a time, allowing the
engine to cool between runs. Vary the throttle between idle and ¾ throttle for the first 30 minutes
of engine run time. Do not exceed ¾ throttle during the break-in. The engine break-in process is
complete after the first four tanks of fuel and you can begin tuning the engine for normal flying.
ENGINE BREAK-IN PROCESS
Because of the nature of radial engines, it is not uncommon for the lower cylinders to accumulate
excess fuel or oil either in storage or during the priming process. Before beginning the starting
process be sure to:
1.
Rotate the propeller by hand. During the rotation, if you encounter a point where there is seri
-
ous resistance to the rotation, STOP. This is an indication of a flooded cylinder and what you are
feeling is hydraulic lock. Any further attempts to force the rotation of the engine can result in
damage to the cylinder or conrod.
2.
If you encountered hydraulic lock, remove the spark plug from the lower two cylinders and the
engine should rotate freely. Continue to rotate until all the excess fluid has been removed from
the cylinder.
3.
Reinstall the spark plug and continue with the starting process.
CHECKING FOR A FLOODED CYLINDER
WARNING:
Use only oil for air-cooled engines. The use of oil for water-cooled engines has
a lower flame point and will overheat the engine. This can damage the engine severely. The
use of the wrong oil is not covered by the warranty.
Use Titan 100s Oil of the Fuchs Company.
PROPELLER SELECTION
Propeller selection is critical for proper engine operation. You can find recommended propellers and
operating RPM ranges in the specification chart. Tomahawk radial engines have a lower operating
RPM range and greater torque within that range that require more blade pitch and increased in-air
pitch speed for your airplane.
To increase climbing and acceleration:
Increase propeller diameter and
decrease blade pitch.
To increase top speed:
Decrease propeller diameter and increase blade pitch.
Make sure the propeller is securely mounted to the crankshaft before attempting to start the engine.
1.
Remove the Allen bolt from the propeller washer.
2.
Install the propeller on the crankshaft.
3.
Secure the propeller with the six allen bolt.
