Before trimming a new airplane, you need to finalize all of you equipment selections and locations. Look for the following:
Fuel tank. Pick one large enough to provide 12 to 15 minutes of flying. Any less will be too short for a good practice
flight, and any more is just extra weight. The tank needs to be mounted on the center of gravity (CG). This is essential,
or your aircraft will change flight characteristics as you burn fuel, making it impossible to trim.
All serious pattern engines include a pump to give consistent mixture at any aircraft attitude, and to pull fuel all the
way forward from the CG. If your engine doesn’t have a pump, then add one. Perry makes several good models that can
be retrofit to almost any engine. If you are running a gasser, you won’t need a pump, as the carburetor will suck a
tank flat if the vent gets clogged. Trust me, cause I’ve done it! Always use a filter, even if the manufacturer says
not to. It will save you untold grief later.
Propeller. You must decide on your propeller before getting serious about trimming. Each propeller sends a unique airflow
pattern back over the airplane. We will be compensating for this airflow in the trimming phase of set-up…so you MUST
finalize your prop selection now. Later, if you change your propeller size or type, you will have to run back through the
The rest of your equipment can be moved as necessary to balance your plane.
If your radio transmitter has adjustable trim steps, set it for a single unit precision. Most come set for 4 units per
trim, but that is not precise enough.
You are now ready to start trimming your plane.