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Set-up and trimming
Besides basic assembly, this is the most important part of preparing your airplane for flight. It can also
be the most time consuming, but once your plane is properly dialed in you will agree it was time well
spent.
One of the most practical ways to check the CG on an aircraft this size is to insert the carbon fiber wing
tube into its sleeve in the fuselage and tie a length of rope around the tube on each side of the fuselage,
forming a loop that you can pick the aircraft up with. Slide the wings into position, install the canopy
and pick up the plane with the rope. The Extra should balance in a horizontal position on the center of
the wing tube. Move your batteries and radio equipment to achieve this condition. This will give you a
safe starting place for the first flights.
One of the best ways to fine tune the CG for your aircraft is the 45 degree line test. Fly the aircraft in
front of you from left to right (or right to left if you prefer) at full throttle. Pull the aircraft into a 45
degree up line and establish this line. Roll the aircraft inverted, neutralize the elevator and pay close
attention to what the plane does. Ideally the plane will continue on this line for several hundred feet
before it starts to slowly level off. If the airplane immediately drops the nose and dives toward the ground
it is nose heavy. If it begins to climb inverted toward the gear it is tail heavy. There is no need to have the
Extra excessively tail heavy to perform 3D maneuvers.
Control surface throws
I highly recommend that you purchase a throw meter that measures in degrees. There are several units
available commercially. These units are a great aid in set-up and definitely beat the “that looks about
right” method. For any type of precision flying, surfaces that travel equal distances are a must. The
following control surface travels are what I use on my own Extra. These are a good starting point, but are
by no means the only way to set up the Extra. Start here and then adjust to fit your own preferences and
style of flying.
Elevator: 10-12 degrees low rate, 18-20% exponential
all you can get for high rate, 50-60% exponential
Aileron: 18-20 degrees low rate, 30-40% exponential
all you can get for high rate, 50-60% exponential
Rudder: 20 degrees low rate, 50% exponential
all you can get for high rate, 60-70% exponential.
Again, this is just a starting point. Adjust to your liking.
Thanks again for your purchase of the Extreme Flight RC 91" Extra 300EXP
ARF. I hope you enjoy assembling and flying yours as much as I have mine.
See you at the flying field!
Chris Hinson
Extreme Flight RC
