Set The Control Throws; Balance The Model (C.g.) - GREAT PLANES RV-4 Instruction Manual

Set the Control Throws

Use a Great Planes AccuThrow
measure and set the control throw of each control surface as
indicated in the chart that follows. If your radio does not have
dual rates, we recommend setting the throws at the low rate
setting for the first flights. NOTE: The throws are measured
at the widest part of the elevators, rudder and ailerons.
These are the recommend control surface throws:
High rate
Elevator: 5/8" [16mm] up
5/8" [16mm] down
Rudder: 1-1/16" [27mm] right 7/8" [22mm] right
1-1/16" [27mm] left
Ailerons: 3/4" [19mm] up
3/4" [19mm] down
Flaps: 1" [25mm] down
IMPORTANT: The RV-4 has been extensively flown and
tested to arrive at the throws at which it flies best. Flying
your model at these throws will provide you with the
greatest chance for successful first flights. If, after you have
become accustomed to the way the RV-4 flies, you would
like to change the throws to suit your taste, that is fine.
However, too much control throw could make the model
difficult to control, so remember, "more is not always better."
(or a ruler) to accurately
™
Low rate
1/4" [7mm] up
1/4" [7mm] down
7/8" [22mm] left
1/2" [13mm] up
1/2" [13mm] down
1/2" [13mm] down

Balance the Model (C.G.)

More than any other factor, the C.G. (Center of Gravity)
can have the greatest effect on how a model flies and
may determine whether or not your first flight will be
successful. If you value this model and wish to enjoy it for
many flights, DO NOT OVERLOOK THIS IMPORTANT
PROCEDURE. A model that is not properly balanced will
be unstable and possibly unflyable.
At this stage the model should be in ready-to-fly condition
with all of the systems in place including the engine, landing
gear, covering and paint and the radio system.
1. Use a felt-tip pen or 1/8" [3mm] - wide tape to accurately
mark the C.G. on the bottom of the wing on both sides of the
fuselage. The C.G. is located 3-3/4" [95mm] back from the
leading edge of the wing.
This is where your model should balance for your first
flights. Later, you may wish to experiment by shifting the
C.G. up to 1" [25mm] forward or 3/8" [9.5mm] back to
change the flying characteristics. Moving the C.G. forward
may improve the smoothness and stability, but it may then
require more speed for takeoff and make it more difficult
to slow down for landing. Moving the C.G. aft makes the
model more maneuverable, but could also cause it to
become too difficult for you to control. In any case, start at
the location we recommend and do not at any time
balance your model outside the recommended range.
2. With the wing attached to the fuselage, all parts of the
model installed (ready to fly) and an empty fuel tank, place
the model upside down on a Great Planes CG Machine, or
lift it at the balance point you marked.
3. If the tail drops, the model is "tail heavy" and weight
must be added to the nose to balance. If the nose drops, the
model is "nose heavy" and the battery pack and/or receiver
must be shifted aft or weight must be added to the tail to
balance. If possible, relocate the battery pack and receiver
to minimize or eliminate any additional ballast required. If
additional weight is required, nose weight may be easily
added by using a "spinner weight" (GPMQ4645 for the 1 oz.
weight, or GPMQ4646 for the 2 oz. weight). If spinner weight
47
3-3/4"