Table of Contents
Advertisement
These are the recommended control surface throws:
High Rate
ELEVATOR:
1" [25mm] up
1" [25mm] down
RUDDER:
2-3/4" [70mm] right 1-3/4" [44mm] right
2-3/4" [70mm] left
AILERONS:
1-1/2" [38mm] up
1-1/2" [38mm] down 3/4" [19mm] down
FLAPS:
1-1/8" [28mm] down
3/4" [19mm] 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."
Balance the Model (C.G.)
More than any other factor, the C.G. (balance point) 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 top of the wing on both sides of the
fuselage. The C.G. is located 4-3/8" [111mm] back from the
LE of the wing.
This is where your model should balance for the first
flights. Later, you may wish to experiment by shifting the
C.G. up to 3/8" [9.5mm] forward or 1" [25mm] back to
change the flying characteristics. Moving the C.G. forward
may improve the smoothness and stability, but the model
may then require more speed for takeoff and make it more
difficult to slow for landing. Moving the C.G. aft makes the
model more maneuverable, but could also cause it to
become too difficult to control. In any case, start at the
recommended balance point and do not at any time
balance the model outside the specified range.
Low Rate
5/8" [16mm] up
5/8" [16mm] down
1-3/4" [44mm] left
3/4" [19mm] up
24
❏
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 upside-down at the balance point you marked.
❏
3. If the tail drops, the model is "tail heavy" and the battery
pack and/or receiver must be shifted forward or 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.
[28g] weight, or GPMQ4646 for the 2 oz. [57g] weight). If
spinner weight is not practical or is not enough, use Great
Planes (GPMQ4485) "stick-on" lead. A good place to add
stick-on nose weight is to the firewall (don't attach weight to
the cowl–it is not intended to support weight). Begin by
placing incrementally increasing amounts of weight on the
bottom of the fuse over the firewall until the model balances.
Once you have determined the amount of weight required, it
can be permanently attached. If required, tail weight may be
added by cutting open the bottom of the fuse and gluing it
permanently inside.
Note: Do not rely upon the adhesive on the back of the lead
weight to permanently hold it in place. Over time, fuel and
exhaust residue may soften the adhesive and cause the
weight to fall off. Use #2 SMS, RTV silicone or epoxy to
permanently hold the weight in place.
❏
4. IMPORTANT: If you found it necessary to add any
weight, recheck the C.G. after the weight has been installed.
Balance the Model Laterally
❏
1. With the wing level, have an assistant help you lift the
model by the engine propeller shaft and the bottom of the
fuse under the TE of the fin. Do this several times.
❏
2. If one wing always drops when you lift the model, it means
that side is heavy. Balance the airplane by adding weight to the
other wing tip. An airplane that has been laterally balanced
will track better in loops and other maneuvers.
Advertisement
Table of Contents
