Great Planes Extra 300S 1.20 ARF Patty Wagstaff - GPMA1305 - Manual (Page 36)

off the controls. The model should go a reasonable distance with
the fuse at an even keel. If the nose pitches down, remove some
nose weight, and the opposite if the nose pitches up. The trick is to
use only the ailerons to get the model up at a 45° bank. We almost
automatically start feeding in elevator, but that’s a no-no. Do the
bank in both directions, just to make sure that you are getting an
accurate reading of the longitudinal balance.
We now want to test the correct alignment of both sides of the
elevator (even if they aren’t split, like a Pattern ship’s, they can still
be warped or twisted). Yaw and lateral balance will also come into
play here, so be patient and eliminate the variables, one-by-one.
The maneuver is a simple loop, but it must be entered with the
wings perfectly level. Position the maneuver so that your assistant
can observe it end-on. Always loop into the wind. Do several loops,
and see if the same symptom persists. Note if the model loses
heading on the front or back side of the loop. If you lose it on the
way up, it’s probably an aileron problem, while a loss of heading on
the way back down is most likely a rudder situation.
Note that the Yaw test is the same looping sequences. Here,
however, we are altering rudder and ailerons, instead of the
elevator halves. We must repeat that many airplanes just will not
achieve adequate lateral trim without sealing the hinge gaps shut.
The larger you make the loops (to a point), the more discernable
the errors will be.
The Lateral Balance test has us pulling those loops very tightly.
Pull straight up into a vertical and watch which wing drops. A true
vertical is hard to do, so make sure that your assistant is observing
from another vantage point. Note that the engine torque will affect
the vertical fall off, as will rudder errors. Even though we balance
the wing statically before leaving for the field, we are now trimming
it dynamically.
The Aileron Coupling (or rigging) is also tested by doing
Hammerhead Stalls. This time, however, we want to observe the
side view of the model. Does the plane want to tuck under a bit? If
so, then try trimming the ailerons down a small bit, so that they will
act as flaps. If the model tends to want to go over into a loop, then
rig both ailerons up a few turns on the clevises. Note that drooping
the ailerons will tend to cancel any washout you have in the wing.
On some models, the lack of washout can lead to some nasty
characteristics at low speeds.
Again, we reiterate that all of these controls are interactive.
When you change the wing incidence, it will influence the way the
elevator trim is at a given C.G. Re-trimming the wing will also
change the rigging on the ailerons, in effect, and they may have to
be readjusted accordingly.
The whole process isn’t hard. As a matter of fact it’s rather fun
— but very time consuming. It’s amazing what you will learn about
why a plane flies the way it does, and you’ll be a better pilot for it.
One thing we almost guarantee, is that your planes will be more
reliable and predictable when they are properly trimmed out. They
will fly more efficiently, and be less prone to doing radical and
surprising things. Your contest scores should improve, too.
We wish to acknowledge the Orlando, Florida, club newsletter,
from which the basics of the chart presented here were gleaned.
Reprinted in part by Great Planes Model Manufacturing Company,
courtesy of Scale R/C Modeler magazine, Pat Potega, Editor,
August 1983 issue.
See the Flight Trimming Chart on Page 38
Great Planes 1/3-Scale Pitts Special ARF
Assembled, extra-aerobatic and covered in Top Flite
MonoKote, the Pitts Special ARF provides crowd-pleasing
performance with pilot-pleasing ease! Dual aileron servos
on both symmetrical wings add authoritative response to
your routines – and a 68.5" wingspan means this Pitts is
IMAA-legal. Lots of quality Great Planes hardware is
supplied, including wheels, a 4" aluminum spinner and
decals. Requires a 4-6 channel radio w/6-8 servos, 2-stroke
1.6-2.7 cu in glow or 2.5 cu in gasoline engine, fuel and
support equipment. GPMA1218
Great Planes 1/4-Scale Giles G-202 ARF
Designed to convince “kitters” that ARFs can be
outstanding! Parts interlock for strength, and are all-wood
except for fiberglass parts factory-painted to match the
preapplied MonoKote covering. Competition mounted
servos (2 each for ailerons and elevators, 1 for the rudder)
plus double-beveled rudder and elevator control surfaces
open the way for wild, 3D stunts. Pilot figure not included.
GPMA1315
OTHER ITEMS AVAILABLE
FROM GREAT PLANES
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