Takeoff; Flight; Landing; 3D Flying - GREAT PLANES U-Can-Do SF Instruction Manual

CAUTION (THIS APPLIES TO ALL R/C AIRPLANES): If,
while fl ying, you notice an alarming or unusual sound such
as a low-pitched "buzz," this may indicate control surface
fl utter. Flutter occurs when a control surface (such as an
aileron or elevator) or a fl ying surface (such as a wing or
stab) rapidly vibrates up and down (thus causing the noise).
In extreme cases, if not detected immediately, fl utter can
actually cause the control surface to detach or the fl ying
surface to fail, thus causing loss of control followed by
an impending crash. The best thing to do when fl utter is
detected is to slow the model immediately by reducing
power, then land as soon as safely possible. Identify which
surface fl uttered (so the problem may be resolved) by
checking all the servo grommets for deterioration or signs of
vibration. Make certain all pushrod linkages are secure and
free of play. If it fl uttered once, under similar circumstances
it will probably fl utter again unless the problem is fi xed.
Some things which can cause fl utter are; Excessive hinge
gap; Not mounting control horns solidly; Poor fi t of clevis
pin in horn; Side-play of wire pushrods caused by large
bends; Excessive free play in servo gears; Insecure servo
mounting; and one of the most prevalent causes of fl utter;
Flying an over-powered model at excessive speeds.
Before you get ready to takeoff, see how the model handles
on the ground by doing a few practice runs at low speeds
on the runway. If you need to calm your nerves before the
maiden fl ight, shut the engine down and bring the model
back into the pits. Top off the fuel, then check all fasteners
and control linkages for peace of mind. If you have dual rates
on your transmitter, set the switches to "high rate" for takeoff,
especially when taking off in a crosswind. Although this model
has good low-speed characteristics, you should always build
up as much speed as your runway will permit before lifting off,
as this will give you a safety margin in case of a "fl ame-out."
When you fi rst advance the throttle the plane will usually turn
left slightly. Correct by applying suffi cient right rudder to hold
it straight down the runway. When the plane has suffi cient
fl ying speed, lift off by smoothly applying up elevator (don't
"jerk" it off into a steep climb!), and climb out gradually.
For reassurance and to keep an eye on other traffi c, it is a
good idea to have an assistant on the fl ight line with you. Tell
him to remind you to throttle back once the plane gets to a
comfortable altitude. While full throttle is usually desirable for
takeoff, most models fl y more smoothly at reduced speeds.
Take it easy with the U-Can-Do SF for the fi rst few fl ights,
gradually getting acquainted with it as you gain confi dence.
Adjust the trims to maintain straight and level fl ight. After
fl ying around for a while and while still at a safe altitude
with plenty of fuel, practice slow fl ight and execute practice
landing approaches by reducing the throttle to see how the
model handles at slower speeds. Add power to see how
the model climbs as well. Continue to fl y around, executing

Takeoff

Flight

various maneuvers and making mental notes (or having your
assistant write them down) of what trim or C.G. changes may
be required to fi ne tune the model so it fl ies the way you like.
Mind your fuel level, but use this fi rst fl ight to become familiar
with your model before landing.
To initiate a landing approach, lower the throttle while on the
downwind leg. Allow the nose of the model to pitch downward
to gradually bleed off altitude. Continue to lose altitude, but
maintain airspeed by keeping the nose down as you turn onto
the crosswind leg. Make your fi nal turn toward the runway
(into the wind) keeping the nose down to maintain airspeed
and control. Level the attitude when the model reaches the
runway threshold, modulating the throttle as necessary to
maintain your glide path and airspeed. If you are going to
overshoot, smoothly advance the throttle (always ready on
the right rudder to counteract torque) and climb out to make
another attempt. When you're ready to make your landing fl are
and the model is a foot or so off the deck, smoothly increase
up elevator until it gently touches down. Once the model is
on the runway and has lost fl ying speed, the tail will settle
onto the ground, giving you steering control. Remember to
mind your fuel level. Do not wait until your tank is empty to
begin your landing approach. You will need some fuel left if
you need to abandon your approach and circle back around.
One fi nal note about fl ying your model. Have a goal or fl ight
plan in mind for every fl ight. This can be learning a new
maneuver(s), improving a maneuver(s) you already know,
or learning how the model behaves in certain conditions
(such as on high or low rates). This is not necessarily to
improve your skills (though it is never a bad idea!), but more
importantly so you do not surprise yourself by impulsively
attempting a maneuver and suddenly fi nding that you've run
out of time, altitude or airspeed. Every maneuver should be
deliberate, not impulsive. For example, if you're going to do a
loop, check your altitude, mind the wind direction (anticipating
rudder corrections that will be required to maintain heading),
remember to throttle back at the top, and make certain you
are on the desired rates (high/low rates). A fl ight plan greatly
reduces the chances of crashing your model just because
of poor planning and impulsive moves. Remember to think.
Learn to manage the throttle and experiment during 3D
maneuvers. The power needed will depend on the maneuver
being performed. C.G. also plays a large role in the 3D
capability of models as well. Experiment a little, but keep in
mind that being tail heavy is not always the best way to go.
Propeller thrust and thrust vectoring need to be considered
for 3D aerobatics. A large diameter prop with a low pitch will
provide a lot of pull for the aircraft but will not offer enough air
moving across the tail surfaces (thrust vectoring) for 3D. Due
to the large number of factors involved, some experimentation
will be necessary to fi nd the right propeller pitch and diameter
for your model.
30

Landing

3D Flying