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If you were dealing with a real model with a glow-fueled
engine, at this point it would be appropriate to take it outside and run
up the engine a few times. This would allow you to fine-tune the
carburetor settings for the various throttle control stick and
trim-lever positions.
A guest author will write an article about fueled
engine operation and the necessary support equipment (fuel type, fuel
pump, starter battery, starter motor, propeller size, tank size, fuel
lines, muffler, etc.) within the next few months.
How much control throw
or control excursion do you need for your first few flights?
Model-aircraft manufacturers and model designers who publish plans in
magazines usually provide guidelines for your initial flights. They may
suggest one-inch rudder throw or travel on either side of the neutral
position and half-inch elevator control on either side of neutral.
If
you don't get a recommendation, ask a friend who has more experience
than you do or use the one-inch rudder and half-inch elevator for
starters. It is probably better to have a little more than less control
for that first flight. Once you get past that point, your instructor
(hopefully you will have one!) will correct the control throws as
necessary to make life easier for you as you learn to fly and solo.
Making adjustments to increase or decrease control throws
(control-surface movements) is generally handled by the selection of the
hole position on the servo output arm and the control horn on the
control surface. Moving the clevis attach point from the outside
control-horn holes to the inside will cause increased throw. The same
can be done (if more convenient) at the servo output arm. Moving from
the outside hole closer in to the servo-output-arm hub will prompt a
decrease in control throw.
Never forget to make safety checks on your
model. Do this before your first flight and on a regular basis
thereafter. One of the most common problems is failing to properly
attach the control-surface hinges. Hinge choices and their installation
will be the subject of a future article.
For now, no matter what type of
hinge you use, physically pull on the control surface to make sure it is
secured properly.
Throughout the years, I can't tell you how many
rudders or elevators I've pulled off of beginners' models before a first
flight. You can have the best radio system and the best model in the
world, but if a rudder or elevator falls off in flight you will have no
model at all!
In the same regard, make sure that all of your control-rod
clevises, or whatever connectors you employ, are locked in place. Small
keepers can be purchased to slip over the clevis so it can't separate.
Other types of "keepers" prevent a Z-bend wire end from dropping off of
a servo output arm.
Also make sure you have that single screw in place
holding the output arm to the servo hub. I've seen many output arms fall
off in flight, only to result in major crashes. The radio and aircraft
worked fine, but those pilots were beaten by a single missing screw
(known as single-point failure).
Most trainer-type models' wings are
held to the fuselage with a few rubber bands. You shouldn't be too
casual with what looks like a simple task; don't use a couple of
leftover rubber bands. Most average to larger models should use the
standard No. 64 rubber bands. The smaller models, such as park flyers,
can use lighter-weight No. 33 size. You can find these rubber bands in
quantity (bags or boxes) at the larger stationery stores (such as
Staples and Office Max).
Each model should employ approximately six
rubber bands to hold down a wing. Use a cross pattern, such as front
left dowel to right rear dowel (three and three). Although seemingly
wasteful, use new rubber bands each time you go to the flying field;
it's cheap insurance.
Every RC receiver will have an antenna wire, which
is usually roughly 40 inches long, exiting its case. On larger models
you will have plenty of room to "hang" or stretch out this length of
wire. On the smaller models you may end up with a considerable excess
length that has to trail off the rear of the model. Don't cut any of
this antenna wire off! Your receiver is tuned for that specific length.
Making the antenna shorter can have a serious effect on your RC
performance. Most important, the range of radio operation might be
reduced.
As you get into the hobby, you will learn that special
shortened antenna rods can be substituted for the full length of wire. A
primary source for these antennas is Eclectic Electric Necessities, or
E-Cubed R/C (www.ecubedrc.com). Several models are available, down to as
short as 11/2 inches in length. Radio reception is said to only be
reduced by 15%. However, you will be required to cut off the existing
antenna close to the receiver case, then solder the wire from the new
rod to the remaining wire stub. For now I'd prefer that you stick with
the supplied, full-length antenna.
Antenna routing, or locating in the
fuselage then out to the tail, is most important. If you get too close
to such noise generators as a servo (the motor inside) or an ESC, you
might see interference in the form of jittery controls or reduced radio
range.
The best idea is to get the antenna wire outside the fuselage as
soon as possible, then route the long wire up to the top of the fixed
vertical fin or out to the tip of the stabilizer. I generally drill two
holes in the stabilizer tip or top of the vertical fin, and pass the
antenna wire in one hole and out the other. I don't like to place any
real tension on the antenna wire because it might eventually break. Nor
do I favor attaching the antenna wire to any moving surface, such as the
elevator or rudder; the constant flexing motion could eventually break
the wire.
With every new airplane and new radio-system installation, you
must run a prescribed range check to make sure you have adequate control
when the aircraft gets hundreds of feet away from you in the air.
The
best way to do that is to collapse the transmitter antenna as much as it
will go. If it retracts all the way into the case, leave a few inches
sticking up above the top of the case. By doing this, you will greatly
reduce your transmitter's transmitting power, which will allow a
simulated range check, but at a much shorter distance.
Turn on the
transmitter then the receiver. Operate all of the control functions.
Have a friend hold the aircraft and walk away from you. You will be
holding the transmitter and moving, say, the rudder control stick hard
every few seconds. At the aircraft end you should see the rudder move
positively to your exact commands.
A point will be reached where the
control surface will start to get nervous or jittery. A little beyond
that point the radio may even stop working (the control surface locks or
simply doesn't move). The exact point at which that happens can vary
between 50 and 100 feet. The exact distance can be determined from your
RC-system operation manual or by contacting the manufacturer directly.
If you only get 10 feet or so, you have a problem. It might be in the
radio itself, the batteries might not be charged, or the antenna-wire
routing might be too close to a servo. No matter what the problem, it
must be resolved before you attempt a first flight.
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