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1) Mechanical and Visual: The first precheck
is mechanical. Thoroughly inspect the exterior of the aircraft; look for
loose, damaged, or torn covering or structural damage. Pull-test the
wheel collars to make sure they are secure. Ensure that the wheels roll
freely.
If you find any damage, forget about flying. Take the model back
to the shop and complete any needed repairs. You will be happier for
doing so. Several times I chose to fly an aircraft with a known
deficiency. The results were seldom good. It costs much more time and
money to completely rebuild a crashed model than to make a minor repair.
Make sure that all bolts and screws—engine bolts, muffler bolts, wheel
collars, wing-mounting bolts, screws holding the landing gear, and servo
mounting screws—are tight. Torque the propeller nut as tight as you can
get it with a 6-inch wrench or one of the four-way wrenches to keep the
propeller from spinning off during the starting process.
2) Control: Do
the controls for the aircraft move easily, without binding? Do they go
the correct direction when you move the control stick?
Pay particular
attention to the ailerons since they are easily reversed with modern
radios. Stand behind the aircraft. If you move the aileron control stick
for a right turn, the right aileron should travel in the upward
direction and the left aileron should travel in the downward direction.
Pull on the control surfaces to check the hinges' integrity. Sometimes a
hinge will break or pull out of the slot where it was glued because of
vibration or rough treatment.
3) Battery: Inspecting the battery can be
done two ways. You can measure its voltage with a voltmeter that places
a load on your receiver's power circuit and confirm that the power
indicator on your transmitter registers more than 80%. The other way is
to verify that the transmitter and receiver are charged for 12 hours the
night before you fly.
4) Radio: Item 1 of the AMA Safety Code for RC
flight (which you can find elsewhere in this magazine) states, "I will
have completed a successful radio equipment ground range check before
the first flight of a new or repaired model aircraft."
To perform this
inspection, have someone watch the aircraft while you stand 30
paces—roughly 100 feet—from it with the transmitter antenna collapsed.
Hold the transmitter in a horizontal position with both hands so the
control sticks point straight up and the antenna stub is pointing
directly at the model. This configuration will give the worst signal
reception, which is what you want for this test.
If the radio system
functions properly in this configuration it will function properly with
the antenna extended while the model is airborne. Move the controls to
activate the servos while your observer verifies their proper operation.
The controls should move freely, smoothly, and with no jitter.
Click on photo to view large image with caption
You can
also do the range check if you are alone. Place the transmitter on the
ground with the antenna collapsed and pointed straight up. Carry your
model 30 paces from the transmitter. If the servos jitter or make noise
before you reach 30 paces, you have a problem with the radio link and an
unsatisfactory range check.
I recommend that you perform a radio range
check before the first flight of every session. I also recommend that
you reperform the radio reception check with someone holding the model
off the ground, with the engine running at full throttle. Why? With the
engine running, the aircraft components will be exposed to the in-flight
vibration that was absent for the quiet range check.
I have seen many
routine preflight range checks reveal equipment failures. These early
detections probably prevented those models from crashing.
The possible
failures are many. Perhaps the flier did not charge the batteries the
night before. Maybe the pilot thought he or she charged the battery but
connected the charger to a switch-controlled receptacle and turned off
the receptacle when leaving the shop. Perhaps one cell in a four-cell
battery has failed. Maybe something is wrong with the antenna
installation in the model.
Vibration caused by the running engine may
cause connection failures. Poor connections may cause the control
surfaces to jitter when exposed to vibration. Seek experienced help to
assist you in troubleshooting if you find a malfunction. ?
At a recent
contest I had planned to fly a glider in one of the events, but the
range check indicated that the receiver battery was dead. Therefore, I
substituted another aircraft to fly in the competition.
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