From the Hi-Sky R/C Flyer, Midland, Texas
Has This Ever Happened to You?
by Bob Kugler
You’re flying your favorite airplane. You’re doing
the maneuvers that you’ve done a hundred times
before. The weather is perfect. The wind is steady,
light, and blowing in your favorite direction. You
are having a great time. You couldn’t feel more
comfortable.
Then, without warning, your old friend develops a
mind of its own. While doing a simple, straight, and
level flyby, your airplane throttles up. It rolls
over and spins into the ground. Something has gone
seriously wrong.
Your first thought is, “I’ve been shot down!” This
may or may not be true. After you have had time to
regroup and analyze the situation, you may be able
to determine the actual cause of the crash. A
postmortem is always worth doing so you can prevent
the problem from recurring.
What are the possibilities?
1. Someone turned on a transmitter on your
frequency.
2. Outside radio interference.
3. Receiver battery failure.
4. Transmitter battery failure.
5. Radio failure.
6. Receiver switch failure.
7. Mechanical failure.
8. Pilot error.
My limited experience has shown that most airplanes
are lost as a result of mechanical or electrical
failure (items 3, 4, 5, 6, and 7). Next comes pilot
error. This includes letting the airplane get too
far away, losing it in the sun, getting confused
while inverted, stalling the airplane too far away,
throwing the wrong switch on your transmitter, or
simply trying one too many turns while dead stick.
The least frequently seen cause of RC airplane
crashes is radio interference (items 1 and 2). Yet
this is the one we think of first. This is probably
because it is one of the few causes that we can
blame on someone or something else.
Here are some things you can do that may prevent
these problems:
1.When installing the switch harness in your model,
you may want to locate it inside the airplane. Cut a
piece of thin music wire so, when bent to shape, it
will extend from the switch to the outside of the
airplane. This will help the switch stay clean and
oil free.
2. When installing the radio in your airplane,
shield the receiver and battery from vibration by
wrapping them in closed-cell, high-density foam. In
time, vibration will loosen the internal electronics
of an unprotected radio. Prolonged vibration can
also cause a short in an onboard battery. While
you’re at it, make sure your servos are shock
mounted by using the little rubber grommets and
sleeves that come with the radio.
3. Before you assemble your airplane, make sure the
servos, battery, and receiver are secure. Ensure all
radio connectors are in place. Check the control
surfaces for excessive play, cracks, or binding.
4. The connection between the antenna of your
transmitter and the transmitting module in your
transmitter must be solid, so check to see that the
link is proper.
5. Walk the flightline and pits. Check to see who is
sharing your frequency. Let them know you are there
and ask them if anyone else is using the channel.
Don’t assume that everyone uses the board when
flying. You may run into a new person who is not
familiar with our system, or you may find someone
whose tag fell off the board.
6. Use the frequency control board.
7. Always do a preflight inspection of your
airplane.
If you use an ESV to check your receiver packs
remember to leave the ESV connected for at least 30
seconds to get an accurate reading. I have tried
this and have seen the needle drop. If the battery
is weak, it will show up here.
Check to see that all controls are working and in
the right direction. When I first started, I could
not remember which way the ailerons were supposed to
work until I started using a catch phrase. When I
test my aileron, I push the stick to the right and
watch the right aileron. I say “right up” to myself.
If the right aileron moves up, it’s working
correctly.
Check the meter on your transmitter. These batteries
are reliable, but they do sometimes fail.
People who faithfully check their receiver batteries
sometimes forget to glance at the transmitter meter.
Range check your radio system. This is rarely done,
but it can uncover an otherwise undetected problem.
It should be done with the engine running so, if any
of the radio components are loose, the vibration may
cause it to act up.
Test to see if another transmitter is turned on.
This can be done by turning on your transmitter and
receiver. Move the sticks to the corners, much like
you would when performing a snap roll. While holding
the sticks in that position, turn off your receiver
switch. Next, turn off your transmitter. This will
leave the ailerons, rudder, elevator, and throttle
off center. Turn on the receiver switch. If the
control surfaces should center themselves or begin
to twitch, your receiver is getting hit by another
radio or some sort of outside interference. Do not
fly!
If you are already flying and your airplane starts
going crazy, hold your transmitter as high as
possible. Notify everyone on the flightline that you
are going on the field. Run toward your airplane. If
you can get your transmitter closer to the receiver
in your model, it may provide a strong enough signal
to override any interference. I have seen this
technique used several times by our chief
instructor, Joe Felonk. It works.
Q
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