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How do we maintain our
model helicopters?
First of all we don't abuse them by knocking them about when we move them
from home to the car to the field to the car to home, and we don't abuse
them by leaving them lying around so they can get abused by passers-by. Care
is the word.
Secondly we keep them CLEAN. If we clean the heli after each day at the field,
we are a lot more likely to spot any damage or wear before we next decide to go
flying. Discovering a problem on the day we want to go flying isn't much fun and
if you don't have a stock of parts, it's even less fun, so clean and check AFTER flying. Of course, that doesn't mean you don't
check the heli BEFORE you go flying or at the field before you fly. If you
want a heli to last and to not drop out of the sky for "no" reason, then
checking it is the ONLY way to ensure the risk is kept to a minimum.
There are NO excuses for anything failing in the air. So we clean and check, but WHAT do we check?
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We check bolts that hold "important" items onto the heli (the rotor head
comes into that category) and we check bolts that hold things onto things that
are bolted onto the heli too. The flybar is a good example. Some flybars
are bolted to the main rotor block (well the cradle that carries the flybar
is) and these bolts need checking because if they drop out, control of the
heli drops out too.
If a main blade fails and flies off the heli, there's no telling where it'll
go. It might not hit YOU, but it could hit someone else and it could be
nasty. It probably won't KILL you, but what it WILL kill, is the heli. Same
thing with a tail blade. Loose one and you'll be lucky not to loose the rest of
the helicopter shortly thereafter. |
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We check that all the servo's are still fastened in their respective holes
properly. Screws can and will vibrate loose and servo mounting screws are no
exception. It doesn't hurt to check the servo output arm screws either. Or
the screws that hold the balls ONTO the arms. Too many helicopters have lawn
darted because one single screw came loose on a servo. If a servo arm drops
off, expect a LOT of damage.
We have screws holding the frames together too, so using the Allen key and
applying enough torque to convince yourself that the screw is tight is
enough. Don't always actually TURN the screws/bolts, just "tweak 'em"
to see
IF they move. They shouldn't if they're tight enough, so don't over tighten
or you run the risk of stripping the threads, particularly on helicopters
where the screws "self-tap" into plastic stand-offs, frames or frame
spacers.
Check your aerial routing hasn't resulted in the wire being chaffed,
snagged, stood on or otherwise damaged. Again, helicopters have lawn darted
because the aerial was broken and not noticed.
Do rotor blades need maintaining? Well in a perfect world, they won't get
damaged, but we don't live in a perfect world, so a visual inspection of the
surface is good, but of course, you'll do that while you're cleaning the heli
won't you?
Tail blades take an enormous amount of un-noticed abuse and if they've
contacted the ground during a flight, check that no cracks were produced or
bits bitten off. They need to be balanced like the main blades, so one blade
missing a chunk won't help the smooth running of a helicopter. Don't mess about
with blades either, if they LOOK damaged, they ARE damaged, and the place
for damaged blades is the bin.
Ok, so we've checked for the obvious things, but what about the VERY obvious
things? Ball links and their balls. They wear out over time and more so the
more stress you place on them and stress comes from two main sources. One is
hard 3D flying and the other is light crashing. Hard crashing usually
results in links snapping or being ripped off the control rods, but LIGHT
crashing just stretches them until they fall off when you least expect
(or want) them to. If the can be flicked off with easy finger pressure, or
they drop off before your trusty ball-link pliers have had chance to exert
any real pressure, they're probably past their sell-by date and should be
changed.
While on the subject of ball links, let's carry on and just say "links"
because there are different types and they all need a check. "Z" bends on
the end of control rods wear the servo output arm hole making it bigger than
it should be. This doesn't mean they fall off, but it does introduce slop
and imprecision, so they need to be checked and any "iffy" looking servo arm
replaced.
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Check the integrity of the battery/gyro/receiver mounting. Unburnt
fuel and oil from the exhaust is circulated by the main rotor and
it DOES get under the canopy on occasion, as can any fuel leaking
from the engine. Not all engines are created equal and some will
throw fuel around for fun, no matter what you do to stop it, and
when this fuel reaches the mounting tape for batteries, receivers
etc, it has a habit of breaking the adhesion, and you don't want
great heavy chunks of battery running around under the canopy
while you're helicopter is inverted a foot off the deck. |
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The gyro needs "special" care here, because it needs to "move", but it needs to
be kept in the same place and if it breaks lose, there's all kinds of fun ahead.
Up elevator should NOT need a large amount of tail rotor too!! None of the above
is imagination either as everything mentioned has already happened to
someone.....
The ON/OFF switch is a pretty
well ignored item on a model, but it can also be contaminated with fuel
and oil, so check it works PROPERLY and replace it periodically. Losing a helicopter
to a £6 switch is ridiculous.
Most of the checks we carry out are fairly simple things, but it's because
they're simple that they're not done as often as they perhaps should be.
Don't make the mistakes others have already made.
This is how your heli should look. Not only after its just been built, but after
thorough maintenance and regular cleaning. |
