By
Will Costin
This
is a brief guide to what to check on a model before during construction
and before the first flight, most of it is common sense however
even the best of modellers over-look things so it's always best
to check before you risk the (often valuable) aircraft.
And
if you are presenting your first ever model for inspection at you
new club this will be the things that your instructor/flight tester
will be looking for. If he finds something htat's not quite right,
he'll probable ground hte aircrat u ntil you can fix it. So to avoid
disappointment read on!
- Structure
Is the structure strong enough?
Have all the glue joints set and adhered properly?
Has anything been damaged during handling?
- Flying
Surfaces
Are all the flying surfaces square to their datums and seatings?
Are they unwrapped and properly secure?
Are all the control surfaces securely hinged, in-line with their
flying surfaces and free moving without binding? If the resistance
is strong the servo may stall and buzz, this is not good for the
servo and requires more power from the onboard battery. Dont
settle for sloppy neutrals and sticky throttles.
Have you set the correct control movements (throws) as recommended
by the plan/instructions?
Are the main control surfaces linked to the servo by strong control
rods/snakes? Dont use screw clamp servo connectors for the
main surfaces, there just not up to the job, proper metal clevises
are a better option, or plastic quicklinks.
-
Radio Gear
Are all 4 servo screws fitted on each servo? Are they tightened
up?
Is the battery and receiver wrapped in foam? Vibration can damage
a receiver usually resulting in a crash.
If the wing is removable, is there an extension lead long enough
to allow you to dismantle and assemble the aircraft without putting
stress on the servo of receiver?
Have all the servo arms got the retaining screw in, is it done
up?
Is the receiver switch in a place where it could get knocked into
the off position? Switches should have on towards
the back of the aircraft or an extension rod, which has to be
pushed in to operate the switch which is placed inside the aircraft.
Are all the plugs in fully?
Are none of the wires damaged?
Older batteries can suffer from black wire corrosion,
check the negative pad on the plug of the battery, if its tarnished
(compared to the +ve) it should be investigated further.
- Fuel
Tank
Make sure the tank is secure, up, down, fore and aft.
Is the tank plumbing correct? The clunk feed should go to the
carburettor. One breather can go to the silencer if a pressure
fuel system is used and the other can be used as a filler. Depending
on how many pipes the owner wants, some will use 2; the silencer
tube as a breather and the carb tube as the filler/ drainer. Others
prefer a 3 pipe system; The silencer tube is used as the breather,
the carb one for draining and a filler for filling.
Is the cluck free moving and not binding with the back wall of
the tank? Some people include a length of rigid fuel pipe in the
clunk line to prevent it doubling back. This may be used on more
aerobatic models to prevent the clunk getting stuck at the front
of the tank and cutting off fuel supply.
Is the line to the carburettor as short as it can practically
be?
Is the tank at the right height? The centre line of the tank must
never be above the spraybar in the carb this may lead to syphoning
and a flooded engine.
- Engine
How easy is it to fit and remove the engine? If retaining nuts
cant be reached then a spiked variety may be preferable
to prevent loss in a cowl.
Have you checked the specified down/side thrust? The more added
usually makes the model more docile, avoid up thrust, unless the
model is a pusher.
Can the needle valve be accessed through any cowl?
Take a few different props of different sizes for the first flights,
possibly a few sizes each side of the manufacturers recommendations.
It may be worth setting an engine up at home first before visiting
the field. It may also be worth keeping the engine a bit rich
for the firstt few flights both to increase reliability and to
help a new engine run in.
It may be better to remove a cowl for the first few flights to
allow easy access to the engine.
- C
of G
Is the centre of gravity in the right place without fue inhte
model? It may be better to have it slightly forward of the designs
location. Moving the flight battery can usually achieve this if
not then lead may have to be added.
Does the model balance laterally? If not then add weight to the
light wing tip. An imbalance can be surprisingly deadly to smaller
models.
General
Notes
If this is your first attempt at RC flying dont try it on
you own, get in touch with the British
Model Flying Association who can then put you on to a local
club. You can also find a Club listing here on Flying Sites. Use
the 'Club Finder' link on the left.
Joining a club will also give you support and if the club is BMFA
affiliated; insurance. At the club you should be able to find an
instructor who can help you through the learning process without
writing off your plane (too often).
Before flying, if there is anything you think you may have forgotten
of done wrong, check it. If the model crashes it is better to know
you flew it into the ground than it failing mid air and crashing.
If you are new to modelling always get the model checked over by
an experienced flyer, they may spot things you didnt.
Have
you remembered to charge up your starter and glow batteries? Dont
forget or you wont be able to fly at worst or have to borrow
at best.
Do a radio range check. The radio should still have full control
over the model at 25-30 paces with the Arial down.
Are
the control surface going the right ways? On the aileron the surface
should rise up to the stick as you push it in each direction.
Are you sure all the screws are done up? Check the engine hasnt
worked them loose.
Do you have full throttle travel? Can you remotely stop the engine
by trimming the engine full shut?
On the take off, if the engine stops, push the nose forward and
prevent stall. Keep her straight and flare when returning to the
ground to prevent bad damage.
As David Boddington once said,
Spectators are best dispensed with
a quiet day is probably best.
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