Pre-flight checking and Winter Maintenance Or The Importance of being Ernest
Now I know there have been a number of articles on this subject, but from observations at the flight line, there appears to be room for another.
Amongst other “happenings” I have seen the following over the last few weeks are :-
1) Ailerons operating in reverse sense;
2) Control surface hinges not pinned/glued in place;
3) Faulty aileron servo giving intermittent centering.
4) And myself, damage to servo wiring (mice being the culprits).
5) Lack of radio range in flight;
The first resulted in substantial damage to a model on its first flight, the second occurred when I checked a club members model for him, as did the third, and the fourth when I detected no tail rotor operation on my heli ,before attempting to hover; the last, near complete loss of control.
We should learn from these the necessity of a thorough check before attempting the first flight of the day, (much like a “daily inspection” on a light aircraft.)
o Say out loud the correct “sense” of control surface deflection and operate slowly over the full range of movement, checking for smoothness with no jumps, judders or inappropriate noises;
o Give them a good tug, not enough to damage the hinge, but more than a token pull, at each hinge point in turn, and then the extremity of the surface;
o Have an in depth check of the wiring, look for cuts, breaks, damage and brittleness;
o Don’t forget a regular range test through different model orientations;
o Do a “load” test on the flight battery;
o The above, essential, in addition to a close inspection of the airframe, engine/mount/silencer/propeller etc.
Now is the time of the year to check your models as if on a C of A (certificate of airworthiness) again for a light aircraft. Add to an extensive check such items as the following:
o Strip out the fuel tank (i.c.model) replace ALL fuel tubing inside and out; pressure test the tank;
o Take out and clean the engine/motor;
o Inject suitable preservative oil (i.c.)if laying up for a few months(I use “duck oil”);
o Thoroughly clean and dry the airframe;
o Repair any damage to covering;
o Re-fuel proof the engine bay (i.c.models);
o Look over the propeller for nicks and damage, re-balance;
o Treat the engine to a new plug;
o Cycle the on board battery(s) and check for holding its charge;
o Remount the engine/motor etc. using fresh bolts;
o Replace any worn servo’s, horns, push rods, output arms etc;
o Re-assemble as if a new model;
o Make a note of the radio set up, particularly if amended during the flying season:- Expo, reversers, EPA, rates etc, and neutralise out any trims or sub trims;
o Consider replacing your flight battery, switch harness or similar if more than a couple of years old;
o Range check at home if possible, and check over the running of your engine/motor.
In addition I make it a practice during the year, at two monthly intervals, to check the capacity of my NiMh rx batteries to see how much they are holding, and recharge even if not being used. They should drop to no less than 80% from a full charge over 2 months.
Also a clean and check over of your flight box, flight equipment, fuel, etc. should be done just before starting the new flying season.
The object of the above is to arrive at the field with a model and flight equipment that has been fully checked over and serviced, to avoid the frustration of unreliable engine running; faulty radio gear, or unsafe airframe.
Remember “SAFE FLYING DOESN’T HAPPEN BY ACCIDENT”