HINTS & TIPS
HINTS, TIPS AND GOOD SOUND ADVICE - if you have done all this and want to improve your flying. Click here for page two.
WE CAN ALWAYS LEARN SOMETHING NEW. Find a better way of doing things or change our views due to experience. Learn from the mistakes we have seen others make, or indeed we have made ourselves. No matter how long you have been modelling, the best way to ensure your new model is airworthy, is to ask another member to check it out before you fly. We have all been guilty of missing some vital point that could lead to an immediate disaster, or some weak link that with ageing, will eventually fail. Disasters are expensive and time consuming at the best, at the worst they may be fatal.
The B M F A safety rule says "that if you cannot fly the model safely, do not fly". Do not be afraid to refuse to check out, or fly a model that is beyond your experience. If you check or test fly a new model, it is reasonable to expect that you will do so thoroughly and give good advice. However, the person asking for help should also understand that with the most conscientious checking and careful handling something can go wrong. In such cases do not expect the instructor to repair the model or contribute to the cost.
IT MIGHT BE GOOD FOR US ALL TO REMEMBER THAT A VERY HIGH PROPORTION OF CRASHES ARE DUE TO PILOT ERROR. IN MOST OF THOSE CASES THE ERROR IS MADE BEFORE THE MODEL HAS TAKEN OFF!
The responsibility of an instructor begins with the following:
¤ Advise on insurance and B M F A membership.
¤ Explain the safety rules of the B M F A.
¤ Refer to the club rules, including flying times and flying area.
¤ Is the flying area suitable for the model in question?
¤ Discuss weather conditions.
¤ Check the airframe, equipment and installation.
¤ Check for correct operation of failsafe.
¤ Before running the engine check that the fuel proofing is adequate.
¤ Make particular reference to the dangers of propellers.
¤ Point out which parts get hot when the engine runs.
¤ Explain the need for good engine starting equipment.
¤ Demonstrate how to use the pit area and peg board system.
¤ Do not cover models, equipment or people in exhaust emissions.
¤ Avoid blowing dust onto models, equipment or people.
¤ Remove articles that may be blown or sucked into the propeller.
¤ Take initial responsibility to start and tune the engine.
¤ Check the engine reliability at low throttle.
¤ Assess and advise on noise levels and solutions.
¤ Fly only if you are sure the flight can be made safely.
¤ Be never afraid to say "NO we will wait until we are sure".
THOROUGHLY EXPLAIN YOUR THOUGHTS SO THAT YOUR STUDENT CAN RELATE TO, AND LEARN FROM YOUR ACTIONS.
BASIC CHECKS AND QUESTIONS YOU SHOULD ASK. SOME ASPECTS ARE NOT IMMEDIATELY OBVIOUS SO LEAVE NOTHING TO CHANCE!
1. Was the model built by you? It may not be easy to ensure that the model is structurally sound but stress check the airframe. Observation and discussion will soon allow you to assess the quality of work, ability and experience of the owner. From this information decide upon the degree of help and the level of advice you need.
2. Investigate the history of the model, equipment and transmitting frequency. Has the model flown before? Is there any evidence of excessive vibration or crash damage? Check the operating range of the equipment. A frequency check might be desirable.
3. Are the batteries a welded pack of rechargeable cells? Are they new? Charge the nicads for at least 16 hours immediately before flying? Is there any evidence of "black wire syndrome"?
4. Is the receiver aerial in good condition?
5. Does the engine shut down to idle if the failsafe operates. Restrain the model.. Increase the throttle to give full power, now switch off the transmitter, the engine should return to idle (or stop if electric). Do not touch any transmitter controls. Make sure the model is still being restrained properly then switch on the transmitter this should give you full throttle and full control.
THE LITTLE THINGS WE MAY OVERLOOK
a. The engine mount and engine should be fixed securely to the firewall. Are four bolts with locking nuts used for fixing the engine to the mount? Check for the correct amount of side thrust. If the engine is soft mounted, check for excessive movement.
b. Very few engine manufacturers have addressed themselves to reducing noise. It is no longer acceptable simply to fit the silencer provided or a propeller that will allow the engine to rev freely. An ‘after silencer' and a propeller of larger diameter or pitch than usually recommended should be fitted to load the engine and reduce the revs. Older engine designs may not take kindly to this kind of treatment due to their cylinder porting and crankshaft timing.
c. Has the propeller been balanced and drilled for a good fit to the shaft? Balance the spinner or discard it. Are the engine crankshaft bearings in good order? Does the glow plug look reasonably new? Is the silencer likely to be effective, is an after silencer fitted and are they secure? Is the throttle linkage free and adjusted for the correct movement? Will the engine stop if the throttle trim is set to low?
d. Is the tank clean and all pipes fitted without leaks? If no special fuel system is fitted, mount the tank as close to the engine as possible, with its centre line level with the spray bar on the carburettor? Is a fuel filter fitted and is it secure? If you are using a pressure fuel system, make sure the blanking plug in the vent pipe is airtight. A screw is not good enough as the treads will allow air to leak from the system.
e. The radio equipment on/off switch should be mounted away from any exhaust emissions, and preferably on the opposite side of the model to the silencer, tank vents and filler.
f. Check that the tail plane and fin are secure and set horizontal and vertical when viewing the model along the fuselage centre line?
g. Check that the control linkages to the elevator and rudder are free running and do not bend under pressure. A good check is: switch off the radio equipment, carefully move the control surface until the servo arm follows the movement, if the push rods bend before the servo arms move, re-route, support or replace the push rods. (Be careful not to rotate the servo arms beyond their normal operating arc. This may damage the wiper on the feedback potentiometer within the servo). Pay particular attention to the fixing of plastic control rods and remember that trim changes can occur with varying temperatures.
h. To decrease the damage to property, and reduce the possibility of death from a model out of control due to interference problems, the failsafe on all PCM radio systems should be set to at least put the engine to idle, (stop if electric) when in failsafe mode. Correct operation of this feature should be willingly demonstrated at any time. If you have any doubt, read your instruction book, talk to a committee member, talk to the BMFA, but do not fly until you fully understand the implications.
i. Pack the receiver and nicads in foam rubber, (not plastic that transmits vibration) Will the receiver and nicads still have protection if they leave the aircraft after an impact? Position the receiver in the fuselage where it cannot move, with the base insulation tight against the firewall. Place the nicads where they will not crush the receiver or the servos when they are thrown forwards during a crash. After the installation is complete tuck wires neatly away, then only move them for periodic checking. Tape together any vulnerable plugs and sockets, especially those concealed.
j. There should be no possibility of vibration between the wing and the fuselage. With elastic bands it is better to fit more bands that are less tight than just two that are very tight. However, they should be tight enough to hold the wing to the fuselage under high stress conditions.
k. The aileron servo lead must be long enough to make a good connection and be routed away from servos and linkages before the wing is fitted.
l. Do not restrict the aileron control horn movement when the wing is mounted on the fuselage. Give extra clearance between the fuselage and control horn arc if the wing is held in place with rubber bands.
m. Secure the servos firmly with FOUR retaining screws on rubber anti-vibration mounts? Do not squeeze the rubber mounts to a solid state with the fixing screws. Check the servo output arm retaining screws are in place.
n. There should be no metal to metal connections: Clevises to control horns, (all metal clevises should be held tight onto the push rods with a locking nut). Wheel hubs to axles. Loose silencers or fuel filters. All these can interfere with radio reliability and give intermittent stray control movements.
o. Are the control surface hinges pinned to the airframe?
p. Wide gaps on the hinge line between the airframe and the control surface will reduce the effectiveness of the surface and reduce control.
q. Check the balance (C/G). Too far back and the model will be uncontrollable, too far forward and the model may not flair when landing at low speed.
EXPERIENCED FLYERS, COMMITTEE MEMBERS AND THOSE WHO ACCEPT THE RESPONSIBILITY TO INSTRUCT OTHERS
Remember that anyone who puts their trust in you to fly their model, whether they are a new member, or an existing member who needs help with a new aircraft, will have spent much time and money getting to the stage of bringing their model to the field. They might also have some apprehension about showing their model to an "expert" and be concerned that some criticism may follow. Perhaps we should point out immediately that we give advice in the interest of personal safety, that of others and preservation of the model. The aim is to achieve a series of successful flights that will lead to the day when we hand over control with complete confidence.
Any member who becomes involved in this side of the hobby will gain much satisfaction in seeing those who have turned to them for help, flying confidently, safely, and eventually being able in turn, to pass on their knowledge and experience to help others.
Give advice based on personal experience or the result of discussion. Seek second opinions which should always be welcome.
Success and satisfaction will depend on the eagerness of the instructor and builder to complete the flight safely.
Do not jeopardize the use of your flying field.
THE GROUND CHECKS COMPLETE,
PREPARE YOUR MIND!
What will happen when the model moves forward during the take off run? Will it track straight? Be ready to correct with rudder. Hold the model on the ground with elevator until more than enough flying speed is achieved. If the model lifts off too soon it will stall into the ground, or you will experience poor control response, usually resulting in the model flying in a different direction to that intended.
Maintain a steady climb and gain speed. Continue with gentle turns until a good height is achieved, then adjust the trim when possible.
Check the control response with gentle manoeuvres (there is plenty of time for aerobatics later). Be prepared for aileron flutter on faster models. At a high altitude, but while still able to see clearly how the model is responding, close the throttle and learn the slow flight characteristics of the aircraft.
Resist handing over control to your student until you are sure you can recover the aircraft from any attitude or position that may prove dangerous.
On the first flight you should land as soon as you are confident to do so. Be sure to make your landing approach with ample fuel so that you can overshoot and go round again if necessary. Avoid tight turns or steep banking at low speeds. Lift in these conditions degenerates very quickly and particularly so on high wing loaded models. Make the landing approach faster than normal to avoid any attempt of the aircraft to stall.
After landing, clear the runway quickly, discuss the flight, check the model thoroughly, and make any adjustments before you fly again.