Getting Started with Helicopters - Part 2

Before you can even think about your first flights you will need the following items.

1. Fuel .
2. Fuel pump.
3. Electric starter.
4. Pitch gauge.
5. Starter battery.
6. Flight box.
7. Training undercarriage.
8. Power panel.
9. Glow clip.

All these items are a must in my opinion. Although you will probably borrow the pitch gauge at first. One item not mentioned here is the remote glow attachement, which although incredibly useful is not always essential.

The manufacturers of your helicopter will have gone to extraordinary lengths to give you all the correct linkage measurements and positions and as each one is different I must leave this to you to read the instructions.

This aside, a good rule of thumb is to have all linkages set so that the bellcranks etc. are all at 90 degrees to one another from servo to swashplate or tail rotor operating lever when the Tx sticks are at neutral.

Usually your kit will include a card template to slide over your main blades so that you can set the pitch angles required for training and sport flying. Although as I mentioned it is far better to use a proper pitch gauge for this process.

It cannot be overstressed how important it is to get these settings correct. You will be pleased that you took the time and trouble in following both your Tx. and kit manuals to the letter. This should then be checked and double checked. for traing your pitch settings should be between about -3-4 degrees at low throttle and plus 7-8 degrees at full throttle. There are various ways to achieve this using a combination of pitch curve settings and servo travel settings on your transmitter (atv). Again your Tx. manual should explain how these work.

Pitch curves are automatic adjustments of the travel of your servo arm to the collective pitch lever. For training it should be 0%, 60%, 100%. approx for a three point curve and 0%, 25%, 55%, 75%, 100%. approx. for a five point pitch curve. These settings will usually give the smoothest response unless your manual says otherwise for some reason.

Looking at the blades end on this is what you should see at high and low throttle settings. It has been known for servos to be reversed and this can have dire consequences. E.g the learning pilot increases the throttle, the blades speed up but the heli stays pinned to the ground. Confused as to the problem he/she closes the throttle thereby adding positive pitch to the rotors and the heli shoots skyward out of control. the natural reaction is then to re-open the throttle at which point the heli slams into the ground (or unfortunate bystander / pilot) under power. Say no more. There is no way out of this except to destroy something. Preferably the helicopter.

DO NOT TRY TO SAVE IT . The way to minimise damage is cut the throttle the heli will fly upwards but as the engine is on tick over the blades will run out of steam and the heli will fall like a rock. If there is anybody nearby get them out of the way and shout "crashing" or "out of control."

These are as the name would suggest very similar in operation to pitch curves. The only difference being that they operate the throttle servo instead and that there are three of them usually.

1. Normal. This is the one you should be concerned with for now and for most of your training. Settings should be : 0%, 60%, 95% for 3 point and 0%, 25%, 60%, 75%, 100% for 5 point curves
2. Idle up 1. For circuits and sport flying : 20%, 60%, 100% (3 point) and 20%, 35%, 60%, 75%, 100% (5 point)
3. Idle up 2. For advanced aerobatics and 3d flying : 100%, 70%, 100% (3point) and 100%, 80%, 70%, 80%, 100% (5point).

These settings are only approximate and should be fine tuned by an experienced flyer.

Your chosen flying field should be away from people and preferably at a suitable club. Also avoid populated fields like the plague, you dont want the public around if you can help it.

It is at this point that you should do all your pre flight checks and range check your radio even though the heli will not be going far away. You only want to learn to hover the heli at first SO DONT GET ANY BIG IDEAS GOT IT :-).

This is the most important part of any days flying and will ensure that the machine is ready to take to the air. This must be done before any flying commences and should be done at home before you leave as well, as this will be where you have access to all the necessary tools required.

1. Check that the model balances at the main rotor shaft or just ahead of this point. grip the rotor head and lift the model so that the main shaft is horizontal. The heli will rotate about the shaft and should stop when the whole machine is level on its side, maybe with a slight nose down attitude.
2. Next make sure that all screws, nuts and bolts are tight.
3. Main and tail rotor blades should just fall under their own weight.
4. check the main gear assy. For chipped or broken teeth.
5. Ensure that all ball joints are secure but move freely
6. Switch on your radio and see that all servos move in the correct direction especially collective pitch, tail rotor and throttle servos. The swashplate should should tilt in the direction of intended roll or pitch.
7. check the range and effectivenes of your radio by collapsing the arial and walking 30 meters away ask your instructor or a friend to tell you if there is any sign of servos jittering .Develop some hand signals to indicate which controls you are operating.

If you complete these checks every time you go out to fly. You should eliminate 60% of crashes and damage to your model. Helicopters are heavy going in terms of maintenance. But its worth the effort.

My next article will be on the very early steps of learning to fly your new heli.

 

Article by Grot from Bumpy Green Model Aerodrome
5th June 2001