Helicopter Safety

It cannot be stressed enough that a model helicopter must have a higher degree of safety built into it than any other flying model.

It is VITAL that you never fly or run up your helicopter in the pit area or near spectators. When starting the model in the pits, hold the rotor head firmly. When the engine is running carry the model a sensible distance from other people before running up or flying.

Do not release the rotor of the model until you are sure that it is safe to do so and NEVER FORGET the amount of energy there is in a spinning rotor. It's an unfortunate fact that people have been severely injured and even killed by model helicopter rotors.

Never hold the model overhead to run up the engine or run up the engine with no rotor blades fitted.

Rotor blades must always be carefully balanced and you should always remember that vibration in helicopters can be very destructive.

A model helicopter must never, under any circumstances, be flown or run up:
 

	In places where many people and children gather.
	In residential districts and parks.
	Indoors or in areas of limited space.
	When there is a VERY strong wind or when it is raining.
	In or NEAR the pits area or close to any spectators.
	Directly towards the pits area or any spectators.
	With metal rotor blades.
	With knife sharp leading edges on main or tail rotors.
	With damaged or out of balance rotor blades.
	With radio equipment un-proofed against shock and vibration.
	In the presence of spectators or at a competition or fly-in until properly tested and proved airworthy.
	Until thorough maintenance checks are carried out.
	Note that all helicopters weighing more than 7kg without fuel are subject to CAA regulations.

Checks before a daily flying session:
 

	Check all ball links for slop and change as necessary.
	Check that all rotor blades are in good condition with no damage apart from minor tip damage.
	Check for loose or missing nuts and bolts.
	Check that there is no backlash in the drive system apart from gear backlash which should not be excessive.
	Check that all servos are secure and free from oil.
	Check that the fuel tank and all piping is secure.
	Check that the receiver aerial is secure and in good condition with no chafing or damage.

Checks before each flight:
 

	If a helicopter suffers damage or a heavy landing re-check all of the above.
	Check all controls before starting especially for binding or slowing of servos.
	Re-check controls at a high rotor rpm just before lift-off.
	Check for vibration and eliminate before flying.
	Check main rotor blades for true tracking in hovering flight.
	Check that the receiver aerial cannot become entangled with any moving or rotating parts.
	Double check that all switches on the transmitter are in their correct positions before EVERY flight.

Helicopter rotor blade safety:

Rotor blade failures have five basic causes:

1. Design and manufacture faults - Most design and manufacturing faults seen are centred around the rotor fixing hole. Typical faults are the hole being drilled on the junction between two wood laminations and incorrect wood selection leading to the hole being drilled in a soft lamination. Blades with this type of fault should not be used. Even root reinforcement may not stop a failure.

2. Incorrect user assembly - This is commonly found in root reinforcements and in blades which have to have tip weight of some description added. In all cases you should take the greatest care that any components added are fitted correctly and with suitable adhesive. Incorrect glue joints and badly applied reinforcing components are probably the biggest single cause of blade failure so it is very important that you take the greatest care with any assembly work you have to carry out.

3. Incorrect repairs - Do not be tempted to undertake major repairs to rotor blades unless you know exactly what you are doing. Minor repairs to blade edges are permissible but you should always re-balance after completion.

4. Unnoticed accident damage - Any ground strike or boom strike will almost certainly cause damage to rotor blades and in many cases this may go unnoticed under the blade covering. If in doubt, have no hesitation in stripping off the covering for inspection. Re-covering and re-balancing the blades is a small price to pay for peace of mind.

5. Ageing and weathering - Ageing of glue joints in wooden structures is common and the high stresses inherent in rotor blade operation mean that you should keep a close eye open for delamination in wooden blades. A problem sometimes seen in composite blades is heat damage. Blades left in a car on a hot day can suffer from softening of the resin and this, combined with an expansion of the foam filler, can make the blades unsafe.