HT-450 Motor – House

Setup:

• This is not a toy – Multicopter motors form part of the aircraft flight system and become your duty of care when purchased
• If a motor fails the Copter can fall from the sky and cause harm to person or property below – Always do a full pre-flight inspection on the motors
• Schedule of maintenance you must perform includes : –

1. Remove and add Blue Loctite® to the shaft grub screw
2. Ensure the Circlip is set (crimped) correctly to hold the shaft in place
3. Add 1 drop of SAE20-50 motor oil with a syringe needle to each bearing every 5 hours flight time – allow the oil to soak in ; wipe away excess oil
4. Spin the motor – Magnetic cogging will slow and stop the motor which is normal – check for any wear or abnormal friction indicating a bearing failure.
5. Use high pressure air to clean any sand or dirt away from an engine after every flight
6. Inspect the wires to ensure the insulation is in-tact
7. Check that the collect (Prop-adapter) is tight and cannot be pulled off with 2kg force
8. Use Blue Loctite® to mount the engine screws to the carbon engine holder
9. Inspect the prop for any fatigue craks or white stress lines – immediately repalce any prop suspected of weakness – Routinely replace props every 10 flight hours.
10. Shaft can be replaced using a 3mm punch – shaft can be reversed by removing the grub screw and using a bench vise
11.  if the motor is observed to be showing some initial warning sign which is noted by the pilot but not considered to be a risk by the pilot – and he decided to continue flight ; this can cause subsequent engine failure and loss of your aircraft if it has less than six engines. Be aware –
    the most common causes of engine failure are
    • ingestion of FOD (foreign object damage) dirt, stones or debris which can enter the motor during take off and landing – causing trauma (cuts) to the windings or insulation of the windings
    • breakage of one or more of the internal lead-in stator winding wires by stress (pulling of the wires) – can be caused in handling or assembly
    • magnetic variation – demagnetising of one or more magnets by placing the magnets on or against other motors/magnets or in magnetic fields – tapping against metal objects of the can of the motor – this partial de-magnetisation can cause the ESC to overheat the engine because the timing cannot be accurately determined by the ESC. Thermal run-away results.
    • dry or inconsistent  connections/soldering between an ESC and a motor leading to timing faults – especially relevant for long wiring runs – USE solder paste

    So it’s important to monitor the temps of all engines on the post-flight check, avoid operations where FOD is a risk and keep motors padded in transport.  It is also recommend to ground the aircraft and 100% locate the cause of any abnormal performance item.