HoverThings Witespy 450 Quad – 900kva Brushless Multicopter Motor

Setup & Maintenance:

• This is not a toy – Aviation requires discipline, inspection and risk analysis – Multicopter motors form part of the critical 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 ; A post flight temperature check for thermal stress (hot motor)
• 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 – inspect closely for any sign of looseness
3. Carefully apply 1 small drop of OIL to each bearing every 5 hours flight time – with a syringe & needle (new SAE20-50 motor oil) – allow the oil to soak in for 1 min; wipe away all excess oil
4. Avoid all dusty Landing/Takeoff zones – We recommend Ops from a dust-free rooftop LZ on a 4WD/SUV vehicle or a 1.5m circular plywood dust-free Helipad on the ground to prevent any dust ingress to the bearings.  Abrasive dust entering bearings will shorten the effective life dramatically – inspect the bearngs for wear and replace if worn -Spin the motor – Magnetic cogging will slow and stop the motor which is normal – check for any wear or abnormal sound/roughness/dryness or non-linear friction indicating a bearing failure.
5. Use high pressure air (can of comressed air – or air line) to clean any sand,dust, grass 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 – Dont assume it’s tight – check it in Pre-flight
8. Use Blue Loctite® to mount the engine screws to the carbon/G10 engine holder.  Check the engine mounting screws never penetrate too far into the engine & short the winding wires
9. Inspect the prop for any fatigue cracks or white stress lines – immediately repalce any prop suspected of weakness – Routinely replace props every 10 flight hours.
10. Shaft must be replaced if bent – using a 3mm punch and tapped out – or shaft can be reversed by removing the grub screw and using a bench vise to push it further in and out the other side – then retighten the grub screw
11. if the motor is observed to be showing some initial warning sign – AN INDICATOR – noted by the pilot but not considered to be a risk by the pilot – and he decided to continue flight ; consider fully the RISK ; this can cause subsequent engine failure and total 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, dust, stones or debris which can enter the motor during take off and landing – causing trauma (cuts) to the windings or insulation of the windings, damage to bearings
    • breakage of one or more of the internal lead-in stator winding wires by stress (pulling of the wires during ground handling or assembly) – can be caused in incorrectly handling a motor, crash impact tension, carry the craft by gripping the motor assembly wires causing a break inside a motor.
    • magnetic variation – de-magnetising 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 – engine overheats because it is effectively overloaded – Copter is too heavy.  Overheated magnets are permanently ruined.
    • dry-joints or inconsistent  loose push-connections/soldering between an ESC and a motor leading to timing faults – especially relevant for long wiring runs – USE solder paste – use a Digital Multimeter DMM to check all 3 wires show the same Resistance in ohms
    • Shorting of any motor wire(s) internally to the metal/carbon booms or too the airframe– INSULATION of ALL WIRES annd joints is vital.  – short of the insulation from sharp carbon edges not filed smooth during construction – leading to timing problems or stuttering – Should you observe ANY motor hesitation or stutter – DO NOT FLY – replace the motor /wires/ESC as applicable to the fault – Beginner fault to observe AN INDICATOR – such as hestition then continue to fly leading to failure and a crash – Pro-Pilots discontinue flight at the slightest hint of a problem – because they realise that warnings are only given once.
    • Poor bearing maintenance lubrication and/or exposure/ingress of abrasive dust leading to bearing breakdown

    it’s VITAL to monitor the temps of all engines on the post-flight check, avoid operations where FOD. dust 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.