Quad laser motor balancing

Basic idea: attach mirror to the quad arm, shine a laser beam reflected onto a wall.  Vibrations show up as a line, when the reflected later light is a point you're perfectly balanced.  Very clever!

Avroto 2814-11 notes

some links

• Monto RC listing
• video showing 5 lb thrust on 5S

Microdan motor for EZ* and related planes

From the EZ* thread on rcgroups, somebody pointed out the Microdan 2505 2535KV motor as a really good (light weight, high thrust) upgrade for EZ* and similar planes.  Apparently several of the EZ* gurus use this motor.  Definitely in the high end, both in terms of performance and price. I will pull out the numbers on the Grayson upgrade I did for comparison.

    weight: 34g, cost $55

    APC 5x5, 21175rpm, 10.9V, 22A, 22oz thrust.
    APC 6x4, 19900rpm, 10.7V, 25A, 25oz thrust.
    APC 7x4, 16300rpm, 10.2V, 36A, 36oz thrust.
    APC 7x5, 15200rpm, 10.1V, 40A, 36oz thrust.

Microdan has a video of it flying in a Hawk Sky:

Arcticopter IV power loading

    battery  amps watts     notes
3S 2200 15c    .5     6     powered on, no props
              3.2    36     armed, motors at lowest speed
             16.0   184     half throttle
             33.3   313     full throttle (15c)
3S 2200 40c  39.3   413     full throttle (40c)


motors: hacker Style Brushless Outrunner 20-22L x 4
ESC:    Turnigy Plush 18A x 4
props:  10x (3.8?? 4.7?? I will check later...)

Motor balancing in addition to prop balancing

Old Man Mike posts an interesting note regarding vibrations.  Not only is prop balancing critical, but blade orientation plays an important role as well.  He says:

This chart shows that even with balanced props, there is a sweet spot for mounting that will provide a minimum vibration level. Without testing, it is very unlikely that a low vibration will be achieved and most likely the number will be at least two times greater than the minimum. It could even be much worse. One of the five motor/prop combination had more than 6 times times the minimum vibration for some prop positions and more than 4 times as much even just 45 degrees away from the minimum position!

It typically takes about 10 mins per motor/prop to find the minimum so it adds a bit of time to my quad builds. Since I'm somewhat obsessed with getting low vibration performance with my quads, I think it is worth the effort.

Blade mSR: Motor Replacement

 The motor on my Blade mSR started getting weak:

• losing lift.
• blades needed a flick to get started.

Consulting RCGroups, the diagnosis was a new main motor replacement.  I ordered a replacement motor from 38oceanss on eBay.  Delivery was quick and replacement was quick and easy.

 First, detach the canopy.  The little grommets pull off the mainframe, and stay attached to the canopy.  Here you can see the first grommet coming off.

Pulling on both sides worked pretty well.  Press your thumbs against the frame and "pinch" the grommets and canopy off.

Here you can see the port side grommets.  They stay quite attached to the canopy.  If you're pulling hard enough on the canopy for the grommets to become loose, reposition your fingers so that you're pulling against the grommets.

With the canopy removed you can see the motor and motor wire.  The motor wire is attached with an L-shaped connector, and the wire goes down the front of the main card.

 Detach the landing gear so you can get a good grip on the bottom of the mainframe.  It's all a bit delicate, so be careful not to grip the card, the servos, and especially any of the tiny wires.  Especially watch out for the antenna wire on the top right (facing forward) of the main board.

 Disconnect the motor wire.  It will slide out easily.

 Here's the tricky part.  Use needle nose pliers to hold the motor, and apply gentle traction.  Wiggle the motor gently and it will start to slide out.  Be careful, the pliers are right next to the servo rods.  Don't break them off!

 After the old motor has been pulled out, use your fingers to push the new motor in.  It will slide in smoothly.  Line up the pinion with the main rotor gear and make sure everything spins smoothly.

 Attach the new motor connector to the main board with the same orientation as the old connector.  The wire will go down and not up.  Power up the unit and check to make sure everything is operating smoothly before reattaching the canopy.

Any use for an old motor?