I've picked up a cheap brushless now, a 2408-21T-3A, at £12 from BRC hobbies and here are my first impressions:
These things are complicated! With a brushed motor, as soon as I got it out of the packet I could connect a few volts to it and see how it ran, from any old batteries which were lying around, or a power supply if available.
With this, you must connect it to its ESC, then to a receiver, then get a transmitter. Your batteries must be fully charged, otherwise the Auto Detect will not work. Once connected, the transmitter throttle position, auto motor calibration (timing?), cell count (?), voltage cut-off and lost signal protection are set up automatically. Only then can you see how it turns. I have not done this yet -I don't know if the motor is safe to run with no load, and there are no instructions which might tell me...
The mount is intended for an aircraft, so will need modifying. I will have to mount it somewhere for testing. Unlike a brushed motor, I suspect you can't just hold this in your hand while test-running it with a few volts...
When I turn the motor it is very notchy, and requires much more of a 'hand twist' to turn than a brushed motor. The impression I get is that this is going to be very powerful...
There are warnings all over the instructions which tell me NOT to fit bigger props than specified, and to keep within Watt limits - use a wattmeter at all times. I had hoped to keep the speed within managable limits by fitting a suitably large prop - it looks like this is forbidden....
The data on power is designed for aircraft use, and compares prop size, number of cells and thrust. It expects you to use Li-Po - there are only two rows showing Ni-Cad, and both assume 8 cells. I had hoped to use 4 cells, or 2 if the motor turned out to be very powerful - it looks like this is forbidden...
You are also warned to 'fly the motor until fully discharged' - probably something to do with the ESC automatic settings. If you are to do multiple flights you must make sure the battery is fully charged prior to each. For a small boat you might want to do a few runs, potter about a bit, pause for a sandwich, potter about some more.. it looks like this is also forbidden....
I suppose my first question to the Brushless experts is - can I use a small pack of 4 AA Nicads with this? And what will happen if the Nicads are not fully charged?