Back-story's this: Colin's over the South China Sea, drafts design for an octocopter built round a framework like a phone-box for 'teleporting' people from A to B. Enters a comp in California, realises even child-size personal air vehicles aren't the easiest thing to check in as baggage via London, Dublin and New York to SFO.
Learns much, specially how much it costs to make anything to fly anyone anywhere.
Donates working prototypes to museums in Weston-super-Mare and Doncaster where they hang to this day, and scales things down to nearer 50% to continue with a series of different designs of human-carrying drones; most of which octocopters to assure redundancy of operation.
Wakes up one day to realise something he was developing long before drones viz. flat-pack boats could benefit from the same method and means.
Develops a mono-ski and a catamaran flat-pack, the latter not necessarily the most efficient but wholly more practical, especially as it can be scaled eventually to carry his royal self.
Has thus inherits eight motors, battery-packs and speed-controllers from the final scale effort at flying people, with which he determines to get something ~ anything ~ on the water for his and your edification.
So let's look again at the table up top. There are three versions of our U7 motor and as I didn't know what I was doing I went for the lowest kV or slowest revving, which is turning the largest available (22") propeller.
The data's for that version running at 24V, but the eight packs are each six-cell and produce only 22V. Looking at the second column we see that the max amperage we can drive through he controllers is therefore less than 35A.
And what ESCs do we have? 80A, which are (a) five times more expensive (and times by eight), and heavier than say a 40A designed for a fixed-wing; which works for us now that it's also a plane (albeit a hydroplane) that we're developing.
So I call a round-table with engineering to ask what the difference is, and when one begins to tell me as I stroll the table I realise he's reading from a phone and hit him over the head with a baseball bat, just like Robert de Niro in The Untouchables:
For one of the joys of working on a boat ~ albeit a flying hybrid ~ is that I can use product designed for a much larger fixed-wing market that comes with lower costs and lighter product. And a battery eliminator circuit (BEC) incidentally is something that can be included in the circuit so as to draw power from the pack supplying the motor, so that a separate source is not required for the receiver (RX).
An additional issue I've had in trying to get the Flame 80A ESC to talk to a motor is that (a) it's a piece of clever-clever shit and (b) its instructions go something like:
You put this wire here
You put that wire there
You press button
We go for noodle*
Specifically instead of a simple throttle calibration (the controller has to know when that joystick is at the top and bottom of its range) it includes this in three options none of which work: much like an EV that can't be fixed by yourself at the roadside.
Having tried once to get the Flame 80A P.O.S. to work I'll probably not try again on the basis a definition of madness is doing the same thing over and again, expecting a different result.
Plan is therefore to retain them for a rainy day. We did have them hooked up to a Pixhawk controller, though that's the royal 'we' and far beyond my own pay-grade.
All that we need do is get four lift motors running in tandem, and as we've seen, we can do it by hooking each up to a separate receiver as the lady with big breasts was explaining yesterday.
Reasonable? For all we need do is get one pontoon up and running on this basis and then it's a question of rinse and repeat and we're at least as far as static runs, albeit without differential.
Which is anyway a task for another day, like Scarlet O'Hara's Tara, isn't it Gromit?
* Ed. And that's the last time T-motor will be supplying us...
