As Jane Austen might have written, "It is a truth universally acknowledged that a single motor in possession of great power, must be in want of a tractor propeller" and I'm moved to tears just penning that.
As we prepare over carrot cake* and tea to fit the lateral laths to each side of the deck, we've to consider how to mount the motors as these are supported at the rear by the laths, and so we need to know by what measure they should each overhang the stern of our mighty vessel.
Now you've probably not dwelt much on mounting electrical motors on drones as I do when sharing afternoon tea with relatives, but almost invariably they're designed with the prop on top... as it should be with consenting couples. This is to promote a maximum of cooling flow, which itself is the reason that in the history of aeroplanes those with props at the rear have always been the exception.
The corollary is that the prop is twisted in away that leaves it largely flush with the surface of the motor: the 'sweep' of its pitch occupying the space filled by the body of that same motor. This in turn has an impact if, as we do here, we would like the drone to be as compact as possible, as this is best served by a tractor arrangement like the one in the picture.
Were we to flip the prop over to run as a pusher, we would have to allow for extra space for that which the twist of the prop takes up nearest the hub. Accordingly we shall see in due time ~ and I know you can't wait ~ how there is an argument for mounting each motor so as to be forward facing and fitted with a tractor.
Turning then to my laser calibration unit on the kitchen sink, each of these units for providing power needs about three inches in which to function, so that an overhang of around six inches is required of the laths.
Go to it, soldier.
* Other types of cake are available.
