Whilst we wait for the kit for the rig to arrive we can draft the outline on the back of a Christmas wrapping-paper (Bah, humbug... best use for it). Then we can overlay motor and speed-controller, which come with stock lengths of cable attached, so as to work out what length of lead we would like on each battery pack.
Quadcopters are normally defined by the diagonal length between each axis, bearing in mind non-people-carrying drones fly with a prop at each corner. For anyone with a flying phone-box there has to be a more logical measurement that we can use to draft builds on the floor. Bear in mind this is what they did at yards in Belfast and Glasgow, which once produced a third of the world's tonnage of shipping... so don't knock it.
Accordingly we'll make the measure the square on which axes of motors are mounted: in our case 36". A reason for defining it this way is that it disregards the thickness of whichever tubing used in construction. Note the arc of the 22" propellers, which seem a good fit. The manufacturers actually do a super-light version of this carbon-fibre prop, which to my mind is like providing the option of lipstick on pigs.
One reason I chose U7 motors is they come with an optional prop-fitting using a single nut fixed on the axle. In turn it means we can run with wooden props if we choose, they being a fraction of the price and more forgiving. If we'd blade damage on the jet airliners I flew, the engineers would just sand them smooth. Rolls-Royce notoriously were bankrupted by an effort to switch to carbon-fibre, having to be baled out by that gift which keeps on giving... the tax-payer.
