Pays to keep an eye on it at every stage of the game, and our proof-of-concept we saw yesterday weighs in at 18lb or 8.2kg.
It also pays to bear in mind that the largest flying-boat closest to commercial service in the shape of the Saunders-Roe Princess was hamstrung by use of Bristol Proteus engines that were rated at 3,500 HP and actually produced only 2,500 HP.
On a somewhat smaller scale I review the performance figures for the T-motor U7's earmarked for use, being the only ones I have lying around the workshop.
My favourite part of the table is the last column, where the operating temperature is normally listed but here simply says HOT.
Well each power-pack in the shape of battery, ESC and motor weighs in at 0.7kg, and the upshot is that with all six motors fitted viz. four for lift and two for cruise, in order to hover we shall have to drive the lift motors at 75% from the get-go.
Things are improved slightly in view of the fact we'll be operating in ground-effect, tho' this only compensates for the drag on propeller efflux induced by the pontoons, aside from the fact that manufacturer performance figures are generally suspect.
Beyond the boat itself weighing 8.2kg, six power units weigh 4.2kg, four weigh 2.8kg and two alone would weigh just 1.4kg.
In turn this might mean that we'll need two prototypes, one to demo the hover and another the cruise i.e. one with just four lift motors and another with just two for cruise demos alone.
(It is at such times as this as you will see the benefit of vectoring propellers, because if the two cruise motors could help with the heavy lifting, you've improved that ability by 50%.)
Nonetheless it is what it is, and as it happens mulling on this overnight I like the idea of going metric and basing the kit-build solely around one- and two-metre lengths of spar.
Beside this reducing the buoyancy, it will make the craft more portable for deployment by an individual besides reducing that basic weight a little...
... and every little helps.
N.B. Thrust appears in grams in the fourth column along from left.
