While we wait for those M3 bolts to arrive, let us consider another aspect of the proof of concept craft relating to battery stowage. Currently we've a pack addressing each of the motors, although we are likely to revert to past practise and use a single pack via a PDB or Power Distribution Board.
The reason for so doing is that I'd like to stow the substantial battery mass behind the head of the occupant on a perforated sheet upon which both this and a head-rest can be mounted.
A further reason is that there is a limited amount of room up top and from operational points of view a pack that can be swapped out conveniently from the rear works best.
The principal benefit of hanging battery packs here however is that it re-balances the vehicle given that the lower limbs of the occupant overhang the outline of its frame.
Building prototypes does take you down rabbit-holes and wondering what our lower limbs weigh is one such. There's a secure unit down the road here and one option was to have interviewed any number of chain-saw murderers to see if they could cast any light on the subject?
Alternatively you can scour the net at cost of being suspected of planning for body-part disposal yourself... though I've taken that bullet for you.
Using the table above we're looking at around 7.5% of body mass for the lower leg and foot (plural) and some 8.5% for a pair of thighs. I'm taking some of that seeing as how they overhang the edge of the seat, and so let's call it 12% all in. Give me a break here, because you're wearing a pair of boots unless you're levitating for enlightenment?
Apparently mens' perceived ideal weight in the UK is 77kg, which is me with clothes on... and no surprise that I'm perfect in that way too. That means we can hang 10kg of battery out back there on a full-scale prototype, which is a very respectable payload. In fact it is just about four of the largest six-cell LiPo battery-packs each providing for 22,000 milliamp hours.
A target application for a machine of this type is shuttling you upwards for a birds-eye view of the world ~ for which tourists will always part with money ~ or else launching parachutists or powder-skiers by a more cost-effective means. For most such uses a means of swapping out battery-packs quickly and efficiently would be required.
