Friday, March 19, 2021

Please Be Seated

For a variety of reasons that you'd only appreciate if you'd spent two years of your life designing and building eVTOL variants, I have elected to go for a half-scale model in the most compact format possible. As such I have reverted to flying perpendicular to that direction you'd expect from an 'H' quad, as it allows for a reduction in the vertical extent of the accommodation. I've also reverted to seating in lieu of standing for the same reason.

I'm also avoiding the complexity of multiple levels of redundancy because at this stage of the game ~ and the project is not alone in this regard ~ it's a case of walking before you can run. As a consequence the lower quad supplies lift alone at a constant RPM across all motors, and these are individually addressed by a battery-pack each to keep life simple from the electrical point of view.

A by-product of this is that even at full-scale the height reduction brings the vehicle back within the remit of the GoFly challenge in terms of size, although larger motors, propellers and batteries would nonetheless be required.

Weight-wise what you see here (without speed controllers, avionics and skids) tips the scales at 35 kgs (77 lbs) with dummy and 31 kgs (68 lbs) without. Having put several such airframes together I can say with confidence that in order to bring the vehicle in below the CAA's official drone classification of under 25 kgs (55 lbs), smaller motors and batteries would certainly be required.

This one will be registered here for testing as a large radio-controlled model, on which basis it will also be devoted to the display circuit in perpetuity, which should do no harm to the prospect of scaling it for human flight. Also you'll notice the upper quad is removable so that it can be tested independently AS a regular drone, prior to fitting to the remainder in order to provide the steering beside a portion of the lift.

This division of 'brains and brawn' will simplify testing altogether, which is ultimately the key to success in such endeavours.