Tuesday, December 3, 2019

E-Street Furniture


Wheel the box out of the hangar for the first time, resplendent in Post Office Red.

It doesn't look quite as much yet like the classic K8 design of old, but will do once I've added the base and dome beside the trim around the window-frames.

It's also light, but as ever, not as light as I'd like... but that's aircraft for you.

Building has, as ever, been the inspiration for each conceptual step and putting this together at these dimensions (eventually 1500 x 500 x 500 mm all told) I realised that (a) it can seat an adult like a wing-chair bu also (b) it might also fly a child stood upright.

Effectively therefore it's a 66% scale working prototype that may yet fly a child-sized dummy and which might also form the basis for a booth around two foot square and six foot six tall equipped with larger motors and 36- or 40-inch propellers.

With a minor stood inside, too, there remains the option to fit one quad at the base and one at the top, as originally envisaged in the draft application for the GoFly Challenge.

Nonetheless we shall run with the modular octo-copter up top for the time being, as it makes the control-laws more straightforward beside parking the propellers in the safest location.

Rotors have always been up there on the helicopter and it is no surprise that the Volocopter has followed suit. Bear in mind its prototype ~ not that long ago ~ featured a pilot sat upon an exercise ball surrounded by a forest of rotors.

What they have produced now looks the part, and looking the part is essential for selling the concept of urban air mobility (UAM) to the public.

I wondered today whether Mercedes and Audi raced in silver because of a reluctance to add much on the way of paint to alloy bodywork for fear of adding weight. As it is I've let five tins of spray-paint loose on this airframe because it has to make a point:

Where once you'd have phoned from here, you'll now be teleported instead.

Monday, December 2, 2019

Its a phone-box, Jim...


... but not as we know it.

I continue construction of the airframe and in doing so, decide that:

(a) it could be lighter, and

(b) the battery compartment could be a separate module.

But that's the benefit of hindsight, and after all my dear, tomorrow's another day.

Friday, November 29, 2019

Velodrone


The Airbus A320 this last week became the best-selling jet-airliner ever, though it nearly didn't happen at all. Though the first jet airliner was developed in the UK in the 1950s, manufacturers in the USA dominated the market in the 1960s by taking advantage of the fragmentation of the market in Europe. Only when the British, French, Germans, Dutch and Spanish combined their efforts in the A300 (the first wide-body twin) did it literally take off.

From the outset then, the Airbus story has been one of moving parts around to tally with the expertise located elsewhere. In a very modest way we've replicated that today: the top-end of the flying phone-box being transported on the roof-rack of a Suzuki Jimny 200 miles south to one of the team-members south of Bristol. Here ~ all being well ~ the avionics controlling the motors are to be wired up so that they can be bench-tested with the propellers in place.

We're also offered the expertise of drone-builders Vulcan (http://vulcanuav.com) for fine-tuning the rig for the purposes of control and stability.

So things are finally looking up... literally.

Thursday, November 28, 2019

Octobus


Proud of this as it encapsulates the best of my thinking over recent months. It's ready to be transferred to another team-member who will attempt to get it flying independently with a smaller of batteries.

Whilst that's happening I shall continue construction of a 'phone-booth' of 50cm square and 150 tall, large enough to include a seated passenger whose lower legs will nonetheless dangle outside.

Beneath the seat a larger set of batteries will transfer the current up the four columns to the motors that you see above, via an avionics bay contained within a 'dome' that surmounts the centre-section.

The net result will look much like the classic K8 telephone-kiosk (as seen at http://www.the-telephone-box.co.uk/kiosks/k8/) but equipped with eight propellers and able to 'teleport' people who might otherwise have telephoned instead.

Tuesday, November 26, 2019

Space-Frame


Phone-booth's taking shape at last. I have ordered too few connectors for each of the corners but can crack on with fitting the base meantimes.

The airframe is constructed from a pair of five-metre lengths of inch-by-inch-by-sixteenth alloy divided into four 1375mm stanchions, eight 450mm cross-bars and two 450mm seat-supports that serve at the same time to brace the sides.

I recycle old alloy plate for the base because (a) I don't like waste and (b) it saves me a trip to the stockholder.

Prototypes are meant to be rough and ready in my book. Just seen the Ford v. Ferrari movie for inspiration, with Carroll Shelby given just ninety days to put the GT40 together.

The '40' referred to the maximum height allowable in inches, which is unusual with France having long organised European motor-racing and them normally working in metric.

There has always been a form of tug-of-war between France and Great Britain when it comes to laying down the regulations for these things, however.

Vital Parts



They used to say in the USA, and perhaps they still do, that an idea's worth a dollar, a product's worth ten and a factory's worth a hundred.

One reason for this is that prototype construction proceeds in fits and starts, not least due the availability or otherwise of its 'nuts and bolts'.

I want to strap the two drones that together form the 'motor-head' of the prototype as non-invasively as possible. Every hole in an airframe ~ and not least the portholes, as proved by the De Havilland Comet ~ is a potential focus for failure.

Accordingly I consider those rubber bonnet-straps you see on rally-cars, but settle instead for sprung fasteners of the sort you see above (which is stressed to 90 kilos, incidentally).

Britain's richest native industrialist, James Dyson, has lamented the dearth of factories left in the UK producing these sort of nuts and bolts. Basically they've all gone west, and when in Shanghai I used to buy them by the sackful, they being 'cheap as chips'.

Good to see therefore that these are marked up 'Redditch UK' and therefore sourced from the Midlands, that great heartland of manufacture in this country.

It's not just me, either. Production of the Boeing Dreamliner has been held up at times due to a shortage of rivets...

Sunday, November 24, 2019

Motorhead


What I should have done yesterday, I suppose, I've done today. Often however unintended breaks prove beneficial, providing space for new ideas to surface unawares and it is during one such that I finalise my 'best shot' as regards what should be fixed to the top of the flying phone-booth.

And this is it, pitched on the floor in order to check the clearance between motors, propellers and wiring. This stands at an inch and a quarter between opposing blades, which is more than sufficient by my reckoning.

I once shared an airfield with the UK agent for Enstrom helicopters, whose heart-stopping aerobatics in same I also witnessed. He said that to see how far they could ~ literally ~ push the main-rotor in flight without it striking the tail-rotor, they would strap a balsa strip to the tail to see how much it would chop off... it being altogether less critical to flight performance.

Question now is do we try to get this motor-head flying independently before such time as fitting it with the passenger compartment and full-size battery-packs? At least one of the GoFly 'webinistas' advised against flight-testing modules independently, if only to avoid the potential waste of time.