THE FLYING WHEELIE-BIN
With every occasion on which a prototype failed in one way or other, there was always the question of whether to rebuild the existing design or to alter it in some way whilst the opportunity presented itself. We had at the outset elected to use eight motors for three principal reasons, in so far as (a) it matched the original outline in the patent specification (b) it provided a measure of failsafe redundancy and © it made for an outline more easily contained within the allowable dimensions for the competition in California whilst still providing sufficient thrust to raise an adult.
In many ways these have each melted away in step with the Arctic ice. From a handling and operational point of view, four motors appears to be altogether the more reliable whilst the redundancy issue can always be addressed by adding a further independent quadcopter in a way that it is overlayed upon the first: whether this meant a quad at foot-level and another above head-height, or simply one stacked upon another as is altogether doable in terms of the current effort.
In an attempt to meet all of these varying contingencies ~ and knowing that an erect accommodation booth with a drone at either end exceeded GoFly’s dimensions ~ an alternative appeared to be halving the height of the box and locating that uppermost drone around the waist of the operator. This time however rather than it being supported bodily by the operator it would be self-supporting in the form of a virtually enclosed box. It had considerable advantages when it came to safety, too, as it provided protection from the consequences of blade-shedding. This is something rarely addressed by drones of whichever size, including those intended for human carriage, although whenever you travel on an airliner there is invariably reinforcement around either turbo-propellers or turbo-fan engines to meet precisely this contingency.
There would also be the benefit that the box was effectively increased in terms of its rigidity, as it retained the bulk of its sides, whilst even the upper face of the box that surrounded the operator’s waist benefited from a form of shear-web. And whilst the current efforts concentrate on a straightforward platform that looks to be more of a flying carpet than either a flying bin or booth, it remains a viable outline that may yet meet some or other requirement.
In an effort to make it more likely to appeal to military consideration I chose as well to render it in drab olive instead of post-box red, although I view this as something of a one-off. Military procurement by the British Army in particular has recently been roundly condemned by a parliamentary committee as unfit for purpose, whilst a much-heralded aircraft carrier has been dismissed ~ probably rightly, although only the first missile will tell ~ as a futile exercise in flag-waving by Dominic Cummings, architect of the same parliament’s policies (or at least until such time as he upset the PM’s girlfriend). The British Army remains a sort of sales outlet for US goods, and thus most entrepreneurs are better off trying to convince the market at its source. If at all, for militaries are rarely interested in anything unproven in the marketplace, as the Wright Brothers themselves found to their cost.
With this prototype as with the preceding I had foregone the four-pronged arrangement that supported the motors with a form of ‘H’ outline not all that dissimilar to that seen amongst purpose-built racing drones. It would be many months later in fact before we would revert to the original layout that we had taken to California, albeit adapted to fit inside an outer frame. Ergonomics would ever be the starting point for various designs including accommodation, however, and it is an effective absence of the need altogether that so attracts me to efforts underway with the current prototype at time of writing.
So far as the bin was concerned however a height of around one metre worked for my own elbows whilst suiting the fact that the nearest supplier worked in sheet material at dimensions of one metre by two. Although a half-metre square would also have suited the box eminently for the same reason, from memory I worked to forty centimetres (or sixteen inches) square, which looked the part. Ideally this box would have been totally separate from the underlying and overlying quadcopters that powered it, and thus made transporting it that much easier, although I elected to join all three parts so as to make a more rigid airframe altogether… especially in view of the fact I now had a trailer from a reputable source in lieu of one of my own devising.
Once complete, this went back to Aled’s workshop on the Welsh borders for wiring and programming. Once there, we had as ever the quandary of where exactly we could pitch the controller, as we have already seen how it is ideally located precisely in the centre of both the volume occupied by the body of any drone, beside its centre of gravity. It is not the easiest of things to locate that centre of gravity, although internet search suggested that our personal C of G is not too distant from our navel, especially if like me you drank a lot of beer. In theory the C of G of the bin was equally not too distant from around its middle, although this would be migrated upward presumably once there was someone on board. As it was likely to be flown with a hollow mannekin instead, we opted in the end to locate the electronic components on a carbon-fibre tray that formed a narrow shelf extending from the front of the box itself.
Again, nothing is ever easy when it comes to scaling up drones, though this most applies whenever manufacture and repeatability is taken into consideration, The reason you will see many hundreds of electrical flying machines on YouTube is precisely because they are flying flashes in the pan, without a hope of being turned into airframes at all easily reproduced. One aspect of the bin that bothered me a lot from this point of view was that the wiring had to be extended like a python’s gizzard throughout the entirety of the airframe, which meant in turn that it could never be easily dismembered for transport. From the outset and continuing today what I see is the most effective solution is two wholly independent drones working on concert to levitate, for instance, that telephone box of yore.
Nonetheless the prototype was ideally to fulfil the original aim upon our return from the competition to garner some impressive video footage, which might form the basis of crowd-funding set to advance the project further. Whereas however previous prototypes featured drones separate from the accommodation, this one could not be static-tested on the purpose-built rig indoors for the simple reason that it would not fit. This in all likelihood may well have been the reason that they flew ‘out of the box’ except after being transported between continents, whereas this one decidedly did not.
In keeping with previous plans to test indoors so as not to qualify for a flight at all, the airframe weighing upwards of 35kg when laden with the mannekin. In an effort to reduce weight so far as possible I had chosen a half-mannekin anyway, as what you could not see from the photos that like Douglas Bader he lacked a pair of legs, and was supported only by a broom-stick. Nonetheless he really looked the part, and whilst he no longer survives ~ or at least outside of the council’s recycling facility ~ I wear the scarf and jacket to this day and still think of him fondly.
Initially then we would ~ we being Alan the drone pilot, and Phil the electrical engineer and proprietor ~ attempt to get this airborne in the latter’s barn. I can recommend a risk assessment at all times with these things, turning as they do 32” propellers at around 3000 rpm. As it happens on this occasion it was only in the aftermath that one switch setting on the transmitter would likely have sent the prototype to (albeit if not through) the rafters of the barn. In fact the whole nation along with its aviation authority would be educated in this by an Australian team who displayed a flying racing-car at the 2019 Festival of Speed at Goodwood, which promptly climbed thousands of feet through the Gatwick Airport airspace until its batteries went flat, whereupon it fell and only narrowly avoiding flattening anybody else. Having shat on our own door-step instead of their own, Alauda subsequently departed wholly unpunished.
The problem though was there had not been sufficing space in the barn to consider whether the thing flew at all, because the moment it drifted for whichever reason it had to be landed for fear of an expensive prop-strike. Accordingly scanning the internet I chanced upon the one-time site of RAF Llanbedr, itself a former facility for testing drones of an altogether different type over Cardigan Bay viz. Meteor fighter-jets that were remotely controlled as targets for military exercise. It had subsequently been part-privatised like Kemble, the former home of the Red Arrows formation team that I had visited in the day, and was thus available to hire. I was therefore able to secure the use of one of its capacious hangars over a weekend in early December of 2020. If you want to see which one too, it’s the one the Red Bull pilots fly through on the YouTube post.
As it happened around the time Wales, whereon the airfield was situated, happened to be effectively closed to visitors and so the four of us had to cross the borders on that Saturday morning like escapees from Nazi Germany, false identification papers to hand. As it turned out there were no obstacles whatsoever to travel as I had feared, probably because on the one hand few people were stupid enough to try it and for another that the police had better things to do. The weather turned out as well to be wholly clement so that the landscape, which included the fabled village of Portmeirion across the bay, was seen at its best. With a comfortable B and B to boot, you’d probably have done it for a pre-Christmas weekend regardless.
The prototype however was not seen at equal best, behaving much as had the previous once unboxed several thousand miles away, whereas this had travelled barely a hundred. Any hobbyists with a drone themselves will be aware of the need to calibrate the flight controller by turning it through 360 degrees in all three planes, and this is yet another thing set to try the patience of anyone scaling them up to inordinate dimensions. We had done this prior to transport and not after, and maybe this would go some way to explaining the instability that encroached only seconds after launch. This one did have a GPS feed that ought to ameliorate the condition, but like a cancer patient it was failing to respond. As a pilot too who was used to calibrating inertial platforms on jet airliners without needing to pick them up and rotate them, this was doubly frustrating.
I had been concerned that combining the skids with the prongs supporting the motors around the base would not protect the propellers sufficiently during landing, although as it happened they did take a deal of punishment without damage. That damage only came ironically when I added a pair of detachable cross-bars that detached themselves during a heavy landing and put paid to the lower set of propellers. We tried flying the machine next day using only the upper set, but for whichever reason they did not have the power whilst theoretically they should. We had anyway reverted to a single pair of batteries in view of the fact I had connected one pair together, shorting them out to great effect. If you’ve ever wondered what it is like to discharge all of those amps in a single moment, incidentally, try lighting a stick of dynamite and not letting go.
It was thus a posse on the grandest of scales, compounded next day by Aled’s complaint that we’d not filled his test-pilot’s tank. Said test-pilot and his girlfriend however were delighted with their weekend away prior to the festive season, we having furnished them with delightful accommodation and a pleasure flight around a snowy Snowdonia in gin-clear conditions, although not thankfully in a wheelie-bin. In fact in terms of flying hours the pilot had earned rather more than I had ever done flying a couple of hundred people around in jet airliners (and was beginning to wish I was still doing so). “What” as Spike Milligan used to ask, “are we going to do now?”.
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| One small step for a bin |
