60" Build Step #2

There are three modules to the 'drone viz. airframe, flight-deck and undercarriage. The reason for this is that like the containerised transport system, the design features a four-cornered means of connection forming the basis of a modular system that offers (a) choice of undercarriage whether skids, floats or castors (b) choice of payload whether seat, stretcher or cargo-box and (c) choice of four or eight propellers.

Altogether, you're spoilt for choice. We'll first build the frame to which flight-deck and skids will be attached, the recipe for which module includes the following:

(a)    4 off 58" and 4 off 38.125" by 1/16th aluminium square tubing, cost £36.47

(b)    2 off 19" square 1.20mm plain aluminium sheet, cost £32.40

(c)    4 off 25mm four-way steel-reinforced tube connectors, cost £44.19

(d)    8 off 25mm square 6M threaded inserts, cost £5.87

(e)    8 off 6 x 40mm hexagonal bolts at £0.40

(f)    Total metal/plastic parts airframe, £119.33

That's just half the cost of lunch at a Michelin-starred restaurant, and you can't share that. Leave those ingredients indoors overnight, as warm alloy is more workable.

60" Build Step #1

Pays to draft the outline at the outset and I've done so in Apple Pages, whose elements a chimpanzee could grasp. I am actually old enough to have worked with the Vydec dedicated word-processing system that could output text to the printer for an equivalent outlay of $60,000... so Pages is rocket-science so far as I'm concerned.

I like what I see, a caveat being I may stretch the central square to 50 cm instead of 19 in (because the sheet-metal supplier does so in metric).

Going to be a leisurely build, but I'll hold your hand throughout.

Go Big, or Go Home.

Few people watching the 2022 Winter Olympics will be aware of the significance of the name, but Jake Burton effectively invented the snowboard, or indeed the sport of snowboarding. Like every other groundbreaking development, most or all of the parts were already there to the extent that what remained was ~ as it had been with every other form of locomotion ~ for someone to come along and demonstrate the possible.

What the HBO documentary Dear Rider makes clear, however, is that the earliest years were in the words of the inventor, decidedly lonely as he investigated various forms of manufacture and shipped in dozens a product that would come to be sold in millions. In truth, the sport never really took off until such time as he collaborated with a small ski manufacturer in Austria called Kiel, who could apply conventional fabrication when every other ski manufacturer had dismissed the notion of the sport going mainstream.

There are parallels now in the polarisation between moneyed air-taxi developers and the comparatively impecunious of personal air vehicles. But what developments like the snowboard demonstrate is that the public at large rarely see which of them might succeed, except in retrospect. Donating prototypes to museums has therefore closed one phase of development, yet at the same time calls for the next.

For what is life after all, without a project?

Nothing Ventured...

I donate the second of the prototypes to Aeroventure, or South Yorks Aircraft Museum in Doncaster  based on the site of the historic airfield... a place where, for instance, all of the wartime DC-3 Dakotas were modified for use by the RAF (to right-hand drive?). 

For me though in the late 1970s it was a place beside the race-course that the crew-bus passed by enroute to Finningley. Each airfield was established by the Royal Flying Corps in WW1 and are thus amongst the oldest in the UK, if not Europe. On a more modest scale altogether it was where I first took to the skies myself: at the controls of the venerable Bulldog and alongside Squadron Leader and Spitfire pilot, Ron Brown.

Like so many exhibits this is a sum of its parts, its duplicate in the Helicopter Museum bearing the original airframe, and this the motors and propellers used in that test-flight of December last year. I like the fact it hangs here from the ceiling, and in the very best of company in the form of Bell's 47.

Enstrom Ending?

Appears Enstrom ~ a company as old as myself ~ is yet to rise from administration like a phoenix. The company was started by someone with no knowledge of aeronautical engineering, but ample enthusiasm (which gives us all hope). But it was the steed of choice for Dennis Kenyon, who passed a year prior to the demise of the company.

I've chanced upon some remarkable pilots unknowingly in years past. One an old man whom I used to pass with a cheery greeting outside the hangar in Bournemouth we were both frequenting whilst he was flight-testing a single-engined turbine aircraft. It turned out to have been Neville Duke, one-time holder of the world speed record.

Dennis I also shared hangar-space with whilst scratching a living a fixed-wing QFI. He returned to flying helicopters later in life from necessity, and for the same reason most men of advanced years with whom I once shared a cockpit did so: divorce. But I witnessed one of the most heart-stopping aerobatic displays I have ever seen, before discovering only now ~ some thirty years on ~ that it was a world champion that I was watching.

I recall how telling me that to refine his craft on the Enstrom they would fix a strip of balsa on the tail-boom to see how close during maneuvers the main-rotor came to slicing through the tail-boom.

We shall never see his like again... or theirs.

Room (for) 101

Added to the hundred existing artefacts in the world's largest collection of helicopters is the fifth of our prototypes, as flown back in the first week of December of last year. And here in the foyer the proprietor himself in front of the oldest surviving helicopter in the world in the shape of Hefner's Revoplane. The cost of this was underwritten by a British cotton millionaire, doubtless derived from the industry in Lancashire... that great seed-bed of aeronautical development in the UK!

The museum: http://helicoptermuseum.co.uk

and exhibit: https://www.instagram.com/p/CZhIPxmM3lm/

and blurb:

Among the many hundreds of experimental ventures worldwide in the field of ‘personal air vehicles’ or PAVs, the TELEDRONE was designed and built by Colin Hilton as a spin-off from his earlier entry into the Boeing-sponsored ‘GoFly’ challenge, which took place at NASA Ames in Silicon Valley early in 2020. 

The development of air vehicles of this kind was made possible by the digital control of increasingly powerful motors, alongside improvements in batteries and electronic components derived in large part from the mobile phone industry. Effectively a scaled-up quadcopter, the operation of this scale prototype by radio-control was possible by registering it as a regular drone ~ an avenue open in both the UK and US up to a weight-limit of 25 kilograms or 55 pounds.

Further development is possible in the UK at weights of up to 150 kilograms by special permission from the CAA, and thereafter at greater weights again under Experimental Category. Thereafter however regular certification would be required, which is a process evolved over decades and aimed at piston and turbine types and as such, prohibitively expensive. It is not the case in the US however, where in an effort to stimulate the development of ‘eVTOL’ types the FAA allows for such aircraft as this to be flown largely without regulation up to a gross weight of over 115 kilograms so long as there is a pilot onboard. Consequently TELEDRONE types like the one seen here will be scaled up to adult size in order to be pitched to the US market in the form of rapid kit-builds.

Technically the airframe comprises a patented four-pronged cantilevered structure to support the centre-body, whose advantage is that it is effectively a two-dimensional construct adaptable to conventional fabrication in aluminium. In the case of this latest version of the machine, however, this is bounded by a 48” square perimeter frame that extends to four undercarriage legs in support of either skids, floats or casting wheels.

In order to pack the remaining components as practically as possible, the avionics are situated on the underside of the central section, and comprise a radio receiver linked to the V-aerial at one corner of the airframe, beside a Pixhawk ‘cube’ flight-controller (to which GPS signals are fed from a disc-shaped antenna located at another corner). The controller is wired in turn to each of four ESCs or ‘electronic speed controllers’ which control the four 6 kilowatt motors digitally as ‘virtual’ AC motors albeit running off a DC supply. The supply itself is drawn from a pair of 22000 mAh battery packs wired in series to produce around 45 volts.

The prototype thus has an endurance of between ten and fifteen minutes, with each motor requiring only a fraction of the potential 100 kilograms of installed thrust required to support the gross weight of 25 kilograms. The test-flight was undertaken on the 2nd of December in 2021 at Frome model aero club on the Somerset Levels, with the wiring, tuning and test-flying pursued by Angus Benson-Blair. The subsequent development phase would see the airframe expanded to 60” square and powered by 10 kilowatt motors driving 40” propellers in pursuit of elevating a mannekin by radio-control and thereafter an adult pilot onboard using hard-wired controls.

Max Speed 63 m.p.h. (FAA Part 103 Ultralight limit) in ground-effect

Empty Weight         20 kilograms

Capacity         1 child

Power 4 x T-motor 5.5 kilowatt motors (equivalent to 22 HP)

Twilight of the Quads

As we move toward full-scale, it has come time to retire the sub-scale: age shall not weary it, nor the years condemn...