Ha'porth of Hydraulics

Behind that sum, which we may as well round up to a fifth of a billion dollars, lies an F-35 falling out of the sky in Alaska recently. I'm minded of an incident on a UK carrier where much the same happened after a foam intake cover protecting the jet engine from the elements was left in situ, where it was ingested and condemned the aircraft to a watery grave.

Problem though with everything is that as it gets bigger, so more complicated, which is why what survives catastrophe tends to be annoying stuff like cockroaches and scorpions (not the band, they're toast). I once looked at a list of what systems are affected by the WoW or weight-on-wheels switch on the Boeing 737, and gave up after the first several pages.

It was not overly cold in Alaska on the day, at zero degrees Celsius, but sufficient to freeze water during a forty-minute holdover. During the time  water in the hydraulic fluid froze, meaning the gear would not retract after take-off. What is concerning is that (a) apparently this was not unknown on the type and (b) it could also affect the flight controls. Which it did.

Following a couple of touch-and-goes to reset the system and straighten an offset nose-wheel, inter-related systems became convinced that the aircraft was back on the ground... where different flight control rules apply. I recall this to be the case on the Airbus, in order to better manage things in two dimensions instead of three.

The pilot ejected unscathed, and beside Lockheed engineers being called out for not having referenced the circular, blame ultimately lay with the aircraftman responsible for storing the hydraulic fluid in a way that would not attract water... which it does. I always say that whenever anything goes wrong, it is always better to work your way down the ranks, because that is where the lowest salaries accrue. And if you've just burned through a 0.20 billion dollars of the taxpayers' money, you'd be looking to save every cent.

For although the F-35 is undoubtedly the finest means of delivery, it is proving to be less so in some cases than 10,000 of the largest delivery drones you may otherwise buy (or rather more given bulk purchase and foreign government subsidy). It could be that sooner rather than later the only things flying or sailing in numbers are ones designed to move large numbers of people or large amounts of freight from A to B.

And drones.

The above replaces the Sunday sermon scheduled for today... what do you expect for free?

Director's Cut: April 2018

Let me touch upon the folly of prototyping a boat at some remove from water.

Aside from the Leeds-Liverpool canal ~ built to enable the woollen mills of Yorkshire to transport their wares across the British Empire ~ the nearest stretch of water is located at a reservoir that, ironically, was also created in order to keep the nearest canal topped up: raising and lowering barges through locks, the reason they needed a constant supply. Carr Mill Dam however is administered by the local powerboating club, and we're all familiar with how, when it comes to jealously guarding the train-set, the young are no match for the old.

Had I lived in the Florida Everglades with water at the end of the garden, as so many of that blessed people do, then this may well have come to fruition. Nonetheless it is a fact that any number of projects are felled by a single hurdle: remember the 'Pond Racers' slated for Reno?

The value of even a handful of tests however is immeasurable, the chief test-pilot at the time of the introduction of Boeing’s 707 suggesting a single flight-test was equivalent to a thousand speculations prior. I had stood on this same boat prior to fitting the (15HP) outboard, and it was decidedly unstable from the get-go in that a third of its buoyancy lay in the keel, which was happier floating flat than suspended. Years on, it is no accident that the prototype features an open keel.

Secondly, and accounting for my apparent obsession to locate the centre of thrust with that of gravity, the offset of the thrust-line ~ exacerbated by the fact that this was a long-legged motor ~ meant that every application of power led to an extreme pitch-up, as you might expect. This might have been ameliorated once the craft was on the plane, but that appeared to be beyond reach; the fact this only occasionally happens to conventional vee-hulls is accounted for by the considerable weight of the front end, which was absent (as it ought to be) in that seen here.

What did for the inaugural test however was the crew who had craned the craft into the dock ~ considering it an ideal pursuit during an extended tea-break ~ decided it was better towing the boat into more open water. This proved calamitous, as the keel area meant that towing would never likely be an option unless that area was reduced considerably by cut-outs in its profile, for instance.

For the thing about a tow-line as distinct from any means of power fitted to the boat is that the vector continues straight even should the boat diverge. In turn this would present a sizeable surface below the waterline that wants to tip over, which is inclined to take the boat with it. Subsequently, the combination of an outboard and inventor needing to be dried out ~ beside the burden of disappointed expectation ~ was enough to convince me to throw in the saturated towel right there.

The primary lesson to learn however is not to expect anything in particular from any one test and expect it to fail instead, so as to be happily surprised if it should not. Combined with what I learned from building and testing sizeable aerial drones, this resistance to failure and a working knowledge of materials is likely to prove a better guarantor of success altogether.

In retrospect I doubt the commercial viability of what was outlined on paper in the form of  the patent publication. At the time both aero-engines and outboards were all-or-nothing viz. large, heavy, expensive. The current (!) availability of electrical motors along with the means to power and control them is literally a game-changer, whether on the road or in the air. It has yet to produce the same revolution upon water, although that is set to change and sooner than you might expect... the flood of investment into Regent’s Seaglider a case in point.

Most of the money is as yet on means of transport for numbers of passengers who are prepared to pay the price. Consider this, however: the number of aerial drones now exceeds that of all the aircraft ever to have been produced. And all of that with barely a sniff of investment capital, the costs having been borne throughout by individual inventors and the subsequent cash-flow from sales.

So.. any takers?

Director's Cut: September 2011

The first recorded grant of a patent for exclusive rights to an invention went in 1421 to someone in Venice, for a boat he'd adapted for transporting marble. I’ve pursued patents since the early 1980s, not least because at the time the Science Reference library still existed in London: with its vast archive of historical patent documents in the form of printed volumes and microfiche. Entrance was free, requiring no pass of the sort required for instance by the British Library nowadays.

 

Most of what I designed at the time and since relates to different forms of transport, with a special interest in anything that flys or floats. I guess this reflects aspirations divided between the merchant navy and some form of flying. Ultimately, as is often the case with inventors and misfits, I never viewed myself as succeeding in either ~ though like me the many thousands of passengers I flew walked away unscathed.

My specific interest though always lay in the transition zone between water and air, which is considered ground-effect but which has been modified as ‘surface effect’ in order to encapsulate flight over water too. The library I referred to also at the time featured volumes of an annual called Janes Surface Skimmers, whose editor I spoke to occasionally and which covered emerging craft that were not quite boat or 'plane.

Sadly the annual would be discontinued, its entries subsumed back into the realm of regular shipping. This would be, I think, because the fantastic beasts that littered its pages either (a) ran short of funding (b) came to grief or (c) were simply ahead of a time that would see remarkable advances in electrical equipment, battery-packs and computing power. Principally if you overlooked hovercraft, the primary exponents of flight just above the water were invariably German, Italian or Russian.

The patent itself touches upon all of these issues, having been built and expensively tested at large scale, having failed that test upon water, and having been conducted at a time that confined experimentation to unwieldy forms of engine: worth recalling here that the aeroplane resulted from a shift from external to internal combustion.

Considering (b) however and discounting the largest-scale efforts of the Russians, wing-in-ground effect or WIGs generally suffered catastrophic loss in ways that had afflicted seaplanes like the Catalina: flight requires the widest span, whilst speed on water requires the narrowest. And the principal problem at that time, comparing to now, is that prototyping was considerably more expensive and loss of the prototype would generally terminate the project as well as the airframe.

Effectively this confined surface-effect craft to inland waterways, or at least 'til now, when sensors and processing power enable aircraft like Regent’s Seaglider to fly at infinitely adjustable height above waves, whether supported by hydrofoils or wings within ground-effect.

None of what went before nor what is advanced nowadays, however, addresses the issues raised in the patent in their entirety i.e. a simple watercraft that can translate from travel on water to flight above it, at high speed without fear of destruction.

For it remains the case that many such designs are unreliable except on the calmest seas. To a great extent the limitation still extends to hydrofoils, unless on the scale seen in challenges like the Americas Cup: which isn't cheap. As witness to all forms of transport, too, I recall how in all of those places where ferries ran on hydrofoils ~ Italy, Greece, Hong Kong and Russia ~ they were all withdrawn. This was principally because of the debris that litters harbours in particular, and the damage it would do regularly to hydrofoil surfaces. Yes, foils work nicely on videos and a turquoise sea, but life is not nearly so predictable.

There it is then: a design able to transition from high-speed on water to occasional flight above it when seas are smooth; lighter and more efficient than a conventional craft; easily built and requiring a minimum of both labour and exotic material... and which is finally suited to autonomous operation, or first-person-viewing from within the comfort of your living-room...

... whilst holding out the prospect of fitting a seat, and speeding off into the sunset.

Silence of the Laminates #14

I've had an enduring pain in the chest, which I now realise stems from the fact that the motors on the fourth prototype were not truly aligned with the axis as they are on the three previous. And the key to good design ~ as with Apple from the get-go ~ is often a refusal to settle for anything less. It's why, as GBS suggested, progress invariably stems from unreasonable people. Were we all to be agreeable then we'd still be eating raw meat, turning it into a YouTube sensation and shifting the merch.

Accordingly I have swapped out the T-bracket securing the rear down-post and used an L-bracket pinned to one side instead, in order to leave the mounting spar flush to the backside of the motor, which is then fitted using two 2x20mm flathead bolts.

August has been used to finalise the configuration of the first POC viz. rear-mounted contra-rotating props which will be used exclusively to bank the craft into turns. What remains of the month will be used to prepare the ground for efforts during the next, which are to include:

(a)    updating the website to reflect the current state of affairs (feat. Coldplay)

(b)    constructing a hydro-static tank in the back garden

(b)    getting the motors 'turning and burning'

Asked to comment on where we go from here, CEO Colin Hilton said 'Construction of the test-tank is to us what the supersonic wind-tunnel is to NASA Ames. I've given it the green light, and it will be a brand-new facility after I rejected the proposal to re-purpose an existing raised flower-bed... which could nonetheless be converted in times of war.

Meantime a review of viewing stats has historically shown, as it has this month, that what the readership of the blog most want is a pictorial record of how prototypes are brought into being in the shed next door. Feedback I do receive from the non-English speaking world, 'Why you stupid man write stupid things instead of making boat?' we take to heart... we feel your pain.

(Ed. Stop digging.)

iDrone SE (Seat Extra)

LIVE STREAM FROM THE VUE CINEMA BOLTON 

Fed up with normal looking boats?

Yeah, man!!!

Ones that float?

Whoo-hoo!

Let me introduce to you today, the iDrone SE!

(Cheers, whoops and applause)

It comes in three colours... Wickes ply, brushed aluminium or carbon-fiber!

Gasp!

Thirty-four inch ultra-high-definition deck, depending on eyesight!

Fuck!!!

Contra-rotating props, GPS, 2.4GHz receiver and VHF antenna as standard...

No WAY!!!

Way. Accessories to include a removable clam-shell seat, as well as a...

Like the old Motorola PEBL?

(Screams) Get out! Get OUT! Security, get him OUT!!!

(Heavy breathing, awkward silence. People sneaking a 'break for nature').

Okay fuckers, questions?

Yeah, why's your head so big?

100k

It's been one small blog for a man, one giant leap for what you can achieve when you pay a team in the Philippines to click on your posts. Asked to comment the CEO said 'We've come a long, long way together, through the hard times and the good, I have to celebrate you, babies, and praise you like I shourrrrrrrd.'*

Do not be discouraged by the lack of followers, incidentally. Becoming one requires a period of indenture involving years of solitary devotion and a diet of quinoa beans, beside your own urine. Last month several of my devotees joined me to graduate at the Shaolin monastery where sadly I had to fail all of them, one admitting to having added sugar to the urine.

No comments either, all novitiates of the blog having pledged a strict vow of silence.

* Indebted to ChatGPT for this thank-you speech, though it broke the spell-checker.

Silence of the Laminates #13

Don't spray-paint the edges of laminated foams as the solvent also dissolves XPS, as will polyester resin. Apply a coat of anything you find in a tin prior to that move to the spray-shop.

Photography by Hilton, lawn-mower by Dior.

Silence of the Laminates #12

A few posts back you'll recall how I had forgotten to nail the motor to the cross-bar that forms the trailing-edge of the deck, but in retrospect there is no harm done as this method ~ which I've trialled during the recent past ~ has much to commend it, for it means the motors can be popped off without disturbing the larger framework.

The original aim was to align the thrust so far as possible with the C of G, because experiments at full-scale with an outboard long ago showed that a sizeable offset in the thrust-line meant the game was over from the get-go. I've flown jets with inline engines (Citation, Hawker 125) and underslung (737), and whilst adding or reducing thrust on the former altered trim not a jot, trimming required on the latter during thrust changes was considerable; as it would be were a water-propeller to be pitched south of this hydroski. 

Nobody notices nowadays as auto-trim papers over such cracks on modern airliners, which adds another way in which modern pilots are unaware of how it is they fly.

But boats or planes, I'm old-school ~ and reviewing this set-up, the weight of the batteries and drive-train raise the C of G some way north of the deck anyways.

All in all I'm happy with how this looks, especially seeing how it came close to being cut up in order to re-use sections of the laminated sheet. It's a fourth prototype and the one that moves on first to testing under power. And there can't be another, as I'm out of the uPVC skirting used for the skis... and am too mean to buy any more.

Lick of paint though, eh Gromit?

* Jet engines are underslung on even the smallest airliners nowadays, being that much easier to inspect, service and maintain. They also allow for structurally lighter wings, but don't ask why. 

Silence of the Laminates #11

Meantimes here's the solution to the wobbly ski on the laminated test-bed, and a fix we've seen before on the first two prototypes: a down-post secured by a T-bracket. It positively hurts to use anything more than timber and a pack of screws, because Liver King wouldn't, would he?

(Ed. his publicist told me that he would, but only off-camera and over a Weetabix).

Silence of the Laminates #10

Here you can see the new-biological keel featured on the cut-out-and-keep template on the website, which fixes altogether securely to the hydroski. It can also include a range of different-shaped sheets of foam to alter trim at rest... what's not to like?

And yes, that's a sneak peak at the seat, the internet alive now with whether or not the tDrone 4 will feature both this and a foot-rest! You'll know the moment I slip on my specs, jeans and Miyake polo-neck and slide onto the stage to whoops of delight and items of underwear.

Silence of the Laminates #9

As we return to the build, it becomes clear why I turned to the ply-and-foam design featured in the website www.teledrone.com (and remember to like, follow and kiss my bottom). For the pair of plywood panels in that outline run the depth of the keel, whereas the factory-applied laminate here literally falls short. This means that if you grasp the ski it is easily twisted, with practically only the cocktail sticks holding on.

The glue, not so much, despite it professing "Sticks Like Sh*t".

I take issue with this, writing to the century-old firm in Staffordshire thus:

Dear Sir,

You claim that your adhesive 'sticks like shit' and yes, it may do to the rear face of a toilet bowl, but does it pass muster on the high seas? So as to test this I did build a drone using my smeared-on stools as a fixative ~ to the extent neighbours thought it was a dirty protest. Believe me it fell well short of an epoxy resin.

Colin H. CEO

I was furious with the Patent Office, who told me that they considered the mark was neither offensive and nor in fact did it contain a swear word; and so I asked if they were happy if I registered ShittyTitAssBollockyBuggeryBumBum for my adhesive?

No, they weren't... why bother?

Sunday Sermon #2

Me:     Good morning and welcome as we gather in this beautiful blog sponsored by.

You:    Tube.

Please be seated. Oh, you already are. Let me begin by saying that many of you are troubled by AI and ask if it is anything to fear; will robots do what we currently ask of our nearest and dearest immigrants? Well look at the handout and what the Book of Netflix recommended I watch on a Saturday evening.

Although I must say, by the end of it I was dressed in cosplay as a Korean virgin in a short skirt and singing along with the rest of them.

But settle down, for instead I watched The Liver King and vowed to bang out dozens of press-ups this morning prior settling down to a breakfast of raw testes. Instead I sit here before you in a dressing gown with a bowl of Weetabix, hot milk and sugar.

But we all fall short when it comes to deceiving the world in general, don't we?

I do though like books about the world's end, and used to enjoy reading them to my child at bedtimes. This week it has been one of Luke Kemp's, who preaches at Cambridge University, about societal collapse and how we can all look forward to it.

Here are my takeaways, many of them quite cheery in view of what went on in the past. POTUS, which is not a medical complaint incidentally, has been berating us in Europe for not spending a sufficient proportion of our annual national wealth on our defence. Reading Luke's book however we practically invented it! Check the stats!

% of GDP Now: Russia 7.0%, Poland 5%, US 3.5%, Europe 2.5% if you're lucky.

% of GDP Then: 1630ish France 90%, Song Dynasty 85%, 18th C. Britain 75%.

Military, millions of: China 2.0, India 1.5, US & N Korea 1.3, Russia 1.1, Ancient Rome 0.5%.

Conscript Percentage Among Men: Russia 0.11%, Ancient Rome 25%.

Brother Luke's message is therefore that we are much less aggressive and warlike than our ancestors! The next bit though not so good, he pointing out we evolve as a global community through successive cycles of beating the shit out of others.

It is interesting where we see ourselves in the West in particular on this score:

'A growing pool of elites competing for status, power, and a limited number of high-status positions turn toward more extreme measures, whether it be starting coups, civil wars, or rebellions... among a wealth of evidence that shows the importance of elite factionalism to crisis and collapse.'

In a nutshell, people become more sedentary and more easily taxed, leading to an organisation headed by an elite who display wealth by building pyramids and shit. Then this is not enough, so they expand by conquest in order to feed the locals and build even bigger stuff. This leads to overstretch whilst the elite continue the status quo despite imperial reverse, environmental catastrophe and popular dissent.

And this is why, with the monkey-house on fire, monkeys prefer fighting to putting out the fire. (Ed. No record of monkeys ever putting out a fire, even on YouTube... but we're on it).

The author ends by pointing out that the longest-lived empires are at least united in a common cause, as was the 1000-year Byzantine by Orthodox religion. Throughout history, though, the world has been governed by narcissists and maniacs on divine missions that eventually lead to social, economic and environmental collapse... from where we start all over again.

Well not us, but the preppers on YouTube practising life without Weetabix.

The vicar apologises for not being here last Sunday instead of at an anime convention.

Silence of the Laminates #8

Tee-ing up the hydroski. You can see from the previous post that the base of the keel also features a length of square-section timber joined to the foam panel in the same way as every other we've seen today. We don't want it separating prior to the adhesive setting, however, and so we'll fit only the trailing end of the ski itself. This is done with the same overhang as will appear top-deck, after which we can screw the laminated uPVC skirting-come-ski to the base of the keel.

We'll have a nice cup of tea over the football scores and fit the motors tomorrow, eh Gromit, for Rome wasn't built in a day?

Silence of the Laminates #7

Here I add the tail-end spar which will support the rearmost motor. Drive a couple of screws in either end or else it will be able to twist on its axis... a feature that may yet come in useful for swapping out propellers after the inevitable wear and tear?

Silence of the Laminates #6

In China they've probably screen-grabbed this to produce a laser-guided jig already, but here I've gone for a tried-and-trusted method to suit every doomsday prepper.

(Ed. anticipating a meltdown on the stroke of 00/01/01/ Colin stashed a 'doomsday pack' in his loft: it consisted of baked beans, real ales and Christmas puddings.)

I clamped the back end to stop the lats from lifting prior adhesive baking overnight. Pinch them together and draw a template on the blocks, with which to drive in nails to hold in place.

Transfer the outline to the hub, which you will have 3D-printed while I scout around for an off-cut plank. Drive a pair of screws in from either side, to fix firmly in place.

This one's not a perfect triangle nor is it set square, but if the prow lines up broadly with the keel then it should all come out in the wash... as I used to say at Airbus.

Silence of the Laminates #5

Here we (that's 'we' in general terms, you just have yourselves a good time and not bother about me) are applying the lateral stripwood that will support the running ski and these bad boys measure two metres (6' 7") apiece.

Don't forget to leave an overhang six inches (150mm) behind the rear spar, where the motors and propellers will be located.

Notice that I forgot to fit the foremost engine to the trailing-edge spar before it was secured in place, which is why I no longer work in assembly at Airbus. People along the line just looked at those wings saying, But aren't we missing something here?

Lunch Break

I always considered the Italians to be designers of the most stylish and innovative forms of transport, amongst which this Piaggio P7 built in 1928-29 to contest the same Schneider Trophy that gave rise to the Spitfire. To avoid the weight and drag of floats it deployed hydrofoils, pre-dating Regent's Seaglider by a mere century.

There are lessons here for our own proj, for the standout obstacles to its success were limited visibility due spray ~ presumably from the airscrew out front ~ and problems with transferring the power from the water-screw to airscrew by dint of a pilot-operated clutch.

Personally I'd have left the water-screw permanently engaged, simple solutions ever the best... the drag and frictional losses would have likely been marginal.

Perfection, the enemy of progress but precisely what Italian designers aim at.

Silence of the Laminates #4

Here's what those tiny holes were for: pressing cocktail sticks into place. Consider it a bodge, then bear in mind it was how British ships built an empire! (Ed. technically it did not involve actual toothpicks and should those we supply be used for building an empire then the warranty no longer applies.)

Be careful here not to push the cocktail sticks all the way in, but snap off the ends prior the taper. Note that some sticks designed for canapés or as tooth-picks don't have tapers at both ends and these can be inserted flush, however I don't want to start a flame-war between advocates of either.

I've been messaged already to ask which I recommend, and I am going for Marks and Spencers bamboo cocktail sticks...

https://www.marksandspencer.com/food/bamboo-cocktail-sticks/p/fdp60597056

...as these have proved able to withstand speeds of 1200kts, albeit on Concorde.

Silence of the Laminates #3

Cut your 20mm section to length, using the craft as both bench and template. Then drill tiny holes of a size that you forgot to check with the guy at the hardware store but is of the order of one millimetre. Squirt a length of adhesive along the edge of the foam, pressing the spar into place as gently as it were the top of a sponge cake.

Historical fact: Napoleon Bonaparte, having conquered Europe and finding himself with nothing to do on a bank holiday weekend, decided that the modern world was to be measured by quantities sprung into being from his head. He therefore took a distance that ran from pole to equator through his apartment in Paris, divided it into 10,000 and called that a kilometre because it was further divided into 1,000 metres. He then divided the metre into 1,000 millimetres in case he had to build a drone.

Silence of the Laminates #2

Here's the raw material, from a single sheet of which I made a a deck, a keel and a pair of outriggers for stability during powered testing. If you look carefully you will see that it reads XPS Insulation NoMorePly 20mm 1200x600x20, doesn't it children?

Turning to our textbook we remind ourselves XPS stands for extruded poly-styrene. It is basically one up from the shitty stuff they use in bean-bags, and still too soft to drive a screw into; although you may have used a bean-bag to assist such purposes in your youth.

Accordingly although we need no more ply, as it says on the tin, we do need means with which to attach the spars. Here these have gone back to a lateral variety unlike the longitudinal spars that proved better on the 3rd prototype, incidentally.

Tune in to the next post now to see how this is best done...

Silence of the Laminates #1

It's a holiday weekend here in the UK, so why not settle the kids down in front of a screen and get back to building maritime drones? I've a fourth prototype on the go in the shape of a 'flying test-bed' of the sort they built before Harriers took shape.

It has sat in the corner of the workshop for weeks, even though Patrick Swayze said it shouldn't have. Originally an experiment to see if we could go down the laminate route, it proved that so long as a cruciform construction like this was used, the keel would be every bit as robust as the cantilevered types that preceded it.

I've put a pencil-sharpener for scale ~ bear in mind it's used on a two-metre pencil.

Go In, Stay In, Tune Out

Preparations for war to date in the UK consist majorly on the PM having mentioned in passing that it's coming to a street near you, and a .gov page on what to do in case of being irradiated. The West now operates a 'rule by slogan' form of administration in which catchy soundbites like 'smash the smuggling gangs' substitute for actions of any sort.

Meantime in Lithuania ~ where I spent much time relating to flying training ~ they are establishing centres where 15,000 adults and 7,000 children are to be schooled in the basics of designing, building, programming and operating drones.

Nothing new, though, the Russians having long organised video gaming conventions for youth, from which participants are cherry-picked for less innocent pursuits.

Have a nice day.

Delta Force

Great thing about the 'net is that it's Darwinian evolution on steroids: people ask to be video'd say, walking around a cliff-face hundreds of feet up and whoops, they're gone.

Likewise these shorts are titled 'Is this safe' and... if you have to ask the question?

They do though demonstrate the aerodynamic stability of delta planforms, which is admittedly not what the average viewer is thinking. Put any form of multihull in that situation, for example, and it's a back-flip you're watching instead: triangular wings simply 'mush' where squarer ones might stall or somersault.

If ever the drone gets on the water, the proof of the watery pudding will be stability in and around situations like these. Whichever way you look at it, however, critical dynamics of hydrofoil and aerofoil surfaces will be much more to the fore as vessels get smaller, lighter, faster and uncrewed.

Both of these videos required constant manipulation of the controls by each jackass, though a computer would make light work of stabilising such angles of attack: as it does with fourth and fifth generation fighter jets.

What Goes Round (and Round)...

It occurs that one day we might sit ~ or stand ~ on a version of our boat, although I'll likely still be imagining it on my death bed:

Colin: We're there, aren't we? On the beach in California?

Priest: We are! The sun's setting. There's a crowd... they're all here for you.

Colin: And they're singing?

Priest: They are... the birds too.

Colin: Lift me up! Set me on the seat!!

Priest: You're on the boat now... the propellers are humming!

Colin: The counter-rotator's?

Priest: The counter-rotators.

Colin: Aaaaaaah.

Priest: I'm done here nurse ~ just one more nut-job at the end of the hall.

Let us examine what is out there however in terms of PAVs or personal air vehicles as opposed to PWC, Personal Water Craft (or Price Waterhouse Cooper).

The Volonaut at top-left will leave you with little change from a million dollars, but is from the same people (person, practically) who brought you the Jetson. It doesn't fly for long, sets fires we could do without and is not new: the Williams X-Jet below appeared in 1974 although you had to tilt it to steer. Nonetheless both are perfect for pissing off (or on) the neighbours.

Alongside, the Skysurfer also comes from a talented and passionate engineer (and I'm neither); but he doesn't quote a price, which is the last thing you want either online or in a brothel. It also has expensive replacement propellers written all over it, but hey, it's out there.

Below it however if it was propellers you wanted then Hiller's flying platform served a purpose back in '55. It was not nearly so practical as the altogether simpler (and safer) gyrocopter, however, and was never going to be parked on your driveway: which is where tech comes into its own as regards universal accessibility.

There's clearly a case for eVTOL taxis flying sightseers and rich people around, but motive means for individuals (there are no single-seat automobiles that I can see) except those on two wheels have a chequered past that I don't see improving any time soon.

But we keep trying, as the flowers bloom each Spring.*

*To paraphrase Herman Hesse, who so far as I know never owned an eVTOL.