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The best hope of developing eVTOL lies in diversifying its core technologies, not least because it has derived any number of them from developments elsewhere. Whisper Aero is thus reaching out for partners wishing to manufacture leaf-blowers instead.

While it may smack of Clive Sinclair's C5 being powered by washing-machine motors, it is not as bizarre as you may think. Leaf-blowers are banned in a number of areas in the US for being too noisy, whereas Whisper's is not. And the first garden vacuum in the UK was built by an aerospace engineer: he didn't want anything else being sucked up beside leaves, and turned to the Magnus effect employed in NOTAR helicopters to eliminate the tail-rotor.

I shan't be recommending fans for the the 'DRONE, however, for as yet they cost upto ten times more than a motor and propeller producing the same amount of thrust.

The pic shows Whisper's own demonstrator... designed and built in just eight months.

Ptero-tactical

Occasionally browse eVTOL videos and this one stands out for garnering rather more views altogether than most others, in view of the fact that it folds its wings during the transition to a hover. What is remarkable about what PteroDynamics has done is that it is among the few configurations that reflects what nature does best whether among birds and insects.

It is worth considering, for why do species evolve towards folding wings whilst aircraft ~ with the exception of a number of carrier-borne types in the past ~ do not? Almost certainly it has to do with the practicalities of manoeuvring on the ground, where (in view of the energy input required to fly) most such species spend much of their time.

To date folding wings have been structurally difficult to arrange and have added a deal of weight to the finished object, but with computer-aided design and the flexibility of installing multiple electric motors this is set to change. Undoubtedly, therefore, what attracts defence budgets to this notion is the facts the footprint lends itself to ready storage and deployment in the field...

... a notion fuelling my own obsession with producing the lightest possible foot-print.

The final assembly and test-flying of the sub-scale TELEDRONE is meanwhile delayed until the start of next month, due engineer-come-test-pilot moving to new premises. Console yourselves with the fact that nothing worthwhile was ever achieved in a hurry.

Air-Go-Nomics

The 'Spinner' is described on the website as revolutionary, and is so only to the extent that its propellers go round. It is though obligatory nowadays for every eVTOL designer to say as much nowadays, whereas a generation ago you'd design a Comet or Boeing 747 and be lucky if anyone else said so.

You could argue that the German brothers who rigged a bathtub to fly were in fact the first to settle on the layout, and prior Jetson too. It does though show how the effort to accommodate seated passengers is a greater ergonomic challenge than standing them in a flying phone-booth. The 'one-size fits all' model is used in every automobile and airliner, but usually accompanied by adjustable seat, steering column and pedals.

The quandary is illustrated by Opener's Part 103 offering, seen here below. More work than attends any other has been afforded Opener's various prototypes, but I may not be alone in feeling this one looks like something that needs eradicating with a medical shampoo?

Moy... Er?

This cargo-carrying drone from Moya in Latin America is not nearly as pioneering as its LA backers LA (Techstars) suggest, being a straight rip-off of Blackfly's Opener albeit adapted for cargo in lieu of a passenger. With the latter set for real-world customers in 2024 and the above with a deal of aviation experience behind it, it looks to succeed as a configuration. Bear in mind though that the cargo version has four rotors in place of eight, bearing as it does a payload of less consequence altogether.

There are four enduring forms of helicopter, viz. main- and dual- rotored, intermeshing  and co-axial in order of numbers commercially produced over many decades.

With eVTOLs the same evolution is likely to take place, though it may yet feature more 'phenotypes' or variations. The simplicity and practicality of this 12-year-old concept is likely to ensure that it is one of them.

As we await the flight-test scheduled for the TELEDRONE sub-scale this month, the notion that if nothing else its layout may stand the test of time is a source of comfort, but not much of one.