Orkney islands could get first electric plane service | Hacker News Reader

Orkney islands could get first electric plane service

bbc.co.uk

68 pointsm-i-l28 comments

The Orkney Isles are setting the example in the UK. Going green and making progress with it is also quite good for the community, not to mention the balance sheet. Another future is definitely possible and the folks in the Orkney Isles are an inspiration.

The Fully Charged Show on YouTube has been following progress for years, here is a recent three part series on wind, hydrogen and big batteries in the Orkney Isles:

https://www.youtube.com/watch?v=Rybpaqhg5Qg

I highly recommend liking, subscribing and giving a thumbs up to Fully Charged Show. Anyone that enjoyed Red Dwarf or Scrapheap Challenge will know the presenter.

Just to make clear something that may be puzzling folk: the famous Westray / Papa Westray link is NOT the only route this plane serves! This plane serves many islands in Orkney: check out the schedule on https://www.loganair.co.uk/travel-information/orkney-inter-i...

This is really cool to see. Orkney has really pushed renewable energy and in fact, on some days they make more than they can use and export!

I thought generating more than they can use or export was the default for Orkney now?

Which is why they're leading the pack adopting EVs, heat pumps, community heat schemes etc, and the hydrogen plan for the ferries. They have to find something to do with it all, or turn off some wind turbines and solar. So they're migrating every remaining use of fossil fuel possible. Which seems a much better plan than anywhere else.

All that for a tiny fraction of the fuel bills the rest of the UK pays. I wish the mainland was a little more inspired to blatantly copy. :)

Have the crypto miners found them yet?

Amature here; Aircraft engines aren't just rated by hours-ran but also cycles. That being start-Takeoff/landing-stop. Maintenance and part life is specified X hours or Y Cycles.

I would think there's no reason to apply any of that to an electric power plant. So can anyone familiar with the topic enlighten if this might have much impact to the cost/benefit going on?

Electric plant is also stressed by higher loads (thermal mainly, which has a number of downstream effects), and cyclic thermal stress would lead to cycle limits just the same. You also still have a lot of mechanical components just the same as combustion engines.

> You also still have a lot of mechanical components just the same as combustion engines.

This certainly wasn't true for cars, a fully electric vehicle is simpler, resulting in an immediately noticeable reduction in maintenance overhead - are you sure it will be different for aeroplanes?

Keep in mind that the combustion engine of a propeller aeroplane will have an entire electrical system as part of the combustion engine because it turns out even most private pilots are not inclined to get out and start the propeller by hand ever time.

I think, if I'm conceiving of this properly in my head, that electrically powered props would alleviate the need for variable pitch propellers; a complicated affair involving oil pressure and governors. Since the torque curve of an electric motor is flat I don't think it'd be needed. Although a feathering system may still be required to twin engine electric planes.

You'd still need it for reverse.

Very view piston powered planes have reverse as it stands. But wouldn't running the prop backwards work?

There would still be benefits to variable pitch propellers with an electric motor (motor efficiency, correct propeller pitch for the airspeed to name two).

I work in the UAV industry and would adopt variable pitch in an instant if it didn't come with complexity and weight penalties!

Interesting. I've always thought of variable pitch propellers as being more efficient by allowing the engine to stay at it's peak horse power. For a piston engine this is obviously at the peak of the nice curve you'll see on any dyno run. A fixed pitch propeller sized for climb would allow the engine to run above this speed in cruise and vise-versa if it were pitched for cruise.

Now an electric motor has maximum torque at 0rpm (stalled) and practically no torque at it's no load speed. The relationship in-between is practically linear. So long as the motor was matched and / or geared so that during all stages of flight the RPM stayed within a reasonable band I don't see what the advantage is. Maybe some second order effects of efficiency at lower speeds perhaps.

Edit: Actually, thinking again, it's the exact same reason that cruising at the lowest possible RPM for the required power output in a piston engine is typically the most efficient. Just less friction. Still think it'd be a smaller effect given we're talking roller bearings rather than plain bearings and piston rings.

Even if you disregard motor efficiency (which I don't, as with a battery powered vehicle you treasure every Wh more than you treasure every gram of fuel!), propeller efficiency is also important. Ideally you want to match your motors power handling and efficiency with your propeller. A given propeller/motor combination will have a design point in terms of torque/airspeed/rpm, and operating significantly outside of that (e.g. having a power system designed for cruise but operating at zero airspeed) has penalties.

Unfortunately I'm traveling at the moment, but I spend a large amount of my time at work balancing propellers and motors and could provide some plots that might help explain this. One of the few things years of working in academia proved to me, is that I'm terrible at explaining things like this!

Tesla maintenance is more expensive than regular combustion engined cars.

EDIT: Yes, I was surprised as well. IIRC the service plan for a new car was more than a thousand euros per year. Considering they don't do oil changes or many other things, that is a lot.

Anyway, maybe not much for someone who spends 70 000 euros on a new car, but it's something that does not further the argument of economics.

Thermal stress on a coil of copper wire must have less of an effect than on a piston engine where wear occurs dramatically faster when cold. Obviously the rest of the airframe would be more-or-less the same but electric motors (especially when running off VSDs) don't really suffer per start the way ICUs do.

It's not so much the copper itself, but the surrounding components, especially insulation.

Tesla just tweeted out photos of the drive train of the Model 3 after a million test miles.

https://twitter.com/Tesla/status/1051911793373638661?s=19

Aircraft maintenance intervals and rotable replacement schedules are intentionally very conservative (and likely to be more so for new types of engine), and I can't imagine that simply being powered by electricity is going to make a propulsion system immune to stresses induced on propellors over takeoff cycles. If the cycles interval is longer than for the piston engines currently used on those route, potentially engine maintenance is required less frequently, particularly with an engine optimised for short hops, but there's still the rest of the airframe that needs maintenance checks and rotable replacements, and your overall engine maintenance cost is going to depend on availability of specialist maintenance shops and component costs too.

Is there a fully released (non-experimental license) electric aircraft out there right now? A couple years ago I saw that a lot of companies wanted to create a "short" flight electric plane but I have not seen any with a full plane license/cert.

I don't know what "non-experimental license" means as I don't know the industry very well, but wouldn't the Pipstrel Alpha Electro be what you're talking about?

or are you talking about larger planes?

https://www.pipistrel.si/plane/alpha-electro/overview

It would be really interesting to see if they can make this viable and reliable.

Side note: no disrepect intended, but when reading the names of some of the islands it feels like they're written in pig Latin.

The names are either old celtic or norse names. If you check out the Wikipedia page for Papa Westray, https://en.wikipedia.org/wiki/Papa_Westray, then follow the links you get quite a history on the origins of the names.

Specifically, the -ay, -ey, -øy suffixes that evoke Pig Latin mean "island" in places that had Norse presence. See https://en.wiktionary.org/wiki/-ey#English and https://en.wiktionary.org/wiki/ey#Old_Norse

Orkney and the Shetland Isles are actually some of the wealthiest regions of the UK, so it makes sense that they might be able to get something like this off the ground.

Some more on this statement: https://www.bbc.co.uk/news/uk-scotland-27138927

To clarify - it is wealth of the council, not average wealth of individual residents. Bear in mind also that the cost of living is very high, given most products have to be imported from the mainland. For example, the Shetland Islands has some of highest petrol prices in the UK despite being the site of the largest oil terminal in Europe (oil has to be exported for refining).

It's because Merlin's mother lived there and hoarded wealth.

Wizard privilege, eh?

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