More on the electric boogaloo
Looks like the RAF are not going to be the first
For those in the know, is there any weight disadvantage in terms of batteries and motors compared to a conventional aircraft?
How does a full charge compare to a full tank?
Is there anything to run electrical items or is it like EVs where using electrical items affects how far you can drive?
Is there a premium on the purchase price like there is with EVs and their normal equivalents?
Massive weight penalty which is pretty much the one and only reason they aren’t in use already. Energy density of jet fuel is (about) 100x more than lithium ion. 1kg of fuel has the energy of 100kg of lithium ion, ish.
Take a 777 and stick 100 tonnes of jet fuel to fly from London to Hong Kong and you’d need 10,000 tonnes of batteries… And the batteries don’t get lighter (well they technically do but not even remotely noticeable!)
Now, little planes like these that are being talked about, much less of an issue. Whilst a turbofan on a modern jet may be 70-80% efficient (how much energy goes in and actually produces useful work) a Cessna type plane with a rackety piston engine may only be 15-20% efficient. A battery powered car/plane is about 80% efficient, so about on par to our 777 running on jet fuel. Turbofans can be up to 5x as efficient as pistons as the heat is actually used for propulsion and not wasted.
This means for our small plane the energy density in terms of what we actually get out is only 20:1. A Cessna could, if needed, be built to have 10 hours of fuel with many tanks. That means a small plane of the same weight could easily get 30 mins of flight time. Make some efficiency savings, only have a couple of seats and prioritise the battery along with modern aerodynamics and you can see how you could get to an hour of flight time in a small plane. You have the benefit of not being constrained by the old designs needing to accommodate an engine of a certain shape.
Timeline looks reasonable for what they’re after. Not a chance for airline type operations though, at least not with today’s technology.
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Whilst I know you said with ‘todays technology’ but United announced this yesterday… so potentially closer than you might think
Up to 250 miles with up to 19 people. That’s the tip of the commercial iceberg and has about 5% of the range of a full bore longhaul jet, and that’s using the pinnacle of battery technology and presumably still needs a huge amount of work.
Fantastic if they can get it to work at that scale though, aviation is in serious need of some green credentials.
Fingers crossed someone like Tesla will make a breakthrough with the battery technology that really works on a comparable basis to traditional fuel and then we’re laughing.
The energy density is an issue but with the previously shared Pipestral aircraft the weights are the same as you would expect. Max Take Off Weight (MTOW) remains the same for the airframe as that is what it is designed to take as a load.
With the lower energy density comes reduced duration. And while the petrol burning version with full tanks can fly for 3-4 hours the electric version can only achieve 50 minutes +10 minutes reserve
One notable influence of electric weight on aircraft is its stays the same. The weight of an empty battery is the same as a full one, unlike a petrol tank where there difference can be 40 kgs or more.
This can therefore influence the load capacity of an aircraft (ie for touring).
Whereas a petrol engine can be loaded with half tanks and some “gear” for a night away (tent and over night bag) and still fit under the MTOW – ie there is more flexibility in how the MTOW is reached, adding persons, fuel and desired luggage a happy compromise can be achieved. Electric aircraft won’t have this same flexibility as the aircraft weight remains the same.
This does come with some advantages as the aircraft is likely to fly more consistently. Aircraft burning fuel are constantly getting lighter as the fuel is burnt off, making the handling characteristics upon landing different to how the aircraft was handling on take off (although accept that this may not be a huge difference – however it is exactly this as to why microlights which have a 450kgs MTOW are moving to 600 MTOW to allow for sufficient fuel when luggage is added as some with luggage and two persons only allow for an hours flight duration. For a good number this is just a change in placard as the airframe is already rated to 600Kgs but limited to 450kgs for UK registration)
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Just from the perspective of endurance in terms of UAS and AEF piggy-backing, you would either need a lot of aircraft, batteries and extremely fast charging kit or combination, which suggest a massive financial investment, which given the MOD’s financial problems would be the biggest stumbling block, regardless of their “green agenda”.
This is my biggest concern about this plan - which was trailed to us a few days before it got into the press. Current AEF typically works on the basis of ~3 sorties before the aircraft and pilot have a break. That’s 1-1.5hrs airborne plus taxy, and none of the current generation of electric aircraft (even in development) are close to that yet. So we’d either need replaceable batteries (change the battery when you change the cadet), more aircraft (change the aircraft when you change the cadet), or bigger gaps between sorties (=fewer sorties).
More ‘leccy plane stuff here
The little tech firm gunning for an airspeed record https://www.bbc.co.uk/news/business-57747128
An industry colleague has just posted this - quite an interesting read!
I would miss the smell of aviation fuel though, reminds me of air shows of my youth
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When I did my PPL at Welshpool, turbine aircraft were a rarity; on one occasion when a Mitsubishi turboprop took off the young instructors all rushed outside to sniff the air.
Not unlike me when we go fullbore shooting…
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I like that smell too
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Already test flown - Its a microlight. No aerobatic capability.
I’d rather have some flying without aeros than no flying!
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You might want to mic drop after that. It’s worth it.
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100% actual airmanship, PofF and general piloting over expensive thorpe park
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