Rolls-Royce say they have completed testing of the “ground-breaking technology” that will power the world’s fastest all-electric aircraft.

The ‘ionBird’ test aircraft will be used to hit speeds of over 300 mph.

All the technology has been tested on a full-scale replica of the aircraft’s core, called an ‘ionBird’, including a 500hp electric powertrain powerful enough to set world speed records and a battery with enough energy to supply 250 homes.

“The plane is part of a Rolls-Royce initiative called ACCEL, short for ‘Accelerating the Electrification of Flight’. Our ACCEL project team includes key partners YASA, the electric motor and controller manufacturer, and aviation start-up Electroflight. The team has been developing the technology while adhering to the UK Government’s social distancing and other health guidelines and the systems will soon be integrated into our ‘Spirit of Innovation’ plane. There is a long history of iron-birds in aviation for testing propulsion systems ahead of flight, but in this case we have named the test airframe ‘ionBird’, after the zero-emission energy source propelling the aircraft.”

UK Business and Industry Minister Nadhim Zahawi said:

“From trains to planes, our transport of the future will be powered by clean, electric sources – with companies like Rolls-Royce developing the tech to help meet our net zero ambitions. The completion of ground-testing for the government-backed ACCEL project is not only a step towards an exciting world record attempt, but a leap towards developing all-electric and hybrid-electric planes that one day could ferry large numbers of passengers around the world.”

The firm say that the first flight is planned for later this year and that they are aiming to beat the current all-electric flight world record early next year. Half of the project’s funding is provided by the Aerospace Technology Institute (ATI), in partnership with the Department for Business, Energy & Industrial Strategy and Innovate UK.

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Nscnick

How long does it take to recharge the batteries I wonder?

Mark B

There is so much work going on on battery technology I doubt that they care. They merely want to be ready when light fast charging hi capacity batteries are available.

Nscnick

It isn’t the battery that is the problem, though always subject to improvement, but the ability of the grid to connect and sustain the energy transfer rate! High charging rates require very heavy duty connectors and cables. They also didn’t quote the flight endurance, which is perhaps telling. Not to say that such developments shouldn’t be looked into. As with cars it isn’t the vehicle that is the limiing factor but the supporting energy infrastructure.

lee1

Actually that is not necessarily true. The energy could be stored in other batteries or capacitors that charge more slowly and these then charge the aircraft battery rapidly. Plus the Grid is pretty resilient and is not going to suddenly fall over when someone plugs in their plane. Also by the time these things are common the grid will have evolved to cope.

Mark B

The issue we all have with batteries is our assumption that their existing limitations will persist to some degree or another.

Perhaps the capacity issue will be resolved so that re-charging from the grid is not an issue. Perhaps … perhaps …perhaps

The biggest issue is we know that huge strides will be made in the technology what is slowing everything down is understanding what those strides will be and consequently what impact that will have.

lee1

charging from the grid is currently not a particular issue for cars anyway, Obviously for large aircraft there are challenges to overcome but there are solutions already available. Battery energy density is the only real problem we currently have for aircraft and we need this tech to get better in order to make large battery electric aircraft a reality. There are technologies coming along that could indeed help with that, for instance there are a number of battery technologies that can increase energy density by up to 5 times which will solve most of the issues. Those technologies also enable… Read more »

Damo

You are correct about the grid. The tech is there too for hyper charging, it’s uust that no one wants it or to pay for it yet

DaveyB

Yes, the latest advance is the inclusion of a graphene layer in between the lithium. This has a number of major benefits. Firstly, it nearly halves the charging time over a conventional Lithium Ion battery, secondly, it helps push up the energy density and thirdly it significantly prevents the battery from overheating during high loads or when charging. It also helps to prevent the battery shorting out internally making them safer to use, especially if it gets penetrated.

David

and a battery with enough energy to supply 250 homes”. What! per unit time? 250 homes for 1 second or 10 hours? doesn’t mean much to me. Can someone explain?

David

looking on the web and found the average house produces 28.9 kWh so are they saying they have a battery capable of delivering 7225 kWh?

lee1

Actually the figures I found say around 10kwh per day so that would be a 2500 kwh battery. Still sounds huge and not correct…

lee1

Just found the info. It has 3 72kWh batteries. I wonder if they mean for the duration of the flight it would power 250 homes?

However that is still a significant amount of battery power.

Nscnick

So that is the equivalent of 3 cars, which take 3 hours to reach 80% charge from flat on a high speed charger. Typical houses are fused at 60A which equates to up to 15KWh or for 250 is 3.75MWh. 500hp is approx 375KW, so if it has 3 of 72KWH batteries that means it has a potential endurance at full power of around 35 minutes, before needing 3 hours of charging from a car type fast charger. Charging faster than this requires much higher currents and voltages so the physical interconnection issues are significant. (Back of the envelope calculations,… Read more »

lee1

The plane is developed to go fast not to go far…

Batteries do not need as much energy density as fossil fuels they need better energy density than they currently have (although that will get much better as we move forward). A battery aircraft is more efficient so does not need the same energy to go the same distance as a fossil fuel aircraft. Also a battery does not take 3 hours to charge to 80% on a high speed charger. In fact the porsche taycan can charge to 80% in 15 mins… (93kWh battery).

Nscnick

Whatever a journey is it will require a certain amount of energy. Batteries have an extremely long way to go before they can match energy density compared to hydrocarbon, but it is horses for courses. Fast and short or long and slow. Efficiency is highly questionable and it is necessary to compare like with like. In theory EVs are more energy efficient than IC but it is necessary to consider the whle system including generation and distribution against battery life (including charging cycles) and mass. A typical car will have a battery pack weighing around half a tonne, against equivalent… Read more »

lee1

Well my car is an old EV now and has a small battery in comparison to any currently available model (I have had it 4 years now). I have no real issues but it does restrict my choices of how I make a journey. A range of around 300 miles is all that is needed to make these issues go away. You should not really be driving any more than 200 miles in one go as that is pretty dangerous but the 300 miles give you choices on where and when you charge on a long journey. Oh and that… Read more »

Nscnick

Interesting but how do 20 or 30 vehicles per hour get charged from two or three outlets, sometimes only one? That is the problem not the actual range or style of vehicle. And getting that energy to the outlets in the first place? Not arguing about efficiency but looking at the energy requirements and how to get that energy into the vehicles in the first place. That is just cars, what about commercial vehicles? And what happens if the battery goes flat on a journey or in a field or moorland?

lee1

National Grid did research into this and found that if everyone in the UK changed to EVs overnight we would need just a 10% increase in capacity. That is not a lot in the grand scheme of things and given the length of time it will take to get everyone to that point it is something that can be done over many years. Charging infrastructure is a different thing. We need the Government to put money into this in order to get more charging available. Given that around 50,000 people die per year from pollution in the UK I don’t… Read more »

Supportive Bloke

I’m dubious that the Porsche really recharged that fast all the way and if it does the number of charge cycles it supports before the battery takes a hit. That might be peak charge rate? Or average charge rate? I’ve got a Tesla with a 100kWhr battery and whilst it does take 200kW at the start of the charge this drops off to about 100kW at 40% and slows all the way from there. The limitation is deliberate to increase charge cycles. that being said the number of times I ever supercharge it is very low. Generally I go where… Read more »

lee1

It absolutely does. I did not mention the charge rate, just that it takes 15 mins to get to 80%. It uses an 800v system compared to teslas 400v system. The main issue with charging is heat rather than speed. If you can keep the battery cool during the charge (something Teslas are also pretty good at) then it does not damage the battery anymore than a slow charge. However you are correct that charging speed drops off as the battery reaches full capacity as this also can damage the battery. The Porsche is no exception to that but it… Read more »

Supportive Bloke

Interesting.

Yes the Tesla does precondition the battery when you are navigating to the supercharger to get it to optimum temp and then you hear the air conditioning running which is the limiting factor I would guess.

Plenty of Tesla 150kW and 250kW chargers about at service stations!

lee1

Yep, there are however only a handful of 350kW chargers in the UK so far as only the porsche can use them fully. They have liquid cooled cables… There are other porsche group cars that will use the 800v system but they will be things like Audi sports cars etc. The more normal cars are still using the 400v system.

Supportive Bloke

FYI The Tesla 250kW also uses liquid cooled cables p.

lee1

Ah, I didn’t know that. I suppose it would given the current.

ChariotRider

Basically you are right, the statement needs to state the length of time or is meaningless. The trouble is few seem to understand the difference between energy and power and in common usage the two are often interchangeable. As an engineer it drives me nuts, especially has it is pretty simple and fundemental to how the world, both technologically and naturally, works. Simply put power is the rate at which energy is delivered. The faster energy is delivered the quicker a job gets done, which is why petrol heads talk power because they get to go fast! However, energy can… Read more »

Nscnick

Exactly! The engineering involved in getting the energy into the vehicle is the problem!

Ian

Hi Nscnick…Not my subject I’m afraid…but is Hydrogen possibility

lee1

Hydrogen might be a solution for some forms of transport (ships for instance) but it is not great at the moment as 90% of it is steam reformed from methane so it is essentially a fossil fuel. It is also bulky as it requires a pressure tank for storage and even then hydrogen does not have the same energy by volume as petrol. Hydrogen cars also need batteries as the fuel cells can only react slowly to changes in demand and also can not store breaking energy. Fuel cells are only 60% efficient (far better than petrol engines but far… Read more »

Ian

Thanks for that informative reply

Albion

in the long term, maybe solar panels to recharge whilst cruising at height in flight?

lee1

Solar panels will have to become much more efficient for them to make a significant difference. Although for long range flights they could indeed help.

Nscnick

Not just much much much more efficient but produce far more energy per sq metre as well. EVs are the way to go but there is an awful lot of things to be done before they can practically replace IC hydrocarbon. I’d love to but they don’t even remotely do any of the tasks I need apart from going shopping once a week.

lee1

What task do you need your car to perform?

Martyn Parker

Th real limiting factor in all this rush to EV is the availability of cobalt, it is a finite resource and not enough exists to replace ICE , at some point it will come down to the little man not being able to have personal transport so the big man can have an EV aircraft

Frank62

Can’t come soon enough. Great progress is being made.