The Spirit of Innovation: Do Electric Aircraft Work?

Updated: Oct 11, 2021

Earlier this month, Rolls-Royce announced that their first all-electric airplane, dubbed the 'Spirit of Innovation' (and henceforth as 'SoI'), had completed its 15-minute maiden flight. Consequently, the news has gone global with congratulations coming in thick-and-fast. Indeed, I do agree with Kwasi Kwarteng, the U.K. Business Secretary, that the aircraft’s flight is “a huge step forward in the global transition to cleaner forms of flight". However, it's certainly not the first electric aircraft flight, nor is it particularly relevant to commercial air travel (at this stage, at least), so why has it garnered so much attention? Further still, is this really the start of the electric revolution and, if so, when do the rest of us mere mortals get to experience it?

Accelerating the Electrification of Flight (ACCEL as Rolls-Royce like to call it) is a programme being run as a collaboration with many partners, including YASA (a wholly owned subsidiary of Mercedes-Benz), NXT Aero (yes, you knew you recognised the SoI's silhouette from somewhere) and the Aerospace Technology Institute (ATI) - who have provided over half the investment, so they really need this to work and get as much attention as possible - with the aim being to cement the UK's competitive position in the design and manufacturing of aircraft and equipment used in civil aerospace for the foreseeable future. This maiden flight was impressive, even if it was rather short. I mean, the SoI certainly hasn't flown further than other electric aircraft (The Swiss took care of this with Solar Impulse 2, which completed a 16-month circumnavigation of the Earth, which would have been quicker had it not sustained damage to its battery cells flying between Hawaii and Japan, using only solar power. This marked the first piloted, fixed-wing, solar powered aircraft to circumnavigate the globe). It isn't the largest electric aircraft to have flown either (the eCaravan - a retrofitted Cessna Caravan - took that crown in 2020), nor has it reached the highest altitude (NASA's Helios managed to reach almost 100,000 feet (although, granted it was unmanned)), so what has it achieved?

Well, Rolls-Royce say that the SoI will be the fastest electric aircraft on the market, being capable of reaching 300mph before the end of the year. The basic principles employed in reaching this record thankfully (for Rolls-Royce) were already in place for them after they bought out Siemens' Extra 330 LE electric aircraft (which managed to reach a still impressive 212.5mph). This meant the Rolls boffins could work their magic on already established technology, ending up with a 400 kilowatt electric powertrain (which, by the way, is enough to power 250 homes and is by far the most dense batteries ever fitted to an aircraft), and subsequently a wonderfully high torque figure and a healthy climb rate. As an aircraft boffin myself, I can tell you that for the teams involved to come close to matching the stats of the Sharp Nemesis NXT kit-plane (on which it is ultimately based) is an impressive achievement in itself. Rolls-Royce, however, obviously aren't satisifed yet as they are also said to be collaborating with Tecnam (famed for their innovative factory-built and kit aircraft and their beautiful Luigi Pascale designs) to be producing the worlds first all-electric commercial aircraft.

They are not the only ones in the race towards electrification of aviation, however, with Airbus, ZeroAvia, NASA, Eviation, Boeing (with their backing of Zunum Aero), Ampaire and Pipistrel (amongst many others) all vying to get attention and a slice of the action. Airbus, for example, has been developing a range of planes all wearing the ZEROe moniker which they say will be up and running and in service by 2035. This would be a mammoth task but an equally mammoth achievement, as this would mean a huge leap away from the current hypothesised solution of hydrogen-powered aircraft and would allow upwards of 200 people to fly at once without creating the vast quantity of emissions currently produced by aircraft (accounting for 2.8% of global fossil fuel CO2 emissions with estimates for 2050 levels reaching as high as 25%).

So, why all the attention? Well, at £6Million the project has been a lot less expensive than others from competing companies. This of course is a good sign, as it signals in an era of cheaper development and building costs and, ultimately, more financially viable aircraft. It is also a key piece of the puzzle for starting electric only fleets, with many airlines in other parts of the world (such as the Arabian Gulf and the Gulf of Mexico) routinely offering short flights with few passengers, but running more frequently. If we can have a solid foundation for the technology and know that it works effecitvely then we can start to upscale so that these types of airlines can utilise electric fleets. Matheu Parr, the Project Leader at Rolls-Royce, explains it by saying that these types of airlines "are very interested in rapidly taking people from the airport into the city. You can move them very fast, in a very pleasant environment straight from an airfield and land them on top of a building right in the city. The technology to do that is real and ready today, it’s just going through a process of production and commercialisation". Lastly, it must be rememebered that the Covid-19 pandemic has resulted in roughly a 90% drop in worldwide passenger numbers within the industry, so be coming out of the pandemic with a success such as this really is the key many airlines need to unlock their potential and bounce back once the pandemic is completely over with. For example, an electric motor for an aircraft would, on average, operate at about 94% efficieny, whilst a traditional turboprop engine would be between 27 and 55% depending on how old the engine is, how large and powerful etc. Combine this with the price of Jet A1 and Avgas rocketing and the price of electricity being comparatively low, and we end up with (at least on the face of it) a very tempting offer for airlines. Of course, battery prices are still high and would need to come down for airlines to be truly captivated by electric aircraft, but we sure are ushering in a new era, wouldn't you say?

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