While not quite a flight from John o’Groats to Land’s End – the far northeast of Scotland to the most westerly tip of England – Ampaire’s Electric EEL will in the coming days have conducted its own long distance tour of the UK.
Having finished up a short series of flights from Kirkwall airport in the Orkney Isles, which lie off the north coast of Scotland, the heavily modified Cessna 337 Skymaster on 16 August departed for Exeter airport in southwest England to later this week begin a second round of evaluations.
In both cases, the test campaigns have been funded by the UK government through its Future Flight Challenge initiative: in Orkney, Ampaire is part of the SATE (Sustainable Aircraft Test Environment) project, which is headed by Highlands & Islands Airports (HIAL); while the Exeter flights will be conducted under 2ZERO (Towards Zero Emissions in Regional Aircraft Operations), a programme led by Ampaire and involving a consortium which includes Rolls-Royce Electrical, Scottish regional carrier Loganair and Exeter and Devon airports.
Speaking shortly after the completion of its part in SATE, including a return flight from Kirkwall to the Scottish mainland on 12 August, Kevin Noertker, Ampaire co-founder and chief executive, described the project as “wonderfully successful”.
Ampaire employees were in Kirkwall for a month beforehand, setting up the required infrastructure and re-assembling the Electric EEL (N337EE), which had been moved from the company’s Los Angeles headquarters in a shipping container.
“I’m so pleased with how all the operations and activities progressed. I’m really proud of the significant amount of work that it took to get to these days,” he says.
But the flights themselves were not particularly significant – the longest by the Electric EEL took place last October in California and route-proving operations have previously been performed in Hawaii. What, then, did the Scottish sorties achieve?
Noertker acknowledges that the plane “flies pretty much the same” whether in California or Orkney, but points to the “fragmented” nature of the sub-regional airline market with operational requirements and constraints, and community perception, changing at each location.
On that basis the flights under SATE were important, he argues. “Each interaction on deployment means we learn something about [operational] integration.” That might be about the need for charging infrastructure at an airport, or what an airline requires in terms of turnaround times or aircraft utility.
While Ampaire also gains “knowledge about the maintainability and reliability” of its powertrain in the field, crucially “we are building the relationships that are needed to deploy [a hybrid-electric aircraft] commercially one day,” says Noertker.
Those on the operational side of SATE – notably HIAL and Loganair – also gain an understanding of the possible benefits and what might be required from them to fly electric or hybrid-electric aircraft.
In addition, prior to its departure for Scotland, the Electric EEL was upgraded with the latest iteration of Ampaire’s battery system “to allow for the more challenging weather in Orkney”.
“When we think about building an aircraft, especially an aircraft with new propulsion technology, our job is to make sure it’s resilient and able to be operated in any weather conditions our customers might typically encounter,” adds Noertker.
To create the Electric EEL, Ampaire replaced the Skymaster’s rear combustion engine, which is in a pusher configuration, with an electric motor and battery system while retaining the forward-facing piston powerplant. Noertker says fuel-burn savings are in the region of 30%.
But it is worth remembering that the at-best five-passenger Electric EEL is chiefly a technology testbed and unlikely to make it into production.
Instead, Ampaire’s focus is now on bringing to market a hybrid-electric conversion of the Cessna Grand Caravan. In that embodiment the stock Pratt & Whitney Canada PT6 engine is replaced with a generator from an undisclosed supplier which will supply power to an electric motor.
Ampaire is also in the process of being acquired by US technology company Surf Air Mobility, which recently announced a deal for up to 150 Grand Caravan EXs and an exclusive relationship with Cessna owner Textron Aviation.
Noertker says that Ampaire has been quietly working on the powertrain for the Grand Caravan “for quite some time and that’s the primary focus for our company”. Service entry is anticipated in 2024, and the modification promises a fuel-burn saving for the nine-seater of around 25%.
But further out – and possibly more attractive for Highlands and Islands-type flights – is a twin-engined aircraft. So far, Ampaire has committed to a conversion of the 19-seat Viking Air DHC-6 Twin Otter – an aircraft it calls the Eco Otter SX – but would also consider the smaller Britten-Norman BN-2 Islander. In either case, an aircraft could be available by mid-decade, says Noertker.
He is confident that Ampaire can achieve a payload of nine passengers in the Grand Caravan and 19 in the Eco Otter SX. But if not all that accommodation is required, then customers may seek to trade passenger capacity for better performance through additional batteries.
Ampaire continues to finalise its supply chain, but is keen to dual-source key components. “It is a new industry where the supply chain is still relatively immature; it is a little bit more of a risk-managed approach,” says Noertker.
The “best in class” lithium-ion cells currently being worked on at Ampaire’s California headquarters deliver 200 watt-hours per kg, but the company sees that figure as only rising as technology improves.
For its participation in SATE, Ampaire UK – its local subsidiary – was allocated £532,510 ($737,742) and £643,890 for 2ZERO from the UK government, in both cases a figure matched by company contributions.
Although Ampaire is overwhelmingly a US company, its UK presence allows it to receive funding from the Future Flight Challenge: to qualify, a participant must simply be a UK-registered company, carry out its project work in the country, and intend to exploit the results of that effort from or in the UK.
Ampaire UK was registered in 2018, although the company remained dormant for the first year of its existence, according to UK Companies House documents. It currently has five full-time employees.
While acknowledging the UK’s aerospace engineering expertise and the government’s commitment to sustainable aviation, Noertker offers no commitment to expanding its in-country presence. Its local workforce will “quite probably” expand, he says, noting that “We see some follow-on opportunities for work.”
However, rather than establish dedicated UK sites, it is likely to utilise the facilities of its local partners. That said, should Ampaire begin delivering aircraft to a UK customer, then there may be a need for a local manufacturing or assembly facility, says Noertker. “But we will let that play out over time,” he says.
Test flights under 2ZERO will last around seven days – although there is a possibility to extend the duration if needed – and are designed to assess the performance of a hybrid-electric aircraft and evaluate its operational requirements.
While these will be similar to the sorties conducted as part of SATE, Noertker points out that other consortium members are conducting work behind the scenes on technology development: for instance, Rolls-Royce is receiving £1.1 million under the project. A follow-on phase is also anticipated which foresees flights of a twin-engined hybrid, answering the question, says Noertker: “How do we get it up and ready for operations out here?”