Elfly - Forsiktig tilnærming hos Cranfield - Royal Aero Society

Could the UK produce its own regional electric 
aircraft design? BILL READ FRAeS reports from 
Cranfield University on the work of Cranfield 
Aerospace Solutions and its ambitious plans to 
compete in the emerging market for ‘green’ 
electric-powered aircraft.

Cranfield Aerospace Solutions (CAeS) is a company owned by Cranfield University with aircraft design organisation capability/approval (DOA) for complex modifications to existing aircraft, which can also design and create new concept aircraft or flying demonstrators. CAeS also has production organisation approval (POA) from the UK Civil Aviation Authority (CAA) and the European Aviation Safety Authority (EASA) for complex modifications, as well as a similar range of military approvals .

Over the past 20 years since the company was set up, CAeS has been working on projects for major OEMs, such as Boeing, Airbus, Lockheed Martin and Raytheon. It also designed and built the X-48 dynamically scaled jet-engined blended-wing demonstrator for Boeing/NASA. “Because we are a small company we are more agile and can do one off demonstrators more quickly than the large aerospace OEMs,” explained CAeS CEO Paul Hutton. “This also means that for projects such as these we are completely at the whim of these companies’ discretionary spend, and we can have good years and bad years depending on how many projects we are working on.”

An electric opportunity

CEO of Cranfield Aerospace Solutions, Paul Hutton.

However, CAeS recently announced plans to use its design and manufacturing capabilities to branch out in a new direction with the ambitious aim of restarting the manufacturing of complete aircraft in the UK. “The core capability of Cranfield Aerospace is that we have retained all the engineering disciplines to enable us to design a whole new aircraft concept or one-off flying demonstrator for clients,” declared Hutton. “However, we can also use these core capabilities to develop our own projects.”

CAeS has been looking at particular aircraft manufacturing sectors where a new entry might be feasible. “How do you introduce a new competitor in the aircraft market?” asks Hutton. “You clearly don’t begin by entering the very competitive single and twin-aisle aircraft market. The answer is to find a niche. We think that where we could be credible and able to compete is in the small sub-regional nine to 19-seat aircraft market. This is currently a neglected sector as, in the present market, such small aircraft are not economical to operate with conventional fuels and airlines have largely upgraded to larger aircraft. However, there has been a lot of attention in the past 12 months on ‘green’ aviation and the potential market for these smaller sub-regional electric aircraft. With electric propulsion, all of a sudden, a sector that didn’t make any economic sense now makes a lot of sense.”

Project Fresson

CAeS is not merely proposing entering the electric aircraft market, it has already done so with Project Fresson. Named after Scottish aviation pioneer Ted Fresson, the £18m project aims to refit a nine-seat twin-engine Britten-Norman Islander with an electric propulsion system (see Electric pioneer, February 2019, p38). CAeS is currently leading a consortium with Britten Norman, Rolls-Royce, Delta Motor Sport, Dennis Ferranti and Warwick Manufacturing Group. Britten Norman is providing the airframe; Rolls-Royce will provide the critical power management design and implementation; Delta Motor Sport will supply the battery pack; Dennis Ferranti the electric motors; and Warwick Manufacturing Group will do the battery testing. Also involved is Scottish regional airline Loganair which plans to introduce the electric version of the Islander on its shortest ‘island-hopping routes’ in the Orkney islands. Critical to solving some of the tougher technical challenges will be the support of Cranfield University.

Half the money for the project has come from the partner companies with the other 50% of funding being providing by the UK Government’s Aerospace Technology Institute (ATI), as part of a match funding programme.

Hybrid design

The electric engines and batteries on the Islander will be supplemented with a conventional motor to provide additional range in the event of an emergency. (CAeS/Loganair)

Phase 1 will begin with partners starting on their own individual projects. CAeS is considering acquiring more than one Islander from Britten-Norman, one to fit the new electric engines to and another non-working airframe for engineers to work on. So that it will be easier for the regulators to certificate, the aircraft will feature a hybrid-electric architecture. The conventional engines will be replaced by two electric motors fed by a battery pack. Behind the battery packs will be a hybrid element - a fuel-efficient conventional motor.

“The architecture will be capable of pure electric flight,” explained Hutton. “The aircraft will be able to fly on batteries for around 20min. The range extender will allow the aircraft to have an endurance similar to the current conventionally-engined version, with necessary safety reserve. We are hoping to have a flying demonstrator within 30 months.” 

Towards an all-new electric aircraft

Phase 2 of the Fresson Project will look at the electrification of a larger airframe, such as a Twin Otter. (Viking Air)

However, the conversion of the Islander is only the beginning of a longer-term plan. CAeS plans to use the knowledge and technology learned from Phase 1 to move onto Project Phase 2 which is the electric conversion of a larger 19-seat aircraft (such as a de Havilland Canada/Viking Air Twin Otter). ‘From the architecture that we develop from converting the Phase 1 aircraft, we can then scale up to convert the Phase 2 aircraft,” said Hutton.

Phase 3 of the project is even more ambitious and is nothing less than the design and manufacture of an all-new British regional electric aircraft. Hutton believes that the UK has a unique opportunity to take the lead in the emerging market for electric-powered commercial aircraft. “The UK has largely lost its own whole aircraft design and manufacturing capability because we’ve focused (for good financial reasons) on being part of the global supply chain of larger non-UK aircraft OEMs,” he explained. “However, with our proven aerospace expertise and approvals, CAeS is well positioned to develop our own aircraft products. We can therefore play a critical role as an early stage new aircraft integrator, working with aerospace partners, to enable the UK to lead the green aerospace revolution.

Airbus automated assembly facility in Hamburg. Could Cranfield’s proposed new British electric aircraft factory take advantage of new technology and materials? (Airbus)

When asked by AEROSPACE whether this meant that CAeS intended to set itself up as a new British aircraft manufacturing OEM, Paul Hutton had an interesting reply: “Setting up a new UK manufacturing centre will take more than us. To build these aircraft in the UK (and deliver other disruptive whole aircraft projects), it will also be necessary to invest in the creation of a new Industry 4.0 flexible aircraft manufacturing facility. It will need a collaboration of government, local enterprise partnerships (LEPs) and the wider UK aerospace industry. We are now seeking third-party investment funding to allow CAeS to grow its capabilities so that we can be correctly sized and structured to play a key role in this.”

Evolution not revolution

The Islander is a well-established aircraft design familiar to regulators. (CAeS/Loganair)

Hutton explained how the plan to create a new electric aircraft design would come in stages: “We’re not going to introduce all-new technology straightaway, as that would delay certification and, so, introduction. Instead, we want to find the quickest way with existing proven technology. We decided that the quickest route to electrically-powered commercial passenger service was to begin with adapting an existing airframe. We can then go to the regulator with an aircraft that they already know. It’s not an end in itself, it’s a means to an end to prove that electric aircraft can be certified for commercial operation.”

“We’re following the lead taken by automotive manufacturers who don’t begin by designing a new engine for a new car but with a new engine for an existing car. Then, you wrap a new car around that engine. We intend to follow the same path. In Phase 1 we will get approval for a new propulsion architecture for an existing airframe. An evolution of that new propulsion system architecture can then be used in a new aircraft. Once we’re got the engine design approved, we can then go to regulators with modifications – for example, more efficient lithium-oxide batteries.”

Creating an electric supply chain

Hutton also explained that another reason why this gradual approach was important was to generate business for companies supplying to the electric aircraft market. “The reason that’s important to the UK is that it creates the supply chain necessary to create that aircraft,” said Hutton. “On the back of that supplemental type certificate (STC) we will have created a supply chain in the UK for battery packs and electric motors. If that supply chain is created in another country, then it will be much harder for UK suppliers to enter this new market at a later date.

Window of opportunity

Hutton believes that there is a brief window of opportunity for the UK aerospace industry to take the lead in electric-powered aircraft. “The UK has currently got a very significant presence in aerospace but, unless we continue developing new technology, we won’t be able to be involved in new projects,” he declares. ‘The UK has got the experience and know-how to develop electric aircraft but we need to move quickly or we will lose the race and other countries are taking the lead.”

However, Hutton is optimistic for the future of Project Fresson now that both the UK Government and major companies have become involved. “The ATI money is very important,” he stated. “It also helps when getting investment for our other projects from third parties if they see that the UK Government is investing in the project, as it gives you a level of credibility. It’s also good that we’ve now got a major OEM in the form of Rolls-Royce involved on Project Fresson Phase 1, as well as experts who know about battery packs, testing and electric motors.”

Hutton also believes that Fresson Phase 3 will be able to take advantage of new manufacturing techniques adapted for line manufacture of super cars. Flexible batch manufacturing can be used to work on different aircraft projects in the same factory. In addition to battery-power, CAeS is also looking at the potential of fuel cells which would have 100% zero carbon emissions.

All this and a flying car too

CAeS is also involved with Aston Martin’s Volante Vision eVTOL concept design. (Aston Martin)

In addition to the Project Fresson, CAeS was also involved with Aston Martin’s Volante Vision concept launched at the Farnborough Air Show in 2018, to create a new eVTOL aircraft aimed at the premium eVTOL market which would not be dependent on the creation of urban ATM environments necessary for air taxis in cities. As well as working on these new enterprises, CAeS will also continue working on other projects with OEMs.

Future challenges

There are still many issues to be resolved. As Project Fresson is still in the early stages of its first phase, it is too early to speculate what form the Phase 3 aircraft might take. However, some issues are already being considered, such as that of intellectual property (IP) rights. “As the projects develop, we will decide who has ownership of what,” said Hutton. “There will be some joint IP but partner companies will retain IP that they develop in their own fields.”

Another question is whether the new electric aircraft should be manned. “The aim is for the first future electric aircraft to be piloted because it will be quicker to certify,” said Hutton. “Then, as technology develops, we might look at autonomous versions.”

The future of electric flight might be closer than we think.