- Second Century
- Issue #2: Retrofitting for the future
Issue #2: Retrofitting for the future
Welcome to the second issue of Airline Food for Thought! First of all a big thanks to the people who subscribed and are now reading this in their email. Not yet a subscriber? Click here and subscribe.
👩✈️On the menu
When it comes to making aircraft more sustainable, the engine is the problem, not the airframe and the wings. So why not just replace the troublemaker? This issue is all about retrofitting existing aircraft with electrical engines.
Starter: A short introduction in retrofitting aircraft.
Main course: Meet the disrupters. Three companies that are disrupting the aviation industry using retrofitting technologies.
Desert: Is this the future of aviation?
A short introduction
In many ways the development of electrical aircraft is following the same path as electrical cars have taken. They are only a few years behind. In the car industry, we have seen that Tesla’s first electrical car was a Lotus retrofitted with an electrical engine, the Tesla Roadster. The same goes for Volkswagen whose first fully electrical car was a retrofitted Golf, the eGolf. What the manufacturers did is taking the fossil fuel engine out and replace it with an electrical one. The only modifications that where made were done to facilitate the new parts like the engine (sometimes more than one in case of the Mercedes SLS AMG Electric Drive, which has four) and batteries. In aviation we now see the same trend. Aircraft retrofitted with new electrical engines that pave the way for sustainable aviation.
🍲 Main course
Meet the disrupters
Pipistrel Velis Electro (Slovenia)
The Slovenian aircraft builder Pipistrel created the first certified electrical aircraft on the market, the Velis Electro. EASA certified the aircraft in June 2020. It is a two-seater with a battery powered electrical engine that can provide 65kW (88 hp) and has a range of one hour. This means that in reality you can do a 45 minute flight and have enough battery power left to make a go-around or two. The Velis is based on the Pipistrel Virus which has a 'regular' Rotax engine that is fueled by AVGAS, like many other light sports aircraft.
Since I have flown both the Velis and the Virus multiple times I can honestly say that retrofitting the Virus with an electrical engine has been a significant improvement. Yes, the range is less, but that's about the only downside. Next to the huge environmental benefit of no exhaust gasses, it produces much less noise. Also the pre-flight checks are much shorter since there are a lot less systems to check. You literally only have to flip four switches to have the engine running and avionics on. By reusing the airframe of the Virus, Pipistrel did good job in taking a shortcut to sustainable flying.
Harbour Air (Canada)
Harbour Air is a regional seaplane airline that operates from the harbour of Vancouver. They operate several types of aircraft, ranging from Cessna Caravan's to De Havilland Twin Otters. In December 2019 their De Havilland eBeaver made its first fully electrical test flight. The eBeaver is a 'regular' De Havilland Canada DHC-2 Beaver retrofitted with an electrical engine. The engine is provided by MagniX, based in Everett, Washington. After the start of their partnership, it only took the two companies nine months to develop the aircraft and execute the first test flight. Thereby giving a great example of how quickly you can progress when using retrofitting technologies.
Unfortunately, there're not there yet. For the eBeaver to be allowed to fly commercially it needs be certified by regulating agencies. Since battery powered engines are new in aviation, there are not many use cases that can proof the reliability of the drive train. Making it more difficult to define certification standards. Also battery powered flying requires a new type of infrastructure to refuel the batteries. Just like battery powered cars. There are companies world wide developing charging networks for aircraft, however, like the certifications, airlines like Harbour Air will have to wait for these products to mature to be able to have a fully electrical commercial network.
If you want to know more about this out of the box airline and their battery powered plan(e)s, listen to the 'Sustainability in the air' podcast episode with Greg McDougall, the CEO of Harbour Air.
When you want your aircraft to have an electrical engine, you need an electrical engine. And when you need an electrical engine, you need to go to MagniX. Founded in 2010, this company has been providing several existing aircraft with electrical engines. Like the Harbour Air eBeaver mentioned earlier. The second aircraft that has flown fully electrically using a MagniX engine is a Cessna eCaravan.
Both these aircraft use the Magni500 Electric Propulsion Unit (EPU) that provides 750 BHP and weighs 135 kg. In case of the Cessna Caravan, the engine that it is replacing is the Pratt & Whitney R-985 Wasp Junior. It produces 400 BHP and weighs 290 kg. This means that the electrical engine weighs less than half of the original while making almost twice as much power. The weight savings can be used to cover for the (lets be honest) heavy batteries.
Is this the future of aviation?
… but it's a very important first step.
Companies like Pipistrel, Harbour Air and MagniX demonstrate that it is possible to make air transport a lot more sustainable in the near future. They can provide regulating agents with use cases to base their certification process on. They will be the business case for companies developing charging infrastructure for electrical aircraft. All of which can be used to accelerate the development of electric propulsion in the future.
The reason it's not the future of aviation is because the airframe of electrical aircraft can be specifically designed to fit the characteristics of an electrical drive train. As mentioned in the MagniX section, the power-to-weight ratio of electrical engines is different from fossil fuel engines. This influences the position of the center of gravity and thereby the flight characteristics of the aircraft. The same goes for batteries, the weight is different from kerosine and its weight does not change during the flight. As is the case while burning fuel. Also electrical engines can be much smaller than the ones we are used to. Making it possible to position them in a different way than we are used to on aircraft.
So, it is not that retrofitted aircraft won't be able successfully operate commercial flights. It's that battery powered aircraft can do so much more than is currently possible. When fitted into airframes that have been designed with these new type of engines in mind, the full potential of electrical engines will be utilized. Until then, these retrofitted aircraft will do just fine!