ForTheDoers Blog

Electric airplane flies best just before sunset

Jacek Ławrecki  ·  31 July 2019

Fortum participated in the development of electric aviation and in the first e-plane flight in Poland.

Electric airplane in sunset

Fortum is gaining further insight into electric aviation. On 8 June 2019, Fortum took off from Wrocław on Poland's first flight of a serial electric airplane, the Pipistrel Alpha Electro. We made our way to Gdańsk, visiting Fortum locations across the country.

Our mission was to collect experience and expertise related to operating electric aircraft. Fortum gained valuable knowledge about the charging of electric airplane batteries, battery life and power consumption during the different phases of flying. The company can apply this information in the development and building of the aviation infrastructure in the future.

The flight across Poland

The trip from Wrocław to Gdańsk was 780 kilometres long, divided into 11 legs. At five Fortum locations along the way we met with journalists and organised display flights. The pilot in command was Nejc Faganelj, the test pilot from the Pipistrel factory, while I occupied the right seat on most legs. Flying the Alpha Electro is similar to flying a typical piston ultralight. But instead of watching the oil temperature and pressure, you watch the battery and power display.

The first learnings

The data and findings gathered during the cross-country flight will be analysed in the upcoming months. But we can already draw some conclusions.

1. Allow for a safety margin when planning the charging locations

The charging network should be planned in such a way that chargers are no further than 100 kilometres apart. Locating chargers within 70-80 kilometres from each other would give pilots a comfortable safety margin for flight planning.

2. Pay even more attention to weather conditions and flight altitude

Planning an e-flight requires more attention to weather than is the case with a piston aircraft. Especially the wind conditions need to be analysed carefully. A 25-knot tailwind may double our range compared to a headwind of the same strength. You should also think twice about altitude. Climbing consumes a lot of energy. It is usually better to stay 1000 feet above the ground.

3. Prepare yourself for a longer charging time

During the project, we used a 20-kW charger, which allowed full charging within about 75 minutes. But it turned out not to be possible everywhere. In order to use the charger’s full capacity, you need a reliable electrical connection with a 32-ampere output. At some airfields, however, we had to charge with 16 amps – and sometimes even 10. This is not a problem, you just press a button on the charger, but it doubles the charging time.

4. Even the timing of the flight matters

The most surprising discovery was related to the timing of the flight. We discovered that the Pipistrel Alpha Electro has a better range just before sunset or in early morning. This is most likely due to thermals, vertical movements of air, which are strongest around noon. That’s when hot air rises in some places, but it cools and falls to the ground elsewhere. Accordingly, you need to apply more power to stay level; as a result, you consume more energy. You can regain some of it in rising air, but the balance will always be negative.

E-mobility expanding to aviation

Fortum has substantial experience in operating car charging systems. In the Nordics we operate more than 3000 car chargers. We believe that the expansion of e-mobility to the world of aviation will gain momentum. We want to be at the forefront of these changes and contribute to making the world cleaner.

Aviation companies are already conducting advanced research on electric passenger planes capable of transporting more than 150 people. It is estimated that the first machines may appear in the sky in the next 10 years.

The use of electricity in aviation reduces emissions into the atmosphere and noise around airports. The solution is to use fully electric motors in small airplanes and hybrid technology in bigger passenger airplanes.

The cross-country e-flight in Poland follows up on the experience gained by Fortum in Finland, where Finland's first flight of an e-plane took place last summer at Helsinki-Malmi airfield.

 

Charge and fly! Video on the first e-plane flight in Poland

Pipistrel Alpha Electro

  • A 2-seat, single-engine, all-electric aircraft designed and manufactured specifically for flight training
  • Operates on a zero-emission lithium-ion battery, a sustainable source of energy that significantly reduces greenhouse gases
  • Cruising speed 157 km/h

An aircraft for pilot training

  • The 21-kWh battery is able to provide enough energy for a 55-minute flight (plus half an hour's reserve)
  • Charging with a 20-kW charger takes one hour
  • Thanks to zero CO2 emissions and low noise levels, flights can be carried out in the vicinity of large cities and easily meet emissions and noise standards

Jacek Ławrecki
Jacek is heading communications in Poland and Baltic countries. He is also responsible for the electric airplane project in Poland.
Tel: +48 662 183 746
[email protected]