Unisphere analysed 30 cities with regards to the annual icing conditions. When deciding where to start any air taxi service, it is highly recommended to analyse the location beforehand to get a better understanding of:

  • the availability for the service
  • the business case
  • the target customers.

Although icing is only one important parameter to consider, considerations should include differences between each season and at different altitudes. 

Highlights from the whitepaper

First, as the name implies, eVTOLs are electrically powered, which has certain drawbacks. Because batteries have a lower energy density than kerosene, eVTOLs tend to be low on energy. As a result, most are not equipped with de-icing systems because (a) it adds weight, which limits the aircraft's range, and (b) the system itself requires energy, which is limited anyway.

Second, eVTOLs are smaller than commercial aircraft. Because of the smaller size, icing that forms on the airframe has a greater impact than we are used to from conventional aviation. In other words, 1 cm of ice on an eVTOL has a much greater impact on aerodynamics than on an airliner. As a result, the pilot has less time to react to icing, making the eVTOL more sensitive.

Third, due to aerodynamic effects in the area of the propulsion system (rotors), icing effects occur at temperatures above zero degrees Celsius, caused by the fact that the rotors generate a low pressure that can lead to a drop in temperature. Similarly, icing can occur on the aircraft at, for example, 2 degrees Celsius and high humidity.

Fourth, eVTOLs are planned to be operated at lower altitudes. At these altitudes, the temperature is more moderate than at high altitudes. Because warmer air can contain more moisture in absolute terms, severe icing is more likely to occur than at altitudes where airliners operate. Due to these characteristics, which are based on the aircraft design and concept of operations, eVTOLs are more sensitive to icing conditions.

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