The Boom SST engine problem

By Bjorn Fehrm

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November 28, 2016, ©. Leeham Co: We covered Boom Technology’s and Virgin Atlantic’s plans to offer supersonic business class passenger traffic over the Atlantic in recent articles. In the first article, we focused on the problem areas that Boom technology must master.

The most difficult area is to find a suitable engine for the aircraft. Engines for long-range supersonic flight are quite different animals than the normal subsonic airliner engine. We will go through why the engines are different and give an example of how such an engine could look.


Figure 1. Boom Technologies Boom Mach 2.2 airliner with 45 seaters. Source: Boom.

By creating a concrete example of an SST engine for an aircraft the class of the Boom SST, it will be possible to understand if Boom’s claim that suitable cores are available holds water, and how realistic is it to make an SST engine from these.


  • An SST engine is very different from a modern engine for a long-range airliner.
  • A high-performing long-range engine for a normal airliner has a high bypass and pressure ratio.
  • A high-perfoming long-range SST engine for a supersonic airliner has a low bypass and pressure ratio.
  • Intakes and exhausts on subsonic engine nacelles are simple.
  • Intakes and exhausts on supersonic engine nacelles are not simple.
  • Considering all these factors, we will design an engine system for the Boom SST to get a deeper understanding of the challenges involved.

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