5 ms·

Jet engines have a thrust to weight ratio of about 10. The power is not so interesting as a lot of the thrust comes from heating the air. Ie the compressor migh

Jet engines have a thrust to weight ratio of about 10. The power is not so interesting as a lot of the thrust comes from heating the air. Ie the compressor might work at 40 MW and turbine also then of course extracts 40 MW from the airflow. I'm not sure why one couldn't build an electric supersonic aircraft. It would have very short range. The design presented, could be made more aerodynamic by fairing the motors. Leave a hole in the tip for cooling air. Add a compressor for low speed cooling if needed. Alternatively have liquid cooling. You could also have a design where the airflow is slowed down in a duct, compressed by a fan and then expanded. The duct would be heavy though. But it might obviate some problems with the free stream propeller.

NikolaeVarius 6y ago
Where are you getting this 10 number from. Wikipedia shows Eurofighter Typhoon as the highest T/W for a Jet airplane at 1.15 and The Concorde at 5.4 https://en.wikipedia.org/wiki/Thrust-to-weight_ratio https://en.wikipedia.org/wiki/Thrust-to-weight_ratio You WANT wings for supersonic flight (For a normal non missile aircraft). Sure it sucks that its hard to optimize for supersonic flight and subsonic, but you go Supersonic at extremely high altitudes to reduce drag on the plane. This requires a shit ton of power to go forward, without even counting the effort to stay in the air vertically.
- Gravityloss 6y ago
  That's the plane. I was talking about the engine.
  - NikolaeVarius 6y ago
    An engine without a plane around it is called a brick
    - baq 6y ago
      yes but a two engines with 10 TWR is worse than two engines with 20 TWR all other things being equal.
      - NikolaeVarius 6y ago
        What is this even replying to
    - tim333 6y ago
      Not always: https://youtu.be/YRBJixCmw1w https://youtu.be/YRBJixCmw1w
    - Gravityloss 6y ago
      https://disciplesofflight.com/wp-content/uploads/2015/05/Aerodyne_SM.jpg https://disciplesofflight.com/wp-content/uploads/2015/05/Aer... Lippisch Aerodyne. Looks a bit like the X-32 if you squint.
- redis_mlc 6y ago
  > you go Supersonic at extremely high altitudes to reduce drag on the plane. Well, that's not really the whole story. - jet engines are much more efficient at high altitudes (the thermodynamic equation) - air density is less at high altitudes - but you would have to calculate how less density and drag compare to engine efficiency.

NikolaeVarius 6y ago

Where are you getting this 10 number from. Wikipedia shows Eurofighter Typhoon as the highest T/W for a Jet airplane at 1.15 and The Concorde at 5.4 https://en.wikipedia.org/wiki/Thrust-to-weight_ratio https://en.wikipedia.org/wiki/Thrust-to-weight_ratio You WANT wings for supersonic flight (For a normal non missile aircraft). Sure it sucks that its hard to optimize for supersonic flight and subsonic, but you go Supersonic at extremely high altitudes to reduce drag on the plane. This requires a shit ton of power to go forward, without even counting the effort to stay in the air vertically.

Gravityloss 6y ago
That's the plane. I was talking about the engine.
- NikolaeVarius 6y ago
  An engine without a plane around it is called a brick
  - baq 6y ago
    yes but a two engines with 10 TWR is worse than two engines with 20 TWR all other things being equal.
    - NikolaeVarius 6y ago
      What is this even replying to
  - tim333 6y ago
    Not always: https://youtu.be/YRBJixCmw1w https://youtu.be/YRBJixCmw1w
  - Gravityloss 6y ago
    https://disciplesofflight.com/wp-content/uploads/2015/05/Aerodyne_SM.jpg https://disciplesofflight.com/wp-content/uploads/2015/05/Aer... Lippisch Aerodyne. Looks a bit like the X-32 if you squint.
redis_mlc 6y ago
> you go Supersonic at extremely high altitudes to reduce drag on the plane. Well, that's not really the whole story. - jet engines are much more efficient at high altitudes (the thermodynamic equation) - air density is less at high altitudes - but you would have to calculate how less density and drag compare to engine efficiency.