United Boom Supersonic

[trumpetfrazz1 89]

Just to add to the interesting conversation here, the Concorde designers originally wanted to place the power plant on top of the wing, but because they were starting from scratch with the aerodynamics, they felt it would be too difficult to get the vortex lift to work at slow speeds because the engines would get in the way. 
 

If Boom choose to follow a similar flight profile to Concorde to avoid the sonic boom over land, I think their main focus would have to be reducing fuel consumption in the subsonic regime.  This was a priority for the Concorde B model that was never built.  If you can get the aerodynamics cleaned up to reduce drag and reduce subsonic fuel burn to a par with subsonic jets, you’d be onto a winner because you can fly it wherever you like without it costing a fortune flying slow like Concorde did.  
 

In an ideal world, a variable cycle engine - fan subsonic, pure jet supersonic - would be a way to do this but whether the technology exists and is affordable is another matter.  I suspect the lower cruise speed of M1.7 is to help the compromise between subsonic and supersonic performance but that’s just a guess.  I think I remember Boom is to be smaller in airliner form than Concorde was, so this will also help the compromise.

I’m sure Boom wouldn’t have gone as far as they have unless they at least think they have answers to these things, else they’d look rather silly in the end!  They aren’t starting from zero like the Concorde team had to and I think we have to remember that.  Different times, different calculators, different knowledge.  
 

Good luck to them I say, I hope they make it work! 

[martin-w 3,235]

3 hours ago, trumpetfrazz1 said:

In an ideal world, a variable cycle engine - fan subsonic, pure jet supersonic - would be a way to do this but whether the technology exists and is affordable is another matter.

 

Rolls Royce are working on the engine as we speak. No details yet though. 

[trumpetfrazz1 89]

3 hours ago, martin-w said:

 

Rolls Royce are working on the engine as we speak. No details yet though. 

At least they have supersonic experience within civil certification standards.   As an aside here, the key to Concorde’s success was the air intake and matching it with the engine, the main component of which being the hybrid digital computers that controlled the intake ramp positions.  The design authority was originally owned by the BAC guided weapons division, Bristol I believe but through a lot of industry takeovers and mergers this has now become owned by another company, I forget which, but I believe this assisted in the design of the Tornado intakes, without which it would never have flown so fast.

I wonder if M1.7 means they don’t need such a sophisticated intake design - I’d have to look up my notes but if they get the intake right, they wouldn’t need variable geometry until around M1.3 maybe even higher, so you are narrowing your problems down.

Also have to consider the engine failure cases which in military supersonics, used to result in catastrophic failure, whereas in Concorde you could have two engines on the same side go at the same instant and everyone got home in one piece!

Fascinating subject, I hope they make a go of it. 

[goates 576]

15 minutes ago, trumpetfrazz1 said:

I wonder if M1.7 means they don’t need such a sophisticated intake design - I’d have to look up my notes but if they get the intake right, they wouldn’t need variable geometry until around M1.3 maybe even higher, so you are narrowing your problems down.

Check out the link I posted above about the YF-23's fixed inlet design for supercruise, as well as the Diverterless Supersonic Inlet research and use. Plenty of research into modern solutions to the supersonic airflow issue, partly thanks to computational fluid dynamics.

https://www.codeonemagazine.com/article.html?item_id=58

[trumpetfrazz1 89]

2 hours ago, goates said:

Check out the link I posted above about the YF-23's fixed inlet design for supercruise, as well as the Diverterless Supersonic Inlet research and use. Plenty of research into modern solutions to the supersonic airflow issue, partly thanks to computational fluid dynamics.

https://www.codeonemagazine.com/article.html?item_id=58

Thanks, I will take a look. 
 

In the 1960’s they had to rely on slide rules….