Speed: Limiting Factors

[+'ve ROC]

We've seen many advances in engines, avionics and materials over the past half century.

However, despite the seemingly mega leaps in these areas; particularly engines and control systems, the speed of airliners has not really increased (although there are rare exceptions of course!) past the M 0.8 mark

What would you say were the real constraining factors here?

Obviously, taking an aircraft over M 1 has consequences, but what technical factors are there to stop modern airliners cruising at closer to this?

It just struck me that the next gen of a/c rolling out of Toulouse / BFI don't get one to their destination much faster than 30-40 years ago. (Although there may be considerably less noise / smoke)

Cheers

[N5528P]

What would you say were the real constraining factors here?

The overly increasing drag when appraoching Mach 1?
Fuel is not that cheap to burn nowadays.

Regards, Bernhard

[Genghis the Engineer]

Yep.

Basic aerodynamics says that most-efficient flight is well away from M=1. Clearly, nobody wants to go around the world at 200kn, you'll never get to half the places, so M~0.8 is the best compromise and all the really clever work is going into making aeroplanes cheaper, safer, and more environmentally friendly.

Above about, say, 0.85, the next best place to be is M=2+, but that presents all sorts of other problems.

So, to be honest, I think that in another 50 years, most air transport will still be around 0.8-0.9.

G

[AtoBsafely]

Ghengis,
You are brave to extrapolate today's designs 50 years into the future. Can't you imagine how much people will pay for a 4 g takeoff followed by 20-40 minutes of 0 g ballistic (meal/drink service in sip tubes) and a 3 g approach for that smooooooth touch down, just to do Tokyo to London in an hour. It would definitely be "cooler" than the concorde!

[Genghis the Engineer]

Precisely.

G