
Is killing the boom the key to supersonic air travel? - bauc
https://www.bbc.co.uk/news/business-44795639
======
slivym
I'd really like to see proper numbers on the fuel economy of these proposed
solutions. Because whilst it's nice to throw your hands in the air and say 'Ah
well it'll be like first class' \- there are many problems with that.

Firstly, all the big commercial investment has gone into sub-sonic planes, so
they've gotten much cheaper. So to just have the same cost-ratio as concorde
between supersonic vs. Standard flight is a big ask today. Secondly, Concorde
wasn't just expensive -it was uneconomical because they couldn't fill the
plane at those prices. Concorde was built in an era before deregulation -
flights are far more cost competitive today. Thirdly, removing the sonic boom
seems to imply inefficient shapes for the aircraft in terms of fitting numbers
of passengers in. So even if the engines were far more efficient, you still
have the fuel efficiency per passenger to worry about. For example Boom
Supersonic are planning a 55 passenger plane. That is laughable as a
commercial proposition.

I'm certain that companies working on this have concrete expectations of the
cost o f a flight per person and the expected demand, I would just love to
know what those are.

~~~
Reason077
_”Boom Supersonic are planning a 55 passenger plane. That is laughable as a
commercial proposition.”_

Do you feel that is too big, or too small? The market for supersonic travel is
likely to align with the very high-end, private jet market. Those who want to
get somewhere fast and don’t care what it costs.

It may be easier to overcome noise issues with a smaller design, too.

~~~
sokoloff
My experience with private aviation suggests that getting somewhere _exactly
when they want_ , flying into airports closer to their destination, stepping
directly out of/into ground transportation and, to a lesser extent, having
privacy en route are significant drivers for the private aviation crowd.

Cessna is killing the X, the fastest civilian airplane, in favor of slower
airplanes. I'm not convinced that supersonic transport to/from major airports
is going to threaten business/private jet aviation.

~~~
Reason077
Assuming noise regulations can be met, is there any reason why a small
supersonic aircraft couldn't operate private flights into those same airports?
Or do supersonic airframes need longer runways for higher-speed take offs and
landings?

~~~
sokoloff
All of today's supersonic aircraft need runways longer than a mile. It is my
belief that these projected supersonic aircraft will still likely need a mile
or more.

There are 19K runways in the US, the vast majority of which have a longest
runway under 4000'.

------
ckocagil
This reminds me of a Wendover video I've seen. The author discovers that
airplanes used to fly much faster in the 1960s than they do today. So our
flight times have actually gone up! He then explains the reasons behind it.

[https://www.youtube.com/watch?v=n1QEj09Pe6k](https://www.youtube.com/watch?v=n1QEj09Pe6k)

~~~
caio1982
There is also another Wendover one explaining the economics or airlines
classes and it talks about specifically why supersonic flights went into
oblivion:
[https://www.youtube.com/watch?v=BzB5xtGGsTc](https://www.youtube.com/watch?v=BzB5xtGGsTc)

------
fabricexpert
I would like to see supersonic travel come back.

But I would LOVE it if we could find a way to speed up the time spent at the
airport. The amount of time I spend traveling to the airport, dropping off
bags, queuing for security, getting pulled aside because I forgot I was
wearing a belt that day, waiting for the gate to open, getting on a train to
the gate, queuing to board the gate, getting on a BUS to the plane, queuing to
get on the plane, waiting to put my overhead bags in the bins, waiting on the
tarmac for the plan to find a free slot on the runway.

In the future I still have to do all this before we finally take off and
travel at supersonic speed (yay), but then I land and basically have to do it
all again.

Most of the time spent traveling by air is spent on the ground.

~~~
struppi
This is _exactly_ the reason why I usually prefer a 6-hour train ride to a
1-hour flight (at least in Germany, Austria, Switzerland).

Train: Go to the station (near city center), arrive 10 mins before train
departs, get on the train, read/work/eat/drink for 6 hours, get off the train.
And then you are already at the city center of your destination!

The total time spent when flying might be shorter (4.5-5 hours), but that is
not worth the hassle.

~~~
kiba
All these security for air travel but not for a train which is also full of
lot of people felt bizarre.

~~~
donaltroddyn
Well, the impetus for enhanced airport security was first the spate of
hijackings in the late '60s to early '80s, and later 9/11.

While you can hijack a train, you can't fly it to a friendly country, and you
can't fly it into a building, so it's a very different threat model.

~~~
hanoz
Locking cockpit doors has already solved both those problems.

~~~
Uberphallus
Germanwings would like to have a word with you.

~~~
JamesBarney
Are you referring to this?

[https://en.m.wikipedia.org/wiki/Germanwings_Flight_9525](https://en.m.wikipedia.org/wiki/Germanwings_Flight_9525)

~~~
Uberphallus
Yeah, the first officer locked himself in then started descent into a
mountain.

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phyzome
The title is a bit silly -- sonic booms weren't what killed the Concorde, it
was cost -- but I'm glad to see the article goes into the need for fixing both
problems.

~~~
mannykannot
True, though the inability to do transcontinental flights exacerbated this by
effectively eliminating any hope of recovering development costs or achieving
any other economies of scale.

Noise around airports was also a very contentious issue - low-bypass jet
engines and, especially, the use of afterburners on the takeoff roll. This
will become an issue again even if the sonic boom problem is solved. Smaller
aircraft may be quieter, but they are unlikely to be welcome at airports that
cater primarily to business jets, if they are any louder than those in use now
- and the trend is towards quieter.

------
kazinator
Nope, killing Amdahl's Law is the key to supersonic air travel.

If it takes me 45 minutes to get to the departure airport, where I have to be
one hour ahead of time to get through baggage check and security, and it takes
2 hours to get to my destination from the landing airport, then cutting a 4
hour flight to 2 hours is only 34% faster.

Like, fix the transportation and traffic problems around the airports and the
logistical delays first, then brute-force the actual flight time.

~~~
mmt
> fix the transportation and traffic problems around the airports and the
> logistical delays first, then brute-force the actual flight time

Why this sequence and not the other way around, or both at the same time?

The two don't seem to be competing for any resources, other than the highest-
level ones like money. In some cases, the airport logistics problem may be
intractable or take too long (witness BER).

I also suggest your times are slightly off, in the context of the target
market. I doubt someone paying that much would need the full hour (though as
little as 30 minutes might be a stretch if we're counting departure time not
boarding time).

I also think, however, that lowering a 4 hour (gate-to-gate) flight from 4
hours to 2 hours is unrealistic, and is too short a flight to make sense for
supersonic, anyway. IIRC, Boom was looking to halve the 7-hour JFK-LHR hop,
comparable to Concorde.

Where it would seem to be far more attractive is the much longer flights, such
as trans-Pacific, where the overall time is much longer, a higher portion of
gate-to-gate (and door-to-door) time is at maximum cruise speed (shaving 8
hours off a 14+ hour SFO-SYD could save a full day of travel). Even Europe to
the US West Coast would be significant, which relates to the premise of the
article.

------
syntaxing
I think the only way to kill the boom is to change the aerodynamics of the
plane at different flying conditions. The only way to do this is to change
what the air "sees" when it hits the planes wing surfaces by changing the
turbulent and laminar regions. Unfortunately most methods are not quite there
yet.

------
baybal2
>Is killing the boom the key to supersonic air travel?

No. Cost is

~~~
geertj
To get to low cost you need a lot of routes to fly on. Without a sonic boom
can fly over land which opens up more routes. Therefore, the lack of a sonic
boom does contribute to the comeback of supersonic air travel.

~~~
baybal2
Sonic boom is a joke of a criterion. US is surely a big market, but nowhere as
important as it was 40 years ago. US will have a choice: to deny SSTs when the
rest of the world flies them, or do not do so.

But, cost above everything. You can't get economies of scale for an SST with
even less than double the cost of regular business class.

~~~
ghaff
I have no reason to think that the US would uniquely ban the use of technology
that Western Europe was fine with. (Though one can certainly imagine e.g.
China allowing for noise levels that the US and other countries wouldn't be OK
with.)

Cost is really the thing though. Produce a modestly-sized supersonic jet that
can do trans-Atlantic and equivalent routes that are profitable with business
class-priced seats and you probably have a market.

Probably. A lot of business class seats today are filled with upgrades and I
believe BA has actually cut back on the business-class only routes between NY
and LCY.

~~~
baybal2
You have to make it as cheap as cheap business class to get needed occupancy,
AND have as many seats as smallest widebodies. And when you have it, you will
have to fly ~7-10 years at loss till you get efficiencies of scale.

In other words, it is not happening.

------
Theodores
I suspect that the solution to the problem may look very different to the
planes and drawings of planes shown in the article.

I know nothing of aerodynamics but what I do know is that innovation in
aerodynamics is more likely to come from the world of F1 than the bowels of
Lockheed Martin these days. This has actually been the case since the 'Gurney
Flap' that was the first innovation in aero to come from motor racing to make
its way to regular aerospace.

In 2017 at the Singapore Grand Prix the Force India F1 team surprised the fans
with a new gadget to get extra downforce. In 2017 F1 cars had a 'sharkfin'
engine cover and on top of this Force India had what looked like a hedge
trimmer, this was 30 or so very small wings that worked together to create two
powerful vortexes with the mini-winglets reinforcing the same vortex created
by the mini-winglets at the front of this 'hedge trimmer' arrangement. From
this they were able to get good downforce from an area of the engine
cover/sharkfin that was not supposed to be downforce creating. The innovation
obviously had to be banned and this is no longer a feature in 2018 cars.

F1 max speeds are lower than a plane and the aero is not about getting
airborne, however, due to the rules there is constant innovation. Regular
planes look as aerodynamically sophisticated as F1 cars from the 1980's. I
suspect that to do supersonic without the boom then aerospace will have to
borrow more than just the Gurney Flap from F1. Furthermore, incentives have to
be better than pork barrel politics or else the Lockheed Martins of this world
will be on this gravy train forever.

~~~
NLips
The key point you're missing is that subsonic and supersonic flows are very
different - in terms of fluid dynamics, supersonic planes are not just faster
than subsonic planes. Commercial jets and F1 cars are optimised for subsonic
flows. To handle supersonic flight, you need to do things which are strange
and suboptimal for subsonic travel. This is partly why subsonic planes don't
look like concorde.

That's not to say cars won't have an effect on the design. Two avenues I can
think of in particular are:

1) Concorde's shape made it _extremely_ noisey upon take-off. That's subsonic
travel, so other subsonic vehicles might provide design inspiration (even
though in some cases going supersonic may mean the inspiration has to be
ignored) 2) Projects like Bloodhound SSC might provide inspiration.

~~~
Theodores
I think I mentioned that F1 cars go a little bit slowly, however, the point I
was making is that some thinking outside of the box is needed, from some area
of engineering that is actually innovative. Innovation isn't just about
funding, no amount of money sponged off the taxpayer and given to NASA and
their greedy contractors will solve the problem. You need engineering talent
and people who can bend the rules and do things that go beyond what can be
learned from studying textbooks.

~~~
NLips
You did mention that "F1 cars go a little bit slowly". The difference is that
speed is pretty much irrelevant. It's sub/trans/super-sonic that matters.

