
Nasa to test ‘quiet’ supersonic flights over Texas - daegloe
https://www.cnn.com/travel/article/nasa-supersonic-flights-testing/index.html
======
JumpCrisscross
There is a fascinating pattern, in aeronautics, whereby the design that works
best is almost always inexplicably beautiful. It's as if humans have a broad
and innate understanding of aerodynamics, even far past our natural
environment. (Contrast that with astrodynamics, where the best design is
usually the ugliest.)

~~~
btrettel
> It's as if humans have a broad and innate understanding of aerodynamics,
> even far past our natural environment.

As a fluid dynamicist, I'd say closer to the opposite is true. The shapes
might look good, but ask a person not trained in basic fluid dynamics to
explain what makes a particular shape aerodynamic and they'll likely do
poorly.

Boundary layer separation phenomena seems to be inherently unintuitive. I can
recall talking about aerodynamics with someone very smart but untrained in the
field. They seemed focused on the high pressure zone created in front, with no
consideration of the size of the low pressure zone in the back. (In a
simplified view of the problem.) If the boundary layer separates prematurely,
it creates a larger low pressure zone and increases drag. So the shape of the
back of an object matters to its drag. There's a reason airfoils are elongated
and not just smooth fronts with abrupt ends.

And the intuitive understanding most people have would not suggest that
roughening an object could decrease its drag. But this is a well known
phenomena explained by boundary layer separation as well.

(Note that I don't know much anything about supersonic aerodynamics and what I
say here is only what I know about subsonic aerodynamics. I am not an
aerodynamicist, just a guy who works broadly in fluid dynamics.)

~~~
hymenoptera
I think you missed his point.

He didn't claim that our innate appreciation for specific forms might imply
that we make good decisions about how to find more.

What he _did_ say was that our degree of appreciation for proven designs,
founded in evidence, seems to show that, as animals, we have buttons buried
deep within us, that these designs manage to push.

We all seem to like the same thing, once someone finds it or figures it out,
even without knowing specifically why. Certain shapes and designs seem to
transcend language, education, formal training and analytical judgement.

There are rule sets that seem to appeal to us, instictively, and yet
spaceships are not bound by those "rules of instinctive appeal" even though
qualitatively, we can't state what those rules are or where they come from.

The mystery, regarding where that post-hoc appeal comes from is what's
interesting.

Not that people aren't master draftsman, and materials scientists out of the
womb.

~~~
btrettel
I disagree. If efficient designs pushed some buttons in your head in a
satisfying way, you'd find people absolutely fascinated by things like the
Sears-Haack body:

[https://en.wikipedia.org/wiki/Sears%E2%80%93Haack_body](https://en.wikipedia.org/wiki/Sears%E2%80%93Haack_body)

Yet I'm not aware of anyone who is. In fact, the Sears-Haack body is basically
a toothpick, which makes it ugly as far as I'm concerned.

There's a simpler explanation for why airplane designs are often beautiful.
Ugly designs typically don't sell as well. So designers look for something
beautiful and at least reasonably efficient. In this view, there's no
particular connection between the beauty of the design and its efficiency.

I know that for car designs, we've known empirically for nearly 100 years how
to make a very low drag body shape. And most car shapes on the market are far
from optimal. While I've had arguments with people about why the most
efficient shapes don't appear on the market (e.g., someone argued they'd have
less cargo capacity, which I don't agree with), ultimately, few people want to
drive a car that looks like a fish or something else that's strange. I imagine
a similar phenomena occurs with planes.

This design is very efficient, but the company folded after about 6 years:

[https://en.wikipedia.org/wiki/Aptera_2_Series](https://en.wikipedia.org/wiki/Aptera_2_Series)

Personally, I don't find the design attractive. And I doubt your average HN
reader feels as compelled by the design as they do about the latest Tesla, for
example.

~~~
hymen0ptera
This continues to invert the premise. The intersection of appealing things and
functional things is more interesting that either taken in isolation.

------
lev99
The podcast .NET Rocks has several "geek out" episodes, which go into depth
about tech. About two years ago they did one on supersonic flight, and I
remember a lot of details about quiet sonic bombs there. Well worth a listen
if someone wants to learn more about supersonic travel. Actually, all of the
geek outs are fantastic.

[Episode summary]

> Concorde is gone, what will replace it? Time for a Geek Out! Richard talks
> about the aeronautical evolution that led to supersonic airliners, Concorde
> being the big one that flew from 1976 to 2003. What went wrong? Why did it
> stop flying? Besides the technological challenges, it all comes down to the
> sonic boom and laws that make it illegal to fly a civilian aircraft above
> the speed of sound. Richard talks about how technology has advanced enough
> now that aircraft can mitigate their sonic boom with specific shapes and
> flying capabilities. However, in the end, supersonics only get you there
> faster, typically for more money. Would you pay for to go faster?

[http://www.dotnetrocks.com/?show=1286](http://www.dotnetrocks.com/?show=1286)

~~~
RCampbell
The place where we ended up in that show is that airlines find that time and
again, customers will pay for more luxury rather than time... a regular
subsonic flight JFK-LHR is a bit over 7 hours, Concorde cut that to 3:15. But
does that matter? People like the idea of getting there faster, but when it
comes to actually spending money on it, most wouldn't do it.

A one-way trip on Concorde was about $5000, and for that money, you got an
old-school business-class seat (they never updated the interior of Concorde),
no overhead bins, no internet access, no entertainment system of any kind. For
that same money, you get the all-encompassing cocoon of the modern business-
class pod on a 787. It may take twice as long, but you don't care because
you're comfortable.

Meantime, we're getting closer to manned hypersonic flight, Mach 5+ with
combined cycle engines. Considering the development time necessary for a new
airliner, especially with experimental technology like new supersonic engines,
I think the LockMarts and Boeings of the world are waiting for more of that
technology to mature. It would suck to develop a brand new Mach 2 airliner
just in time for someone else to build a Mach 5 airliner.

Also, the Mach 5 designs using ramjets would fly high enough (>80,000 feet)
that sonic booms are really not an issue. The SR-71 at Mach 3 and 80,000 feet
was virtually inaudible.

Much of the experimentation going on around shaping sonic booms is proving
contemporary fluid dynamic models that show that you can "customize" your
N-Wave and make the kind of boom you want to make.

Interesting times!

------
chx
> Japan Airlines invested $10 million into Boom Technologies,

OK so Boom has raised 47.3M so far according to techcrunch which is ...
nothing? Even something as relatively simple as the Sukhoi Superjet 100 had a
program cost of 1.5B. I can't even imagine how much a supersonic jet will
cost.

~~~
dingaling
I don't think anyone in aerospace expects Boom / Aerion / Spike etc to
actually deliver. More likely they're positioning for acquihire.

------
grendelt
Hey! Hey! I live in Galveston.

I didn't know there was a citizen-scientist branch of this operation. (NASA
did announce their plans earlier this year.) I'm actually quite excited about
this happening.

------
abhiminator
This is exciting. Concorde's withdrawal from active service back in 2003
dragged the aviation industry back by at least a couple decades imo, though I
concede that its critics are right in pointing to the fact that the aircraft
was an absolute disaster when it came to its carbon footprint and overall eco-
efficiency. [0]

This project, if successful, could be a 'Wright brothers' moment for
supersonic travel and would dramatically cut down inter-continental travel
time, thereby propelling the aviation industry into stratosphere and
increasing the global financial throughput as a result of decreased flying
duration -- in the next decade or so.

[0] [https://www.tapatalk.com/groups/concordesst/concorde-s-
envir...](https://www.tapatalk.com/groups/concordesst/concorde-s-
environmental-impact-t837.html)

~~~
ant6n
Bringing our carbon footprint into the stratosphere as well (both via
passenger miles, and via carbon per passenger mile).

And the chances for electrification are even more remote than for subsonic
planes -- at least its conceivable that electric propeller planes could work,
in 50 years or so.

~~~
abhiminator
How about hybrid propulsion systems?

I agree with your assertion that complete electrification of the aviation
industry is several decades away, but a hybrid solution should be optimally
feasible given the advances in battery density and related industries. [0]

[0] [http://www.eenewseurope.com/news/hybrid-electric-aircraft-
ne...](http://www.eenewseurope.com/news/hybrid-electric-aircraft-next-step-
electrification-mobility-0)

~~~
delibes
I think battery for commercial jet airliners might be a long way off, due to
jet fuel's energy density. Small planes might manage.

One idea I recall from Virgin Airlines a while back was to have planes towed
around the airport so they didn't have to burn fuel on the ground. Ah here we
go (2006!) :

[http://news.bbc.co.uk/1/hi/business/6203636.stm](http://news.bbc.co.uk/1/hi/business/6203636.stm)

~~~
dx034
I guess we'll end up creating fuel on the ground with renewable energy and use
that for jets. This would go a long way towards reducing emissions and only
needs minor adjustments to planes/engines. I believe some airlines already
tested alt fuel sources as a mix (although they were based on plant oil iirc).

------
sien
There is an episode of the excellent Inside Skunkworks podcast about the
Lockheed team that is building the aircraft for these tests:

[https://soundcloud.com/user-291478498](https://soundcloud.com/user-291478498)

It's well worth a listen, as are the other episodes in the series.

~~~
Already__Taken
"A low rumble" I presume? Thanks for the recommendation

------
fergbrain
I wonder if this is related to Boeing’s announcement:
[https://www.boeing.com/features/2018/06/hypersonic-
concept-v...](https://www.boeing.com/features/2018/06/hypersonic-concept-
vehicle.page)

------
keyle
It's weird to see real innovation happen again. For so many years innovation
has been about how to fit as many meat bags as possible in a shoe box,
prentending to be luxurious, at the adequate speed to save the most fuel as
possible.

~~~
JumpCrisscross
> _innovation has been about how to fit as many meat bags as possible in a
> shoe box_

That's an odd way to describe the most accessible era of global travel in
human history. It's not like first class tickets, which provide a comparable
experience at a comparable inflated-adjusted price, aren't available to bring
back the 60s.

There are more travelers who want a cheaper ticket than there are those who
want, more than cheaper tickets, (a) more comfort or (b) faster travel.
Evidence for this is in the demand for cheap tickets with long layovers and
repeat flyers in basic economy.

~~~
always_good
I recently paid bottom dollar for a flight and was annoyed when my knees
jammed up against the seat in front of me. I had to contort myself a bit to
fit.

Then I chuckled at the annoyance since I, myself, had decided to get the dirt-
cheapest flight available. Couldn't even be bothered to pay +$15 for an
emergency exit seat.

...And I would've done it all the same again for that 2 hour flight.

I just saw a Reddit thread where someone asked how many people would pay extra
for a flight with no babies allowed. I had to roll my eyes at every commenter
who said they would.

~~~
slavak
> Flying is the worst one because people come back from flights and they're
> telling you their story, and it's like a horror story. They act like their
> flight was a cattle car in the 40s in Germany. They're like, 'it was the
> worst day of my life! First of all, we didn't board for like 20 minutes and
> then they made us sit there on the runway for 40 minutes! We had to sit
> there!' Oh really? What happened next? Did you FLY in the AIR incredibly
> like a BIRD? Did you partake in the miracle of human flight, you non-
> contributing zero?! ... You're sitting in a chair in the SKY! Here's the
> thing: people say there's delays. Delays? Really? New York to California in
> 5 hours. That used to take 30 years! And a bunch of you would die on the way
> there, and have babies... you'd be a whole different group of people by the
> time you got there. Now, you watch a movie, you take a dump, and you're
> home!

— Louis CK

------
ploek
Am I understanding correctly that in the tests not the actual prototype will
fly, but rather F/A-18s that somehow mimic the wave patterns generated by the
X-59? How does that work?

~~~
thornjm
Complete guess but they might use multiple F/A-18s, each with their own boom
in a specific formation, to mimic the non-combining booms of the X-59?

------
m-p-3
I'm curious to hear that, hopefully someone will record the attempts!

------
DocTomoe
In a bid to save America's transatlantic and transpacific airline industry,
the US banned the Concorde from flying over the mainland because of "noise
concerns".

I feel like Europe should return the favor should this ever result in an
airliner.

~~~
Reason077
Noise “concerns” were very much genuine with the Concorde.

An incredible achievement of technology and engineering, but an environmental
disaster.

~~~
sschueller
What about all the military aircraft?

~~~
Someone1234
Military aircraft are highly restricted from going supersonic over populated
areas too[0].

We live near a US Air Force base, we had a single sonic boom last year and the
base put out a tweet/statement apologizing, and the pilot got written up.

During national security incidents like 9/11 all bets are off.

[0] [https://aviation.stackexchange.com/questions/44759/do-
usaf-f...](https://aviation.stackexchange.com/questions/44759/do-usaf-fighter-
jets-go-supersonic-over-land)

~~~
WalterBright
When I was a kid in the 60s, sonic booms were regular from the AF. I always
enjoyed them.

------
Tempest1981
Please capitalize NASA -- it's an acronym (for National Aeronautics and Space
Administration)

~~~
bbrian
In Ireland, DART means Dublin Area Rapid Transit, but since it's pronounced
"dart" rather than "d", "a", "r", "t", it's appropriate to write it "Dart". Or
so my brother tells me.

------
Sarki
[https://en.wikipedia.org/wiki/Magnetohydrodynamics](https://en.wikipedia.org/wiki/Magnetohydrodynamics)

But yeah, it's a breakthrough...

Oh look
[https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive](https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive)

No one mentions as well that the optimum form factor for such a technology
consists in two round plates facing each other (wink-wink).

------
Theodores
So the F-104 Starfighter tests in Oklahoma in 1964 were not good enough then?

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

It seems that the military have more money than sense to pursue a failed idea
that isn't going to help win The War Against CO2 levels. Only in America.

~~~
Already__Taken
Good enough for what? This is about aircraft design to reduce/eliminate the
booms. Those test were about finding what the public would put up with, that
being none at all.

