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Old March 6th 19, 03:47 PM posted to rec.aviation.piloting
Larry Dighera
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Default Boeing shows off new transonic wing concept

https://newatlas.com/boeing-transoni...concept/57940/

Boeing shows off new transonic wing concept

Boeing has taken the wraps off of a new ultra-thin wing concept
designed to improve the performance of transonic aircraft traveling at
speeds of Mach 0.8 (593 mph, 955 km/h). The latest version of the
company's Transonic Truss-Braced Wing (TTBW) can fly higher and faster
than previous iterations thanks to its optimized support truss and
adjusted wing-sweep angle.

We hear a lot these days about the return to commercial supersonic
https://newatlas.com/nasa-supersonic...ontract/42093/ air
travel and even the advent of hypersonic flight
https://newatlas.com/hypersonic-flight/50801/ , but the real cutting
edge in aerospace engineering at the moment is in transonic flight.
Almost all flying outside of military circles takes place in the
subsonic realm. That is, speeds under Mach 0.8 (609 mph, 980 km/h).
However, in the highly competitive world of commercial passenger and
freight hauling, that's not quite good enough.

You might be asking yourself, if the speed of sound is Mach 1 (767
mph, 1,235 km/h), why is subsonic below Mach 0.8? The reason is that
the realm between Mach 0.8 and Mach 1.2 (913 mph, 1,470 km/h) is what
is known as transonic. That is, the range of speeds just before
breaking the sound barrier, and just after that's marked by an
increase in air resistance and other factors that can be rough on an
airframe.

Ideally, engineers would like to get as close to transonic as possible
without pushing the sound barrier, but it's far from easy. That's
because it isn't a matter of the whole aircraft going from subsonic to
transonic. As one approaches the transition point, some parts of the
plane will be over the limit while others will be below it. An example
of this is prop-driven fighter planes at the end of the Second World
War that would suddenly start to shake themselves apart because they
were flying so fast their faster-spinning propellers were breaking the
sound barrier.

According to Boeing, the TTBW was originally designed to operate in a
range of Mach 0.70 to 0.75 (519 to 556 mph, 835 to 895 km/h), but the
new truss, wing sweep, and integrated design allows for better speed
and altitude performance by creating a thin, foldable wing with a span
of 170 ft (52 m).

The purpose of this is not only to produce a better wing for transonic
flight, but also one that is more eco-friendly. It was developed as
part of NASA's Subsonic Ultra Green Aircraft Research (SUGAR)
https://newatlas.com/boeing-sugar-vo...ircraft/15915/ program,
which aims at creating sub and transonic aircraft that are 71 decibels
quieter than current FAA noise standards, have a 71-percent reduction
in nitrogen oxide emissions, and burn 70 percent less fuel.

Source: Boeing:
http://www.boeing.com/features/2019/...?sf205320177=1