TIHI, ALI BRŽI OD ZVUKA: NASA je angažirala Lockheed Martin za izgradnju prototipa supersoničnog aviona, letjet će već za četiri godine?

  • 04.04.2018. u 15:26

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US Space agency NASA has ASA has taken another step toward re-introducing supersonic flight but without the noise.California-based Lockheed Martin will complete the design and building of an experimental aircraft, known as an X-plane.It will be able to cruise at a height of 55,000 feet / 16.75 kilometres at a speed of about 940 mph / 1,500 kilometres an hour.
That's neary twice the speed of a coventional long haul passenger planeAmazingly the sound it creates will be about as loud as a car door closing, 75 Perceived Level decibel (PLdB), instead of a huge sonic boom.Once NASA accepts the aircraft from the contractor in late 2021, the agency will perform additional flight tests to prove the quiet supersonic technology works as designed, aircraft performance is robust, and it’s safe to operate in US airspace.A sonic boom is the noise caused when an aircraft breaks the sped of sound, to a gentle thump.It was this that curtailed sales of the Anglo-French supersonic aircraft Concorde which was forbidden to fly at the speed of sound over land masses.The Lockheed Martin contract is valued at $247.5 million USD.Work under the contract began on April 2 and runs through Dec. 31, 2021.Beginning in mid-2022, NASA will fly the X-plane over select U.S. cities and collect data about community responses to the flights. This data set will be provided to U.S. and international regulators for their use in considering new sound-based rules regarding supersonic flight over land, which could enable new commercial cargo and passenger markets in faster-than-sound air travel.NASA’s associate administrator for aeronautics Jaiwon Shin said:” It is super exciting to be back designing and flying X-planes at this scale.“Our long tradition of solving the technical barriers of supersonic flight to benefit everyone continues.”The key to success for this mission , known as the Low-Boom Flight Demonstrator , will be to demonstrate the ability to fly supersonic, yet generate sonic booms so quiet, people on the ground will hardly notice them, if they hear them at all.Current regulations, which are based on aircraft speed, continue to ban supersonic flight over land. With the Low-Boom Flight Demonstrator, NASA intends to gather data on how effective the quiet supersonic technology is in terms of public acceptance by flying over a handful of U.S. cities, which have yet to be selected.The answer to how the X plane design makes a quiet sonic boom is in the way its uniquely-shaped hull generates supersonic shockwaves. Shockwaves from a conventional aircraft design coalesce as they expand away from the airplane’s nose and tail, resulting in two distinct and thunderous sonic booms.But the LBFD Low-Boom Flight Demonstrator design’s shape sends those shockwaves away from the aircraft in a way that prevents them from coming together in two loud booms. Instead, the much weaker shockwaves reach the ground still separated, which will be heard as a quick series of soft thumps – again, if anyone standing outside notices them at all.The LBFD X-plane’s configuration will be based on a preliminary design developed by Lockheed Martin under a contract awarded in 2016. The proposed aircraft will be 94 feet / 28.6 metres long with a wingspan of 29.5 feet /nine metres and have a fully-fuelled takeoff weight of 32,300 pounds / 14,650 kilos.The jet will be propelled by a single General Electric F414 engine, the power-plant used by F/A-18E/F fighters.A single pilot will be in the cockpit, which will be based on the design of the rear cockpit seat of T-38 training jet used for years by NASA’s astronauts to stay proficient in high-performance aircraft.Two primary NASA pilots will fly the X-plane after Lockheed Martin’s pilots have completed initial test flights to make sure the design is safe to fly.One of them, Jim Less, said: “A supersonic manned X-plane!“This is probably going to be a once-in-a-lifetime opportunity for me. We’re all pretty excited.”Less is the deputy chief pilot for the tests. He and his boss, chief pilot Nils Larson, have already provided some input into things like cockpit design and the development of the simulators they will use for flight training while the aircraft is under construction.Less added:” It’s pretty rare in a test pilot’s career that he can be involved in everything from the design phase to the flight phase, and really the whole life of the program.”
OPS: Lockheed Martin artist's concept of a Low Boom Flight Demonstrator X-plane
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Render supersoničnog aviona Lockheed Martina

Američka svemirska agencija NASA angažirala je Lockheed Martin za projektiranje, izgradnju i testiranje aviona koji će letjeti brže od zvuka i probijati zvučni zid uz vrlo nisku razinu buke, naveli su dužnosnici.

Ugovor je vrijedan 247,5 milijuna dolara, a probni let zrakoplova najavljen je za 2021. godinu.

Eksperimentalni zrakoplov "kružit će na visini od 55.000 stopa (16,8 kilometara) brzinom od oko 940 kilometara na sat, a pri probijanju zvučnog zida neće proizvoditi zvučni udar već zvuk nalik zatvaranju vrata automobila, na percipiranoj razini buke od 75  decibela (PLdB)", navela je američka svemirska agencija u priopćenju objavljenom u utorak.

Već sredinom 2022. godine zrakoplov bi prema NASA-inim planovima trebao letjeti iznad skupine američkih gradova radi prikupljanja podataka i reakcija zajednice.

Cilj je projekta omogućiti tihi let brzinama većim od brzine zvuka i otvoriti "nove trgovačke komercijalne teretne i putničke putove u zrakoplovnim putovanjima bržima od zvuka", priopćila je NASA.

U ožujku je američki predsjednik Donald Trump potpisao proračun iz čijih se sredstava u cijelosti financira taj projekt te naglasio da će se novim zrakoplovom "otvoriti novo tržište za američke tvrtke u izgradnji bržih komercijalnih zrakoplova, stvoriti nova radna mjesta i prepoloviti broj letova preko kopna“.

Putnička sjedala ipak nisu dio projekta na kojem radi Lockheed Martin, bar ne za sada. Tvrtka prvo mora dokazati da je moguće letjeti takvim zrakoplovom. Slijedi nužna promjena propisa iz kojih bi trebalo izbaciti važeću zabranu komercijalnih letova takvih zrakoplova nad kopnom.

Slične projekte pokrenule su i druge tvrtke, uključujući Virgin Galactic i Spike Aerospace, napominje agencija AFP.

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