Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1). For objects traveling in dry air of a temperature of 20 C (68 F) at sea level, this speed is approximately 343.2 m/s (1,126 ft/s; 768 mph; 667.1 kn; 1,236 km/h). Speeds greater than five times the speed of sound (Mach 5) are often referred to as hypersonic. Flights during which only some parts of the air surrounding an object, such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2.
Sounds are traveling vibrations in the form of pressure waves in an elastic medium. Objects move at supersonic speed when the objects move faster than the speed at which sound propagates through the medium. In gases, sound travels longitudinally at different speeds, mostly depending on the molecular mass and temperature of the gas, and pressure has little effect. Since air temperature and composition varies significantly with altitude, the speed of sound, and Mach numbers for a steadily moving object may change. In water at room temperature supersonic speed can be considered as any speed greater than 1,440 m/s (4,724 ft/s). In solids, sound waves can be polarized longitudinally or transversely and have even higher velocities.
At the beginning of the 20th century, the term "supersonic" was used as an adjective to describe sound whose frequency is above the range of normal human hearing. The modern term for this meaning is "ultrasonic".
The tip of a bullwhip is thought to be the first object designed to break the sound barrier, resulting in the telltale "crack" (actually a small sonic boom). The wave motion travelling through the bullwhip is what makes it capable of achieving supersonic speeds. However, the first man-made supersonic boom was likely caused by a piece of cloth, spurring the whip's eventual development.
Most spacecraft are supersonic at least during portions of their reentry, though the effects on the spacecraft are reduced by low air densities. During ascent, launch vehicles generally avoid going supersonic below 30 km (98,400 feet) to reduce air drag.
To date, only one land vehicle has officially travelled at supersonic speed, the ThrustSSC. The vehicle, driven by Andy Green, holds the world land speed record, having achieved an average speed on its bi-directional run of 1,228 km/h (763 mph) in the Black Rock Desert on 15 October 1997.
Most modern fighter aircraft are supersonic aircraft. No modern-day passenger aircraft are capable of supersonic speed, but there have been supersonic passenger aircraft, namely Concorde and the Tupolev Tu-144. Both of these passenger aircraft and some modern fighters are also capable of supercruise, a condition of sustained supersonic flight without the use of an afterburner. Due to its ability to supercruise for several hours and the relatively high frequency of flight over several decades, Concorde spent more time flying supersonically than all other aircraft combined by a considerable margin. Since Concorde's final retirement flight on November 26, 2003, there are no supersonic passenger aircraft left in service. Some large bombers, such as the Tupolev Tu-160 and Rockwell B-1 Lancer are also supersonic-capable.
The main key to having low supersonic drag is to properly shape the overall aircraft to be long and thin, and close to a "perfect" shape, the von Karman ogive or Sears-Haack body. This has led to almost every supersonic cruising aircraft looking very similar to every other, with a very long and slender fuselage and large delta wings, cf. SR-71, Concorde, etc. Although not ideal for passenger aircraft, this shaping is quite adaptable for bomber use.
Boom Supersonic, the high-profile aviation company building modern supersonic airliners for commercial service, will build its manufacturing and final assembly facility in Greensboro, creating more than 1,750 jobs by 2030, Governor Roy Cooper announced today. The project will bring an investment of more than $500 million through 2030 at a site located at the Piedmont Triad International Airport in Guilford County.
"The team at FTT has a decades-long history of developing innovative, high-performance propulsion solutions," company president Stacey Rock said in a press release. "We are proud to team with Boom and its Symphony partners and look forward to developing the first bespoke engine for sustainable, economical supersonic flight."
Designed to operate on 100% sustainable aviation fuel, the new medium-bypass turbofan engine will emit net zero carbon, feature 35,000 pounds of takeoff thrust, have low-weight materials, and reduce overall operating costs by 10% compared to other supersonic engines.
The news comes just a few months after every major manufacturer said it would not help Boom create an engine for Overture, with Rolls-Royce saying the "commercial supersonic market is not currently a priority for us."
"United and Boom share a passion for making the world dramatically more accessible through sustainable supersonic travel," he said in a press release. "The team at Boom understands what we need to create a compelling experience for our passengers, and we are looking forward to a United supersonic fleet powered by Symphony."
Watch video coverage of the panel online to hear industry insights on: current research and development efforts, enabling technologies, current tests and upcoming first flights, technology challenges in need of innovative solutions, potential myths supersonic professionals are anxious to dispel, and whether all the technology challenges have been solved to bring supersonic commercial transport to reality.
The SSTs investigated are expected to burn 7 to 9 times more fuel per seat-km flown than the subsonic baseline, creating substantial environmental impacts and poor economics. In the hypothetical case where supersonics have access to e-kerosene at cost parity with fossil jet fuel (Jet A), e-fuels could reduce lifecycle CO2 emissions by about 90% compared to Jet A, but only modestly reduce (6 to 24%) CO2 per seat kilometer compared to more fuel-efficient subsonic designs operating on Jet A. We find significant tradeoffs, however, in the use of e-fuels in supersonic aircraft owing to the high altitudes at which they fly. Operating the Large SST on e-kerosene could increase the medium-term RF of commercial aviation by two-thirds despite covering less than 1% of all traffic in ASKs.
Overall, we conclude that environmental considerations are likely to tightly constrain supersonic markets for the foreseeable future. Both low-boom designs and ultralow cost sustainable aviation fuel (SAF) will be needed for a sizeable supersonic market to develop. In the near-term, any supersonic aircraft developed are likely to be operated on fossil fuels, not e-kerosene, after being delivered.
Architected materials with nanoscale features have enabled extreme combinations of properties by exploiting the ultralightweight structural design space together with size-induced mechanical enhancement at small scales. Apart from linear waves in metamaterials, this principle has been restricted to quasi-static properties or to low-speed phenomena, leaving nanoarchitected materials under extreme dynamic conditions largely unexplored. Here, using supersonic microparticle impact experiments, we demonstrate extreme impact energy dissipation in three-dimensional nanoarchitected carbon materials that exhibit mass-normalized energy dissipation superior to that of traditional impact-resistant materials such as steel, aluminium, polymethyl methacrylate and Kevlar. In-situ ultrahigh-speed imaging and post-mortem confocal microscopy reveal consistent mechanisms such as compaction cratering and microparticle capture that enable this superior response. By analogy to planetary impact, we introduce predictive tools for crater formation in these materials using dimensional analysis. These results substantially uncover the dynamic regime over which nanoarchitecture enables the design of ultralightweight, impact-resistant materials that could open the way to design principles for lightweight armour, protective coatings and blast-resistant shields for sensitive electronics.
The P-270 Moskit missile, which has the NATO reporting name or SS-N-22 Sunburn, is a medium-range supersonic cruise missile of Soviet origin, capable of destroying a ship within a range of up to 120 kilometers.
A simple slogan that recognizes time is limited and there is so much to do, to enjoy, to see, to create and to love. If time is precious to you, we believe supersonic flight will give you back your time and let you do whatever you wish.
But other competitors are also planning supersonic passenger jets. Spike Aerospace is developing an ultra-fast business jet, and startup Hermeus is developing a plane that would travel five times the speed of sound.
The agreement puts American, the largest U.S. airline, in a position to have the world's largest fleet of supersonic jets. The deal includes an option for the carrier to purchase an additional 40 aircraft, which would carry 65 to 80 passengers, Boom Supersonic said in an announcement Tuesday.
"Looking to the future, supersonic travel will be an important part of our ability to deliver for our customers," Derek Kerr, chief financial officer at American, said in a statement. "We are excited about how Boom will shape the future of travel both for our company and our customers."
"The idea that you could bring back supersonic is an exciting idea, but a heck of a lot of people got burned the first time around, especially with the cost," Jenks said. "It's got this fantastic cost-inefficiency once you break through the sound barrier that you have to compensate for by having sufficiently high fares."
"The first version of this plane is not for the vast majority of us who sit in the back of the plane behind the curtain. But for senior-level executives and business travelers, people for whom time is money, supersonic travel might be viewed as very attractive," he said. 041b061a72