New supersonic passenger plane

[Scooter]

SON OF CONCORDE: SUPERSONIC PASSENGER JET TO TAKE OFF NEXT YEAR

An American firm is promising the return of supersonic passenger aviation, with transatlantic airfares “about the same price as today’s business class tickets”.

Boom, based in Denver, says London-New York will cost £2,000 one-way and take just 3 hours 15 minutes. With a planned cruising speed of 1,451mph, the plane is almost 100mph faster than Concorde.

The firm is building an aircraft called XB-1, “a one-third scale realization of the Boom passenger airliner”. It is claimed to be the first independently developed supersonic jet and history's fastest civil aircraft.

“It is under construction now and will fly next year,” says Boom, with scheduled supersonic services on a 55-seat plane by 2023.

Subsonic flight tests will be conducted in Colorado, with supersonic flight proving taking place near Edwards Air Force Base in California. Virgin Galactic, Sir Richard Branson’s space venture, will be involved in the tests.

Concorde was fitted with noisy and thirsty military engines. The 1960s technology used for the Anglo-French project was extremely challenging, with the aluminium airframe extending by about 15 inches due to the heat of supersonic flight. Boom will use carbon composites, which are lighter and expand much less with heat. The testbed aircraft uses three General Electric J85-21 turbojet engines.

The firm is inviting American executives to “Leave New York at 6am, make afternoon and dinner meetings in London, and be home to tuck your kids into bed.”

The 11-hour flight time from San Francisco to Tokyo will be halved, again making day-trips possible. And the 7,500-mile Los Angeles-Sydney run will take under seven hours: “Leave LA at 7am, enjoy an operetta in Sydney, and be back before midnight.” promises the company.

The small print reveals that the maximum range is 5,180 miles (4,500 nautical miles), less than London to Mexico City or Buenos Aires.

The firm says: “Routes over 4,500nmi include a brief tech stop, included in listed flight times. Passengers do not need to deplane or exit their seats.”

It is telling airlines: “The breakthrough Boom airliner allows you to offer Mach 2.2 flights profitably at the same fares as subsonic business class.

“A major problem with Concorde is that it had more seats than could be filled at the required prices. The Boom aircraft has 55 seats, similar to the premium cabin in a typical widebody aircraft.”

Since the demise of Concorde — hit by high oil prices, low demand and concerns about safety following the 2000 crash in Paris — plans for high-speed civil aircraft have foundered.

The price of the Boom passenger jet is set at $200m (£160m).

[MajGenl.Meade]

Fly a little longer.... the stretch limo of the air:

One of the greatest challenges aircraft designers confront when building a supersonic plane is the effect of high temperature on the vehicle. These high temperatures are the result of kinetic heating caused by friction between the outside air and the skin of the rapidly moving aircraft. The following diagram illustrates just how hot different parts of the Concorde became at its cruise speed of Mach 2. The skin temperature ranged from a peak of 127°C (260°F) at the nose to 90°C (194°F) at the tail.



Temperature contours on the Concorde during cruise flight


These temperatures rose even higher at the Concorde's maximum rated speed of Mach 2.2, with a peak nose temperature of 153°C (307°F). If those temperatures aren't impressive enough on their own, just consider that the outside air temperature at the Concorde's cruise altitude of 17,000 m (56,000 ft) is only -57°C (-70°F)!

This external heating had a significant impact on the construction of Concorde. Perhaps the most important issue designers had to contend with was the fact that heat causes materials to expand. I've seen different values on exactly how much the aircraft expanded, but most sources indicate that the airframe stretched by 5 to 12 inches (12 to 30 centimeters) at Mach 2. Given the aircraft's normal length of 204 ft (62.2 m), that change amounts to less than a 5% increase in the size of the Concorde fuselage.

That is not to say that the issue was not a problem. Far from it! The most significant challenge the manufacturers had to address was to select a material that could withstand the heat and expansion while maintaining its mechanical properties throughout the life of the aircraft. Most conventional airliners are built out of aluminum because of its high strength and relatively low weight. Unfortunately, traditional aluminum alloys cannot survive the high temperatures experienced by Concorde. More exotic materials like titanium could have been used, but these are very expensive and often too heavy for use on such a large plane.

The manufacturers instead chose a new advanced alloy of aluminum developed by Rolls-Royce to survive high temperatures. This alloy was known as CM001, CM002, or CM003 depending on the recipe used for the various components. While this aluminum alloy lowered costs and saved weight, it was still inadequate for some areas of severe heating where steel or titanium had to be used.

A further problem designers had to address was the uneven changes in temperature across the aircraft during different phases of flight. This problem was most significant during acceleration to Mach 2 to reach cruise conditions and deceleration prior to landing. These uneven changes in temperature caused some parts of the plane to expand or contract more rapidly than others. This problem resulted in greater stresses and loads acting on the plane's structure at different phases of the flight. Designers were able to overcome these effects by allowing various parts of the plane to move with respect to one another, thereby easing the internal stresses. Examples of these sliding connections included corrugated spar webs, diamond-shaped cutouts, and slotted lug attachments.

While it may seem low-tech, the Concorde's external paint was also chosen to help alleviate the problems of thermal expansion. The white paint was specially developed to help dissipate the heat generated on the surface of the plane at high speed. The paint was also designed to be flexible so that it would not flake off the plane during the thermal expansion and contraction experienced in flight.

http://www.aerospaceweb.org/question/pl ... 199a.shtml

[oldr_n_wsr]

Engineering, engineering, engineering.
It makes the world a better place. (usually)


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[RayThom]

Next year? I'm skeptical. I'll believe it when I see it flying.