Introduction : About me

The Cessna Citation X

• World’s fastest business jet : -Citation X held the record with MMO of Mach 0.92 since 1995, only Concorde was faster in the civilian world.

-Gulfstream G650 took the crown briefly with a MMO of Mach 0.925 in 2009

-The upgraded Citation X+ took the speed crown back the following year with a MMO of Mach 0.935

• Accidentally reached Mach 1.18 in dive testing for certification

• Ceiling of 50,000ft

My Hobby…

A Brief History Lesson(Bear with me…)

• 1945: End of world war 2

• Beginning of ‘the Cold war’

• The nuclear arms race ensues…

The Space Race – Wolves in Sheep’s Clothing?

• During WW2, the V2 rocket was developed as a means of delivering a weapons payload without the need for an airfield or carrier vehicle.

• After WW2, Rocket scientists such as Von Braun and Grottrup continued to develop rockets for the opposing adversaries, but under the pretence of science and progress…

The Need to go Supersonic

^ What might have been: The Miles M-52

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The Bell X-1

The perceived need…

Advances in Britain – The DNA of Speed

11 years

1941 1952

1964

12 years

???12 years?

Concorde – what Might have been?(or what was actually intended?)

Olympus 593 Development : Pyestock

• Nation Gas Turbine Establishment at Pyestocknear Farnborough developed the RR/SNECMA Olympus turbojets for Concorde at great expense…

• Olympus 593 engine was an offshoot of developments for the TSR2 and Vulcan

Concorde – Early Orders (1963-1972)

• When Concorde was under development, it originally received more than 115 orders from 18 different airlines

• All were later cancelled, with only British Airways and Air France taking deliveries

Tu-144 : USSR’s Effort, but Why?

• During the height of the cold war, the USSR, a communist nation, decides to develop a luxury high-speed transport….

• Ultimately was used more frequently as a cargo plane than a passenger plane

• And unlike Concorde, it could not supercruise.

Boeing 2707 : The US Contender

• The Boeing 2707 beat the Lockheed L-2000 to win the US government tender to build a civilian SST

• Is the reason why Seattle’s basketball team is called ‘the sonics’

• At one point, more than 120 orders had been placed by airlines

• Significant systems development work was done for the Boeing 2707, but it was cancelled after negative public reaction to the Oklahoma City Sonic Boom tests….

STOP! Rewind! Before Yeager, what did people believe about the sound barrier?

• Early understandings of the speed of sound…

The Prandtl–Glauert Singularity

Ernst Mach : Photographing Bullets

• The picture on the left of a speeding bullet was taken by Ernst Mach in 1887.

• The unit of ‘speed of sound’ is known as ‘Mach’ as a result of his work.

• The actual speed of sound changes with altitude, density and humidity, but is nominally about 750mph

The Sonic Boom Imagined

• ‘Fireflash’ (Gerry Anderson’s Thunderbirds, 1965)

Actual Sonic Booms & Transonic Vapour Cones

The Sonic Boom : What is it really?

• A sonic boom is a pressure wave created by passage through the air at a speed higher than sound waves may propagate, much like the bow wave of a boat on a still lake.

• A ‘boom’ is never experienced by the vehicle itself : it IS the boom, the double pressure-wave is experienced by stationary bystanders, not the occupants.

Toolkit: What do you need to Cruise above Mach 1?

• A lot of thrust!

• A Whitcomb area-ruled body (e.g. the Sears-Haack body, bottom right)

• Afterburners to accelerate through the Mach hump…?

• Variable geometry inlets to enable supercruise!

Operation Bongo II – The Oklahoma City Sonic Boom Tests

• For 6 months during 1964, the people of Oklahoma City were deliberately subjected to 8 sonic booms per day.

• F-104 and B-58 aircraft were used, which flew at various altitudes and speeds to achieve varying psf (pounds-force of ‘overpressure’) shockwaves

• Similar tests were done in the UK with Lightnings, but not on the same scale.

Surprising Reactions & Expected Reactions…

• Most residents felt they could live with 8 sonic booms a day.

• Control houses exhibited no signs of damage, yet there were numerous complaints

• Some used the regularity of the ‘booms’ to signal lunch breaks

• Those who complained were predominantly middle aged housewives (!?)

Fallout from the Oklahoma City Tests

• During the tests, 147 windows in the city’s two tallest buildings were broken.

• There were 9,594 complaints of damage to buildings, 4,629 formal damage claims, and 229 claims for a total of $12,845.32

• The FAA’s responses to the claims, and tardy payment of them, led some to sign petitions and complain to their congressman

• In 1971, Nixon finally relented to public negative perception and pressure from congress fermented by the sonic boom tests and cancelled the Boeing 2707.

• In 1973, the FAA finally banned supersonic flight over land – 3 years before Concorde entered service

America’s Concorde?(Candidate 1)

• Nixon apparently fought hard against congress to keep funding for the Boeing 2707, but ultimately lost out, and the project was cancelled.

• Ultimately, Nixon redirected funding that might have gone to Boeing for the 2707, to NASA for the Space Shuttle Program instead.

America’s Concorde?(Candidate 2)• No attempt was ever made to try to hide the true

design purpose of the XB-70 Valkyrie

• The XB-70 was studied for potential to convert it into a passenger liner, but this never happened

The Boeing 2707 : Systems Retrospective• By the time the Boeing 2707 was cancelled, it was

deep into the design phase – at the equivalent of a ‘CDR’ decision gate

What’s Next?

• Aerion are planning to build a supersonic business jet.

• Boom supersonic have venture capital funding and are planning to build an SST.

The End