NASA opens new chapter in supersonic flight-2003

[kach22i]

NASA opens new chapter in supersonic flight
http://spaceflightnow.com/news/n0309/06supersonic/

Flight tests completed by NASA, with government and industry partners, may have demonstrated a way to reduce the window-rattling impact of sonic booms.........................................An aircraft traveling through the atmosphere continuously produces air-pressure waves similar to waves created by the bow of a ship. When the aircraft exceeds the speed of sound (approximately 750 mph at sea level), the pressure waves merge to form shock waves, which are heard as a sonic boom, when they reach the ground. The flight tests showed by designing the aircraft to a specific shape, the pressure waves can be kept from merging. When these weaker waves reach the ground, the loudness of the sonic boom is greatly reduced.

Credit: NASA


Interesting comments by Craig Fink:
http://www.usenet.com/newsgroups/sci.aeronautics/msg00104.html

[Joeaksa]

Old news, they have been working on that for years. Glad to see them working on this issue but the changes needed to modify the sonic signature were massive.

That plane has been around Edwards for a long time.

[fastpat]

The biggest issue for supersonic flight has always been, and will always be, fuel consumption. Only if a very low cost fuel source is created, will ultra high speed flight be a reality.

[kach22i]

From a year ago.........................

http://www.machinedesign.com/ASP/viewSelectedArticle.asp?strArticleId=59901&strSite=MDSite

Market research studies predict a worldwide demand for as many as 500 supersonic business jets (SBJ) that can cruise at Mach 1.5 and be bought for about $80 million. Major business-jet companies — including Dassault, Cessna, and Gulfstream — claim to be working on their versions of SBJs, but are reluctant to talk details. Only Bombardier, the Canadian business-jet builder, says it just doesn't see an SBJ in its future. In the meantime, two upstart startups — Aerion Corp. and Supersonic Aerospace International (SAI) — each say they will have an eight to 12-passenger SBJ with a 4,000-nautical-mile range FAA-certified and on the tarmac early in the next decade. Strangely, the two companies are taking almost diametrically opposed paths.

The supersonic business jet from Aerion relies on natural-laminar-flow wings to fly efficiently at super and subsonic speeds.


The QSST from SAI will use a Skunk Works design that features an inverted-V tail.

EDIT:

http://www.saiqsst.com/about.html

As the founder and former CEO of Gulfstream, Allen E. Paulson............

http://www.aerioncorp.com/about_aerion-corp-management.html

Mr. Barents leads Aerion’s effort to develop a consortium to produce supersonic aircraft. He is the former CEO of two business jet manufacturers, Learjet and Galaxy Aerospace.

[m21sniper]

Pat, Supercruise(supersonic flight without afterburner) was/is a massive breakthrough in regard to fuel effficeincy at supersonic speed.

Hence the massive range of the F-22 and it's unheard of supersonic persistence. One of the engineers at my site works the F-22 program. He gushes about the F-22.

[motion]

Wow... can't even remember the last time I hears a sonic boom.

[kach22i]

Originally posted by motion
Wow... can't even remember the last time I hears a sonic boom.

Turn up the sound:
http://video.google.com/videoplay?docid=-269376791712267206&q=sonic+boom&hl=en

[MFAFF]

Guys...

Concorde used supercruise (supersonic flight without the use of continuous after burner) as a basic design parameter....and its persistance is sufficient for it to cross the Altantic (just).. not to mention its also quite quite fast in supercruise.. (M2.02, fastest recorded was M2.23)

Just a comparison; in the supersonic cruise part of its flight Concorde matched the efficiency of the 747 Classic series...but getting there was, unsurprisingly massively fuel hungry, thanks to the use of turbojets rather than fans...

The issue with supersonic flight over land is that the sonic boom WAS the only factor that prevented it from becoming a reality....

The tests undertaken by the USAF/NASA and the FAA with both the B-58 and the XB-70 during the 60s proved the lingering suspicion that any large and heavy aircraft flying supersonically over the ConUS was never going to be acceptable....hence the legislation banning it.

That it was formulated around the planned time of introduction of Concorde (which was then delayed not entering commercial service til 1976) was a co-incidence....not necessarily a deliberate 'protectionist' measure.

The aim of that NASA programme was to try to 'reshape' the boom form to reduce the initial rate on increase of overpressure and the rate of decrease...in real terms the pressure change is not a problem to people and things.. its the rate of change of that pressure that doe the damage.. like hitting a wall at speed... the speed doesn't kill you, its the slowing down..

If that pressure curve can be refined and the max overpressure reduced then overland ss flight may be acceptable... and then the market for much higher speeds will be open again....

Remember Concorde was retired not because of its direct operational costs were excessive, (fuel, crew etc) but because a single user (BA) was being asked to shoulder ALL of the product support cost.. a cost increase, in the order of 80%, which the business plan could no longer support profitable operations.. remember she would have in all probability been retiring this year anyway...

I miss her everyday... around 17.25 as she flew directly over my office coming bakc from NYC...

[artplumber]

Originally posted by MFAFF

The tests undertaken by the USAF/NASA and the FAA with both the B-58 and the XB-70 during the 60s proved the lingering suspicion that any large and heavy aircraft flying supersonically over the ConUS was never going to be acceptable....

Beautiful planes....