Why isn't the Boeing Sonic Cruiser a Supersonic Cruiser?

[Obi Wan Kirk]

It's interesting to see Boeing working on redesigning the Boeing Sonic Cruiser in order to effectively compete with Airbus. I honestly think they should develop a Supersonic version that goes around Mach 1.8-2 and carries 250 pax. Throughout history speed has always been the way of technology, you just have to look at aviation, computer and technology world to see this. I think that if Boeing keep insisting on this sonic airplane they'll do a big flop and may even be taken over by Airbus.

Another consideration is the scramjet that was launched in Australia the other day, all this technology should be used to develop the airliner of the future.
:cool:

[Konkordski]

If it's travelling at Mach 0.98 and then hits a Mach 0.02 headwing, do you get a sonic boom...? ;)

[ETOPS773]

Problem with SST is its a great idea in theory,but we have a little problem called shockwaves.

To cut a long story short,a new aerodynamic method has got to be found / developed to reduce the intenity of the sonic boom,which has a reputation of smashing windows,especially greenhouses,scaring cows (in cornwall they go bonkers apparently...) and causing disruption which people won`t tolerate.

Once thats been pioneered,then a aircraft could go overland at supersonic speed,thats when the SST age will really happen.

[moggie]

No- .98M will be .98M whether or not you have a headwind.

Same as IAS!!!!!

[Green Guard]

Moggie,
You may be right if there is no wind speed change over some specified time!For example minus or plus 7kts per second.
Some people even call it a wind shear.

[Freak On A Leash]

Not the same as IAS, but TAS!;)
TAS + wind component gives you groundspeed.
Mach# is the speed in relation to the (local) speed of sound;

M = TAS/LSS

[DC Meatloaf]

Perhaps the idea is to fly subsonic (just) over land and supersonic everywhere else?

Just a thought.

[Captain Stable]

Whatever speed you are doing, if the headwind suddenly picks up, your airspeed will increase, if only temporarily, due to your momentum.

It's what catches most people out when hitting the first effects of a microburst.

[twistedenginestarter]

Everyone would love a supersonic passenger aircraft. Unfortunately no-one has come up with a solution notably better than Concorde. And that just wasn't good enough.

[desmadronic]

LSS 38.94 x square root of the temperature.!!

[Standard_Departure]

I'm not a pilot, only an ATC, but :

Is the sonic cruiser not intended for close to Mach 1 but sub-sonic speeds?

AND,

Travelling at speeds close to Mach 1 (but sub-sonic), and then entering an airmass of less density (low pressure or higher temp) can cause temporary super-sonic speed and thus sonic boom. Heard of this happening with mil jets at low level and causing damage to houses on the deck.

- Just a thought. -

SID

[Rubberchicken]

I heard that it was Boeing's answer to DVT. It sits at Mach 1 and shakes the BEJESUS out of everyone....:D :eek:

[RadarContact]

I don't expect the SC to fly close to Mach 1 at low levels, plus above the tropopause OAT and pressure levels are a little more constant and reliable than at 500'AGL ;)

[Fokker-Jock]

I guess you're probably all pretty right here.

The IAS corrected for position and instrument error gives CAS
CAS corrected for compression = EAS and EAS corrected for temp and pressure gives TAS. TAS corrected for Wind = GS.

LSS is as mentioned here before given as function of temperature, not pressure. Although a quick change in pressure effects the TAS and therfore the mach number, you can theoretically cross the barrier of 1.0 although I have problems seeing such a rapid pressure change in such a short time, but you never know perhaps if cruising in and out of clouds this does tend to happend.

Therefore if cruising at a given altitude and hence given pressure and temp, a wind gust in conjuction with a jetstream shear the IAS will change momentarily therfore also the TAS and the mach number, so theoretically you can end up in a situation where you cross the M1.0. The effects of this with regard to a sonic boom or structural interference can be discussed as I honestly don't know. But I would suggest that the effects are pretty much the same as a normal mach 1.0 break.

As also mentioned; above the tropopause the inversion layer is pretty stable, but you never know :p

[mach2moose]

If my memory serves me correctly, I was led to believe that below Mach 1.2, the shock waves would be attenuated by the atmoshere, and not reach ground level when above 28000 feet.
Only in a turn at these low supersonic speeds would "boom focusing" occur, increasing the intensity of the shock to the point that the good people of Cornwall would be affected.
Turning during the acceleration was definitely not recommended.

[BroomstickPilot]

I am interested in another possible ramification of introducing the Boeing Sonic Cruiser.

I understand Concorde can not be placed into a holding pattern, but has to be given a straight in approach on every occasion. You can imagine the fun we would be having now (with present conjestion levels in controlled airspace) if Concorde had gone into large scale production.

Will the Sonic Cruiser be racetrackable, or will the Air Traffic Control authorities have to come up with some slight of hand to accomodate another straight in wonder?

[NW1]

Broomstick: Your information is completely incorrect.

Concorde can and does hold, just like any other aircraft. There are no type-specific restrictions on normal manoeuvring procedures, and holding is handled just like any other type. It is unusual to have less than 20 minutes fuel holding capability inbound LHR from JFK, and much more can be carried if the situation warrants it. It might be an idea to check your facts before making inappropriate comments like <<some slight of hand to accomodate another straight in wonder>>.

Hope this helps.