Supersonic business jets

[chris]

http://mysite.verizon.net/1995hoo/Aerion_Newsweek.jpg

Very interesting new Supersonic business jet.

But surely countries outside of USA won't allow that to fly supersonic over their land. Particularly not France or Britain. ;)

[VQ]

Only Mach .89? It's not that fast, doesn't the Concorde go to mach 2 or 3?

I like Bombadiars however.

[chris]

That plane is actually a thing made by http://www.aerioncorp.com/

They are talking about Mach 1.6 performance. Not bad, but still much slower than the last commercial supersonic airliner.

Back in 1985, BA let a Concorde participate in some NATO combat training exercise, or something like that. F14's, F15's, F16's, Mirage, F104 and Lightning were all trying to catch Concorde above the North Sea.

Only the Lightning could catch the SST at 57,000ft. None of the others could. The English Electric Lightning flew at Mach 2.2 to overhaul the Concorde at Mach 2.02 (1350mph). However, even the Lightning could only keep up this burst of speed for a short while, and certainly not for 3 hours.

I do think this Aerion SSBJ is not so attractive. I prefer delta-winged planes with a less exagerated nose.

[Frank N. O.]

First off, am I the only one that thinks this looks like the old X-3 Stiletto?
Secondly, yes it is not that nice looking, and even worse, I don't think it'll be allowed to fly supersonic over land either, and flying around transonic speeds would probably need a lot of thrust/fuel due to the barrier and I doubt they have the technology to develop/use the techniques developed to decrease those problems.
Thirdly, wouldn't a supersonic plane require a specific certification? Meaning not many pilots would be able to fly one, and certainly not civilian ones. Planes are a lot more complicated than any car and flying a lot more complicated than driving any car and every single plane-type handles differently to a much greater extent than different cars drive so I don't think that will be a very easy plane to own, let alone use.

Speaking of the Concorde test, isn't it claimed that a F-15 can blast up to Mach 2.5? Howcome it couldn't catch it? Was it launched too late? I asume the training was to see if the Concorde, acting as an intruder bomber, could be spotted on radar and fighers scrambled fast enough and with enough speed to be able to intercept and get a lock on it right?

Frank

[Venom800tt]

That does indeed remind me of the X-3. Lockheed's Skunk Works is also developing a supersonic buisness jet, but it will use a weird design to muffle it's sonic boom. I'm sure there are pics floating around on the net (too lazy to look for the magazine it was in).
And are you sure the F-14 or F-15 couldn't catch the Concord?
The F-14 can reach Mach 2.34 or 1,544 mph while the F-15 can reach Mach 2.5+ or 1,650+ mph. Both also have good acceleration (both use the 30,000lb thrust GE F110) :confused:

[Justin Martin]

It would also depend on the circumstances of the test. It reminds me of a test the US Air Force ran once where they were able to lock onto and (hypothetically) shoot down an SR-71 using a fighter. (a F-15, IIRC) Most air-air missles are faster than a SR-71, so it's simply a matter of having a fighter in the right place at the right time.

However, the SR-71 was flying a straight path with radar jammers off. Thus the fighter pilot had plenty of time and all the information he needed to get in the right place at the right time. Of course, a SR-71 wouldn't normally fly in a predictable path or fly with radar jammers off, so normally it would be almost impossible for a fighter to get into position to shoot down a SR-71. By the time the enemy has detected it on radar and scrambled their fighters, it's already long gone...


I suspect a similar thing may have happened with the Concorde test. The Lightning may have been the only plane in the right place at the right time to have any chance of catching the Concorde.

[chris]

I suspect a similar thing may have happened with the Concorde test. The Lightning may have been the only plane in the right place at the right time to have any chance of catching the Concorde.

That was the case. It's also worth noting that quoted thrust may be at particular altitudes as well. At 50,000ft+, a given planes thrust may be significantly less than the claimed amount. At high altitudes, a Concorde has about 32,000lbs per engine without afterburners.

Worth noting also that at no time will a Concorde ever likely descend below 50,000ft, not during something like that. It'll be staying right on Mach 2.02 for the whole time. It'd only need to make a few little turns and it'd end up far out of range. ;)

Thirdly, wouldn't a supersonic plane require a specific certification? Meaning not many pilots would be able to fly one, and certainly not civilian ones. Planes are a lot more complicated than any car and flying a lot more complicated than driving any car and every single plane-type handles differently to a much greater extent than different cars drive so I don't think that will be a very easy plane to own, let alone use.I think they don't need any special piloting skills. Any pilot with the required normal training (to learn the aircraft systems) could fly one.

[Frank N. O.]

I think they don't need any special piloting skills. Any pilot with the required normal training (to learn the aircraft systems) could fly one.Oh, sorry my mistake, I just thought sonic booms and such extreme speeds and altitudes would at least require some specific extra certification and not that every LearJet or KingAir pilot would be allowed to blast like that, that would be like going from a Mercedes-Benz E420 and going to a Bugatti Veyron. I also think you mentioned that Supersonic planes like the Concorde (as if there was any other supersonic airliner) spend a long time accelerating and decelerating compared to "normal" aircraft so I thought that flight-safety would require some special education/certification.

I just found this btw, not read much but it looks a lot better :cool:
http://www.aeroworld.net/3in03159.htm
Edit: While doublechecking the link I just noticed something strange around the tail, is that a third engine?

Edit2: Found another one, interesting, smooth and definately different.
http://www.saiqsst.com/faq.htm

Frank

[chris]

The Dassault one looks about the best of the lot to my conservative eyes. It is indeed planned to be a tri-engine design.

I wonder how the third (middle) engine impacts on the pitch of the aircraft?

A Concorde does spend a fair amount of time accelerating, but it normally didn't present any great challenges since the autopilot system was (and still is) extremely sophisticated and greatly reduced the work-load for the pilots.

To put it basically, in simplified form, they cruise up to 27,000ft and Mach 0.93 or Mach 0.95 and stay at that speed until the acceleration point, and then punch the reheat again, and use the Max Climb function.

This took care of climbing at the maximum speed, while preventing overspeeding. From there on, the plane would climb at VMO, until reaching the corner point (Mach 2.02 - at whatever altitude that was achieved at), then it would simply do whatever was needed to remain at Mach 2.02, like climbing more to stay at Mach 2.02, or indeed reducing engine power if an overspeed was inevitable.

Decelleration was simply a matter of careful planning with various mathematical formulas to ensure the plane was below Mach 1 before getting near land, and from there on, planning the descent so the plane would descend all the way to its landing without remaining at low altitudes for extended periods of time. That was a fuel economy measure, and a noise reduction measure.

Prolonged level flight at low-altitudes is not only fuel thirsty (in any plane) but also creates plenty of noise, particularly with a nose tilted down and landing gear extended.

Decelleration from say FL590 or FL600 (way above what any of the SSBJ's would ever likely achieve) to FL410 and Mach 1.0 from speeds of Mach 2.02 would normally take about 8-10 minutes and cover something around 100-110Nm. IIRC the descent was done with engines set at fixed power levels and the armed (but not engaged) auto-throttle would "catch" 350KIAS as it got near that speed. But remember descent distances and times depend also on prevailing winds, and air-temperature, along with throttle amount.

So any well designed plane shouldn't place excessive demands on its crew.

[Wazza]

VQ: You'll find many aircraft, including most airliners fly around Mach 0.84 - Mach 0.89, as the air becomes extremely turbulent as you approach the sound barrier. Quite a lot of resistance to break through.

[VQ]

Yeah I didn't think it was that high a speed..

[chris]

The Aerion plane is supposed to do Mach 1.6, and Dassaults one (temporarily put to one side while engines are sorted for it) is said to do Mach 1.8.

IIRC Sukhoi and Gulfstream were considering one that was very fast.