quote:

Originally posted by sns3guppy:
<snip>
So far as multiple engines, that didn't save the Concorde, nor UAL232's DC-10 at Sioux City
<snip>

The multiple engines of UAL232 almost certainly prevented total loss of life after the loss of engine #2 and all hydraulic control pressure.

Varying the power of engines #1 and #3 was the only means remaining to the crew and training captain Dennis Fitch (who happened to be on board) for significant flight control.

That's still the procedure for the DC-10 and the MD-11, but the reality is that the odds of 999 out of 1000 who fly it is that it won't be survivable or work. Having run it in the simulator, I successfully managed to crash.

The DC10 and MD-11's were provided with what's referred to as the "Sioux City" valve, which limits systems loss in the event of a catastrophic failure in the no. 2 engine. A loss of system 3 is still catastrophic, however, let alone a loss of all three systems.

A comparison between the DC-10 with large, underslung engines and broad, asymmetric thrust with high bypass turbofans, and the Boom offering, however, would be uneven. What it does do is illustrate what can happen with systems loss, especially associated with powerplant loss.

I spoke with Al Haynes about the UAL232 event. He spent much of his life after the event in deep guilt, but came to accept that he, and the survivors, were very lucky. Everyone else, was not.

Would it be able to fly from LA to Melbourne? It’s about an extra hour of flight time verses Sydney right? That is a BRUTAL 16hr flight. Cutting it down to 8 hrs would be a game changer for Australian tourism. The #1 reason Americans choose not to vacation at Australia is that horrific flight. I’ll never forget watching three films and a documentary on Robin Williams only to be shocked and saddened to discover we were only half way to Australia. I will say even with the current ass kicking flight from LA to Melbourne it’s still 100% worth going to Australia. Both Sydney and Melbourne and the surrounding areas are incredibly beautiful and fun.

As I recall, the plan was for the Concorde to be used on Trans Pacific flights, but they couldn’t get something right. Presumably, they can do better modeling now. I think lots of folks will pay 5-6k for short trans pac flights.

quote:

Originally posted by TXJIM:
I get the play on words but “Boom” seems like an unfortunate name for an aircraft manufacturer. I guess it beats splash though.....

Beat me to it.

American Airlines on Tuesday agreed to buy up to 20 Overture jets from aircraft maker Boom Supersonic, saying they will cut the time of long-haul flights over water nearly in half.

Still under development, the Overture is expected to reach speeds of Mach 1.7, or about 1,300 mph, double the speed of current commercial jets and making the trip between Miami and London in five hours, down from nearly nine.

American, which also has an option to purchase 40 additional Overture jets, made an unspecified non-refundable deposit on the initial 20 planes, each of will carry some 65 to 80 passengers when they debut in 2029.
……
American becomes the second U.S. customer for Boom after a similar announcement last year from United Airlines, which committed to buying at least 15 of the planes…”

DailyMail article:
https://mol.im/a/11116883

quote:

Originally posted by oldbill123:
I worry about pollution

I would be more worried about the amount of pollution being created by an aircraft that needs 3 or 4 times as much time to get to the same place.

Flying at M 0.86 versus flying at M 2.2 seems to be a much larger source of pollution

I worked at PTI from the start of HondaJet(they had a small R&D office) until the jet was flying and selling, now they have a huge campus with several manufacturing and corporate facilities. Boom will be across airport property with room to grow also, live close enough to get lots of touch and goes flying over. I hope Boom goes well and can't wait to see those birds taking off.

“MOJAVE, Calif. and DENVER, March 22, 2024 /PRNewswire/ -- Boom Supersonic, the company building the world's fastest airliner, Overture, today announced the successful flight of XB-1, the world's first independently developed supersonic jet, at the Mojave Air & Space Port in Mojave, California. Like Overture, XB-1 leverages state-of-the-art technologies to enable efficient supersonic flight including carbon fiber composites, advanced avionics, digitally-optimized aerodynamics, and an advanced supersonic propulsion system.
……

XB-1 was flown by Boom Chief Test Pilot Bill "Doc" Shoemaker and Test Pilot Tristan "Geppetto" Brandenburg flew the T-38 chase aircraft which monitored the flight. XB-1 took off from the Mojave Air & Space Port and flew in the same airspace that hosted many historic first flights, including the flights of the Bell X-1, the North American X-15, and the Lockheed SR-71 Blackbird. XB-1 met all of its test objectives, including safely and successfully achieving an altitude of 7,120 feet and speeds up to 238 knots (273 mph). …”

PR Newswire report:
https://www.prnewswire.com/new...craft-302097339.html

nice to see progress being made

quote:

Originally posted by Lefty Sig:


But I like drinking free booze in business class, falling asleep watching a movie, and waking up sober, finishing the movie before landing, and getting to the hotel by late afternoon.

My first thought as well. Haha.

Some of you guys keep talking about 3 engines for transatlantic flights, but I think there is some confusion...

The "test" aircraft, the XB-1, DOES have 3 engines, but the actual transatlantic airliner is the "Overture", and it has 4 engines... two under each wing.

Just wanted to clarify...

quote:

XB-1 met all of its test objectives, including safely and successfully achieving an altitude of 7,120 feet and speeds up to 238 knots (273 mph).

Color me unimpressed, thus far. It would seen the objective was simply to fly and NOT crash! Let me know when it surpasses the performance current commercial passenger airliners, and then I'll anxiously await the follow-up report once it goes supersonic.

quote:

Originally posted by nhracecraft:
<snip>
Color me unimpressed, thus far. It would seen the objective was simply to fly and NOT crash!
<snip>

I suspect that the first test flight of the XB-70 Valkyrie and the Concorde had similar modest goals.

So the "Test XB-1" is a 1/3 scale size model, looks nothing like the finished project.

quote:

Originally posted by nhracecraft:
Color me unimpressed, thus far. It would seen the objective was simply to fly and NOT crash! Let me know when it surpasses the performance current commercial passenger airliners, and then I'll anxiously await the follow-up report once it goes supersonic.

that will be great to see too, but for now, like any high risk new build with large dollars invested, they take baby steps, no way that management or the engineers are going to put billions of dollars of development and pre-production money at risk on the first flight.

quote:

Originally posted by TXJIM:
I get the play on words but “Boom” seems like an unfortunate name for an aircraft manufacturer. I guess it beats splash though.....

That was good.

quote:

Originally posted by Lefty Sig:

quote:

Originally posted by DaveL:

quote:

Originally posted by P250UA5:
Proposed Mach 2.2
4,500nmi range

That's plenty for trans-Atlantic flights but they'd really be onto something if they could get the range over 6,500 nautical miles. You'd be able to fly from LA to Hong Kong or Sidney in about 5 hours, which would be truly revolutionary.

San Francisco to Seoul is 10 hours, Tokyo is 11 hours, Beijing 12, Shanghai 13 hours, Hong Kong 14 hours. So yeah 5-7 hours from west coast to Asia if they can get the range to 6500+.

But I like drinking free booze in business class, falling asleep watching a movie, and waking up sober, finishing the movie before landing, and getting to the hotel by late afternoon.

That's a very good point. Some professionals need an excuse for some forced downtime.

quote:

Originally posted by sns3guppy:
A big part of making a long distance run is capability enroute after a failure; a pressurization, or a failure of one or more engines. All planning revolves around that, not necessarily what the aircraft can do with all engines operating.

Speed is great, but speed is irrelevant after an engine-out, especially when the flight requires a descent lower altitude where those speeds aren't possible, where fuel consumption skyrockets, and where a diversion to an alternate airport becomes necessary.

The airplane may have long legs based on all-engines operating and the capability to fly at its optimum altitudes, but it all goes out the window with a failure. That's when the true capabilities of the airplane, and it's limitations, will come into play. The aircraft still requires the ability to divert to an alternate airfield with the capability to handle that aircraft, and the weather to do it. At lower altitudes and speeds, that range doesn't exist, and that's the real range that must be considered when flight planning a trip.

Good reminder of classic engineering tradeoffs, no way around it.

Just want to say I really appreciate guppy's posts on this, I learned a lot--I knew nothing before.