Boom Supersonic Overture M1.8 SST

Kiltonge said:
Is it really a huge leap in aerodynamics over, say, the F-105 that went supersonic on its maiden flight in 1955?
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Yes. Because configuration wise, it's representative of what we were doing in the eighties which was much better aerodynamically than an F-105. Where it improves on the eighties tech is in terms of materials, propulsion, and being able to use cameras/spatial computing for the cockpit so one doesn't need the windshield and/or the lowering nose for vision cockpit vision, allowing for much better cockpit integration and lower weight. I'm sure there are other areas I'm missing, but the key is in getting the costs down compared to what was done before.
 
Kiltonge said:
Is it really a huge leap in aerodynamics over, say, the F-105 that went supersonic on its maiden flight in 1955?
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Yes.

for example, in the 1970s, Nasa developed a supersonic supercritical wing, which greatly improves efficiency (lower drag, lower fuel burn).

The whole idea of shaping to reduce boom effects is something that wasn't even realized as possible until the late 1990s!
 
Scott Kenny said:
Yes.

for example, in the 1970s, Nasa developed a supersonic supercritical wing, which greatly improves efficiency (lower drag, lower fuel burn).

The whole idea of shaping to reduce boom effects is something that wasn't even realized as possible until the late 1990s!
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Remember that Boom is not doing shaping for sonic boom reduction. Their scheme is to take off and fly subsonic at partial thrust over land and only go supersonic outside the 12-mile limit.

The goal of Boom's current test flights is mainly to validate their simulation and design tools. They want to see how closely the demonstrator flies compared to their computer models, which will tell them whether the tools are good enough or not.
 
TomS said:
Remember that Boom is not doing shaping for sonic boom reduction. Their scheme is to take off and fly subsonic at partial thrust over land and only go supersonic outside the 12-mile limit.
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I thought they were? That super long nose looks like it's for boom reduction, for example.
 
TomcatViP said:

FAA Clears Boom For XB-1 Supersonic Tests | Aviation Week Network

The special flight authorization is the first ever issued by the FAA for tests of a civil supersonic aircraft.
aviationweek.com aviationweek.com

As guessed earlier the lateral stability and AoA were problematic. It is then understandable that adding the SAS for the next flight takes them time. I am only wondering why it wasn´t part of the first flight configuration.
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The aircraft had a SAS system on board for first flight. It just wasn't active.
 
Scott Kenny said:
I thought they were? That super long nose looks like it's for boom reduction, for example.
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They may be doing some minor boom shaping efforts but it's not a significant part of the design now.

From their website FAQ:

How is Boom dealing with the sonic boom?
When flying over land, Overture can fly significantly faster than subsonic commercial jets—about Mach 0.94, without breaking the sound barrier. This is about 20% faster than subsonic flight.

Globally, there are more than 600 mostly transoceanic routes on which Overture offers a compelling speedup without changes to today’s overland flight regulations.
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TomS said:
They may be doing some minor boom shaping efforts but it's not a significant part of the design now.

From their website FAQ:
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Makes sense, the X59 needs to establish what the acceptable boom limits are before it's worth spending a lot of design time/$$ shaping to minimize boom.
 
Boom opens a "Giga factory*" (the size of regular boutique hangar shop**) that will start producing next year a plane that hasn´t been completed, flown, tested or certified (but get State support):

https://www.wral.com/story/boom-sup...sboro-bringing-2-400-jobs-to-region/21486650/

Humm, what´s your delusional level Tars?

iu

Not fair, I can´t really gawk at it, Cooper.


*Notice that AW reports 200k sqft when it´s 25% less with 150k only dedicated to manufacturing. In case G. Norris reads these lines, I advise him to revisit the chapter on rounding numbers in his mathematics textbook.
**As an example, the giant production line of the A380 is rated at 1,6M sqft

Edit:
The video featuring the surrealistic CEO speech seems to have been deleted in no times.
 
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TomcatViP said:
Boom opens a "Giga factory*" (the size of regular boutique hangar shop**) that will start producing next year a plane that hasn´t been completed, flown, tested or certified (but get State support):

https://www.wral.com/story/boom-sup...sboro-bringing-2-400-jobs-to-region/21486650/

Humm, what´s your delusional level Tars?

iu

Not fair, I can´t really gawk at it, Cooper.


*Notice that AW reports 200k sqft when it´s 25% less with 150k only dedicated to manufacturing. In case G. Norris reads these lines, I advise him to revisit the chapter on rounding numbers in his mathematics textbook.
**As an example, the giant production line of the A380 is rated at 1,6M sqft

Edit:
The video featuring the surrealistic CEO speech seems to have been deleted in no times.
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Did Boom hire some of the former Aerion folks? Aerion provided nothing from the outset but I guess they were consistent? Depending how this plays out, we are Boom Supersonic, then I'll have the soup.
 
All joking aside (until next time), I would really like Boom to succeed, they flew their XB-1 and they need to complete their flight test program. I think we are at the cusp of a reasonable supersonic platform. Put the giga factory on-hold and finish testing at Mojave, really crunch the data and progress properly. Boom needs to seriously work with an engine maker and do not make the mistake of prematurely unveiling grandiose plans for the future, that will sink them just like Aerion.
 
Hydroman said:
All joking aside (until next time), I would really like Boom to succeed, they flew their XB-1 and they need to complete their flight test program. I think we are at the cusp of a reasonable supersonic platform. Put the giga factory on-hold and finish testing at Mojave, really crunch the data and progress properly.
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Yes, their flight testing allows them to verify the computer model they developed, and that is a HUGE step forward.


Hydroman said:
Boom needs to seriously work with an engine maker and do not make the mistake of prematurely unveiling grandiose plans for the future, that will sink them just like Aerion.
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The problem is, they really need something like F101s. A CFM56 with a 2-stage or 3-stage fan some 55" in diameter, with an afterburner.

And those are LOUD.

Passing modern aircraft noise requirements is going to be difficult.
 
Completely agree with you guys. I was flabbergasted yesterday by the surging "evidences" of a potential crumbling scenario (that had traces rooted as far back as a couple of year; if I do remind well we commented on it then).

If they do not have really a Super factory (seems there is some semantic gymnastics here - see also the absence of tools (an open hangar is not a factory)), still they have a beautiful airplane that we all want to see for real:

View: https://youtu.be/-befoZ6nDpM

boomsupersonic.com

Boom - FlyBy - Superfactory - Boom Supersonic Completes Construction of the Overture Superfactory

The first flight of XB-1 paves the way for the return of supersonic travel that’s more affordable, more convenient, and more sustainable
boomsupersonic.com boomsupersonic.com

@Scott Kenny : many airplane started their life with subpar engines, not fully adapted to their innovative design philosophy. I would tend to think that rationally nobody could care much that F101 engines are fitted to the earliest model. Customer will adapt to the exceptional abilities of the plane that would be a market breaker, leaving room for aggravated user constraints and overpriced seating.
 
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TomcatViP said:
@Scott Kenny : many airplane started their life with subpar engines, not fully adapted to their innovative design philosophy. I would tend to think that rationally nobody could care much that F101 engines are fitted to the earliest model. Customer will adapt to the exceptional abilities of the plane that would be a market breaker, leaving room for aggravated user constraints and overpriced seating.
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The problem is that the F101s would be entirely too loud to operate from most airports. Any operators would either need a waiver, pay whatever fines there are per flight if that is an option, or figure out a way to quiet the engines if paying a fine per flight is not an option.

The 2707 had a big muffler section on the engines, as did the 727 Hush Kit engines.
 
Yes. Pay fines, make special arrangements, fly secondary destinations with dedicated connection flights, use gliding approaches, takeoff at minimum Gross weight and stopover for hot-refueling on a private airfield etc...

Early operations won´t see multiple flights per day with fast turnaround, as pricing will narrow the clientele. Transatlantic flights would be also de-facto offset in departures for example as crossing time will be halved. Hence, more opportunity to takeoff at less disturbing hours for the public.
Marketing will also help turning away from the today meat-cargo image back to the Jet-set spirit that bloomed with the 707, creating an esprit de corp that will make passengers more compliant with the small disagreements of trimmed and tuned destinations and services.

Obviously all those are temporarily measures and perennial solutions would have to be incorporated in the airframe as you mention (muffler as suggested?)
 
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Remember that Boom's operating concept is to take off and cruise subsonic at partial power before accelerating to supersonic speeds over water. That's one way they propose to mitigate noise.

And also that they do have their own plans for a new engine that is not an F101 and does not involve an afterburner. From this time last year:

boomsupersonic.com

Boom - FlyBy - Boom Announces Significant Overture Program Advances at Paris Air Show

Tier-one structure suppliers announced for Overture’s wing, fuselage, and empennage; Overture systems configuration revealed; Symphony™ design accelerated with engine architecture unveiled, and initial production partner signed
boomsupersonic.com boomsupersonic.com

Now, I'm also skeptical about whether they can actually pull off this engine but let's critique their actual plans, not ones we make up.
 
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Scott Kenny said:
Yes, their flight testing allows them to verify the computer model they developed, and that is a HUGE step forward.
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They've made one test flight which achieved 238 knots. Given the completely different configuration proposed for Overture, I don't know how much validation that can provide.
 
Kiltonge said:
They've made one test flight which achieved 238 knots. Given the completely different configuration proposed for Overture, I don't know how much validation that can provide.
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The question is how far off those results were from what the model predicted they would be. If it's close, that validates the modeling tools to some degree, at least for lower speeds. Supersonic of course is a different kettle of fish, since aerodynamic models that work fine for subsonic flight can completely flake at transonic or supersonic regimes.
 
You are too kind with them and... Science. Nobody with its right mind would consider one single test flight as being a blank check to validate anything. Especially the one we were given to see. Especially with a startup that has produced nothing.
 
Kiltonge said:
They've made one test flight which achieved 238 knots. Given the completely different configuration proposed for Overture, I don't know how much validation that can provide.
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They still have the predictions the computer made for the test article. If flight tests show that the predictions are lining up with the actual results, then it's likely to be accurate for the Overture as well.


TomcatViP said:
You are too kind with them and... Science. Nobody with its right mind would consider one single test flight as being a blank check to validate anything. Especially the one we were given to see. Especially with a startup that has produced nothing.
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Who said one flight test would validate the model? No, it's going to take a lot of flights to validate the model, all the way into supersonic speeds.

And note that Boom has produced SOMETHING, their demo plane. Which flies. You're thinking of Aerion(sp?), another company that talked a lot of stuff for a supersonic transport and didn't even make a demo plane before running out of other people's money.
 
TomS said:
And also that they do have their own plans for a new engine that is not an F101 and does not involve an afterburner. From this time last year:

boomsupersonic.com

Boom - FlyBy - Boom Announces Significant Overture Program Advances at Paris Air Show

Tier-one structure suppliers announced for Overture’s wing, fuselage, and empennage; Overture systems configuration revealed; Symphony™ design accelerated with engine architecture unveiled, and initial production partner signed
boomsupersonic.com boomsupersonic.com

Now, I'm also skeptical about whether they can actually pull off this engine but let's critique their actual plans, not ones we make up.
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Must have missed that!

Interesting. Looks like a moderate bypass turbofan (~3:1 or so BPR) with 1 fan stage, 3 stage LP compressor, 6 stage HP compressor, and 4-5 turbine stages however they're split (looks like 1 HP, 3 LP, and maybe one for the fan). Aiming for 35,000lb thrust with no afterburner. Has a fairly complex mixing stage between the fan bypass and the core exhaust, which will help reduce core exhaust velocity and noise while increasing fan exhaust velocity. And written descriptions on Wiki suggest that the engine will have a plug nozzle for the converging-diverging back pressure control.

Gross layout is actually quite similar to a CFM56, which has 1 fan, 3stg LP, 9stg HP, 1 HPT, 4 LPT. I suspect that the fewer stages in the HP compressor compared to the CFM56 is to lower overall pressure ratio to improve performance at supersonic speeds. Downside is that lower OPR increases fuel consumption pretty significantly. I'd want to juggle max speed versus fuel burned, I suspect that at Mach 2.7 you get close to equal fuel burn compared to a jet at Mach 0.9, but Boom doesn't seem to be chasing that high a speed.
 
Scott Kenny said:
And note that Boom has produced SOMETHING, their demo plane. Which flies. You're thinking of Aerion(sp?), another company that talked a lot of stuff for a supersonic transport and didn't even make a demo plane before running out of other people's money.
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There is indeed a difference that I have myself been alerting on in the debate. Still, I would expect we understand that Producing an airplane is something different from manufacturing a single experimental airframe.

Garage build are not industrial products.
 
TomcatViP said:
There is indeed a difference that I have myself been alerting on in the debate. Still, I would expect we understand that Producing an airplane is something different from manufacturing a single experimental airframe.

Garage build are not industrial products.
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I'm still willing to give Boom a lot more credit than any of the other modern SST companies, because they built a demonstrator to validate their computer model.

I'm also oddly amused at how much their current proposed airframe looks like a 2707.
 
Scott Kenny said:
I'm also oddly amused at how much their current proposed airframe looks like a 2707.
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Interestingly it looked like Concorde (except the third engine) whilst they used the services of the wonderful ex Concorde engineer/regular genius Ted Talbot. A while after Ted pass away it went all Boeing 2707-esk. My guess is an old fellow from that project replaced him.

Four engines is two to many, and don’t they know of B58’s woes if an outboard engine surge…. It swapped ends while flying at M2…. Engine surge is just a matter of time for an SST. Ted once told me that the key to any commercially successful SST was to make the surge of any engine benign to the pilots.

He once told the story of Concords first FAA demo flights;- When at M2 Trubshaw called for a deliberate surge on number 4, the FAA and former B58 pilot, turned white. He really thought Trubshaw was joking because such a test in the B58 was very high risk and killed quite a few test and service pilots. He didn’t know Concorde had been designed to be surge benign right from the get go…. And indeed it was.
 
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