Boom Supersonic Overture M1.8 SST

Ah, yes, they will face animosity. As the industry is structured today, it sees selling a blend of airliners and Business jets with de-multiplied engine sales as being more profitable.*
It is often funny to see people comparing the economics of subsonic Vs faster aircraft, always discarding the increased number of rotations with their repercussion on daily flight schedule. Seems as if yield management among the airline industry, inexplicably fall through a trap door (without even Spirit & Boeing being the cause).
Sadly, it is blatantly evident that the present model of engineered obsolescence is not sustainable. We have experienced massive financial frauds and lenient quality management, gone through a spike. IMOHO, those, among others, are clear signs of the end of an era.
It´s up to the industry to have that achieved only by outsiders, with the inherent risks on passengers safety... And profitability,

*But as expressed earlier, it´s only the very long range Business jets that will be affected.
 
Last edited:
TomcatViP said:
It is often funny to see people comparing the economics of subsonic Vs faster aircraft, always discarding the increased number of rotations with their repercussion on daily flight schedule.
Click to expand...
From the few times I’ve seen private jet users, pure speed is rarely the #1 priority. What’s more important is time efficiency in its broadest sense:

1) Point to point flexibility (flying to/from small airports to save ground travel time & hassle, or to get to remote locations)

2) Schedule flexibility (eg. the ability to change flight times on short/no notice… « let’s go wheels up »)

3) Use of time on the plane for meetings/calls, resting etc

There probably still is a niche “Concorde market” across the Atlantic (NY <-> London/Paris), or across the US (NY <-> LA/San Francisco) if you can fly supersonic above land, but your typical hedge fund or business leader who lives in a nice suburb 1hr-1.5hrs from a major airport hub might prefer his own private bizjet flying 20min from home and taking him direct to his destination, even if the biz jet has a 3hr longer block time.

Plus most bizjet flights are on shorter legs and/or random direct routes where there will never be a supersonic scheduled option. So I don’t think this makes much of a dent in bizjet usage.

Where I think there will be a market is people who fly first class commercial between major airport hubs but don’t have a transcontinental bizjet… but these travelers switching to supersonic would actually increase their carbon footprint so is not really desirable!
 
We are not talking forcing them flying to a hub airport and having them driven to their end-destination in a Trabant taxi.

iu


If you only replace the long leg of the crossing with a Supersonic and then switch over to a private jet, you still gain a lot of time without loosing in flexibility.
All this was already detailed earlier. But, as we are not here discussing Boom Supersonics per se, I will refrain to repeat myself.

Just imagine a hub airport in Brittany. You flew there from LaGuardia. In Zip time you are in Chamonix, London or Dublin. Idem Landing in Amsterdam that would connect you all across central Europe. Etc...
 
TomcatViP said:
Just imagine a hub airport in Brittany. You flew there from LaGuardia. In Zip time you are in Chamonix, London or Dublin. Idem Landing in Amsterdam that would connect you all across central Europe. Etc...
Click to expand...
OK I can see some of the promise then. To work I see 2 requirements:

1) Use bizjet hubs like London Farnborough/Luton, Paris Le Bourget, Teterboro NJ, Los Angeles Van Nuys etc and avoid commercial hubs as much as possible. This is to remove weather/ATC delays and the hassles on the ground with large airports (also often far from city centers). Requires relatively short runway capability (7,000ft / 2,100m).

2) Really good instant transfers to/from supersonic shuttle to smaller private bizjet / helicopter for the regional leg. This requires some thought around ground logistics, immigration clearance and boarding procedures etc. Probably not impossible, but just can't be an afterthought.

If you can save 3hrs block time, and 1hr on the ground on each end, plus still retain the flexibility to continue onwards by bizjet then you have something potentially very attractive (though I doubt is any better for the environment).
 
H_K said:
2) Really good instant transfers to/from supersonic shuttle to smaller private bizjet / helicopter for the regional leg. This requires some thought around ground logistics, immigration clearance and boarding procedures etc. Probably not impossible, but just can't be an afterthought.
Click to expand...
A case of back to the future, perhaps?
hs-vtol-02-jpg.614340

A proposed British 'VTOL port' from the 1970s, h/t zebedee.
 
 

Attachments

  • GV6vAAVXQAAYiEl.jpg
    GV6vAAVXQAAYiEl.jpg
    1.3 MB · Views: 33
Last edited by a moderator:
Still really nose up and very fast on landing , but I guess there's not much they can do to change that, just manage it.

Seems like a reasonable envelope expansion campaign, four months for 10 flights should be doable barring any trouble.

Still intensely skeptical of their long-term plan but props for getting past the first demonstration flight.
 
TomS said:
Still really nose up and very fast on landing , but I guess there's not much they can do to change that, just manage it.

Seems like a reasonable envelope expansion campaign, four months for 10 flights should be doable barring any trouble.

Still intensely skeptical of their long-term plan but props for getting past the first demonstration flight.
Click to expand...
The high angle of attack is the result of the wing have no high lift devices.
 
Look at the tuft on the upper surface. Not bad. (would need a full video to get sure).

From Boom:

successfully demonstrated a new digital stability augmentation system, and used tufting to assess wing aerodynamics.
Click to expand...

Landing is quite fast. AoA is noteworthy. Look also at the tailplane deflection that would look pretty much maxed out on other a/c (and how small they are).

240827_Boom-FwdSynVis.jpg

Tufts and smoke generator at the wing tip

240827_Boom-SmokeGen.jpg

View: https://youtu.be/MLEg8qR0j64
 
Last edited:
NMaude said:
That's what I thought too, why doesn't it have flaps?
Click to expand...
Concorde didn't have flaps either, they would destabilize the delta wing and require an empennage to stabilize the aircraft. Maybe modern FBW could handle it, but I assume this demonstrator is playing it safe. Their production aircraft should probably pursue the dynamic drooping leading edge (not slats) that the Concorde Mk2 was working on.
 
Still, I think it was crazy to fly that a/c without the SAS. Especially when you see that the pilot only wears a parachute ; hence, he has to blow the canopy off, unstrap and manage to get out of the cockpit with enough alt b/w him and the ground, not withstanding getting enough separation with the shoulder mounted Delta...
 
TomcatViP said:
Still, I think it was crazy to fly that a/c without the SAS. Especially when you see that the pilot only wears a parachute ; hence, he has to blow the canopy off, unstrap and manage to get out of the cockpit with enough alt b/w him and the ground, not withstanding getting enough separation with the shoulder mounted Delta...
Click to expand...

Why wasn't it fitted with an ejection-seat?
 
No need for certification. It´s an experimental prototype. No airlines are going to check the ejection seat option. ;)

As @NMaude ask, IMOHO,,, Cost (or more exactly, a narrow vision on cost benefits from unprofessional decision makers - see how much Boom would loose if a crash happens).
 
Last edited:
TomcatViP said:
No need for certification. It´s an experimental prototype. No airlines are going to check the ejection seat option. ;)

As @NMaude ask, IMOHO,,, Cost (or more exactly, a narrow vision on cost benefits from unprofessional decision makers - see how much Boom would loose if a crash happens).
Click to expand...
Still need to make sure that the seat will get the pilot clear of the plane without killing him.
 
Another evidence that Supersonic travel for 1st class is a need for all, Customers and airlines:

https://airlive.net/news/2024/09/02...install-lead-plates-in-its-a330-300-aircraft/

The customers targeted by this seat design would probably have paid more and be happy with a Jump seat... traveling at Mach2!

The lack of imagination is a recursive sign in aviation that we are reaching the apex of an old paradigm. (see the days preceding the long range metallic monoplane).
 
TomcatViP said:
Another evidence that Supersonic travel for 1st class is a need for all, Customers and airlines:

The customers targeted by this seat design would probably have paid more and be happy with a Jump seat... traveling at Mach2!
Click to expand...

There's pretty good evidence that this just isn't true. Concorde, which was exactly this, economy seats at Mach 2, clearly lost the battle against comfortable First/Business at Mach 0.8 across the Atlantic.
 
TomS said:
There's pretty good evidence that this just isn't true. Concorde, which was exactly this, economy seats at Mach 2, clearly lost the battle against comfortable First/Business at Mach 0.8 across the Atlantic.
Click to expand...

The Concorde fleet finally broke even and started making a profit in the 1990s IIRC, what finished it off was that very unfortunate and public crash of an Air France Concorde taking off from the Paris international airport 21 years ago.
 
'Concorde flights were relatively rare and, worst, deserved only a selected numbers of airports that were mostly major hubs, hence with a poor flexibility for passengers transfers to business jets, And when the intercontinental private jets made really their boom, Concorde was already an old airframe that was plagued with departure delays.

Concorde flight being rare, there was a ow flexibility for last minute reservation, to the point that large administrations bought their seat on a long lead time, unrelated to the reality of their needs. This is not an economic model that a private business can adhere (think Taxes reduction).

This is why, introducing a new engine will only burden Boom's profitability with their inherent risk of being unreliable. Departure times and arrivals are of an outmost importance, Dispersion out of major international hubs is also necessary to safeguard transfers and departures of Business jets owners. As I have written before, using a stopover to deplan and refuel in order to fly at a low weight (hence lowering the noise level during approach and departure).
 
NMaude said:
The Concorde fleet finally broke even and started making a profit in the 1990s IIRC, what finished it off was that very unfortunate and public crash of an Air France Concorde taking off from the Paris international airport 21 years ago.
Click to expand...

Sure, they started to make money on planes whose entire development cost was subsidized by the British and French governments rather than being amortized across the actual production run.

TomcatViP said:
'Concorde flights were relatively rare and, worst, deserved only a selected numbers of airports that were mostly major hubs, hence with a poor flexibility for passengers transfers to business jets,
Click to expand...

Boom will be similar -- there simply won't be enough volume to support point-to-point flights to everywhere.
 
TomS said:
Certifying a plane and ejection seat combo takes a lot of time and money.
Click to expand...

I know but I doubt that the additional costs would add much to the total programme cost also by not fitting this high-performance supersonic aircraft implies that they don't value the safety of the test-pilot much.

TomS said:
You'd need at least a partial second fuselage for sled tests
Click to expand...

Correct but as I said this shouldn't have added much to the total cost of the programme.
 
I live in a SoCal sweet(?) spot where depending on wind conditions with open second level windows I can hear the Disneyland nightly 9:30 PM fireworks and/or some USMC Camp Pendleton post dark artillery exercises on a fairly regular basis, and I've also listened intently to a daytime Space Shuttle return to Edwards, which definitely left me less than nonplussed, so hit me with some actual supersonic traffic and I'll get back to you on the comparative nuisance levels. But then again, my wife would tell you that my hearing levels are less than optimal :) ...
 
Flyaway said:

Boom Advances Supersonic Engine Development Plan | Aviation Week Network

Speaking at Farnborough Airshow, Boom founder and CEO Blake Scholl shared plans to begin full-scale core tests of its Overture airliner's Symphony engine in 18 months.
aviationweek.com aviationweek.com
Click to expand...
Could someone please explain - from a propulsion system point of view - how is it possible to fly Mach 1.7 (or so) with a 3:1 fan ratio turbofan without afterburner? Does the fan accelerate the bypass stream to supersonic speeds? I cannot imagine that it is sufficient if only the core stream reaches supersonic speeds ... in this case the fan would act as a huge air brake.
 
Basil said:
Could someone please explain - from a propulsion system point of view - how is it possible to fly Mach 1.7 (or so) with a 3:1 fan ratio turbofan without afterburner? Does the fan accelerate the bypass stream to supersonic speeds? I cannot imagine that it is sufficient if only the core stream reaches supersonic speeds ... in this case the fan would act as a huge air brake.
Click to expand...

Well, the GE Affinity was supposed to get the Aerion AS2 up to Mach 1.6 or so with a 3:1 bypass ratio, so clearly it's at least theoretically doable. The engine was never Aerion's main problem.
 
TomS said:
Well, the GE Affinity was supposed to get the Aerion AS2 up to Mach 1.6 or so with a 3:1 bypass ratio, so clearly it's at least theoretically doable. The engine was never Aerion's main problem.
Click to expand...

Yes, I read about it (Mach 1.4, I think) but the question remains how they work at high speeds. I have never heard of a bypass stream reaching a >mach 1 number ... and additionally doing this efficiently.
 
Basil said:
Could someone please explain - from a propulsion system point of view - how is it possible to fly Mach 1.7 (or so) with a 3:1 fan ratio turbofan without afterburner? Does the fan accelerate the bypass stream to supersonic speeds? I cannot imagine that it is sufficient if only the core stream reaches supersonic speeds ... in this case the fan would act as a huge air brake.
Click to expand...
I expect a major converging/diverging nozzle at the back, though another possibility is a plug type that moves in and out (picture the Blackbird's inlet cones, but with air flowing the opposite direction).

IIRC the 2707 use plug type nozzles and had a large "muffler" section between the end of the engine and the plug.
 
Basil said:
Could someone please explain - from a propulsion system point of view - how is it possible to fly Mach 1.7 (or so) with a 3:1 fan ratio turbofan without afterburner? Does the fan accelerate the bypass stream to supersonic speeds? I cannot imagine that it is sufficient if only the core stream reaches supersonic speeds ... in this case the fan would act as a huge air brake.
Click to expand...
The bypass ratio isn’t the driver - it is the fan pressure ratio. A FPR of 2:1 with zero ram recovery will give a nozzle pressure ratio of 2:1 which will get approximately Mach 1 nozzle exit speed at the average exhaust temperature (which is faster than M1 at ambient temperature. Add ram recovery at aircraft M1 of approximately 1.5 x FPR = NPR of 3:1, which will give supersonic nozzle exit velocity. If you can maintain FPR of 2:1 at M 1.7 with a ram recovery of 3:1, NPR will be around 6:1, which will provide exit velocity over M2 (at the average exhaust temperature).

A FPR of 2:1 with a single stage fan is extremely aggressive and may not be possible. FPR of 1.8 is more likely, with lower NPR throughout the flight envelope.

My guess is that the engine will be significantly larger than necessary for takeoff and will be severely flat rated below its thrust capability. Takeoff with a FPR of 1.6 - 1.7 will keep the exhaust subsonic and the noise level tolerable. As the aircraft goes above 10K it can be turned up to its max FPR capability, which will still be flat rated below the maximum rotor speed and turbine temperature. Transonic acceleration will be marginal and will need a Rutkowski dive to pass thru. The flat rating will enable the engine to maintain max FPR as the inlet temperature increases with Mn, hitting the rotor speed and TIT limit around M1.6, keeping the M2 exit velocity. A plug nozzle would be a good guess to maintain supersonic nozzle expansion without variable convergent / divergent nozzle geometry.

This means the engine needs to have a very aggressive FPR for a single stage fan, a large speed and temperature margin, and be significantly heavier than a typical subsonic fan engine. Since the overall pressure ratio is lower than a modern high bypass turbofan, SFC will be significantly worse, although probably better than the F119 in F-22 supercruise conditions.
 
TomcatViP said:
Look at the tuft on the upper surface. Not bad. (would need a full video to get sure).

From Boom:


Tufts and smoke generator at the wing tip
1727065707224.jpeg
Click to expand...
That isn't a smoke generator at the wing tip, it's an exciter so they can test for flutter at lower speeds by exciting the wing for how it would react at higher speeds. It allows for a safer expansion of the flutter envelope.
 
F119Doctor said:
The bypass ratio isn’t the driver - it is the fan pressure ratio. A FPR of 2:1 with zero ram recovery will give a nozzle pressure ratio of 2:1 which will get approximately Mach 1 nozzle exit speed at the average exhaust temperature (which is faster than M1 at ambient temperature. Add ram recovery at aircraft M1 of approximately 1.5 x FPR = NPR of 3:1, which will give supersonic nozzle exit velocity. If you can maintain FPR of 2:1 at M 1.7 with a ram recovery of 3:1, NPR will be around 6:1, which will provide exit velocity over M2 (at the average exhaust temperature).

A FPR of 2:1 with a single stage fan is extremely aggressive and may not be possible. FPR of 1.8 is more likely, with lower NPR throughout the flight envelope.

My guess is that the engine will be significantly larger than necessary for takeoff and will be severely flat rated below its thrust capability. Takeoff with a FPR of 1.6 - 1.7 will keep the exhaust subsonic and the noise level tolerable. As the aircraft goes above 10K it can be turned up to its max FPR capability, which will still be flat rated below the maximum rotor speed and turbine temperature. Transonic acceleration will be marginal and will need a Rutkowski dive to pass thru. The flat rating will enable the engine to maintain max FPR as the inlet temperature increases with Mn, hitting the rotor speed and TIT limit around M1.6, keeping the M2 exit velocity. A plug nozzle would be a good guess to maintain supersonic nozzle expansion without variable convergent / divergent nozzle geometry.

This means the engine needs to have a very aggressive FPR for a single stage fan, a large speed and temperature margin, and be significantly heavier than a typical subsonic fan engine. Since the overall pressure ratio is lower than a modern high bypass turbofan, SFC will be significantly worse, although probably better than the F119 in F-22 supercruise conditions.
Click to expand...

Thx for this in-depth explanation! I was not aware that - adding ram recovery - the cold stream can be accelerated to such high speeds (Mach 2 is very impressive!). I ask myself why such an engine configuration has not been used for military applications.
 
Basil said:
Thx for this in-depth explanation! I was not aware that - adding ram recovery - the cold stream can be accelerated to such high speeds (Mach 2 is very impressive!). I ask myself why such an engine configuration has not been used for military applications.
Click to expand...
Because it doesn't give you much acceleration. It's fine for supporting cruise once you're fast, but terrible for accelerating to that speed.

Afterburners are much better for sudden acceleration demands.

Also, it doesn't take much diameter increase to get a 3:1 bypass ratio, even from a straight turbojet. Early JT8Ds with a roughly 1:1 bypass ratio only had a fan that was 2" larger in diameter than a J52 turbojet that made up their core, 1" longer fan blades. Getting up to a 1.74:1 bypass ratio with the JT8D-200 variants meant going to a fan that was 12" larger in diameter than the core, 6" longer fan blades; but that fan had a lower pressure ratio. Because bypass ratio is determined by air mass flows, it's not quite the direct relationship between fan diameter and core diameter, or even between core cross-sectional area and fan cross-sectional area.
 
Sundog said:
Tufts and smoke generator at the wing tip

240827_Boom-SmokeGen.jpg
Click to expand...
Those aren't the tufts either, those are the pieces of tape holding the tufts (tufts are visible in a hi-res photo). If those were the tufts, they'd be indicating world-beating span-wise flow.(Which is what I first thought!)
:eek:
 
Scott Kenny said:
Because it doesn't give you much acceleration. It's fine for supporting cruise once you're fast, but terrible for accelerating to that speed.

Afterburners are much better for sudden acceleration demands.
Click to expand...

Sure, but you could add an afterburner or cold stream burner for acceleration and then cruise supersonically more efficiently than with a smaller bpr like the F119. Of course you would have to integrate the larger fan into aircraft structure.
 

Similar threads

Please donate to support the forum.

Back
Top Bottom