Boeing at X-Roads?
@fdr. In the proposed design 35T of 76T MTOW are battery mass. How good would such a design perform with normal Jet-A1 engines. The electric motors will need more mass than comparable jet engines, so you compare a fuel tank with batteries. 1500 battery lifetime cycles are not much for an passenger plane. So you think that the airline is willing to replace the battery set 20-40 times during the airframe lifetime? I think if there is no more crude oil to find and we are in a Mad Max type of world, those electric planes might be economic. As current Airbus or Boeing CEO I would not loose sleep on that competition..
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Or is this just because Tim Clark is tired of seeing schedules slip for not great reasons?
Last edited by remi; 5th Feb 2024 at 08:43.
Petit P; whatever the source of conversion from a fuel to an output to achieve some work, in the end y'all gotta convert that output from the engine to a means to develop a useful force.
Nootin' gave us a heads up with his Rule #3, where push meets shove, and that is how every current means of propulsion works, whether it is a Saturn V, Cessna 150, or arguably even your drive tyres on your bicycle. For aircraft, we have simple matters, f=m.an and that is restated as mdot.V. Whether it is an afterburner, turbojet, turbofan or propeller, force is generated by pushing a mass out the back, at a velocity greater than free stream. That bit ain't going away anytime soon. A core massflow happens to be hot, so the local speed of sound is higher, that helps avoid massflow choking at Mach 1.0. A fan massflow is a lower velocity, but higher mass flow, and it gives a better propulsion efficiency from less V losses in the far field. Unfortunately, the faster you fly, the lower the fan thrust component for the engine, for two simple reasons....
1. The fan is effectively a fancy fixed pitch prop. It is limited in the blade angle that can be set for takeoff, static, as stall has to be avoided, (blades are susceptible to flutter, and there is a lot of uglies that occur around non axisymmetric flow into the engine... Those mid span shrouds... dampers... they are there as they need to be normally. The fan blade actually is subject to torsion-bending that is pretty neat, as it is a splined section, the resultant aero forces cause torsion not just bending, and that happens to torsion to higher blade angles. All good when steady case, and when your blades don't have stress concentration built in as a design "feature".
2. The gross thrust output is great at relatively low speeds, but at cruise speed, all that TAS is working against your fan thrust output. For my turbofan in flight test, static 54% of the thrust is derived from the fan normally at sea level, but at FL400, M080, that is below 25%. (thats standard... my engine does something rather different).
Way back when, Mr Froude n' Co sorted out ways to explain how a propeller works, by the means of an actuator disc, and that is a nice and simple analysis so long as you aren't running into compressibility, which unfortunately almost every prop on the planet does in use. (Keeping the tip velocity subsonic with respect to relative airflow is one thing, but if the blades have any level of resultant force giving a thrust component will be transonic, accelerating flow on the suction face to greater than Mach 1, and generating shocks (gaining entropy, sucks), mussing up the boundary layer, and the "CL's" and the "CD's" and the "Cm's". Your vibration isn't all from the engine, much of it is from the unsteady aero effects on the propeller. Prandtl added blade element theory to the propeller understanding, and yet, it is still just achieving Nootin's 3rd law, just as the the turbojet and the turbofan do.
The higher bypass achieves better propulsive efficiency, to a point. As the area of the intake gets bigger, so does the drag from the nacelle. Somewhere a bit past the GE90, we are about at the end of the diameter game for the engine, and can only improve stuff by gearing or variable blade angles or doing some magic.
For anyone who looks at the spoilers below, this causes some curious outcomes in the equations for turbomachinery.
1. Yes, we have removed a specific fluid mechanics limitation that exists in turbomachinery, and it was done by some neat aerodynamics.
2. Yes, the equations of propulsion efficiency look odd, I can't help that, I can only go by what the plane does, and it suggests that we are already overstating propulsive efficiency a tad. Anyone who likes algebra, we have a group of people working on resolving the surprise of propulsive efficiency.
3. No, we do not alter thermodyamics of the core of the blender at all. We do however alter profoundly the entropy of the fan, and the mass flow and velocity of the bypass flow. Amazingly, the engine core doesn't know that it is being fooled, the only difference is that at low RPM, fuel flow is slightly higher, but within error margins, and at higher RPM, fuel flow is around 1% lower than standard for a given RPM, with EGT following suit.
4. It has been flown to FL450, M080 so far, and seems happy enough to go to STC.
5. Vibration is lower, and loads on the fan blades and disc are lower than standard. That is a necessary outcome of the aerodynamics, and has been observed on propellers, helicopter rotors and turbo fans.
What magic looks like....
https://youtu.be/PNt12O7wFNA
Magic at FL400, M076
Nootin' gave us a heads up with his Rule #3, where push meets shove, and that is how every current means of propulsion works, whether it is a Saturn V, Cessna 150, or arguably even your drive tyres on your bicycle. For aircraft, we have simple matters, f=m.an and that is restated as mdot.V. Whether it is an afterburner, turbojet, turbofan or propeller, force is generated by pushing a mass out the back, at a velocity greater than free stream. That bit ain't going away anytime soon. A core massflow happens to be hot, so the local speed of sound is higher, that helps avoid massflow choking at Mach 1.0. A fan massflow is a lower velocity, but higher mass flow, and it gives a better propulsion efficiency from less V losses in the far field. Unfortunately, the faster you fly, the lower the fan thrust component for the engine, for two simple reasons....
1. The fan is effectively a fancy fixed pitch prop. It is limited in the blade angle that can be set for takeoff, static, as stall has to be avoided, (blades are susceptible to flutter, and there is a lot of uglies that occur around non axisymmetric flow into the engine... Those mid span shrouds... dampers... they are there as they need to be normally. The fan blade actually is subject to torsion-bending that is pretty neat, as it is a splined section, the resultant aero forces cause torsion not just bending, and that happens to torsion to higher blade angles. All good when steady case, and when your blades don't have stress concentration built in as a design "feature".
2. The gross thrust output is great at relatively low speeds, but at cruise speed, all that TAS is working against your fan thrust output. For my turbofan in flight test, static 54% of the thrust is derived from the fan normally at sea level, but at FL400, M080, that is below 25%. (thats standard... my engine does something rather different).
Spoiler
Way back when, Mr Froude n' Co sorted out ways to explain how a propeller works, by the means of an actuator disc, and that is a nice and simple analysis so long as you aren't running into compressibility, which unfortunately almost every prop on the planet does in use. (Keeping the tip velocity subsonic with respect to relative airflow is one thing, but if the blades have any level of resultant force giving a thrust component will be transonic, accelerating flow on the suction face to greater than Mach 1, and generating shocks (gaining entropy, sucks), mussing up the boundary layer, and the "CL's" and the "CD's" and the "Cm's". Your vibration isn't all from the engine, much of it is from the unsteady aero effects on the propeller. Prandtl added blade element theory to the propeller understanding, and yet, it is still just achieving Nootin's 3rd law, just as the the turbojet and the turbofan do.
The higher bypass achieves better propulsive efficiency, to a point. As the area of the intake gets bigger, so does the drag from the nacelle. Somewhere a bit past the GE90, we are about at the end of the diameter game for the engine, and can only improve stuff by gearing or variable blade angles or doing some magic.
For anyone who looks at the spoilers below, this causes some curious outcomes in the equations for turbomachinery.
1. Yes, we have removed a specific fluid mechanics limitation that exists in turbomachinery, and it was done by some neat aerodynamics.
2. Yes, the equations of propulsion efficiency look odd, I can't help that, I can only go by what the plane does, and it suggests that we are already overstating propulsive efficiency a tad. Anyone who likes algebra, we have a group of people working on resolving the surprise of propulsive efficiency.
3. No, we do not alter thermodyamics of the core of the blender at all. We do however alter profoundly the entropy of the fan, and the mass flow and velocity of the bypass flow. Amazingly, the engine core doesn't know that it is being fooled, the only difference is that at low RPM, fuel flow is slightly higher, but within error margins, and at higher RPM, fuel flow is around 1% lower than standard for a given RPM, with EGT following suit.
4. It has been flown to FL450, M080 so far, and seems happy enough to go to STC.
5. Vibration is lower, and loads on the fan blades and disc are lower than standard. That is a necessary outcome of the aerodynamics, and has been observed on propellers, helicopter rotors and turbo fans.
What magic looks like....
Spoiler
https://youtu.be/PNt12O7wFNA
Magic at FL400, M076
Spoiler
I am in wild agreement, hence my more generic comment about different thrust devices and different energy sources, and also regarding potential changes in the underlying travel market.
Tell me, regarding your thrust widgetry which you seem justly proud about, how would it fare if the energy source was not burning long-dead dino juice ? Would your widgetry still be at all relevant, or would one design 180-220 seat aircraft around other thrust devices ?
If you were an airframer considering a market entry would you jump in now, or hold back ten years and wait and see ?
And in the meantime am I right in guessing that you see your widgetry as being most interesting in sweating the existing fleets to perform better, rather than switching out for new fleets entirely ?
regards, pp
Last edited by petit plateau; 5th Feb 2024 at 16:36.
fdr,
I am in wild agreement, hence my more generic comment about different thrust devices and different energy sources, and also regarding potential changes in the underlying travel market.
Tell me, regarding your thrust widgetry which you seem justly proud about, how would it fare if the energy source was not burning long-dead dino juice ? Would your widgetry still be at all relevant, or would one design 180-220 seat aircraft around other thrust devices ?
If you were an airframer considering a market entry would you jump in now, or hold back ten years and wait and see ?
And in the meantime am I right in guessing that you see your widgetry as being most interesting in sweating the existing fleets to perform better, rather than switching out for new fleets entirely ?
regards, pb
I am in wild agreement, hence my more generic comment about different thrust devices and different energy sources, and also regarding potential changes in the underlying travel market.
Tell me, regarding your thrust widgetry which you seem justly proud about, how would it fare if the energy source was not burning long-dead dino juice ? Would your widgetry still be at all relevant, or would one design 180-220 seat aircraft around other thrust devices ?
If you were an airframer considering a market entry would you jump in now, or hold back ten years and wait and see ?
And in the meantime am I right in guessing that you see your widgetry as being most interesting in sweating the existing fleets to perform better, rather than switching out for new fleets entirely ?
regards, pb
My text Is agnostic to the manner that torque is applied to the propeller, rotor or fan blade. The engine is either purely a source of tprque to spin a shaft that does something to generate a force and hopefully achieve some work output. Electric, hydrogen, SAF, Jet A, or white spirits, it doesn't matter.
While I am pushing ahead with the STC for props and the turbo fans that I have funding or JV's to cover, and that is a major effect on CO2 and NOx, I am not a proponent of electric propulsion for aircraft use at present. The fundamental problems of a plug in electric motor is the risk in accidents; they have a significant fire risk that appears to be difficult to mitigate. Hope that Toyota gets somewhere with their onboard electrolysis processing, but not certain the enegy balance works, unless they have some seriously magic ceramic catalyst tech in the background. In the absence of that, it seems that using renewable electric harvesting to generate hydrogen in a distributed network would allow a move towards FT, CO added ethanol, which may avoid having to disinvite a number of the citizenry from eating and living on this fair planet.
The rate of CO2 addition is an issue, as is NOx, particularly where we inject it into the atmosphere. Cycling CO2 within a loop process to give a high energy density fuel still seems to make sense IMHO.
boring stuff
Spoiler
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Yet another problem? Or an old problem being no longer ignored?
https://www.nytimes.com/2024/02/05/b...-problems.html
https://www.nytimes.com/2024/02/05/b...-problems.html
Petite P;
My text Is agnostic to the manner that torque is applied to the propeller, rotor or fan blade. The engine is either purely a source of tprque to spin a shaft that does something to generate a force and hopefully achieve some work output. Electric, hydrogen, SAF, Jet A, or white spirits, it doesn't matter.
While I am pushing ahead with the STC for props and the turbo fans that I have funding or JV's to cover, and that is a major effect on CO2 and NOx, I am not a proponent of electric propulsion for aircraft use at present. The fundamental problems of a plug in electric motor is the risk in accidents; they have a significant fire risk that appears to be difficult to mitigate. Hope that Toyota gets somewhere with their onboard electrolysis processing, but not certain the enegy balance works, unless they have some seriously magic ceramic catalyst tech in the background. In the absence of that, it seems that using renewable electric harvesting to generate hydrogen in a distributed network would allow a move towards FT, CO added ethanol, which may avoid having to disinvite a number of the citizenry from eating and living on this fair planet.
The rate of CO2 addition is an issue, as is NOx, particularly where we inject it into the atmosphere. Cycling CO2 within a loop process to give a high energy density fuel still seems to make sense IMHO.
boring stuff
My text Is agnostic to the manner that torque is applied to the propeller, rotor or fan blade. The engine is either purely a source of tprque to spin a shaft that does something to generate a force and hopefully achieve some work output. Electric, hydrogen, SAF, Jet A, or white spirits, it doesn't matter.
While I am pushing ahead with the STC for props and the turbo fans that I have funding or JV's to cover, and that is a major effect on CO2 and NOx, I am not a proponent of electric propulsion for aircraft use at present. The fundamental problems of a plug in electric motor is the risk in accidents; they have a significant fire risk that appears to be difficult to mitigate. Hope that Toyota gets somewhere with their onboard electrolysis processing, but not certain the enegy balance works, unless they have some seriously magic ceramic catalyst tech in the background. In the absence of that, it seems that using renewable electric harvesting to generate hydrogen in a distributed network would allow a move towards FT, CO added ethanol, which may avoid having to disinvite a number of the citizenry from eating and living on this fair planet.
The rate of CO2 addition is an issue, as is NOx, particularly where we inject it into the atmosphere. Cycling CO2 within a loop process to give a high energy density fuel still seems to make sense IMHO.
boring stuff
Spoiler
Thank you for a helpful answer.
It is good to know that your widgetry is applicable to any torque consumer. Knowing that, my suspicion is that industry will be even more motivated to sweat the existing airframe designs for longer, maybe even the existing actual in-service airframes. That in turn suggests that other airframers may be slightly more reluctant to gatecrash the Boeing-Airbus duopoly in the next 10-years.
I am not sure I agree with you on the electric propulsion front given the timelines of interest, but we will see and I am very unlikely to be involved in making the decisions. With regard to your thoughts on hydrogen (via various carriers) may I politely disagree for all timeframes at any serious volume in civil use at economic prices, and again we will see.
Good luck with your widgetry.
regards, pp
Yet another problem? Or an old problem being no longer ignored?
https://www.nytimes.com/2024/02/05/b...-problems.html
https://www.nytimes.com/2024/02/05/b...-problems.html
Personally the detail that really defines how deeply delusional Boeing management is, is the fact that the FAA had to refuse Boeing’s request to up the 737 production rate.
Everyone knows that the fundamental problem at Spirit and Boeing itself is too few, too new employee’s being ask to do too much too fast, yet Boeing wants to stress the production line more to generate short term profits and protect C Suite bonuses.
Boeing simply isn’t serious about addressing the root cause of the QA production problems. Instead we are see a continuation of the standard bean counter MBA playbook. Incentivize a culture where there will never be enough time, money, or people to do the job right and then scramble for find the cheapest, nastiest, fastest way to do the job over after problems get so big they can’t be explained away.
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The engineering and physics discussion going on about propulsion systems and potential systems . . . . don't you think we should wait for the report? (okay, not really funny enough, but anyway....)
To right the Boeing ship something like "magic" evidently is going to be required. If for no other reason, the confidence of the traveling public, and all the commercial activities which depend on air transport, requires - or at least strongly recommends - that calls and initiatives for vengeance against Boeing go unheeded. Turning out the rascal Directors and Execs, fine. But burning down the company in order to save the air transport system which has significant dependencies upon the company in order to save that system, won't solve anything.
A source of beneficial redirection might be found in the aviator community. I mean, the community writ large. Besides IFALPA, there are other major labor-organization types of pilot groups worldwide, are there not? Give them some Board seats without a lot of process to get there. FAA - as has been repeatedly, many times, noted, has never received the levels of funding to do all that has been asked of it, especially after its mandate was changed. We know the bonus-seeking Execs and their cadres of running dogs of Bean Counting cannot be looked upon for solvency initiatives. Who then? Well, who has the most learned and dedicated focus upon getting safe aircraft built properly and with all safety built in rather than randomized, if not the aviator community? As Starbuck said to Steelkilt (though in a mutinous situation), "Look to yourself!". Actually, a mutinous attitude might be a decent substitute service for vengeance.
And speaking of understanding that hot motive, i.e., vengeance, how about some Mitsubishi Heavy with your hand-flying skills? They were pretty good at stick-and-rudder in the Second WW, were they not? And you want by the book, first time, next time, every time? - I dunno, maybe I just enjoyed the 777-300ER rides Chicago O'Hare-Tokyo Narita, Narita-NYC JFK too well, little while back.
As for strategy, let the engineering community in the Western world get itself organized and empanel some grouping at the level of IFALPA. Board seats of course.
FInally, and here I know I've gone to the edge of the proverbial deep end.... someone has got to channel Winpisinger. Because he was Aggressive, Radical, Blunt, Outspoken, and Flamboyant. Due respect to those noted above, still somebody's got to kick some.
To right the Boeing ship something like "magic" evidently is going to be required. If for no other reason, the confidence of the traveling public, and all the commercial activities which depend on air transport, requires - or at least strongly recommends - that calls and initiatives for vengeance against Boeing go unheeded. Turning out the rascal Directors and Execs, fine. But burning down the company in order to save the air transport system which has significant dependencies upon the company in order to save that system, won't solve anything.
A source of beneficial redirection might be found in the aviator community. I mean, the community writ large. Besides IFALPA, there are other major labor-organization types of pilot groups worldwide, are there not? Give them some Board seats without a lot of process to get there. FAA - as has been repeatedly, many times, noted, has never received the levels of funding to do all that has been asked of it, especially after its mandate was changed. We know the bonus-seeking Execs and their cadres of running dogs of Bean Counting cannot be looked upon for solvency initiatives. Who then? Well, who has the most learned and dedicated focus upon getting safe aircraft built properly and with all safety built in rather than randomized, if not the aviator community? As Starbuck said to Steelkilt (though in a mutinous situation), "Look to yourself!". Actually, a mutinous attitude might be a decent substitute service for vengeance.
And speaking of understanding that hot motive, i.e., vengeance, how about some Mitsubishi Heavy with your hand-flying skills? They were pretty good at stick-and-rudder in the Second WW, were they not? And you want by the book, first time, next time, every time? - I dunno, maybe I just enjoyed the 777-300ER rides Chicago O'Hare-Tokyo Narita, Narita-NYC JFK too well, little while back.
As for strategy, let the engineering community in the Western world get itself organized and empanel some grouping at the level of IFALPA. Board seats of course.
FInally, and here I know I've gone to the edge of the proverbial deep end.... someone has got to channel Winpisinger. Because he was Aggressive, Radical, Blunt, Outspoken, and Flamboyant. Due respect to those noted above, still somebody's got to kick some.
I don't think that would have happened a couple months ago...
The good news is that the report was effective now. At least while attention remains focused on the issue.
One mechanic on the shop floor said that if anyone on the Boeing line pushed a big red 'stop' button, management's response would be to dust it for fingerprints. Whether true or not, the thinking was there. As was the fear of the button
The lad (operator) they tried to place all the blame upon was blameless, a Royal Commission investigation so found. Never the less it destroyed the young man psychologically, also his marriage. A large, large American company by the way with a complete lack of standards.
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On Thursday Feb. 8 the Commerce, Science and Transportation Committee of the United States Senate is scheduled to mark-up the Senate version of the FAA reauthorization legislation. It's a fair guess at this point that the extension of the mandatory retirement age to 67, which is part of the bill passed by the House, will not be approved by the Committee or the Senate. Vehement opposition by Sen. Duckworth especially (and in light of the Senator's military aviation career and experience) as well as other legislators, plus the position taken just days ago by the FAA on the item, point to the outcome. Likewise, probably, on modifications of the so-called 1500-hour rule. (These observations aren't meant to comment on the merits of either proposal.)
Though sadly there's precious little making much sense in Washington at present, it does appear that the legislation will get through the Senate now and move to conference where the House and Senate conferees will reconcile the two somewhat different bills and derive a final bill.
The point is, with the significantly ramped up scrutiny of Boeing announced by FAA in the aftermath of thr Flight 1282 door plug accident, getting reauthorization legislation done (and enacted and signed into law), finally, will enable if not empower the recently-confirmed Administrator to press forward more deliberately. Provisions in the bill also are designed to address ATCO staffing directly if not aggressively. The legislation also addresses issues in several other parts of the aviation sector.
This SLF/attorney had observed that the nomination and confirmation of Mr. Whitaker was praised widely throughout various parts of the aviation community (and deservedly so). Once the reauthorization of FAA finally is complete, curb your surprise over FAA taking more intensive approaches to issues with Boeing. And other safety-critical issues too.
Though sadly there's precious little making much sense in Washington at present, it does appear that the legislation will get through the Senate now and move to conference where the House and Senate conferees will reconcile the two somewhat different bills and derive a final bill.
The point is, with the significantly ramped up scrutiny of Boeing announced by FAA in the aftermath of thr Flight 1282 door plug accident, getting reauthorization legislation done (and enacted and signed into law), finally, will enable if not empower the recently-confirmed Administrator to press forward more deliberately. Provisions in the bill also are designed to address ATCO staffing directly if not aggressively. The legislation also addresses issues in several other parts of the aviation sector.
This SLF/attorney had observed that the nomination and confirmation of Mr. Whitaker was praised widely throughout various parts of the aviation community (and deservedly so). Once the reauthorization of FAA finally is complete, curb your surprise over FAA taking more intensive approaches to issues with Boeing. And other safety-critical issues too.
WillowRun. I fixed the last sentence of your excellent summary for you….
Once If the reauthorization of FAA finally is complete, curb your surprise over FAA taking more intensive approaches to issues with Boeing. And other safety-critical issues too.
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All kidding aside - and even though I'm not claiming sources on Captiol Hill - there's a vested interest at work here. Very few Members on either side of the Hill walk to work.
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14 - 13
Committee vote against raising the mandatory retirement age. Projecting ahead, assuming the House will accept the Senate version (and that the Senate passes the bill reported out by Committee first), the age of mandatory retirement stays as it is.
Which leaves a pretty significant problem. If a principal barrier - according to opponents of raising the age level - is the ICAO rule, how is anyone who supports raising the mandatory retirement age level rationally expecting progress to be made at ICAO while the United States has not had a Permanent Representative at ICAO with rank of Ambassador since Sullenberger resigned, way back in..... oh, never mind.
Which leaves a pretty significant problem. If a principal barrier - according to opponents of raising the age level - is the ICAO rule, how is anyone who supports raising the mandatory retirement age level rationally expecting progress to be made at ICAO while the United States has not had a Permanent Representative at ICAO with rank of Ambassador since Sullenberger resigned, way back in..... oh, never mind.
More fine journalism regarding Boeing issues:
Wonder if the US Congress will launch an investigation of this defect
Wonder if the US Congress will launch an investigation of this defect
But you notice that it doesn’t say that the 777 is unable to maintain altitude with empty fuel tanks. Therefore, a reasonable conclusion is that, with sufficient struggle, the 777 can maintain altitude with empty fuel tanks. Unclear who or what is doing the struggling or what level of struggle is required.