Smart throttle
As I recall - experience from ‘have a go flying’; the Bereguet 941 only had one ‘throttle’ (power inceptor) controlling all four engines.
Fightdeck photo halfway through the article; interesting history and background, and opportunities for photo captions.
Video at the end as ‘MD188’
http://histaero.********.com/2014/11...-de-ladac.html
[ replace ***s by blog_spot, but as one word without underscore]
http://histaero.blog _spot.com/2014/11/breguet-940941-linvention-de
Fightdeck photo halfway through the article; interesting history and background, and opportunities for photo captions.
Video at the end as ‘MD188’
http://histaero.********.com/2014/11...-de-ladac.html
[ replace ***s by blog_spot, but as one word without underscore]
http://histaero.blog _spot.com/2014/11/breguet-940941-linvention-de
tdracer
It's always difficult trying to imply irony on an internet forum and as you are a resident of the "western colonies" I should have known better than to attempt it.
All I know about Falcons is what they look like. "Give way to the Falcon" is the limit of my interaction with them. I don't have any experience of MCAS either, so I can't comment on it, but I'm sure the rot set into Boeing long before the 737MAX was contemplated. (Even the 747 had multiple "hair raising" issues, my Father was one of the early FE's, so i know) If you were really so unhappy with the slide back then why didn't you quit at the time? Don't lecture me on operating an aircraft and I won't lecture you, or anyone else, on how to design them. Aviators have been putting up with both design and commercial "comprimises" as long as aviation has existed. You are an obviously experienced fellow but you are not solely the truth and the light, sorry pal, it's very easy to become a preacher in retirement, and there's quite a few on here! haha.
It's always difficult trying to imply irony on an internet forum and as you are a resident of the "western colonies" I should have known better than to attempt it.
All I know about Falcons is what they look like. "Give way to the Falcon" is the limit of my interaction with them. I don't have any experience of MCAS either, so I can't comment on it, but I'm sure the rot set into Boeing long before the 737MAX was contemplated. (Even the 747 had multiple "hair raising" issues, my Father was one of the early FE's, so i know) If you were really so unhappy with the slide back then why didn't you quit at the time? Don't lecture me on operating an aircraft and I won't lecture you, or anyone else, on how to design them. Aviators have been putting up with both design and commercial "comprimises" as long as aviation has existed. You are an obviously experienced fellow but you are not solely the truth and the light, sorry pal, it's very easy to become a preacher in retirement, and there's quite a few on here! haha.
This (american) saying is what has stifled progress in a lot of areas in the US, who amongst other things still produce busses that look and feel as leftovers from the Korean War era… totally unfit for cattle transport, let alone humans.
Had a problem when one of the engines was starting to run low on oil. "No, don't shut it down" said Maintrol. "Just throttle it back until the oil loss is OK".
Wonder how you will reduce power on one engine using this set up.
Wonder how you will reduce power on one engine using this set up.
Last edited by Zeus; 23rd Jun 2021 at 20:02. Reason: Spelling
Private Jet
I try to avoid personal attacks, so I'm going to ignore the overt patronizing in your last post.
But to the point, the reason I brought up MCAS is because of this post:
The MCAS designers went through the failure modes, and had "reversion and abnormal procedures in place.." They looked good on paper, maybe even in a simulator, but in the real world they failed miserably and 300 people died. Simply having "reversion and abnormal procedures in place.." isn't always enough when things don't work...
As a designer, you don't just design for when things work - you have to design for when they don't work. If everything always worked, we wouldn't need redundant systems. But they don't always work (or don't work per design intent) and redundancy is needed.
We have two (or more) engines for redundancy. We have multiple Air Data and Inertial Reference systems for redundancy. We have multiple electrical power systems for redundancy. We have individual thrust levers for each engine for redundancy. Eliminating redundancy has to be done very, very carefully.
Many years ago I did several Failure Mode and Effects Analysis (FMEA) for thrust lever assemblies. One of the failures was "Lever Seizes" - effect was "Loss of Thrust Control on the affected engine, if necessary affected engine can be shutdown". So what are you going to do with that fancy smart throttle if the it seizes or jams?
I've noticed with all the smart ass replies comparing having redundant thrust levers with living in caves and crappy buses, I've yet to see anyone mention any advantage to having a single, non-redundant thrust lever. If you want the levers to move together, a simple link that can be readily removed seems like a far simpler and safer solution.
I try to avoid personal attacks, so I'm going to ignore the overt patronizing in your last post.
But to the point, the reason I brought up MCAS is because of this post:
lol. I'm sure it will be thought through though, with reversion and abnormal procedures in place..
As a designer, you don't just design for when things work - you have to design for when they don't work. If everything always worked, we wouldn't need redundant systems. But they don't always work (or don't work per design intent) and redundancy is needed.
We have two (or more) engines for redundancy. We have multiple Air Data and Inertial Reference systems for redundancy. We have multiple electrical power systems for redundancy. We have individual thrust levers for each engine for redundancy. Eliminating redundancy has to be done very, very carefully.
Many years ago I did several Failure Mode and Effects Analysis (FMEA) for thrust lever assemblies. One of the failures was "Lever Seizes" - effect was "Loss of Thrust Control on the affected engine, if necessary affected engine can be shutdown". So what are you going to do with that fancy smart throttle if the it seizes or jams?
I've noticed with all the smart ass replies comparing having redundant thrust levers with living in caves and crappy buses, I've yet to see anyone mention any advantage to having a single, non-redundant thrust lever. If you want the levers to move together, a simple link that can be readily removed seems like a far simpler and safer solution.
Only half a speed-brake
I've long suspected "if it ain't broke" is another way of saying "you're not re-inventing the wheel here, are you?". Similar to saying "Occam's razor" instead of K.I.S.S., both really mean the same thing.
The determination to misunderstand what's being said ... it must be an internet thing, right?
The determination to misunderstand what's being said ... it must be an internet thing, right?
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tdracer
That is actually one of the things where the airbus non-moving thrust levers have a slight advantage: if the lever seizes or jams, one still has autothrust available on that engine up to that thrust lever angle (if it is below the CLB detent). I have no idea how Dassault plans to implement its system, but that may be a way of working around that particular issue.
It will be interesting to see how they will implement that system and how it works in its final version.
That is actually one of the things where the airbus non-moving thrust levers have a slight advantage: if the lever seizes or jams, one still has autothrust available on that engine up to that thrust lever angle (if it is below the CLB detent). I have no idea how Dassault plans to implement its system, but that may be a way of working around that particular issue.
It will be interesting to see how they will implement that system and how it works in its final version.
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In the ainonline article above, the test pilots make it very clear that, since pilots do not hand fly a lot, they are creating "aircraft for the dummies". Training, anyone? Ever heard of "automation dependency"?
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All I can see is that except there's one lever there's absolutely no more information. Armed with only that all objections actually they are queries are natural. At the same time they are so basic that the manufacturer can also foresee that and must have provided the answers. Only they can provide satisfactory answers.
If I'd responded what you wrote, I'd be banned...
Now go troll someone else.
Oh, and I'm still waiting for someone to explain the benefits of getting rid of one throttle per engine...
Now go troll someone else.
Oh, and I'm still waiting for someone to explain the benefits of getting rid of one throttle per engine...
Moderator
Gents,
Tech Log is not for battleground antics - there are other forums where such is appropriate.
Normally, I don't see any great need to wield a stick in this forum but, if needs be, I can do so.
Let's play the ball, please, and not the player.
regards,
John
Tech Log is not for battleground antics - there are other forums where such is appropriate.
Normally, I don't see any great need to wield a stick in this forum but, if needs be, I can do so.
Let's play the ball, please, and not the player.
regards,
John
Avoid imitations
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Those with any knowledge of twin turbine engined helicopters will realise that this is completely normal. The collective lever controls main rotor blade pitch and the engines respond together to maintain rotor RPM. Admittedly, there is only one main rotor on most helicopters but obviously the Chinook and Tilt Rotor have two.
Individual control of the engines is done by separate controls. These are not normally moved because there is no need in normal use.
Individual control of the engines is done by separate controls. These are not normally moved because there is no need in normal use.
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automatic engine failure management. Thus less training needed. Also, no need for cross check on thrust lever management, in an aircraft that is being developed with single pilot cruise in mind.
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Why does that need a single thrust lever? The airplane can automatically pull back the individual lever for the failed engine, if they want to design it to do so. My plane does that for an unlocked thrust reverser, and it doesn't even have autothrottles.
The earlier linked article also talks about them integrating thrust more tightly into the control law, and automatic upset recoveries. But it doesn't say why either of those need a single thrust lever.
edit: OK, I can see one case: a descent where both levers are at idle. Then the single lever could prevent a misidentification and shutdown of the wrong engine. (second edit: changed "would" to "could." The computer could display "LEFT engine failed, shut down the LEFT engine, note: that is the same side of the airplane as your wristwatch and the side the guy with 4 stripes is sitting on" and someone could still get it wrong, unless they go one step further and change to a single shutoff button
)
The earlier linked article also talks about them integrating thrust more tightly into the control law, and automatic upset recoveries. But it doesn't say why either of those need a single thrust lever.
edit: OK, I can see one case: a descent where both levers are at idle. Then the single lever could prevent a misidentification and shutdown of the wrong engine. (second edit: changed "would" to "could." The computer could display "LEFT engine failed, shut down the LEFT engine, note: that is the same side of the airplane as your wristwatch and the side the guy with 4 stripes is sitting on" and someone could still get it wrong, unless they go one step further and change to a single shutoff button
)
Last edited by Vessbot; 25th Jun 2021 at 20:45.