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Smart throttle

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Smart throttle

Old 22nd Jun 2021, 08:09
  #21 (permalink)  
 
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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
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Old 22nd Jun 2021, 15:29
  #22 (permalink)  
 
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swh

The article says that backup individual levers are there only in the test version, while the final installation is expected to have the single lever only.
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Old 22nd Jun 2021, 16:33
  #23 (permalink)  
 
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FullWings

Not much use with tail mounted engines, so not really a factor for this particular model.
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Old 22nd Jun 2021, 19:31
  #24 (permalink)  
 
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Exactly...
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Old 22nd Jun 2021, 19:40
  #25 (permalink)  
 
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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.
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Old 23rd Jun 2021, 03:49
  #26 (permalink)  
 
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swh

You could have a set up with two separate levers controlling the thrust to each engine, I think that’s been done before
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Old 23rd Jun 2021, 11:12
  #27 (permalink)  
 
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Originally Posted by dixi188 View Post
WHY?
If it ain't broke, don't fix it.
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.
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Old 23rd Jun 2021, 18:20
  #28 (permalink)  
 
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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.

Last edited by Zeus; 23rd Jun 2021 at 20:02. Reason: Spelling
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Old 24th Jun 2021, 01:22
  #29 (permalink)  
 
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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:
lol. I'm sure it will be thought through though, with reversion and abnormal procedures in place..
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.
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Old 24th Jun 2021, 03:13
  #30 (permalink)  

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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?
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Old 24th Jun 2021, 05:49
  #31 (permalink)  
 
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If you really insist on reinventing the wheel, could you please make sure it is round??
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Old 24th Jun 2021, 07:18
  #32 (permalink)  
 
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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.
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Old 24th Jun 2021, 08:11
  #33 (permalink)  
 
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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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Old 24th Jun 2021, 10:37
  #34 (permalink)  
 
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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.
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Old 24th Jun 2021, 19:33
  #35 (permalink)  
 
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tdracer

Well, You've said what you want to say, and avoided what I asked. I suggest you run for political office, you obviously have a talent for it.
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Old 25th Jun 2021, 02:09
  #36 (permalink)  
 
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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...
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Old 25th Jun 2021, 07:00
  #37 (permalink)  
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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
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Old 25th Jun 2021, 07:15
  #38 (permalink)  

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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.
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Old 25th Jun 2021, 07:23
  #39 (permalink)  
 
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Originally Posted by tdracer View Post
Oh, and I'm still waiting for someone to explain the benefits of getting rid of one throttle per engine...
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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Old 25th Jun 2021, 20:08
  #40 (permalink)  
 
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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 )

Last edited by Vessbot; 25th Jun 2021 at 20:45.
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