Thrust on during flare...Q for AIRBUS test pilots...
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Surely the last paragraph advising the a higher ROD than 700 fpm will result in going below GS and a 1 deg pitch correction causes 100 fpm change IS ALL YOU NEED TO SEE HOW THEY WANT YOU TO CORRECT IT....
I mean do they have to hand feed you too????
I mean do they have to hand feed you too????
What I'm saying is that you manage the aircraft energy with the thrust. And that is applicable in all phases of flight. You don't have to invent a new rule of thumb for every different phase of flight.
If the energy state (the forces that act on the aircraft) is not in equilibrium you will see either speed or vertical speed changes. Which in effect are pitch changes.
but when your buddy Bloggs starts to contest that a flightpath is the resultant of vertical and horizontal movement then something is seriously wrong with basic understanding of physics. and in that case those type of people meed to be handfed information!
The difference is that when I feel an updraft, seat of the pants and all. I immediately reduce thrust in order to balance the energy and at the same time I adjust the pitch required.
You lower the nose and then wait for the speed change that WILL follow, only then you reduce the thrust thinking that you are controlling the speed, whereas you are simply reducing the energy the aircraft has in order to reach your desired stable flightpath. Its the same thing.
See speed doesn't change on its own, it changes due to an energy change, this change is absorbed into vertical speed or speed depending on the pitch.
What are we inventing exactly??
Apart from CLB or OPEN DESC what modes aren't THRUST for SPEED?
When I feel an updraft I immediately ease forward on the pitch to maintain the GS then and only then do I adjust the thrust to maintain the speed. The thrust may not even need to be adjusted for minor changes....
When I feel a sink I immediately ease back on the pitch to correct the ROD, most times considering the inertia of the heavy Jet I still won't need to increase the thrust BUT I'm ready to just in case.
You cannot effectively use pitch to vary the IAS at it takes too long to effect an outcome and you'd need to adjust the thrust anyway. Not to mention they don't want you push forward at low level!!
There in lies the crux of the whole matter, THRUST CONTROLS THE SPEED MUCH MORE EFFECTIVELY IN JET A/C.
Apart from CLB or OPEN DESC what modes aren't THRUST for SPEED?
When I feel an updraft I immediately ease forward on the pitch to maintain the GS then and only then do I adjust the thrust to maintain the speed. The thrust may not even need to be adjusted for minor changes....
When I feel a sink I immediately ease back on the pitch to correct the ROD, most times considering the inertia of the heavy Jet I still won't need to increase the thrust BUT I'm ready to just in case.
You cannot effectively use pitch to vary the IAS at it takes too long to effect an outcome and you'd need to adjust the thrust anyway. Not to mention they don't want you push forward at low level!!
There in lies the crux of the whole matter, THRUST CONTROLS THE SPEED MUCH MORE EFFECTIVELY IN JET A/C.
Originally Posted by 737jock
The difference is that when I feel an updraft, seat of the pants and all. I immediately reduce thrust in order to balance the energy and at the same time I adjust the pitch required.
Energy? May the energy force be with you, 737jock.
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well bloggs I refer you to my first post on the matter post 47
clearly if you could read... You would see that I actually said the pitch will change.
Cause the pitch controls the speed and the vertical speed, which controls the path. But you don't even understand what a flightpath is.
So instead of thinking that I'm coming around how about you study a bit. Cause nothing what I said is contradictory.
The statement that thrust controls speed is as correct or incorrect as the statement that thrust controls vertical speed. It only does so because we are unable to detect energy requirement changes fast enough.
You have a lot of studying to do Bloggs, physics, aerodynamics, but more importantly reading.
I would start with learning how to read and actually understand. Its probably why you are having so much trouble with physics and aerodynamics.
The flying techniques are just that techniques. Thrust and pitch are linked, cause what we want to fly is performance.
It doesn't matter one bit what you change first. It's just an easy way to teach students and give them some good concepts to quickly deal with matters. But it is as easy as I said.
But I bet your ass that when you feel a kick in your back due to a gust you immediately reduce thrust, which in a Boeing will automatically lower the nose due to it being trimmed for speed. You know this you have this experience, a student might actually lower the nose (increasing speed) and then reduce thrust to reduce speed. No experienced pilot would do this.
In an airbus you will immediately take thrust off and lower the nose with the sidestick to maintain speed.
It doesn't matter one bit what you change first. It's just an easy way to teach students and give them some good concepts to quickly deal with matters. But it is as easy as I said.
But I bet your ass that when you feel a kick in your back due to a gust you immediately reduce thrust, which in a Boeing will automatically lower the nose due to it being trimmed for speed. You know this you have this experience, a student might actually lower the nose (increasing speed) and then reduce thrust to reduce speed. No experienced pilot would do this.
In an airbus you will immediately take thrust off and lower the nose with the sidestick to maintain speed.
Cause the pitch controls the speed and the vertical speed, which controls the path. But you don't even understand what a flightpath is.
So instead of thinking that I'm coming around how about you study a bit. Cause nothing what I said is contradictory.
The statement that thrust controls speed is as correct or incorrect as the statement that thrust controls vertical speed. It only does so because we are unable to detect energy requirement changes fast enough.
You have a lot of studying to do Bloggs, physics, aerodynamics, but more importantly reading.
I would start with learning how to read and actually understand. Its probably why you are having so much trouble with physics and aerodynamics.
Cause the pitch controls the speed and the vertical speed, which controls the path.
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Bizjet - in general I'd agree with you but you but I doubted the accuracy of your comment about the wing loading of 1960 fighters vs. modern airliners. Turns out you were correct. Learned something new today.
Fighter from that era were in the 70-80 lbs/sqft range. Modern airliners are in the 120-140 lbs/sqft range. The only 'F' series a/c that approach 120-130 lbs/sqft is the F-111.
Nicely done.
Comparison of Aircraft Wing Loadings - Military and General Aviation - CombatACE
Fighter from that era were in the 70-80 lbs/sqft range. Modern airliners are in the 120-140 lbs/sqft range. The only 'F' series a/c that approach 120-130 lbs/sqft is the F-111.
Nicely done.
Comparison of Aircraft Wing Loadings - Military and General Aviation - CombatACE
Last edited by misd-agin; 28th Mar 2014 at 15:43. Reason: typo
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Capn Bloggs - you need more energy? What's your potential vs kinetic energy state? What's your energy state vs. your desired flight path? Is your thrust in a fixed position or is it variable(ie not at full power).
Like I said, I'm glad we finally solved this issue.
Like I said, I'm glad we finally solved this issue.
Weak arguments and trying to ridiculize your opponent. Typical for people who lack intellect.
You have a lot of studying to do Bloggs, physics, aerodynamics, but more importantly reading.
I would start with learning how to read and actually understand. Its probably why you are having so much trouble with physics and aerodynamics.
I would start with learning how to read and actually understand. Its probably why you are having so much trouble with physics and aerodynamics.
No but clearly they have to hand feed it to you.
Mate study some physics!
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All those statements are based on your posts. Or in reply to nitpickers post who also has the tendency to ridiculize. You (Bloggs) misread and misinterpret.
You demonstrate a lack of knowledge in physics and aerodynamics. And when confronted with verifiable information you ignore it instead of trying to understand it.
It's not ridiculizing to point out simple facts.
But keep working on those emoticons. Another sad example of not being able to have a proper debate.
You demonstrate a lack of knowledge in physics and aerodynamics. And when confronted with verifiable information you ignore it instead of trying to understand it.
It's not ridiculizing to point out simple facts.
But keep working on those emoticons. Another sad example of not being able to have a proper debate.
John Tullamarine
Time to lock this thread buddy, waste of time now.
These Physics professors and Aerodynamic class room experts can fly their chalk board the way they wish and there can be no doubt their theories are correct with regards to momentum path vectors inertia etc etc.
Me? I'm sticking to the way Airbus want me to. Keeping it simple easy to use and safe for real world operations. KISS method.
LOCK IT IN EDDIE. ( John knows what I mean )
Time to lock this thread buddy, waste of time now.
These Physics professors and Aerodynamic class room experts can fly their chalk board the way they wish and there can be no doubt their theories are correct with regards to momentum path vectors inertia etc etc.
Me? I'm sticking to the way Airbus want me to. Keeping it simple easy to use and safe for real world operations. KISS method.
LOCK IT IN EDDIE. ( John knows what I mean )
Last edited by nitpicker330; 29th Mar 2014 at 01:18.
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The airplane does not care what you think controls what. The reality is: the throttle controls ENGINE POWER (Thrust) and the yoke / stick controls PITCH (or indirectly, AOA). The combination produces performance. You choose which controls which as a TECHNIQUE based on what you are trying to get the airplane to do. Obviously by the endlessness of these arguments, they both work. Regarding jets, if you observe how modern auto flight systems work (A330 and B717) you will see 2 main ways they are programmed to handle speed. First is "speed-on-pitch", where power is fixed at a set value by the autothrust / auto throttle (climb, TOGA, flight idle) and pitch is varied to maintain selected speeds. Second is "speed on thrust", where flight path (vertical rate or angle, a glideslope, VNAV path, or level flight) is maintained by pitch and the power is varied by the autothrust to maintain speed.
Notice that in "speed on thrust" mode both adjustments always occur; if you are in (Airbus speak) ALT CRZ and hit a mountain wave updraft, the autopilot will pitch down slightly to hold altitude, and reduce thrust to hold something close to cruise mach. This is, strictly speaking, a technique. It makes the most sense to think in this manner so the designers programmed the airplane to think this way. It could be argued that the airplane pitches up to maintain speed, and concurrently reduces power to prevent a climb. Some people fly this way (or at least that is what they choose to think, rather than visualizing the "speed on thrust" scenario). Imaging you were hand flying a 172 in a similar, smooth wave updraft and wanted to hold altitude and speed (good luck). You would probably follow an intuitive technique similar to one the Airbus uses to fly itself. However, you COULD choose to think differently and be a strict "elevator controls speed" guy, jockeying the throttle back to reduce excess thrust and therefore counter the updraft, while gingerly pitching up in opposition to the thrust reduction to get the speed back. For light planes that do not have much excess power, this is a good way to think; it will help you make the right move when you suddenly find yourself closer to a stall than you thought you were. Come to think of it in light of AF447 it has a place in jet flying, too. The point is in the end it doesn't matter how you think about it, you will intuitively move both at the same time, as needed to get the job done. Yoke = elevator / pitch, throttle = engine power / thrust. Speed is part of the resulting performance.
This argument is ages-old as we all know. Bob Buck in his many books advocated the "elevator for airspeed" theory (and with his varied experience I would listen to him); Jim Webb in "Fly The Wing" (the American equivalent to "Handling the Big Jets") advocates the opposite. I would listen to him, too. And really, don't we tend to use both? On the glideslope a momentary above-path deviation can be quickly countered by a little pitch down; we pull back the power to keep the speed from building. But if we keep trending high over the long term, a very slight reduction in approach power setting is probably what is going to do the trick. We then subtly adjust pitch with power to hold our speed. It's all just in how we think about it. So we use the most appropriate technique for our airplane, situation, maneuver, and in some cases just personal preference. In the Boeings and Airbii (particularly the latter, as the fly by wire system decides your technique for you a great deal of the time) with the autothrust on, we fly whatever technique we have the system programmed for. And if we disengage the autoflight, autothrottles, and flight directors (talking 717 here) we fly just as in any other plane.
Recall that in a STABLE idle power descent, we can switch between VS and OPN DES / Idle Clamp all day long and the flight path, attitude, and power setting will not change if nothing disturbs the airplane's "groove".
Everybody here needs to take a deep breath, drink a beer, and focus less on how we THINK about flying and just go out and enjoy DOING it. Myself included. Ready 3-2-1... pf-FSSSS! That is a Peroni opening. I believe I will let the airplane do all the thinking this weekend and just enjoy the flying part.
Notice that in "speed on thrust" mode both adjustments always occur; if you are in (Airbus speak) ALT CRZ and hit a mountain wave updraft, the autopilot will pitch down slightly to hold altitude, and reduce thrust to hold something close to cruise mach. This is, strictly speaking, a technique. It makes the most sense to think in this manner so the designers programmed the airplane to think this way. It could be argued that the airplane pitches up to maintain speed, and concurrently reduces power to prevent a climb. Some people fly this way (or at least that is what they choose to think, rather than visualizing the "speed on thrust" scenario). Imaging you were hand flying a 172 in a similar, smooth wave updraft and wanted to hold altitude and speed (good luck). You would probably follow an intuitive technique similar to one the Airbus uses to fly itself. However, you COULD choose to think differently and be a strict "elevator controls speed" guy, jockeying the throttle back to reduce excess thrust and therefore counter the updraft, while gingerly pitching up in opposition to the thrust reduction to get the speed back. For light planes that do not have much excess power, this is a good way to think; it will help you make the right move when you suddenly find yourself closer to a stall than you thought you were. Come to think of it in light of AF447 it has a place in jet flying, too. The point is in the end it doesn't matter how you think about it, you will intuitively move both at the same time, as needed to get the job done. Yoke = elevator / pitch, throttle = engine power / thrust. Speed is part of the resulting performance.
This argument is ages-old as we all know. Bob Buck in his many books advocated the "elevator for airspeed" theory (and with his varied experience I would listen to him); Jim Webb in "Fly The Wing" (the American equivalent to "Handling the Big Jets") advocates the opposite. I would listen to him, too. And really, don't we tend to use both? On the glideslope a momentary above-path deviation can be quickly countered by a little pitch down; we pull back the power to keep the speed from building. But if we keep trending high over the long term, a very slight reduction in approach power setting is probably what is going to do the trick. We then subtly adjust pitch with power to hold our speed. It's all just in how we think about it. So we use the most appropriate technique for our airplane, situation, maneuver, and in some cases just personal preference. In the Boeings and Airbii (particularly the latter, as the fly by wire system decides your technique for you a great deal of the time) with the autothrust on, we fly whatever technique we have the system programmed for. And if we disengage the autoflight, autothrottles, and flight directors (talking 717 here) we fly just as in any other plane.
Recall that in a STABLE idle power descent, we can switch between VS and OPN DES / Idle Clamp all day long and the flight path, attitude, and power setting will not change if nothing disturbs the airplane's "groove".
Everybody here needs to take a deep breath, drink a beer, and focus less on how we THINK about flying and just go out and enjoy DOING it. Myself included. Ready 3-2-1... pf-FSSSS! That is a Peroni opening. I believe I will let the airplane do all the thinking this weekend and just enjoy the flying part.
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I have followed this thread for many days now and have enjoyed every part of it. I del I have to be a part of it before it goes inactive.
One of the easiest examples to understand what controls path, is while we maintain steady descend and we realize we are going below path.
At this point, further pitch up without thrust addition might produce a greater rate of descent and cause the airplane to sink more below the desired glide path.
This makes clear that path is controlled by thrust.
I see that old jocks have withdrawn their interest in the thread, and the ones seemingly "celebrating" their win are the ones that (to me) are advocating the wrong way of teaching things.
i have no Airbus experience, but I have a lot of jet experience. Light, heavy, military, supersonic, all kinds of.
The physics behind the flight and handling of jets will always be the same. Engineers come up with new solutions to make dumber pilots feel better, but the physics will always be the same.
An the truth is that pitch controls the airspeed. i will have to agree and support the minority in this thread. It is difficult to do so, but it is not unusual that the minority is right, and that most people do it the wrong way.
Engineers will come up with their best way to make them feel like the best pilots, but the credit must go the engineers.
Some replies about "region of reverse command" etc, are utter bollocks if I may say. The person that posted this is entirely clueless of what he is referring to. I would say that 50% of the replies are irrelevant and -simply- wrong.
The simple truth is that modern aircraft can fly any way you want them to, forgiving many mistakes. BUT, a good aviator is the one that does not rely on a good engineer (only), and knows the principles of flight and how to control his machine without any automation.
Some posts use all the terminology they can fit in a sentence. Just to cover their lack of knowledge and understanding of the basics. Remember, in science, it is the simplest theories that take the longest to really understand.
Physics is one of them and principles of flight is the best example.
I am old school too, and I will have to say that the old books have served me well along with many others, unlike the sim games and the youtube videos.
So I will encourage the new ones in this trade to study these old textbooks and listen to the minority in this thread. Keep it simple, it will never change. Maybe a brilliant engineer will make it seem like it changed, but it will be the computer correcting and anticipating your incorrect input instead.
The Naval Aviator's book is a brilliant one to read and refer to throughout one's career. It is too scientific for most, but it is very explanatory and covers all aspects of flight. Pity that most people think it is obsolete nowadays.
You should try reading it.
Fly safe and learn as you go.
One of the easiest examples to understand what controls path, is while we maintain steady descend and we realize we are going below path.
At this point, further pitch up without thrust addition might produce a greater rate of descent and cause the airplane to sink more below the desired glide path.
This makes clear that path is controlled by thrust.
I see that old jocks have withdrawn their interest in the thread, and the ones seemingly "celebrating" their win are the ones that (to me) are advocating the wrong way of teaching things.
i have no Airbus experience, but I have a lot of jet experience. Light, heavy, military, supersonic, all kinds of.
The physics behind the flight and handling of jets will always be the same. Engineers come up with new solutions to make dumber pilots feel better, but the physics will always be the same.
An the truth is that pitch controls the airspeed. i will have to agree and support the minority in this thread. It is difficult to do so, but it is not unusual that the minority is right, and that most people do it the wrong way.
Engineers will come up with their best way to make them feel like the best pilots, but the credit must go the engineers.
Some replies about "region of reverse command" etc, are utter bollocks if I may say. The person that posted this is entirely clueless of what he is referring to. I would say that 50% of the replies are irrelevant and -simply- wrong.
The simple truth is that modern aircraft can fly any way you want them to, forgiving many mistakes. BUT, a good aviator is the one that does not rely on a good engineer (only), and knows the principles of flight and how to control his machine without any automation.
Some posts use all the terminology they can fit in a sentence. Just to cover their lack of knowledge and understanding of the basics. Remember, in science, it is the simplest theories that take the longest to really understand.
Physics is one of them and principles of flight is the best example.
I am old school too, and I will have to say that the old books have served me well along with many others, unlike the sim games and the youtube videos.
So I will encourage the new ones in this trade to study these old textbooks and listen to the minority in this thread. Keep it simple, it will never change. Maybe a brilliant engineer will make it seem like it changed, but it will be the computer correcting and anticipating your incorrect input instead.
The Naval Aviator's book is a brilliant one to read and refer to throughout one's career. It is too scientific for most, but it is very explanatory and covers all aspects of flight. Pity that most people think it is obsolete nowadays.
You should try reading it.
Fly safe and learn as you go.
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St martin: I would like to see how you manage to stay on the glideslope in an approach with fluctuating speed (say +/- 5 or 10kts). You will be all over the place if you chase the speed with pitch mate. The larger the aircraft the more obvious this becomes.
The simple fact is thrust overcomes drag which causes an acceleration and therefore a speed change. It is because of this speed change that the RoD eventually changes.
The simple fact is thrust overcomes drag which causes an acceleration and therefore a speed change. It is because of this speed change that the RoD eventually changes.
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Some replies about "region of reverse command" etc, are utter bollocks if I may say
Get on a sim of a falcon 10, select full flaps on a 3° ils, let the speed decay to below 1.2 Vs, and tell us what is controlling your speed/ ROD.... Then step on a F7X sim and do the same... Alternatively, choose a 727 and a A320 if you do not like 'small' planes... then do it on a 172 with jet.. aka Citation 500..
Start the exercise at 200 ft, and let's post which configuration made it to the runway....
Last edited by CL300; 30th Mar 2014 at 08:33. Reason: spelling
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My dear friend, your comment is quite childish.
Why chase the speed?
+/- 5-10 while on glideslope with unstable weather conditions, you should keep the thrust unchanged and it will come back to where it is supposed to right after the gust.
The larger the aircraft. the more the inertia it carries.
You never chase the speed in a large airliner.
I suggest you read my post again, as you are replying to something irrelevant.
Realizing a trend to go below path while steady on the speed, you should add some thrust to bring her up to path again.
Thrust can overcome drag and cause acceleration of the mass, I agree. But you choose the vector. Your airspeed does not necessarily change if you start climbing. Right?
Why chase the speed?
+/- 5-10 while on glideslope with unstable weather conditions, you should keep the thrust unchanged and it will come back to where it is supposed to right after the gust.
The larger the aircraft. the more the inertia it carries.
You never chase the speed in a large airliner.
I suggest you read my post again, as you are replying to something irrelevant.
Realizing a trend to go below path while steady on the speed, you should add some thrust to bring her up to path again.
Thrust can overcome drag and cause acceleration of the mass, I agree. But you choose the vector. Your airspeed does not necessarily change if you start climbing. Right?
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Pff-FSSSSSSSS!!!!*
That's an Anchor Steam Lager now, San Francisco's greatest gift to the aviation community. Come on boys, cut the semantic nonsense and start drinking and relaxing. It's a damn airplane, not a moon launch. We're all right and we're all wrong, depending on who you ask. Don't get so worked up about it.
Pfff-FSSSSSSSSS!!*
This Bud's for you!
