B737NG roll control via ailerons/spoiler changeover speed
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B737NG roll control via ailerons/spoiler changeover speed
Hi,
I open the topic again after removing the old one with the misleading header.
Is there a certain changeover speed/configuration where roll control is accomplished by spoilers alone?
bbj
I open the topic again after removing the old one with the misleading header.
Is there a certain changeover speed/configuration where roll control is accomplished by spoilers alone?
bbj
There is no speed threshold mentioned in the Boeing NG manual.
What it does say is that when the ailerons reach 10 degrees up deflection, spoiler deflection is initiated. As speed increases the amount of physical control deflection required to make the aircraft roll decreases. Therefore you can deduce that flight spoilers only supplement the roll authority of the ailerons at the lower end of the speed regime. Does that help?
What it does say is that when the ailerons reach 10 degrees up deflection, spoiler deflection is initiated. As speed increases the amount of physical control deflection required to make the aircraft roll decreases. Therefore you can deduce that flight spoilers only supplement the roll authority of the ailerons at the lower end of the speed regime. Does that help?
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BBJ, saw your original post and thought I knew what you were referring to. This paste is from a description of the 727 flight controls, lifted from www.boeing727.com (hope Benson doesn't mind).
"The flight spoilers, which operate in conjunction with the ailerons, provide the major portion of roll control by spoiling lift on the low wing. After a small movement of the control wheel, spoiler action is programmed in proportion to the further movement of the control wheel. A full roll control input would cause the flight spoilers of the low wing to rise to a maximum of approximately 25 degrees. The spoiler panels of the high wing would remain down."
Sorry I can't help with the new fangled stuff!
Sorreeee! www.boeing-727.com Epreye
"The flight spoilers, which operate in conjunction with the ailerons, provide the major portion of roll control by spoiling lift on the low wing. After a small movement of the control wheel, spoiler action is programmed in proportion to the further movement of the control wheel. A full roll control input would cause the flight spoilers of the low wing to rise to a maximum of approximately 25 degrees. The spoiler panels of the high wing would remain down."
Sorry I can't help with the new fangled stuff!
Sorreeee! www.boeing-727.com Epreye
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The only time roll control is by spoilers only on any 737 is in the event of a jam in the cable system on the capt side.Then,control would be through the F/O's cables direct to the spoiler mixer so using spoiler control only.
Control is normally through Capt's cables into the aileron tower shaft inputting rods into the PCU's direct,then operating cables out to the ailerons.
Control is normally through Capt's cables into the aileron tower shaft inputting rods into the PCU's direct,then operating cables out to the ailerons.
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eng123 is dead right. Being licensed on the AF and Eng, everything he said is correct, and also, you will always have flight spoilers working, due to the fact that they have a direct input, just when you , for example, turn right, the inboard spolier then proceeding out, will rise first, and as more turn is required, the next outboard spoiler will rise, and ultimately, when they are all full up, they all have their different angles..
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Thanks for your kind words tykon but I'm not sure you are correct about the spoilers rising progressively inbd to outbd.As all spoilers are operated by the same cable run,don't see how this can work,even with a cable jam.
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b737ng roll control
Yes eng123. You are correct in saying that they are on the same cable. HOWEVER.......... I am assuming you are an engineer yourself? If you are, well, then you would know how you adjust the spoilers, and that they ARE progressive in their raising as this happens when you adjust the pick up at the spoiler itself. This adjustment determines the individual point at which each spoiler panel will lift, as as said before, when the aileron wheel is turned a little(cant remember the exact figures), the inboard will start to rise first, followed by the next and so on, until you reach a point in which the aileron control wheel is turned and all spoilers will be fully extended, but they have different "full extended" angles.
Hopes this clarifies this for you.
Hopes this clarifies this for you.
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tykon is correct, somewhat.
The flight spoilers don't all move in unison.
But the manner in which they are adjusted to do so isn't as complicated as it sounds. Every spoiler doesn't have an angle at which they deploy.
The Next gen 737s have 12 spoilers, numbered 1-12 from left to right. There are 2 flight spoilers on each wing: 3 and 5 on the left wing, 9 and 11 on the right wing. There are 2 adjustments for flight spoilers: the initial deployment, roughly 11 degrees and their full travel angle. Having said that, only spoilers 3 and 9 get the initial deployment adjustment. The others are adjusted for their full travel angle. Of course, all of the spiilers are adjusted so that they must fair with the flaps when retracted.
I have supplied the flight spoiler system adjustment/test so that maybe you could better understand how the flight spoilers work.
E. Flight Spoiler System Test
(1) Turn the control wheel clockwise until the spoiler No. 9 starts to move up.
- Make sure the spoiler starts to move up when the control wheel is 11 +/-1 degrees clockwise.
(2) Continue to turn the control wheel to 87 degrees clockwise.
- Make sure that the spoiler No. 9 is up 37 +/-3 degrees.
- Make sure that the spoiler No. 11 is up 32 +/-3 degrees.
- Make sure that the spoilers No. 2, No. 3, No. 4 and No. 5 are in the fully down position.
(3) Turn the wheel counterclockwise until the spoiler No. 9 starts to move down.
- Make sure the spoiler starts to move down when the control wheel is a minimum of 70 degrees clockwise.
(4) Continue to turn the control wheel counterclockwise until the spoiler No. 9 is in the fully down position.
- Make sure the spoiler is in the fully down position when the control wheel is 5 +/-3 degrees clockwise.
(5) Turn the control wheel counterclockwise until the spoiler No. 3 starts to move up.
- Make sure the spoiler starts to move up when the control wheel is 11 +/-1 degrees counterclockwise.
(6) Continue to turn the control wheel to 87 degrees counterclockwise.
- Make sure that the spoiler No. 3 is up 37 +/-3 degrees
- Make sure that the spoiler No. 5 is up 32 +/-3 degrees.
- Make sure that the spoilers No. 8, No. 9, No. 10 and No. 11 are in the fully down position.
(7) Turn the control wheel clockwise until the spoiler No. 3 starts to move down.
- Make sure the spoiler starts to move down when the control wheel is a minimum of 70 degrees counterclockwise.
(8) Continue to turn the control wheel clockwise until the spoiler No. 3 is in the fully down position.
- Make sure the spoiler is in the fully down position when the control wheel is 5 +/-3 degrees counterclockwise.
The flight spoilers don't all move in unison.
But the manner in which they are adjusted to do so isn't as complicated as it sounds. Every spoiler doesn't have an angle at which they deploy.
The Next gen 737s have 12 spoilers, numbered 1-12 from left to right. There are 2 flight spoilers on each wing: 3 and 5 on the left wing, 9 and 11 on the right wing. There are 2 adjustments for flight spoilers: the initial deployment, roughly 11 degrees and their full travel angle. Having said that, only spoilers 3 and 9 get the initial deployment adjustment. The others are adjusted for their full travel angle. Of course, all of the spiilers are adjusted so that they must fair with the flaps when retracted.
I have supplied the flight spoiler system adjustment/test so that maybe you could better understand how the flight spoilers work.
E. Flight Spoiler System Test
(1) Turn the control wheel clockwise until the spoiler No. 9 starts to move up.
- Make sure the spoiler starts to move up when the control wheel is 11 +/-1 degrees clockwise.
(2) Continue to turn the control wheel to 87 degrees clockwise.
- Make sure that the spoiler No. 9 is up 37 +/-3 degrees.
- Make sure that the spoiler No. 11 is up 32 +/-3 degrees.
- Make sure that the spoilers No. 2, No. 3, No. 4 and No. 5 are in the fully down position.
(3) Turn the wheel counterclockwise until the spoiler No. 9 starts to move down.
- Make sure the spoiler starts to move down when the control wheel is a minimum of 70 degrees clockwise.
(4) Continue to turn the control wheel counterclockwise until the spoiler No. 9 is in the fully down position.
- Make sure the spoiler is in the fully down position when the control wheel is 5 +/-3 degrees clockwise.
(5) Turn the control wheel counterclockwise until the spoiler No. 3 starts to move up.
- Make sure the spoiler starts to move up when the control wheel is 11 +/-1 degrees counterclockwise.
(6) Continue to turn the control wheel to 87 degrees counterclockwise.
- Make sure that the spoiler No. 3 is up 37 +/-3 degrees
- Make sure that the spoiler No. 5 is up 32 +/-3 degrees.
- Make sure that the spoilers No. 8, No. 9, No. 10 and No. 11 are in the fully down position.
(7) Turn the control wheel clockwise until the spoiler No. 3 starts to move down.
- Make sure the spoiler starts to move down when the control wheel is a minimum of 70 degrees counterclockwise.
(8) Continue to turn the control wheel clockwise until the spoiler No. 3 is in the fully down position.
- Make sure the spoiler is in the fully down position when the control wheel is 5 +/-3 degrees counterclockwise.
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Thank's fella's.Work in line maintenance and apart from adjusting the 'down' fair of one of the spoiler's several years ago and changing the odd actuator have had little to do with the spoiler system.
tykon,the confusion arose with your description of 'the inbd will rise first,then the next and so-on'.By this description I thought you were saying that turning the control wheel would result in [bearing in mind I thought there were 3 flight spoiler's on each wing!] R/H wing 9 rising first to its full actuator length,then 10 to it's then 11 to it's.I knew there were different angles for each full spoiler deployment but misunderstood what you were saying.
Still,you can't know everthing so thanks again guys,I'll have to read up on the spoiler's next time at work.
tykon,the confusion arose with your description of 'the inbd will rise first,then the next and so-on'.By this description I thought you were saying that turning the control wheel would result in [bearing in mind I thought there were 3 flight spoiler's on each wing!] R/H wing 9 rising first to its full actuator length,then 10 to it's then 11 to it's.I knew there were different angles for each full spoiler deployment but misunderstood what you were saying.
Still,you can't know everthing so thanks again guys,I'll have to read up on the spoiler's next time at work.
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Hi again.............
Each spoiler must have their pick-up point adjusted. If you install a new spoiler actuator, then you have to adjust the hex nut on the individual linkage for the spoiler. Did you include the total spoiler test? I think you are right if you are just testing that the number 3 and 9 spoilers "pick-up" at their right angle, but what about the others? Next time at work I will pull out the full amm ref. and then post the mm ref on here, with a quick overture.
Each spoiler must have their pick-up point adjusted. If you install a new spoiler actuator, then you have to adjust the hex nut on the individual linkage for the spoiler. Did you include the total spoiler test? I think you are right if you are just testing that the number 3 and 9 spoilers "pick-up" at their right angle, but what about the others? Next time at work I will pull out the full amm ref. and then post the mm ref on here, with a quick overture.
