What are these “pimples” on the jet engine for?











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When looking into the General Electric CJ 805-23B jet engine, I have discovered that all forward section of the compressor is covered by a number of near identically looking "pimples". What are these tiny devices for, what are they doing? And why only front section of the compressor has them?



enter image description here






jet-engine feature-identification







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  • 1




    Are you asking about the things that look like nuts and bolts? The ones that we can see 3 of on the left, 4 in the middle, and 4 on the right? If not, then maybe you could circle the things you're talking about? I don't see anything in this picture that looks similar to a pimple to me.
    – Tanner Swett
    5 hours ago












  • Yes, there are 11 of them in the photo. Each has a plate attached on the left side.
    – h22
    5 hours ago








  • 1




    @h22: It would be helpful to circle the part(s) you are referring to.
    – summerrain
    4 hours ago















up vote
6
down vote

favorite












When looking into the General Electric CJ 805-23B jet engine, I have discovered that all forward section of the compressor is covered by a number of near identically looking "pimples". What are these tiny devices for, what are they doing? And why only front section of the compressor has them?



enter image description here






jet-engine feature-identification







share|improve this question




















  • 1




    Are you asking about the things that look like nuts and bolts? The ones that we can see 3 of on the left, 4 in the middle, and 4 on the right? If not, then maybe you could circle the things you're talking about? I don't see anything in this picture that looks similar to a pimple to me.
    – Tanner Swett
    5 hours ago












  • Yes, there are 11 of them in the photo. Each has a plate attached on the left side.
    – h22
    5 hours ago








  • 1




    @h22: It would be helpful to circle the part(s) you are referring to.
    – summerrain
    4 hours ago













up vote
6
down vote

favorite









up vote
6
down vote

favorite











When looking into the General Electric CJ 805-23B jet engine, I have discovered that all forward section of the compressor is covered by a number of near identically looking "pimples". What are these tiny devices for, what are they doing? And why only front section of the compressor has them?



enter image description here






jet-engine feature-identification







share|improve this question















When looking into the General Electric CJ 805-23B jet engine, I have discovered that all forward section of the compressor is covered by a number of near identically looking "pimples". What are these tiny devices for, what are they doing? And why only front section of the compressor has them?



enter image description here






jet-engine feature-identification




jet-engine feature-identification






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 3 hours ago

























asked 6 hours ago









h22

5,05712762




5,05712762








  • 1




    Are you asking about the things that look like nuts and bolts? The ones that we can see 3 of on the left, 4 in the middle, and 4 on the right? If not, then maybe you could circle the things you're talking about? I don't see anything in this picture that looks similar to a pimple to me.
    – Tanner Swett
    5 hours ago












  • Yes, there are 11 of them in the photo. Each has a plate attached on the left side.
    – h22
    5 hours ago








  • 1




    @h22: It would be helpful to circle the part(s) you are referring to.
    – summerrain
    4 hours ago














  • 1




    Are you asking about the things that look like nuts and bolts? The ones that we can see 3 of on the left, 4 in the middle, and 4 on the right? If not, then maybe you could circle the things you're talking about? I don't see anything in this picture that looks similar to a pimple to me.
    – Tanner Swett
    5 hours ago












  • Yes, there are 11 of them in the photo. Each has a plate attached on the left side.
    – h22
    5 hours ago








  • 1




    @h22: It would be helpful to circle the part(s) you are referring to.
    – summerrain
    4 hours ago








1




1




Are you asking about the things that look like nuts and bolts? The ones that we can see 3 of on the left, 4 in the middle, and 4 on the right? If not, then maybe you could circle the things you're talking about? I don't see anything in this picture that looks similar to a pimple to me.
– Tanner Swett
5 hours ago






Are you asking about the things that look like nuts and bolts? The ones that we can see 3 of on the left, 4 in the middle, and 4 on the right? If not, then maybe you could circle the things you're talking about? I don't see anything in this picture that looks similar to a pimple to me.
– Tanner Swett
5 hours ago














Yes, there are 11 of them in the photo. Each has a plate attached on the left side.
– h22
5 hours ago






Yes, there are 11 of them in the photo. Each has a plate attached on the left side.
– h22
5 hours ago






1




1




@h22: It would be helpful to circle the part(s) you are referring to.
– summerrain
4 hours ago




@h22: It would be helpful to circle the part(s) you are referring to.
– summerrain
4 hours ago










1 Answer
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They are the roots of the variable stator vanes that control the direction of the airstream as it enters each compressor stage to manage and optimize the angle of attack of the compressor blades in each stage. The vanes are connected to the ring shaped gang bar and somewhere around the circumference there is an hydraulic actuator, or a series of them, that drives the gang bar rings to move all the vanes connected to it at the same time. The hydraulic actuator is usually powered with pressurized fuel and is operated by the fuel control system to keep the vanes at the optimal rotational position.






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    1 Answer
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    up vote
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    accepted










    They are the roots of the variable stator vanes that control the direction of the airstream as it enters each compressor stage to manage and optimize the angle of attack of the compressor blades in each stage. The vanes are connected to the ring shaped gang bar and somewhere around the circumference there is an hydraulic actuator, or a series of them, that drives the gang bar rings to move all the vanes connected to it at the same time. The hydraulic actuator is usually powered with pressurized fuel and is operated by the fuel control system to keep the vanes at the optimal rotational position.






    share|improve this answer

























      up vote
      16
      down vote



      accepted










      They are the roots of the variable stator vanes that control the direction of the airstream as it enters each compressor stage to manage and optimize the angle of attack of the compressor blades in each stage. The vanes are connected to the ring shaped gang bar and somewhere around the circumference there is an hydraulic actuator, or a series of them, that drives the gang bar rings to move all the vanes connected to it at the same time. The hydraulic actuator is usually powered with pressurized fuel and is operated by the fuel control system to keep the vanes at the optimal rotational position.






      share|improve this answer























        up vote
        16
        down vote



        accepted







        up vote
        16
        down vote



        accepted






        They are the roots of the variable stator vanes that control the direction of the airstream as it enters each compressor stage to manage and optimize the angle of attack of the compressor blades in each stage. The vanes are connected to the ring shaped gang bar and somewhere around the circumference there is an hydraulic actuator, or a series of them, that drives the gang bar rings to move all the vanes connected to it at the same time. The hydraulic actuator is usually powered with pressurized fuel and is operated by the fuel control system to keep the vanes at the optimal rotational position.






        share|improve this answer












        They are the roots of the variable stator vanes that control the direction of the airstream as it enters each compressor stage to manage and optimize the angle of attack of the compressor blades in each stage. The vanes are connected to the ring shaped gang bar and somewhere around the circumference there is an hydraulic actuator, or a series of them, that drives the gang bar rings to move all the vanes connected to it at the same time. The hydraulic actuator is usually powered with pressurized fuel and is operated by the fuel control system to keep the vanes at the optimal rotational position.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 5 hours ago









        John K

        12.4k11240




        12.4k11240






























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