# How are helicopter cyclic and collective jacks connected?

Regardless of the degree of collective pitch applied, the cyclic pitch controls must retain their full range. Both controls are via jacks, so how are the jacks connected?

• Have a look at this related question and answers. The jacks connect to the fixed bottom part of the swash plate. Moving the swash plate up and down (collective pitch) has no effect on how much it can tilt (cyclic pitch) – Simon Jun 20 '15 at 7:32
• Perhaps I should elaborate on my question. Movement of the collective jacks will push or pull the swashplate which will pull or push the cyclic jacks. So how are all the jacks connected at their lower ends? – Howard Barnes Jun 21 '15 at 8:40
• You may want to edit your question, rather than have the clarification in a comment, and state by "jacks", are you only interested in heads controlled by hydraulic jacks or also by push rods? If you really are interested in jacks, then I don't understand your question since the lower end of the jacks are fixed. – Simon Jun 21 '15 at 10:00
• This may help – Simon Jun 21 '15 at 10:44
• What model of helicopter are you referring to? – KorvinStarmast Jun 3 '17 at 17:59

The helicopter Collective and Cyclic controls are connected to the rotor bladesby swash-plates. The following is a swash-plate :

The following animation shows the connection assembly working :

Swash plate in the resting position.

A raised swash plate causing negative collective blade pitch and thus down force. Note that the control arms are on the trailing sides of the blades, causing raised swash plate to decrease the blade pitch.

A tilted swashplate giving cyclic blade control. Note the change in pitch of the blades during rotation.

Source : Wikipedia

• That rotor head looks suspiciously like a model helicopter. RC helicopter heads are quite different to real ones. Your answer also does not address the question. – Simon Jun 24 '15 at 19:52
• Wikipedia reference – Victor Juliet Jun 24 '15 at 20:04
• I know how a swashplate works. It's the bottom end of the jacks (or actuators - same thing) that I am asking a question about. – Howard Barnes Jun 26 '15 at 4:41
• Ah, yes, it is a model helicopter. Compare it to real ones. There are significant differences since the constraints of weight and strength are largely removed and full articulation is the goal. Model helicopters can do things a real helicopter can only dream of ;) – Simon Jun 26 '15 at 7:22

There are three "jacks" providing both collective and cyclic movement to the swash plate, the difference is in how many are moving.

• All three are used for collective input: they all move, so the swash plate goes up/down

• For longitudinal and lateral movement, only one (or two) depending on configuration) are deflected, so the swash plate cants.