resolver synchros, what do we use them for ?

[flame_bringer]

i know that a synchro is a device that we use to measure the angular movment of a shaft , and i understand how a torque synchro and a control synchro work.
i also understand that a resolver synchro is used to split the polar signal to its cartesian coordinates but what i dont understand is , whats the purpose of doing this , and in what applications do we use resolver synchros usually in the aircraft .

Thanks in advance

[Blue Coyote]

I too understand that a synchro is used to measure an angle of rotation. I'm only a simple mechanical guy at heart and am a bit confused by your reference to polar and cartesian co-ordinates. My understanding of these is that it goes beyond angular displacement and is now looking at distance moved from a central point. (i.e. we are looking at angle and distance or X and Y co-ordinates).

I've seen resolvers used in FADEC systems to provide power lever/thrust lever positional information. Other than that I can't help.

I look forward to learning a bit more from better qualified people than myself!:}

[NutLoose]

Muirhead Aerospace: Synchros (http://www.muirheadaerospace.com/motion-technology/synchros.html)

http://techaidproducts.com/PDFs/Tech-AidSynchroArticle.pdf

[NutLoose]

The Course select knob on an Autopilot Mode Control Panel

And I always thought that one was the pilot :p

[flame_bringer]

so we just use it for phase shifting ? coz thats what i understand and thats what they use it for in the course select knob .

[747MC]

folks ... i think the best way to think of it this ... a syncro and a resolver are the same things ..... one sets and sends the signal for rotational movement of the other in a system where you have 2 mechanical movents to be made... makes a proportional mechanical change via electrical input at the front end ... ie... fly by wire ... the input being the syncro side normally ..... they are also termed resolvers as well when used alone to measure rotational input.. ie.. TLR Throttle lever resolver ... it measures the angular input and sends the signal to to a FADEC or EEC or other computer for further processing and action out the other end. Now enter into the picture RVDT and LVDT's low amperage units to make Rotational or Linear inputs to control solenoids, or varying electrical input to circuit boards that actually carry or control the current ... or ... transmit positional movement to instruments and indicators and computers for monitoring. So syncro or resolver ? .... ask the engineer why he termed it that way .... they are wired the same .... :)

[superliner]

My book says they're also used in the Flight Director System and Integrated Instrument System.

[Blacksheep]

They're used all over the place but you have to be an Avionics genius (like me) to understand them. Stick to hydraulics, its much simpler. ;)

[VRD_Mcontrol]

You mean like the throttle resolvers to indicate throttle position?