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[Tug-Kenny RIP]

Hiya folks,

I was wondering if a servo is made commercially that will turn both ways just under 350 degrees from centre.  The normal ones turn under 90 degrees each way.  These will be for some schottel drives that I propose to get hold of as soon as I've re- mortgaged the house.   

I have experimented by tab cutting and balanced resistors to go continuously around either way, but I am after a stop position to enable reverse.

Cheers

k

[malcolmfrary]

1:4 gearing or pulleys?  Obviously less torque, but using a high torque servo as used for sail arms on smaller yachts might do the job OK.  Alternatively, one of the 2 turn winches, drum replaced with 2:1 gearing should give all the torque needed and the wanted angular travel.

[Netleyned]

Have you seen these Ken?
Lots of ideas here.
https://www.google.co.uk/search?q=model+schottel+drives&es_sm=122&tbm=isch&imgil=ZpSV2fg3BesPkM%253A%253B46Z7ehYCiG4HsM%253Bhttp%25253A%25252F%25252Fwww.conrad-electronic.co.uk%25252Fce%25252Fen%25252Fproduct%25252F264729%25252FSchottel-Drive-Ii&source=iu&pf=m&fir=ZpSV2fg3BesPkM%253A%252C46Z7ehYCiG4HsM%252C_&usg=__pw_ghbWnzYUnrvk0i4G_qoRNfqU%3D&biw=1366&bih=705&ved=0CEAQyjc&ei=GcwGVbmDKu6Q7Aa5wIGIDQ#imgrc=ZpSV2fg3BesPkM%253A%3B46Z7ehYCiG4HsM%3Bhttp%253A%252F%252Fwww.conrad-electronic.co.uk%252Fmedias%252Fglobal%252Fpartner%252F2000_2999%252F2600%252F2640%252F2647%252F264729_00_1000.jpg%3Bhttp%253A%252F%252Fwww.conrad-electronic.co.uk%252Fce%252Fen%252Fproduct%252F264729%252FSchottel-Drive-Ii%3B1000%3B1000


Ned

[tigertiger]

Alternative
Get a sail drum winch servo, there are cheap ones, and an ACTion electronics Servo Morph (can't remember the P#).


Drum winches usually turn about 2.5 times in each direction. With the servo morph you can modify the amount of turning downwards to your desired 350 degrees.


I am sure DM will step in if I am wrong.

[Netleyned]

If you have an allsingingalldancing transmitter, using a sail winch and the end point adjustment
should suffice.
Otherwise the servo morph will do the job as TT explains.


Ned

[inertia]

It's P96, chaps.
DM

[rickles23]

Hi,

Look at:

https://www.youtube.com/watch?v=Kz2JMwXI00Q

Regards

[john44]

Hi, I'm sure component shop do a 1 turn sail winch.


John

[Netleyned]

They do a 1.5 or a 2 turn at 6.1 Kg torque.


Ned

[Time Bandit]

Not with a servo, but with "real" Schottel control:

http://imth.de/index.php/de/videosde?showall=&start=6
http://rc-schottel.ch/

[Tug-Kenny RIP]

All brilliant stuff there.  Thank you everyone.   It's certainly given me a lot to consider.  Some very good ideas indeed.      

My reasoning against continuous rotation  (I may be wrong)  was that when stopped, I wouldn't know what direction they were facing when I started again.  I liked the hundreds of pictures thrown up by Mr Google.  plenty to digest there.  I do have one sailing winch servo which I've never used so perhaps a trial run might throw up some ideas, although it's rather a large beast for practical use,  at least I would get a feel for the way it performs.

Thank you all

k