ORIGINAL: GeeBeeJim
The DS 821's are pretty darn good sport digitals. ...
I would be very careful on where I use the DS821 servos.
Quoted from here: [link]http://spektrumrc.com/Articles/HobbyWire.aspx[/link]
New Guidelines for DS821 Servo Use
Tuesday, February 20, 2007
The DS821 servo is a powerful, accurate sport digital servo recommended for RC airplane applications up to 1.20-size. For helicopters, the DS821 operates best with 30-size glow models, and up to 50-size electric. Loads and vibration in larger models may cause premature failure of the servo resulting in damage or injury to property and persons.
Important: Do not use liquid thread lock with the DS821 servo!
Do not use any form of liquid thread lock to secure the servo arm screw to the output shaft of the DS821 servo. Chemicals in these liquids react with the polycarbonate gear set causing the plastic to become brittle, fracturing the final output gear.
Read between the lines of the statement in bold and underlined. I am unsing a "set" of 821 in a 30 sized helicopter and will keep a very sharp eye on them.
Rafael