Each mfg has their own chart with servo specs and recommended usage.
Personally, I usually head over to http://www.towerhobbies.com and click on
the Radio Accessories link on the left side. From there I can cruise through
the mfg. I am interested in and see the specs and prices.
Also, http://www.rcairport.com allows you to choose 3 different
servos/radios/planes/engines and compare them side-by-side.
As for what servos to use, it really depends. I don't rely on the mfgs
recommendation, but instead look at the gears, speed and torque for my
particular application. In my .30 size heli, I had a very fast/hi torque
servo (~.10sec 130oz - from memory) matched to my gyro, and .15sec ~90oz
servos for the rest. In my Nitro cars, I run a semi-fast/strong ~70oz ~18sec
servo for my throttle/brake (fast for throttle, hi torque for brake) and hi
torque for steering (~100oz .18sec). For my planes, I fit the speed/torque
to my particular plane and intended flying habbits with such plane (normal
flying Cub-like get the standard ball-bearing servos, funfly's get faster
servos with slightly more torque, bigger planes with higher wing loading get
hi-torque servos).
You usually can't go wrong with semi-fast (.15-.19sec ) hi-torque servo's
(70oz), depending on your budge, expect when matching one to your gyro. For
that, I would look at your gyro manual and get the highest torque servo you
can find which falls within the speed guidlines for your gyro. You need the
speed for the gyro to keep the tail from wagging in fast forward flight, and
the torque to pull the tail out of the fast piroettes (if you like doing
that sort of thing:) )
One last thing when looking at servo specs: Most are rated with 2 torque
ratings. The lower value is on 4.8 volts, while the higher value is on 6
volts.
"Paul Aspinall" <paul@nospamaspy.co.uk> wrote in message
news:HgSna.2622$OG4.2592@news-binary.blueyonder.co.uk...
> I'm a newbie.... but...
>
> I'm interested in the different servos that are available.
> I have Futaba 148s on my Shuttle....
>
> I'm interested in buying another (larger) heli, and possibly even a Vario
> Big Airwolf (although I won't be flying, or building it for some time)
>
> What are the differences in the servos?? Is there a chart which shows the
> torque, response times, gearing (plastic vs metal) etc etc??
>
> Can anyone recommend a good servo to use for a 60 size Heli??
>
> Any help appreciated
>
> Thanks
>
>