Great Planes Extra 300S 1.60 ARF - GPMA1365 - Manual (Page 21)

recommended 3D control throws you could have a conflict
between the elevator and rudder servos and servo arms. If
your primary flying will be 3D we recommend you set the
linkage as shown for 3D flight.
Note: When using the extreme throws of 3D flight you
need to make the tail wheel control arm longer so that the
mechanical linkage from the rudder servo to the rudder will
not limit the distance the rudder can travel.
❏
2. Cut one of the Dubro Super Strength Arms as shown.
❏
3. Glue the cut servo arm to the arm on the tail wheel with CA.
❏
4. Install a small screw though both horns.
Complete the assembly following the instructions on page
14 step 10 of the instruction manual
Larger than stock servo arms are highly recommended for
getting the 3D throws for the Extra 300S ARF. Do not move
the pushrods in on the control horns to get the increased
throw, as doing that intensifies any play in the system.
Dubro Super Strength Arms sets (DUBM6670) were used
on the test models.
The large control throws require servos with great
centering. The digital servos are second to none in this
department. Digital servos such as the Futaba S9250
(FUTM0220) should be used on all control surfaces of this
airplane for optimum performance. The test models were
also flown successfully in 3D mode with analog Futaba
S9304 (FUTM0095) servos.
COMPUTER RADIOS
As you prepare to fly your Extra 300S 1.60 ARF for the
first time, there are a few features on computer radios we’d
like to mention.There are many others, of course, but these
are commonly used features on most computer radios. If
you are using a non-computerized radio, this information
may still be of interest to you for future installations.
ATV or Travel Volume: ATV is a wonderful feature of
computer radios which allows you to make minor
adjustments to how far a servo travels at its extremes.
For example, you install the throttle pushrod, and it’s
almost perfect, except you have some binding at wide
open. Instead of struggling with the clevises to try to
keep full throttle but not have the binding, you can turn
down the ATV slightly until the binding is gone. Why only
adjust ATV slightly? Control linkages are really just a
lesson in leverage. The less distance the servo is
moving for a given throw at the surface, the less
leverage you have given the servo to do the job. Thus
the lower you set the ATV the less power you are leaving
for the servo to apply to the surface. Additionally, a servo
has only so many points within its range of motion. By
cutting its range in half, you’ve also diminished the
precision of the servo by 50%. Because of both of these
issues, we strongly recommend setting the high rates as
close as possible to 100% on the ATV.
Dual Rates: Setting dual rates helps make your model
easier to fly in a variety of situations. For example, an
expert pilot who wants to do torque rolls will need a
large amount of control throw. However, he does not
want that same huge volume of throw when he is trying
3D Servos
3D Servo Arms
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