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Rates and Expos
Use Expo to soften the feel of the model. On high 3D
rates, use quite a bit of expo. The goal on 3D rates is to
get the model to feel the same around neutral as it does
on low rates.
Control Throws
Setting the control throws for your Sukhoi does require
some attention to detail. To correctly set the throws, it
is highly suggested to use the following procedure to
achieve the greatest mechanical advantage from your
servos.
Step 1
Determine the maximum amount of control surface throw
from the throws listed. Use the high rate throws listed
to set the maximum amount of throw, then use your
computer radio for the lower rate listed.
Step 2
Set the Travel Adjust (ATV on a Futaba transmitter) to
about 15% under the max. (On a JR transmitter, that
is 135%.) Make sure to set both directions during this
process.
Step 3
Adjust the position of the clevis on the control horn and
position of the ball link on the servo arm to achieve the
throw decided in Step 1. It is highly recommended not to
change the position on the servo arm unless absolutely
necessary. Use Travel Adjust (ATV) to finalize the throws.
That is why we left a little margin in the percentages back
in Step 2.
Step 4
If setting a dual elevator or aileron, match the linkage
locations used back in Step 3. Increase or decrease the
Travel Adjust (ATV) a few points as necessary to fine-tune
the throws to match up left and right sides and up and
down throws so all is symmetrical.
Use low rate settings for all flying except for 3D
aerobatics. For precision flying or general sport hot-
dogging, the low rate throws are perfect, even for snap
rolls. The only exception is rudder rates. Use 3D rudder
rate when doing stall turns and rolling circles, since
the more rudder the better for these. When doing 3D
aerobatics, flip to 3D rates just before the maneuver. As
soon as the maneuver is done, flip back down to low rate
to avoid over-controlling the model.
This is all necessary to tune the mechanical advantage as
good as possible. When setting up a model for 3D, the
mechanical advantage will be less because of the large
throws, and thus the servo will work harder and wear
faster. Using an insufficient servo for the job, or trying
to get too much throw, will cause something to give,
probably the servo.
There isn't an exact geometry to the linkage, as it depends
on how much throw each individual modeler requires.
The linkage geometry should always be maximized so the
servo isn't working any harder than it has to.
Aileron:
High Rate: 40 Degrees up, 55% Exponential
40 Degrees down, 55% Exponential
Low Rate:
21 Degrees up, 40% Exponential
21 Degrees down, 40% Exponential
Elevator:
High Rate: 42 Degrees up, 75% Exponential
42 Degrees down, 75% Exponential
Low Rate:
10.5 Degrees up, 45% Exponential
10.5 Degrees down, 45% Exponential
Rudder:
High Rate: 39 Degrees left, 50% Exponential
39 Degrees right, 50% Exponential
Low Rate:
23 Degrees left, 40% Exponential
23 Degrees right, 40% Exponential
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