Diag Q
Rudder control link: install the servo just like you did the elevator one. Attach the
extension servo horn to the original one using kevlar line and CA. Thread the two
M2 x 5 screws into the extension horn. The pull – pull system uses the included
kevlar line. Glue the line to the M2 screws, you can use them to tighten the line
when necessary. On the rudder side, just tie the line into the control horn (and also
use a drop of CA to prevent the sharp hole edges from tearing through the line).
Setting up and Trimming
We hope that you know how to connect and set up your RC system. If not, refer to
the relevant instruction manual or better ask a more experienced model aviator.
For maximum flight envelope, use the biggest mechanically possible control throws.
The rudder throws may be slight less, say 50°. The aileron throws should be the
same up and down. For first flights, or if you do not feel like an expert 3D flyer, use
somewhat lower throws – some 60% of the maximal ones. Use exponentials of 30
to 60% or to your best liking.
For first flights, we recommend centre of gravity (CoG) at some 125 mm from the
leading edge (root of the wing). At the beginning, use adhesive velcro tape to attach
the battery. This will help you find the right CoG (we like it quite aft, so much that the
plane tends to fly „hands off“ both normal and inverted). When happy with the CoG,
you may (or may not) cut a slot for the battery in the (upper) fuselage. The vertical
CoG may influence rolling tendencies (there should be none) in knife edge (KE) –
you may want to put the battery under the backbone if the model rolls to inverted
from KE. Some people don’t go this far and simply just use mixes to fix KE issues.
Our method for getting the right elevator trim is a power off vertical dive – the plane
should fall straigh down, like a brick J.
Aileron trim should be perfect both normal and inverted – if not, you may have a
lateral balance issue. Try putting the battery to the other side of the fuselage, this
should do most of the time.
After all these steps, the model should fly straight and also hover without any bad
tendencies. Hover can be adjusted by slight thrust line adjustments (insert washers
between the motor and the motor mount), but most likely there will be no need for
going that far.
Clean rolls (with no „barrel“ tendencies) can be achieved by dialing in the correct
aileron differential. If your radio does not allow this, you may just set different up and
down aileron throws). Equal up and down throws should work just fine, though.
Enjoy your new EPP Sukhoi!
Your RC Factory team.
Specifications:
Wingspan: 1200 mm
Length: 1252 mm
AUW: 600 – 800g
Motor: 200 – 300W outrunner (ca 70 – 120g)
Servos: 12 – 20g good quality servos
Battery: 1600 – 2500 mAh 3s lithium polymer
