Sukhoi SU 31—2.75m/2.6m Page|23
The centre of gravity position of the SU-31 is
195mm
from the trailing edge of the wing at the tip. Picking the com-
pleted model up at the tips will not harm the airframe, but due care should be taken in the method you use. Do not use
any pointed implements to hold the model up, you may penetrate or damage the fuselage or wing structure. It s quite
simple to have someone give you a hand, and using your fingers carefully lift the model at the C of G points you have
measured.
Control throws:
This is another area, where your personal preferences are going to determine what you actually need. We have listed
below what we believe is a good starting point. From there on you can fine tune your SU-31 to suit your requirements.
The SU-31 has a top skin hinge system, and as such it needs reverse differential, that is you will need more down
travel than up! The reason for this is, as the aileron goes down, it actual looses area volume, part of the aileron disap-
pears into the wing, decreasing the amount of surface area exposed to airflow. A good principle to work with is to give
your aileron 10mm more down at full rates. Although at full rates the roll rate will be blistering, as you move into low or
mid rates the preset differential will become more evident. Obviously you can use your transmitters differential settings
if it is capable of doing so, just remember this type of differential is reverse to what is considered normal.
C of G and Control Throws
Surface
Low Rate
Low Rate Expo
High Rate
High Rate Expo
Aileron (Up)
50mm
30%
70mm
40%
Aileron (Down)
55mm
30%
80mm
40%
Elevator
50mm
30%
90mm
40%
Rudder
60mm
30%
100mm
40%
We hope you have enjoyed assembling your Composite Arf SU-31 and you have many years of happy flying with it.
We have strived to cover as many area s as possible to ensure the assembly process flowed as smoothly as possi-
ble. If you have found yourself in difficulty and need some assistance, your sales rep is only an email away. Please
contact your rep and they will endeavour to assist you, and get you back on track. Alternatively you can contact us
via the emails below. We also welcome your feedback, please contact us if you would like to see something added
or altered. We are always looking to improve our products and the information we supply.
Technical support;
Feedback;
www.carf-models.com
SU-31 2.6m/2.75m manual V1 (March 2015)
