HITEC Sky Scout (KIT) - Manual (Page 22)

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Fly high with Hitec
Appendix A: The Basics of Model Flying
Centre of Gravity
Like any other aircraft, your model aeroplane must be balanced at a particular point if it is to have stable flying characteristics.
It is absolutely essential to balance the model correctly before its first flight.
The balance point, or Centre of Gravity (CG), is stated as a linear distance measured from the wing leading edge, close to the fuselage.
When supported at this point on your fingertips, or - preferably - using the MPX CG gauge, # 69 3054, the model should balance level.
If the model does not balance at the marked point, this can usually be corrected by re-positioning the airborne components (e.g. flight battery).
If this is not sufficient, the correct quantity of ballast (lead or modelling clay) should be fixed securely to the nose or tail of the fuselage.
If the model is tail-heavy, fit the ballast at the fuselage nose; if it is nose-heavy, attach the ballast at the tail end of the fuselage.
Neutral point
The neutral point of an aircraft is the point at which the aerodynamic forces are in equilibrium.
If an aeroplane flies in a stable attitude, then its neutral point is always aft of the Centre of Gravity.
Any aircraft whose Centre of Gravity is aft of the neutral point will be inherently unstable in the air.
Manual control of an aircraft trimmed in this way is impossible; it requires a computer system for stabilization and control.
Longitudinal dihedral
This term refers to the difference in incidence between the wing and the tailplane.
Provided that you fit and secure the Sky Scout’s wing and tailplane to the fuselage as stated in these instructions, then the longitudinal dihedral will
automatically be exactly correct.
If these two settings (centre of gravity and longitudinal dihedral) are correct, you will encounter no problems when flying your aeroplane, especially at
the test-flying stage.
Control surfaces and control surface travels
The model can only fly safely and precisely if the control surfaces are free-moving, operate in the correct “sense” (direction relative to stick movement),
and are set up to deflect by the appropriate amount.
The control surface travels stated in the building instructions have been established by a test-flying programme, and we recommend that you adopt
these settings initially.
You may wish to adjust them subsequently to suit your personal preferences.
Transmitter control functions
The radio control system transmitter is fitted with two primary sticks which cause the servos - and therefore the model’s control
surfaces - to deflect when moved.
The stated function assignment is correct for stick mode 2, but other stick modes are possible.
The following control surfaces are controlled from the transmitter:
The rudder (left / right)
The elevator (up / down)
The throttle (motor off / on)
The ailerons (left / right)
The stick which controls the throttle (motor speed) must not be of the self-centering type.
It is usually fitted with a ratchet which operates over the full stick travel.
How this setting works you can read up in the operating instructions supplied with your radio control system.