RC AIRPLANE MAKING
This page is especially to discuss the basic phenomenon of RC Aircraft making.
Terminology
Control surfaces
How wings
generate lift?
A cross section
of a typical airplane wing will show the top surface to be more curved than the
bottom surface. This shaped profile is called an 'airfoil' (or 'aerofoil').
Angle of attack
A crucial factor
of lift generation is the Angle of Attack - this is the angle at which
the wing sits in relation to the
horizontal airflow over it. As the angle of attack increases, so more lift is
generated - but only up to a point until the smooth airflow over the wing is broken
up and so the generation of lift cannot be sustained. When this happens, the
sudden loss of lift will result in the airplane entering into a stall,
where the weight of the airplane cannot be supported any longer.
However, a direct
reaction to lift is drag and this too increases with airspeed. So airfoils need
to be designed in a way that maximizes lift but minimizes drag, in order to
be efficient.
Design-foil
The shape of the
airfoil is determined using a software called Design Foil,
with the help of the lift coefficient obtained.
Wing dimensions
• For Level flight,
Weight = Lift (W=L)
• Using wing loading
value, we obtain the planform area.
• To get the value of
Chord Length, we assume Aspect
Ratio (AR) around 6
to 8.
• In rectangular wing
AR = span/Chord
• Weight is approx. 2 kgs.
OTHER PARTS
Fuselage – 70-75 % of
wing span.
• Horizontal
Stabilizer – 25% of the wing area
• Vertical stabilizer
– 50% of HS
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