RC Plane and Aerofoil Design bst - CACULATIONS 2-1-1 (1).pdf

Rc plane

1. AERO MODELLING CLUB

NIT KURUKSHETRA

Presents Workshop on :
Coroplast RC Plane Design workshop

2. Forces on the Plane:

3. Parts of Plane:

5. Model Specification:

1.T/W <=0.75 without payload (If excess thrust is measured, it will be neutralized
by adding weight below the aircraft at center of gravity)
2.Propeller diameter should not be greater than 13 inches.
3.Total wingspan should be a maximum of 1.2 m.
4.Only electrical motors are allowed. The use of IC engines or any other means
of providing thrust is prohibited.

6. Thrust and weight calculation

maximum thrust:

BLDC A2212 1400kv with 10*4 propellors = 480gm
BLDC A2212 1000kv with 10*4 propellors = 800gm
BLDC A2212 1000kv with 8*4 propellors = 650gm

Thrust/Weight |max = T/W <= 75% = 0.75

Maximum Weight of plane:

weight of plane should be less than T/0.75
BLDC A2212 1400kv with 10*4 propellors = 640gm
BLDC A2212 1000kv with 10*4 propellors = 1066gm
BLDC A2212 1000kv with 8*4 propellors = 866 gm

#if we are making plane using any of these BLDC Motors and propellor
combination , its T/W should be maintained accordingly.

7. WING DESIGN

8. TOPICS COVERED
1.Basics of wing
2.Wing calculation

9. Aerofoil Nomenclature:

10. ●The leading edge is the point at the front
of the aerofoil that has maximum
curvature.


●The trailing edge is defined similarly as the
point of maximum curvature at the rear of
the aerofoil.
●The chord line is a straight line connecting
the leading and trailing edges of the
aerofoil.
●The chord length, or simply chord,  is the
length of the chord line and is the
characteristic dimension of the aerofoil
section.

11. ●The mean camber line is the locus of points
midway between the upper and lower
surfaces. Its exact shape depends on how
the thickness is defined;
●The thickness of an aerofoil varies along the
chord. It may be measured in either of two
ways:
○Thickness measured perpendicular to the
camber line This is sometimes described
as the "American convention“.
○

Thickness measured perpendicular to the
chord line. This is sometimes described as
the "British convention".
●Most linear dimensions are measured as
a percentage of chord length.

12. Types of Airfoils
There are three types of airfoils:
1.Symmetric Airfoils:
2.Positive cambered
3.Negative cambered

14. Angle of Attack:

16. Taper ratio (λ)

17. Sweep angle (Λ) : Affects speed of the aircraft
(At supersonic speed for reducing drag)

18. Sweep angle from leading edge = phi

19. Dihedral angle (Γ)

●Used to increase lateral
stability of an aircraft at the
cost of lift, adds complexity to
construction.
Why
??

20. Aspect ratio (AR)

●High aspect ratio decreases rolling sensitivity but make airplane fly in
much efficient manner.

21. Wing Calculation

1.According to our problem statement, out wing span should not be greater
than 120cm.
2.Depending upon our requirement we determine the following wing
parameters -
a. Aspect Ratio
bombers = 4 to 5
aerobatic plane = 5 to 6
Normal powered flight = 5 to 7
sail planes = 8 to 16
gliders = > 16
b. Taper Ratio - For wing we take it 1.
c. Sweep angle - 0 degrees
d. Dihedral angle - we can make it 2-5 degrees to increase stability.
e. Airfoil.

22. Let AR
W
= 6
wing span = b = 120cm



s = wing area
wing area = s = 120*120/6 = 2400 cm sq.

Assuming our wing to be rectangular.
Taper ratio (λ) = Root chord / tip chord = 1
=> root chord = tip chord = chord = c
s = wing area = span * chord
chord = wing area/span = s/c = 20cm.

23. Choosing an airfoil
●Most aero modellers like us choose their airfoils from
already designed set of airfoils like NACA or Eppler
aerofoils etc.
●Try to figure out what sort of airplane you need
**
:
•Slow flying airplane like sailplane or glider (look for high C
l
/C
d
ratio)
•Aerobatic stunt plane (symmetric aerofoils)
•High speed race aircraft (very low C
d
, thin and semi symmetric aerofoils)


**above points are just for very rough idea, for final selection of airfoil many parameters are considered.

24. NACA Aerofoils
NACA 4 digit Aerofoils

•This NACA aerofoil series is controlled by 4 digits e.g. NACA 2412.
It stands for National Advisory Committee for Aeronautics
•These designate the camber, position of the maximum camber and
thickness of an aerofoil.
•If an aerofoil number is NACA MPXX 
e.g. NACA 2412

•Here M is the maximum camber as % of chord length. M=2 so the camber
is 2% of the chord

•P is the position of the maximum camber as tens of % of chord length. P=4
so the maximum camber is at 40% of the chord.

•XX is the thickness as % of chord length. XX=12 so the thickness is 12% of
the chord.

26. Airfoil analysis (NACA 0015)

28. ρ

ρ

29. TAIL DESIGN

30. Horizontal stablizer


λ
λ
λ

(4*600)^0.5 = 48cm
17cm
8cm

34. Axial movements of Plane

36. Electronic Components:
•Brushless Motor
•ESC (Electronic Speed Controller)
•Li-Po Battery/Charger
•Servo motors
•Rx-Tx

37. Brushless
Motor:
●KV is motor velocity constant
RPM per volt (kilovolt)
●RPM of motor = KV * voltage
●Thrust- Depends on propeller,
Battery, ESC and power of motor

39. ESC: To control the current:

41. ESC SPECIFICATIONS

42. Li - Po Battery and Charger:

44. ●Battery voltage
●1S = 3.7V
●2S battery pack means that there are 2 cells in Series.
●So a two-cell (2S) pack is 7.4V, a three-cell (3S) pack is 11.1V
●CAPACITY
●1000mAh = 1 Amp Hour (1Ah)
●Discharge Rating ("C" Rating)
●50C = 50 x Capacity (in Amps)
●Calculating the C-Rating of our example battery: 50 x 5 = 250A
●CHARGING
●The safest charge rate for most LiPo batteries is 1C, or 1 x capacity of battery in Amps.
●Watts = Voltage x Amperage
●A LiPo cell should NEVER be discharged below 3.0V

45. Servo Motors:

46. Rx-Tx
Pair:
TRANSMITTER
RECEIVER

47. Some other Imp. Parts:

48. Circuit diagram: