it gives information about designing RC planes.

1. Vertical tail design and Spiral Stability
Vertical tail design
Central of lateral area
Inertial roll coupling
Locating the CLA
Vertical tail aspect ratio
Dorsal fins
All –moving horizontal T-tails
Rudder power
Rudder aileron effect
Spiral stability
Levels of spiral stability
Lateral and directional coupling
Balance of forces
Spiral stability margin

2. Verticlal Tail Design
Wing dihedral
Fuselage
Landing gear side areas
CG location
Tail area
Rudder
CLA (spiral stable)
-25% of TMA aft CG
-a line through CLA & CG horizontal
-the wing joining the front CLA &rear CLA sloped
upward to the front
-

3. Inertial roll coupling
Aerodynamic axis & inertia axis aligned –no inertial
coupling.
Rotation abt aerodynamic axis will create CF.
CFs produce pitching moment

4. Dihedral
sweepback 2 to 3 deg. equivalent to 1deg. Dihedral
High wing-2
Mid wing -3
Low wing -4
Locate CLA
Profile of design
Settle to 25% of TMA to get good VT
Left right lateral surface due to dihedral

5. -large VT area with no dihedral angle leads to sideslip
Large tail resist slip

6. Vertical aspect ratio
-ARv=1.55*Bv^2/Sv
Dorsal fin
-Increase fuselage stability at high speed angle
-Reduce VT stalling
Rudder power
-Area 30% of VT
-Rudder aileron effect –reduce aileron efffect ( forced yaw)
-Rudder area center above horizontal tail line through CG
will act as aileron

7. Spiral Stability
-Degree of spiral stability
-Spirally stable
-neutrally spirally stable
-spirally unstable-angle of bank slowly increases ,speed gradually
increases
-for sailplanes good SS, sport model moderate , aerobatic models
neutral

8. Lateral & directional coupling
SS requires a balance between
lateral and directional forces
Dutch roll-
-large dihedral angle with small VT
lateral forces are high wagging
coupled with a slight side to side
roll
Balance of forces –
Lateral &directional forces
LS-
Dihedral , angle of sweep back , Cl , AoA
Forward sweepback- destabilizes , increases yaw
-VT area prevents yaw
-advantage -wing stall at root first

9. DS-
-Dorsal fin-to overcome a lack of VT effectiveness flaps
extended & high side slip
-Sweepback- aids DS
- Drag moment reduces yaw
Aileron eliminate aileron induced adverse yaw
-SSM 25% of VTMA
-CG moved aft of the wing SSM VTMA decrease