1. ARRANGEMENT OF THE EMPENNAGE Requirements: A. Slipstream / Jetstream Effects A1. The empennage must never be in the jet efflux of the engines (must be outside cone w. 6 deg. semi-apex angle). Solutions: A1.1 Divert the centerline of the jet. A1.2 Horizontal stabilizer dihedral. A2. The empennage must not be close to a jet efflux because the jet pumping effect will affect the direction of the airflow and diminish the stabilizing effect of the tail. A3. The empennage must be as far away as possible from sources of noise to avoid acoustic fatigue.

2. ARRANGEMENT OF THE EMPENNAGE Requirements: B. Stability & Control A1. The fin and the rudder must provide the counteracting YM in case of engine failure. A2. The empennage must allow for a safe recovery from stall and spin (especially avoid deep stall).

3. ARRANGEMENT OF THE EMPENNAGE 1. Fuselage or Fin-Mounted Stabilizer Pros  Structural simplicity & stiffness.  Having one surface at the tip of the other increases the AR eff by about 50% (winglets). As a result, the horizontal stabilizer can increase the slope of the fin by about 15%. Cons  T-tails may suffer from flutter and deep stall problems.

4. Cessna 550

5. BAE-146

6. ARRANGEMENT OF THE EMPENNAGE 2. Twin Vertical Tail Pros  Increased effectiveness of the horizontal stabilizer (winglets)  If the fin turns out to be too large, rudder deflection will cause a RM as a result of the large vertical distance of its ac from the longitudinal axis of the ac. A twin vertical will minimize this effect (F-14, F-15, F-18).  If twin tail booms are used, the twin vertical is the only solution available (Cessna Skymaster).  Decreases combat vulnerability (A-10).

7. Fairchild Republic T-46A

8. F-14

9. F-15

10. F-18 Hornet

11. Cessna Skymaster

12. A-10 Warthog

13. ARRANGEMENT OF THE EMPENNAGE 3. Butterfly Tail Pros  Avoids damage to the tail when landing on overgrown terrain (sailplanes).  Keeps tail surfaces clear of the engine efflux.  Looks cool (V-tail Bonanza)! Cons  Moving surfaces serve as both rudders (differential deflection) and elevators (simultaneous deflection); complicated control system design.

14. Thermik-Excel Vetron Sailplane

15. Beechcraft V-Tail Bonanza