Aircraft Design: A Systems Engineering Approach, M. Sadraey, Wiley, 2012 Chapter 12 Design of Control Surfaces. Tables

Transcription

1 Aircraft Design: A Systems Engineering Approach, M. Sadraey, Wiley, 2012 Chapter 12 Design of Control Surfaces Tables No Term 1 Trim, balance, equilibrium Definition When the summations of all forces exerting on an aircraft; and the summations of all moments about aircraft center of gravity are zero, the aircraft is in trim. 2 Control A desired change in the aircraft trim condition from an initial trim point to a new trim point with a specified rate. 3 Stability The tendency of an aircraft to oppose any input and return to the original trim point, if disturbed by an undesired force or moment. 4 Static stability The tendency of an aircraft to oppose any input if disturbed from the trim point. 5 Dynamic stability The tendency of an aircraft to return to the original trim point if disturbed. Table Definition of fundamental terms 1

2 No Control surface Symbol Positive control surface deflection 1 Elevator E Producing a negative pitching moment; (Down: + E ; Up: - E ) 2 Aileron A Generating a positive rolling moment; Left and right aileron are considered ( A left-down, A right-down ); A = 0.5 ( Aleft + Aright ) 3 Rudder R Producing a positive side-force and a negative yawing moment(left:+ R, right: - R ); Table Convention for positive control surface deflections 2

3 Control Surface Elevator Aileron Rudder Control surface area/lifting surface area S E /S h = S A /S = S R /S V = Control surface span/lifting surface span b E /b h = b A /b = b R /b V = Control surface chord/lifting surface chord C E /C h = C A /C = C R /C V = Control surface maximum -25 deg (up) 25 deg (up) - 30 deg (right) deflection (negative) Control surface maximum deflection (positive) +20 deg (down) 20 deg (down) +30 deg (left) Table Typical values for geometry of control surfaces 3

4 No Control Surface Configuration Aircraft Configuration 1 Conventional (aileron, elevator, Conventional (or canard replacing elevator) rudder) 2 All moving horizontal tail, rudder, Horizontal tail and elevator combined aileron 3 All moving vertical tail, elevator, Vertical tail and rudder combined aileron 4 Flaperon, Elevator, Rudder Flap and aileron combined (e.g. X-29 and F- 16 falcon) 5 Taileron, Rudder All moving horizontal tail (elevator) and aileron combined (e.g. F-16 Falcon) 6 Elevon, Rudder (or equivalent) Aileron and elevator combined (e.g. Dragon, F-117 Night Hawk, Space Shuttle) 7 Ruddervator, Aileron V-tail (e.g. UAV Global Hawk and Predator) 8 Drag-Rudder, Elevator, Aileron No vertical tail (e.g. DarkStar) 9 Canardvator, Aileron Elevator as part of canard, plus aileron 10 Four Control Surfaces Cross (+ or ) tail configuration (e.g. most missiles) 11 Aileron, Elevator (or equivalent), Split Rudder No vertical tail. Aileron-like surfaces that is split into top and bottom sections (e.g. bomber B-2 Spirit) 12 Spoileron, Elevator, Rudder Spoiler and aileron combined (e.g. B-52) 13 Thrust vector control Augmented or no control surfaces, VTOL UAV Table Control Surface Configuration Options 4

5 Class Aircraft characteristics I Small, light aircraft (maximum take-off mass less than 6,000 kg) with low maneuverability II Aircraft of medium weight and low-to-medium maneuverability (maximum take-off mass between 6,000 and 30,000 kg) III Large, heavy, low-to-medium maneuverability aircraft (maximum take-off mass more than 30,000 kg) IV Highly maneuverable aircraft, no weight limit (e.g. acrobatic, missile, and fighter) Table Aircraft Classes 5

6 Category Examples of flight operation A 1. Air-to-air combat (CO); 2. Ground attack (GA); 3. Weapon delivery/launch (WD); 4. Aerial recovery (AR); 5. Reconnaissance (RC); 6. In-flight refueling (receiver) (RR); 7. Terrain following (RF); 8. Antisubmarine search (AS); 9. Close formation flying (FF); and 10. Lowaltitude parachute extraction (LAPES) delivery. B 1. Climb (CL); 2. Cruise (CR); 3. Loiter (LO); 4. In-flight refueling in which the aircraft acts as a tanker (RT); 5. Descent (D); 6. Emergency descent (ED); 7. Emergency deceleration (DE); and 8. Aerial delivery (AD). C 1. Takeoff (TO); 2. Catapult takeoff (CT); 3. Powered approach (PA); 4. Wave-off/go-around (WO); and 5. Landing (L). Table Flight phase categories [8] 6

7 Level Definition 1 Flying qualities clearly adequate for the mission Flight Phase. 2 Flying qualities adequate to accomplish the mission Flight Phase, but some increase in pilot workload or degradation in mission effectiveness, or both, exists. 3 Flying qualities such that the airplane can be controlled safely, but pilot workload is excessive or mission effectiveness is inadequate, or both. Category A Flight Phases can be terminated safely, and Category B and C Flight Phases can be completed. Table Levels of acceptability 7

8 Level Meaning Pilot Comfort Level Pilot Status 1 Very comfortable 1 to 3 2 Hardly comfortable 4 to 6 3 Uncomfortable 7 to 10 Table Levels of acceptability and pilot comfort 8

9 No Aircraft type Rotation time during take-off (second) Take-off pitch angular acceleration (deg/sec 2 ) 1 Highly maneuverable (e.g acrobatic GA and fighter) 2 Utility; semi-acrobatic GA Normal General Aviation Small transport Large transport Remote control, model Table Take-off angular acceleration requirements 9

10 Level of acceptability Requirement 1 Damping ratio of phugoid mode ( ph ) Damping ratio of phugoid mode ( ph ) The time-to-double the amplitude of at least 55 seconds. Table Phugoid mode requirement 10

11 Flight phase Short period damping ratio ( s ) Level 1 Level 2 Level 3 Minimum Maximum Minimum Maximum Minimum Maximum A No maximum B No maximum C No maximum Table Short period mode damping ratio specification 11

12 Level Flight Phase Category A B C Time to achieve a bank angle of 60 o Time to achieve a bank angle of 45 o Time to achieve a bank angle of 30 o seconds 1.7 seconds 1.3 seconds seconds 2.5 seconds 1.8 seconds seconds 3.4 seconds 2.6 seconds a. Time to achieve a specified bank angle change for Class I Level Runway Flight Phase Category A B C Time to achieve a bank angle of 45 o Time to achieve a bank angle of 45 o Time to achieve a bank angle of 30 o Time to achieve a bank angle of 25 o 1 Land-based 1.4 seconds 1.9 seconds 1.8 seconds - Carrier-based 1.4 seconds 1.9 seconds 2.5 seconds - 2 Land-based 1.9 seconds 2.8 seconds 3.6 seconds - Carrier-based 1.9 seconds 2.8 seconds seconds 3 Land-based 2.8 seconds 3.8 seconds seconds Carrier-based 2.8 seconds 3.8 seconds seconds Level b. Time to achieve a specified bank angle change for Class II Speed range Flight Phase Category A B C 1 Low 1.8 seconds 2.3 seconds 2.5 seconds Medium 1.5 seconds 2.0 seconds 2.5 seconds High 2.0 seconds 2.3 seconds 2.5 seconds 2 Low 2.4 seconds 3.9 seconds 4.0 seconds Medium 2.0 seconds 3.3 seconds 4.0 seconds High 2.5 seconds 3.9 seconds 4.0 seconds 3 All 3.0 seconds 5.0 seconds 6.0 seconds c. Time to achieve a 30 o bank angle change for Class III 12

13 Level Speed range Flight Phase Category A B C 30 o 50 o 90 o 90 o 30 o 1 Very Low 1.1 sec sec 1.1 sec Low 1.1 sec sec 1.1 sec Medium sec 1.7 sec 1.1 sec High sec sec 1.1 sec 2 Very Low 1.6 sec sec 1.3 sec Low 1.5 sec sec 1.3 sec Medium sec 2.5 sec 1.3 sec High sec sec 1.3 sec 3 Very Low 2.6 sec sec 2.0 sec Low 2.0 sec sec 2.0 sec Medium sec 3.4 sec 2.0 sec High sec sec 2.0 sec d. Time to achieve a specified bank angle change for Class IV Table Roll control requirements 13

14 Level Class Crosswind speed 1 I 20 knots II, III, and IV 30 knots 2 I 20 knots II, III, and IV 30 knots 3 I, II, III, and IV One-half the value for levels 1 and 2 Table Crosswind velocity requirements 14

15 Flight Phase Aircraft Class T R (seconds) Level 1 Level 2 Level 3 A I, IV II, III B All C I, IV II, III Table Roll mode time constant specification (maximum value) 15

16 Aircraft Class Flight Phase Minimum time to double amplitude in spiral mode Level 1 Level 2 Level 3 I and IV A 12 seconds 8 seconds 4 seconds B and C 20 seconds 8 seconds 4 seconds II and III A, B, C 20 seconds 8 seconds 4 seconds Table Time to double amplitude in spiral mode 16

17 Level Flight Phase Aircraft Class min d min d nd (rad/s) min (rad/s) 1 A I,IV II, III B All C I, II, IV III All All All All 0.02 No limit 0.4 Table Dutch roll mode handling qualities n d 17

18 No Aircraft Type m TO b C A /C Span ratio Amax (deg) (kg) (m) b i /b/2 b o /b/2 up down 1 Cessna 182 Light GA 1, Cessna Citation Business 9, III jet 3 Air Tractor AT- Agriculture 7, Gulfstream 200 Business 16, jet 5 Fokker 100A Airliner 44, Boeing Airliner 247, Airbus Airliner 368, Airbus A Airliner 368, Table Characteristics of aileron for several aircraft 1 Inboard aileron 2 Outboard aileron 18

19 No Aircraft Type m TO S E /S h C E /C h Emax (deg) (kg) down up 1 Cessna 182 Light GA 1, Cessna Citation III Business jet 9, Gulfstream 200 Business jet 16, AT-802 Agriculture 7, ATR Regional airliner 18, Lockheed C-130 Hercules Military cargo 70, Fokker F Transport 33, Fokker F-100B Airliner 44, McDonnell Douglas DC- 8 Transport 140, McDonnell Douglas DC Transport 51, McDonnell Douglas DC- Transport 251, McDonnell Douglas MD-11 Transport 273, Boeing Transport 76, Boeing Transport 50, Boeing Transport 247, Boeing Transport 377, Airbus A-300B Transport 165, Airbus 320 Transport 78, Airbus A Airliner 368, Lockheed L-1011 Tristar Transport 231, Lockheed C-5A Cargo 381, Table Specifications of elevators for several aircraft 19

20 E Tail-to-elevator-chord ratio; C E /C h (deg) ± ± ± ± ± ± Table Reduction in tail stall angle ( h E ) in degrees when elevator is deflected 20

21 No Aircraft Type m TO (kg) S R / S V C R /C V Rmax (deg) Max cross wind speed (knot) 1 Cessna 182 Light GA 1, ±24 2 Cessna 650 Business jet 9, ±25 3 Gulfstream 200 Business jet 16, ±20 4 Air Tractor AT-802 Regional airliner 18, ±24 5 Lockheed C-130E Military cargo 70, ±35 - Hercules 6 DC-8 Transport 140, ± DC-10 Transport 251, ±23/± Boeing Transport 50, Boeing Transport 247, ± Boeing Transport 377, ± Lockheed C-5A Cargo 381, Fokker 100A Airliner 44, ± Embraer ERJ145 Regional jet 22, ±15 14 Airbus A Airliner 368, ±31.6 Table Characteristics of rudder for several aircraft Tandem rudder 3 21

22 No Requirements Brief description Aircraft 1 Asymmetric thrust When one engine fails, the aircraft must be able to overcome the asymmetric thrust. Multi-engine aircraft 2 Crosswind landing An aircraft must maintain alignment with the All runway during a crosswind landing. 3 Spin recovery An aircraft must be able to oppose the spin rotation and to recover from a spin. Spinnable aircraft 4 Coordinated turn The aircraft must be able to coordinate a turn. All 5 Adverse yaw The rudder must be able to overcome the All adverse yaw that is produced by the ailerons. 6 Glide slope adjustment Aircraft must be able to adjust the glide slope by increasing aircraft drag using a rudder deflection. Glider aircraft Table Rudder design requirements 22

23 No Aircraft The most critical flight condition 1 Glider/sailplane Glide slope adjustment 2 Single engine Normal GA Crosswind landing 3 Single engine Utility/Acrobatic GA Spin recovery 4 Multi-engine Normal GA Asymmetric thrust 5 Multi-engine Utility/Acrobatic GA Asymmetric thrust/ Spin recovery 6 Multiengine transport (fuselageinstalled Crosswind landing engines) 7 Multiengine transport (winginstalled Asymmetric thrust/ Crosswind landing engines) 8 Military fighter Directional maneuverability/spin recovery 9 Remote controlled/ model Coordinated turn Table The most critical flight condition for a rudder 23