ARMY ADS 29-1986 STRUCTUML DESIGN CRITERIA FOR ROTARY WING AIRCRAFT.pdf

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1、US ARMY AVIATION SYSTEMS COMMAND ADS - 29 AERONAUTICAL DESIGN STANDARD STRUCTUML DESIGN CRITERIA FOR ROTARY WING AIRCRAFT SEPTEMBER 1986 Approved for Public release; distribution unlimited UNITED STATES ARMY AVIATION SYSTEMS COMMAND ST. LOUIS, MISSOURI DIRECTORATE FOR ENGINEERING Provided by IHSNot

2、for ResaleNo reproduction or networking permitted without license from IHS-,-,-AERONAUTICAL DESIGN STMJDARDS STRUCTURAL DESIGN CRITERIA FOR ROTARY WING AIRCRAFT SEPTEMBER 1986 APPROVED FOR PUBLIC RELEASE: DISTRIBUTION LJNLItIITED UNITED STATES ARMY AVIATION SYSTEMS COMMAND ST. LOUIS, MO DIRECTORATE

3、FOR ENGINEERING Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-U. S. ARbfsn AVIATION SYSTEMS COBIAND ST. LOUIS, MISSOURI This Army Aeronautical Design Standard is prepared under the authorization of AMC Reg 70-32. Any recommended corrections, additi

4、ons, or deletions which may be of use in improving this document should be addressed to: U.S. Army Aviation Systems Command ATTN: AMSAV-E 4300 Goodfellow Boulevard St. Louis, Missouri 63120-1798 APPROVED: DANIEL M. McENEANY Director of Engineering Provided by IHSNot for ResaleNo reproduction or netw

5、orking permitted without license from IHS-,-,-CONTENTS PARAGRAPHS SCOPE APPLICABLE DOCUMENTS DEFINITIONS AND SYMBOLS REQUIREMENTS General Flight Loading Conditions - Rotary Wing Flight Loading Conditions - Fixed Wing Ground Loading Conditions Control System Loads PAGE - 1 1 2 4 4 Provided by IHSNot

6、for ResaleNo reproduction or networking permitted without license from IHS-,-,-1. SCOPE - 1.1 Scope. This standard establishes the structural design criteria for Amy rotary wing aircraft. The term “rotary wing“ includes conventional helicopters, as well as tilt rotor, tile wing and compound aircraft

7、. 1.2 Application. This standard is applicable to rotary wing aircraft, including all associated subsystems, equipment, components , and stores, and is mandatory for use by th Department of the Army unless specific deviations are authorized. 1.3 Classification. Rotary wing aircraft shall be divided

8、into the following classes : Class I - Those aircraft whose primary mission falls under one of the following general headings: Rescue, evacuation, assault (cargo and troop), liaison, reconnaissance, artillery spotting, utility, training, or antisubmarine warfare. Class 11 - Those aircraft whose miss

9、ion falls under the general heading of cargo and are designed for a cargo loading of 5,000 pounds or less. Class 111 - Those aircraft whose mission falls under the general heading of cargo and are designed for a cargo loading in excess of 5,000 pounds. 2. APPLICABLE DOCUMENTS 2.1 Government Document

10、s. The following documents of the issue listed in the Department of Defense Index of Specifications and Standards (DODISS) and its supplements, form a part of this Standard to the extent specified herein. The date of the applicable DODISS and supplements thereto shall be specified in the solicitatio

11、n. In the event of conflict betrleen the documents referenced herein and the contents of this standard, the contents of this standard shall be considered a superseding requirement. Where these documents are specified elsewhere in this standard, only the basic document numbers are stated. 2.1.1 Speci

12、fications. 2.1.2 Standards. 2.1.3 Handbooks. MIL-HDBK- 5 Flying Qualities of Piloted Airplanes Aluminum Alloy Castings, High Strength Tiedown, Airframe Design Requirements for Climatic Extremes for Military Equipment Castings, Classification and Inspection of Metallic Materials and Elements for Aero

13、space Vehicle Structures Plastics for Aerospace Vehicles Structural Sandwich Composites Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3. DEFINITIONS AND SYMBOLS. The definition of terms and symbols used in this standard are given below. 3.1 Airspee

14、d, equivalent (EAS). The product of the true airspeed and the square root of the relative density at the altitude concerned. 3.2 Airspeed, true (TAS). The speed of the aircraft along its flight path with respect to the body of air through which it is moving. 3.3 Area, rotor-disk (A). The area enclos

15、ed by the projection of the arc swept by the rotor blade tips. The area of the overlapped portions of a multirotored helicopter should not be included in the disk area. 3.4 Autorotation. The ability of a rotary wing aircraft to maintain sufficient velocity to sustain forward flight under a controlle

16、d rate of descent while main- taining the rotors angular velocity without engine power, the rotating force being provided by the forward component of the lift forces acting on the rotor blades. 3.5 Conditions, critical. A critical condition is the design loading condition for which margins of safety

17、 and testing, if applicable, indicate the structure is most likely to fail at ultimate loads or develop permanent set at limit loads. 3.6 Density, relative. The ratio of air density at altitude to the air density at sea level, s = e/e . 3.7 Dive. A maneuver executed for the purpose of increasing spe

18、ed while simulta- - neously decreasing altitude. 3.8 External Stores. The term external stores should be interpreted to mean any item mounted externally on the aircraft. 3.9 Factor of Safety, Ultimate. The factor of safety specified for the determi- nation of ultimate loads. 3.10 Factor of Safety, Y

19、ield. The factor of safety specified for the determina- tion of design-yield loads. 3.11 Limit. The value of a parameter, the magnitude of which is sufficiently large thatthe probability of being exceeded corresponds to a minimum acceptable level of operational safety. - 3.12 Load Factor, n. The rat

20、io of a given mean, steady-state load to an arbitrary reference load. The arbitrary reference load will be indicated by the context and is usually the weight of the aircraft (w). When employed, the subscript indicates the direction of the given load. 3.12.1 Limit Load or Limit Load Factor. A load or

21、 load factor which establishes a strength level for design of the aircraft. 3.13 Load, Yield. A limit load multiplied by the specified yield factor of safety. 3.14 Load, Failing. The load at which failure of a structure occurs. Provided by IHSNot for ResaleNo reproduction or networking permitted wit

22、hout license from IHS-,-,-3.15 Load, Proof. Any load which will not cause permanent deformation of the structure to which it is applied (normally limit load). 3.16 Load, Ultimate. A limit load multiplied by the specified ultimate factor of safety. 3.17 Maximum Safe. A phrase which, in combination wi

23、th a parameter such as speed, load factor, altitude, etc., denotes the boundary for which limit strength of airworthiness is available. 3.18 Rotor Speed, Design Minimum, Power On. The minimum practical rotor speed attainable in power on flight at the structural design gross weight. 3.19 Rotor Speed,

24、 Design Maximum, Power On. The rotor speed attainable using military-rated power or thrust as controlled by speed limiting devices. 3.20 Rotor Speed, Limit, Power On. The design maximum rotor speed, power on, multiplied by the factor 1.25. If rotor speed is limited by a speed limiting device, the li

25、mit rotor speed shall be 1.05 times the maximum attainable with the device operating. 3.21 Rotor Speed, Design Minimum, Power Off. The minimum practical rotor speed attainable in autorotative flight at the structural design gross weight. 3.22 Rotor Speed, Design Maximum, Power Off. The maximum rotor

26、 speed attainable in stabilized autorotational descent with enginecs) delivering zero power or thrust. 3.23 Rotor Speed, Limit, Power Off. The design maximum rotor speed, power off, multiplied by the factor 1.25. 3.24 Speed. Speeds specified herein are equivalent airspeed in knots (KEAS). 3.24.1 Spe

27、ed, Design Maximum Level Flight, VH: The design maximum level flight forward speed attainable at the structural deslgn gross weight, using intermediate rated power or thrust, or as limited by blade stall or compressibility effects. 3.24.2 Speed, Limit Dive, (Rotary Wing), V . The dive speed shall be

28、 VH in forward flight multiplied by the factor of P.20. 3.24.3 Speed, Slow Down for Gust, V . The slow-down speed for gust shall be determined by mission requirements, ghe permissibility of reducing speed, and the slow-down speed attainable. Adequate stability margin and stall margin shall be provid

29、ed. 3.24.4 Speed, Limit Dive, (Fixed Wing), VL. The dive speed shall be V multiplied H by the factor 1.2. Tne limit speed for the basic and high-drag confinurations is the maximum attainable speed commensurate with the operational-use of-the aircraft considering shallow and steep dive angles, thrust

30、, operation and nonoperation of speed brakes, and inadvertent upsets from gusts, or as specified in the contract documents. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.24.5 Speed, Limit Landing, Approach and Takeoff, V . The takeoff, approach,

31、and landing limit speed is the maximum speed at whichLFhe landing gear and other devices shall be open or extended for the takeoff or landing operation. 3.24.5.1 VTOL or STOL Capability. For configurations having either VTOL or STOL capability that can thrust horizontally on takeoff, the speed VLF s

32、hall be the greater of the following: a. 160 percent of the minimum speed for level flight with devices extended or open for atakeoff in the takeoff positions at the maximum alternate gross weight and with zero thrust. b. 180 percent of the minimum speed for level flight with devices extended or ope

33、n for landing in the landing position at the structural design gross weight and with zero thrust. c. 150 percent of the minimumspeed for level flight at the maximum alternate gross weight and with zero thrust. Devices that are normally used during takeoff or landing shall be in their fully retracted

34、 or closed position. For other config- urations, the speed V will be 160% of the maximum rotational speed for STOL takeoff. For aircrafEFhaving variable geometry surfaces, these surfaces shall be in all positions within the design limits consistent with the operational requirements. d. 120 percent o

35、f the maximum speed attainable with maximum thrust without exceeding a 200-foot altitude after takeoff in the time required to fully close or retract devices extended or open for takeoff at the structural design gross weight. 3.24.5.2 VTOL, No Horizontal Thrust. For other VTOL configurations having

36、no horizontal thrusting devices, the speed VLF, shall be 160 percent of the speed for minimum power required flight. 3.24.6 V . The maximum level flight speed using maximum continuous power. cruise 3.25 VVMaximum. Maximum design sinking speed. 3.26 VtN. Maximum speed for stabilized autorotation. - 3

37、.27 Elargin of Safety (MS) - Allowable Load (or Stress) Applied Load (or Stress) 3.28 Structural Design Gross keight (SDGW). Defined in System Specification. 3.29 Maximum Alternate Gross Weight (MAGN). Defined in System Specification. 4. REQUIREMENTS. 4.1 General. 4.1.1 Limit Loads. The load factors

38、, formulas and load condition definitions of this standard represent limit loads, unless otherwise specified. Yielding of the structure shall not occur at design limit load. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.1.2 Ultimate Loads. Except

39、 for loading conditions for which specific ultimate loads are delineated, ultimate loads are obtained by multiplying the limit loads by the ultimate factor of safety. The ultimate factor of safety to be used for the design of the structure shall be 1.50, except that in certain cases for considera- t

40、ions of added safety, rigidity, quality assurance, and wear, additional strength or multiplying factors of safety are specified. Failure shall not occur at the design ultimate load. Crash conditions, as defined in MIL-STD-1290, and ballistic damage shall have a factor of safety of 1.0 with yielding

41、permitted. 4.1.3 eformations. The cumulative effects of elastic or thermal deformations which result from application of design landing loads for landings on land or ship, application of repeated loads, and from application of design limit loads for other conditions shall not interfere with the mech

42、anical operation of the aircraft, affect adversely its aerodynamic characteristics, require repair, or require replacements of parts other than as specifically approved by the procuring agency. 4.1.4 Load and Temperature Redistribution. If thermal or elastic deformations of the structure occur as a

43、result of limit flight conditions, design landing condi- tions, and limit ground handling loads, the external load and temperature distribu- tions shall include the effects of those deformations. Load redistributions shall include those caused by thermally induced deformations, by airload redistribu

44、tions caused by surface temperature changes, and by rigidity changes resulting from thermal stresses and by other thermally induced effects. 4.1.5 Superimposed Loads. Residual loads remaining after extending or retracting landing gear and flaps, opening and closing doors, or caused by rigging loads

45、of magnitudes specified in the aircraft maintenance instructions, and preloads such as those occurring when swaybracing is fitted, shall be combined with the loads resulting from the pertinent loading conditions. Loads acting upon the aircraft structure as a result of the operation of armament and e

46、quipment, blast loads, impingement of engine exhaust, and full engine power shall be combined with the loads acting on the aircraft structure at rest on the ground and the loads acting on the aircraft structure during flight and during landings, as applicable. 4.1.6 Transient Response. The magnitude

47、s and distributions of loads shall include the effects of the dynamic response of the structure resulting from the transient or sudden application of loads, such as the dynamic response resulting from abrupt maneuvers, detonation of special weapons, gusts, landings, taxiing, water loads on hulls, as

48、sisted-takeoff-unit loads, and release or ejection of stores. 4.1.7 Thermal Considerations. The design of the aircraft shall include the effects of operation in ambient atmospheres consistent with the world-wide cold and hot temperature-versus-altitude relationship defined in MIL-STD-210 referenced

49、to a ground level temperature of -40C and a lapse rate of 2“C/1000 ft for hot days. The maximum ambient temperature shall be 70C or as provided in the system specification. The design shall include the cumulative effects of the time- temperature-load history of the aircraft for its planned service life. 4.1.8 Authorized Changes. Government-responsible chan