1、Designation: F2355 10Standard Specification forDesign and Performance Requirements for Lighter-Than-AirLight Sport Aircraft1This standard is issued under the fixed designation F2355; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers design and performance re-quirements that apply for the manufacture of lighter-t
3、han-airlight sport aircraft.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements
4、 prior to use.2. Referenced Documents2.1 ASTM Standards:2F2353 Specification for Manufacturer Quality AssuranceProgram for Lighter-Than-Air Light Sport AircraftF2354 Specification for Continued Airworthiness Systemfor Lighter-Than-Air Light Sport AircraftF2356 Specification for Production Acceptance
5、 TestingSystem for Lighter-Than-Air Light Sport AircraftF2427 Specification for Required Product Information to beProvided with Lighter-Than-Air Light Sport Aircraft3. Terminology3.1 Definitions:3.1.1 airshipengine-driven lighter-than-air aircraft thatcan be steered.3.1.1.1 DiscussionThis definition
6、 can include “and thatsustains flight through the use of either gas buoyancy or anairborne heater, or both.”3.1.2 balloonlighter-than-air aircraft that is not engine-driven, and that sustains flight through the use of either gasbuoyancy or an airborne heater, or both.3.1.3 design useful loadload (ot
7、her than structure, engine,enclosure, and systems) that a lighter-than-air aircraft can carrywhile achieving the design defining performance requirements.3.1.4 gross weighttotal aircraft system weight(s) at take-off. The weight limits must be established so that it is: (1) thedesigned maximum weight
8、 at which compliance with eachapplicable structural loading condition is demonstrated, or (2)the highest weight at which compliance at each applicableflight requirement is demonstrated.3.1.5 lighter-than-air aircraftaircraft that can rise andremain suspended by using contained gas weighing less than
9、the air that is displaced by the gas.3.1.5.1 DiscussionAirships may include dynamic lift thatderive as much as 30 % lift from other than buoyancy.3.1.6 maximum takeoff weightgross weight limit as de-fined by the manufacturer, proven through compliance withthis specification and placarded on the airc
10、raft as the not-to-exceed gross weight.3.1.7 thermal airshipcraft with design features to preventcollapse due to forward motion for which buoyancy is createdor enhanced by heating of the gas in an otherwise unpressur-ized envelope.3.1.8 vectored thrust ballooncraft that can move laterally,but is lim
11、ited to lateral speed by its lack of design features toprevent collapse due to forward motion.3.1.9 weight limitationsoperational weight restrictions(maximum/minimum) as defined by the manufacturer andproven through compliance with this specification to demon-strate controllability.4. Flight Require
12、ments4.1 Performance Requirements for Airships and ThermalAirships, except as noted:4.1.1 Proof of ComplianceEach of the following require-ments shall be met at the maximum takeoff weight and mostcritical center of gravity (CG) position. To the extent that CGadjustment devices may be adjusted for fl
13、ight, these compo-nents will be evaluated in the least favorable recommendedposition as it affects either performance or structural strength.4.1.2 General PerformanceAll performance requirementsapply in and shall be corrected to International Civil AviationOrganization (ICAO) defined standard atmosp
14、here in still airconditions at sea level. Speeds shall be given in indicated (IAS)and calibrated (CAS) airspeeds in knots.1This specification is under the jurisdiction of ASTM Committee F37 on LightSport Aircraft and is the direct responsibility of Subcommittee F37.60 on Lighterthan Air.Current edit
15、ion approved Feb. 1, 2010. Published March 2010. Originallyapproved in 2005. Last previous edition approved in 2008 as F2355 05a (2008).DOI: 10.1520/F2355-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of A
16、STMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.3 Flight PerformanceFor all flight operations it shallbe shown that control sufficie
17、nt to safely maneuver or land theairship, or both, can be maintained.4.1.4 ClimbThe following shall be measured:4.1.4.1 Distance to clear a 15-m (50-ft) obstacle not toexceed 213 m (700 ft) from point of lift-off. Compliance withthe requirements of this section must be shown at each extremeof altitu
18、de and ambient temperature for which approval issought.4.1.4.2 Climb rates of 1.5 m/s (300 fpm) and 0.5 m/s (100fpm) with one engine inoperable for multi-engine configura-tions.4.1.5 Controllability and ManeuverabilityThe aircraftshall be safely controllable and maneuverable during takeoff,climb, le
19、vel flight (cruise), approach, and landing.4.1.5.1 Demonstrate a smooth transition between all flightconditions shall be possible without excessive pilot skills norexceeding pilot forces of 59.1 kg (130 lb) for the foot-operatedcontrol, 9.1 kg (20 lb) prolonged application, or 29.5-kg (65-lb)hand co
20、ntrols, 4.5 kg (10 lb) prolonged operation.4.1.6 DescentThe following shall be measured.4.1.6.1 It must be shown that in the event of the mostcritical uncontrolled descent from either: (1) an engine orpropeller failure, (2) burner failure for thermal airship, (3)valve leak for either hot air or capt
21、ive gas airship, or (4) themaximum permitted envelope failure as specified in 5.1.2.NOTE 1Procedures must be established for landing at the maximumvertical velocity attained and procedures must be established for arrestingthe maximum descent rate within the manufacturers specified altitude.4.1.7 Lan
22、dingIt must be shown that a pilot of normal skillcan achieve landing sink rates of no more than 0.77 m/s (2 ft/s).4.1.8 Stability and Control:4.1.8.1 Vertical Stability and ControlStability and controlof the airship shall be determined at maximum gross weight,with minimum in-flight turbulence/wind f
23、or:(1) Maximum duration of envelope valve operation (ifequipped), during which the airship must not enter into adangerous descent.(2) Minimum burner fuel pressures (if equipped), whichwill arrest the maximum descent rate as determined in 4.1.6and climb as determined in 4.1.4.4.1.8.2 Longitudinal Sta
24、bilityLongitudinal stability of theaircraft will be demonstrated by performing 2 min of flightwithout control input for three conditions. In each case, theaircraft must not enter into dangerous or unusual altitudes. Atest must be conducted at maximum gross weight, with aminimum of in-flight turbulen
25、ce. The three conditions areascent, descent, and level flight.4.1.8.3 Longitudinal ControlWith all engines operating atmaximum power, the airship must be capable of:(1) A nose-down pitch from a stabilized climb with a 30nose-up deck angle,(2) A nose-up pitch from a stabilized descent with a 30nose-d
26、own deck angle, and(3) Longitudinal upset response shall be evaluated byanalysis or test, or both, to show that it does not result in unsafeconditions.4.1.8.4 Lateral and Directional Stability:(1) Lateral stability will be demonstrated by maintainingthe surface controls in a fixed position, which wi
27、ll initially givean unaccelerated level flight condition. The aircraft must notenter into a dangerous altitude during the 2 min that the flightcontrol surfaces are fixed. A test must be conducted atmaximum operating weight, with minimum in-flight turbu-lence.(2) Directional stability will be demonst
28、rated by a separateand full deflection of each directional flight control surfaces forthree full turns of 360 without the aircraft entering anydangerous flight altitude during the maneuver. A test must beconducted at minimum flight weight, with minimum in-flightturbulence. The demonstrated turn rate
29、 shall not be less than6/s (60 s for a 360 turn) in either direction.4.2 Performance Requirements for Balloons:4.2.1 Proof of ComplianceEach of the following require-ments shall be met at the maximum takeoff weight.4.2.2 General PerformanceAll performance requirementsapply and shall be corrected to
30、International Civil AviationAssociation Organization (ICAO) defined standard atmospherein still air conditions at sea level.4.2.3 Flight PerformanceFor level flight, climbs, de-scents, and landing, it shall be shown that control sufficient tosafely land the balloon can be maintained.4.2.3.1 ClimbEac
31、h balloon must be capable of climbingat least 300 ft in the first minute after takeoff with a steady rateof climb. Compliance with the requirements of this sectionmust be shown at each altitude and ambient temperature forwhich approval is sought.4.2.3.2 ControllabilityThe balloon shall be controllab
32、leduring takeoff, climb, level flight, approach, and landing.4.2.3.3 DescentThe following shall be measured. It mustbe shown that in the event of the most critical uncontrolleddescent from either: (1) burner failure for hot air balloon, (2)valve leak for either hot air or captive gas, and (3) themax
33、imum permitted envelope failure as specified in 5.2.2.Procedures must be established for landing at the maximumvertical velocity attained and procedures must be establishedfor arresting the maximum descent rate within the manufac-turers specified altitude.4.2.3.4 LandingIt must be shown that the pil
34、ot canachieve a landing sink rate of not more than 1 m/s.4.2.4 Stability and ControlStability and control of theballoon shall be determined at maximum gross weight, withminimum in flight turbulence/wind for:4.2.4.1 Maximum duration of envelope valve operation,during which the balloon must not enter
35、into a dangerousdescent.4.2.4.2 Minimum burner fuel pressures that will arrest themaximum descent rate as determined in 4.2.3.3 and climb asdetermined in section 4.2.3.1.5. Structure Requirements5.1 Structure for Airships and Thermal Airships (except asnoted):5.1.1 LoadsUnless otherwise specified, a
36、ll requirementsare specified in terms of limit load.F2355 1025.1.1.1 Ultimate loads are limit loads multiplied by thefactor of safety defined below. Loads shall be redistributed ifthe deformations affect them significantly.5.1.2 Factors of SafetyThe factor of safety is 1.5, exceptas shown in the fol
37、lowing:5.1.2.1 3.0 on castings,5.1.2.2 1.8 on fittings,5.1.2.3 6.67 on control surface hinges,5.1.2.4 3.3 on push-pull control systems,5.1.2.5 2.0 on cable control systems, and5.1.2.6 5.0 on envelope structures (fibrous or non-metallicparts) and rigging.5.1.2.7 In applying factors of safety, the eff
38、ect of tempera-ture and other operating characteristics, or both, that may affectstrength of the balloon must be accounted for.5.1.2.8 For design purposes, an occupant weight of at least170 lb must be assumed.5.1.3 Strength and Deformation:5.1.3.1 The structure must be able to support limit loadswit
39、hout permanent deformation of the structure.5.1.3.2 The structure must be shown by analysis, test, oranalysis supported by test to be able to withstand ultimate loadswithout failure.5.1.3.3 The structure shall be able to withstand ultimateloads for 3 s without failure when proof is by static test. W
40、hendynamic tests are used to demonstrate strength, the 3-s require-ment does not apply. Local failures or structural instabilitiesbetween limit load and ultimate load are acceptable if thestructure can sustain the required ultimate load for 3 s.5.1.4 Proof of StructureEach critical load requirements
41、hall be investigated either by conservative analysis or tests, ora combination of both.5.1.5 Proof of StrengthEnvelope material, attachments,and car frame shall all be demonstrated by test to meet the loadfactor requirement with the required factor of safety. Thisevaluation shall include suitable te
42、ar resistance testing for theenvelope.5.1.6 Load Factor:5.1.6.1 Positiven = 1.5 (comprised of a maneuvering loadmultiplied by a gust load factor).5.1.6.2 Negativen =0.5.1.6.3 Additional load considerations shall be evaluated forselected design airspeeds and resultant dynamic pressures.5.1.7 Design A
43、irspeedsThe selected design airspeeds areequivalent airspeeds (EAS) except as provided in specificrequirements.5.1.7.1 Design Stall Speed, V(SI)shall be calculated basedon area, lift coefficient estimates, and maximum negativeboyance.5.1.7.2 Design Maximum Level Flight Airspeed, V(H)V(H) is the maxi
44、mum speed obtainable in level flight with allengines operating at maximum continuous power and theairship loaded to achieve minimum drag.5.1.7.3 Design Airspeed for Maximum Gust Intensity,V(B)V(B) shall not be less than 35 knots or 0.65 V(H),whichever is least.5.1.7.4 Maneuver loads considering the
45、maximum forcesthat can be generated by the envelope and surfaces at V(H) andmaximum control deflections, unless placarded to limit deflec-tion at specific conditions.5.1.7.5 Gust loads of a discrete gust of 7.6 m/s (25 fps) atV(H) and 10.6 m/s (35 fps) at V(B).5.1.8 Control Surface LoadsControl surf
46、ace loads on theairship shall be evaluated at loads defined in flight tests of theenvelope by the envelope manufacturer.5.1.9 Ground Mooring Conditions (when equipped)Anairship that is normally moored to a mooring mast when not inflight, such as overnight. The mooring mast system shall beadequate to
47、 allow the airship to swing around the mast 360 aswind direction changes. The strength of the mast shall besufficient to safely moor the airship in high or gust windconditions as specified by the manufacturer. Accommodationshall be made to allow the car to accept these sidewardmovements without dama
48、ge.5.1.10 Control System and Supporting StructureThe con-trol system structure shall be designed to withstand maximumforces, and in the case of dual controls, the relevant systemshall be designed for the pilots operating in opposition, ifgreater than the control system forces.5.1.11 Ground Load Cond
49、itionsDesign features shalllimit the landing sink rate to less than or equal to 1 m/s (3.3ft/s). Testing by drop test will use a drop height to achieve a 1m/s (3.3 ft/s) drop rate. This will be a dead drop test of the carwithout envelope lift at maximum takeoff weight.5.1.12 Emergency Landing ConditionsDesign structure toprotect each occupant from serious injury when the aircraftexperiences three independent ultimate load conditions: 1.5-gsupward, 6-gs forward, and 3-gs sideward. Test articles thathold this load for more than 3
