1、Designation: F2355 14Standard 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:2F2354 Specification for ContinuedAirworthiness System forLighter-Than-Air Light Sport AircraftF2356 Specification for Production Acceptance Testing Sys-tem for Lighter-Than-Air Light Sport AircraftF2427 Specification for Required Product Infor
5、mation to beProvided with Lighter-Than-Air Light Sport AircraftF2483 Practice for Maintenance and the Development ofMaintenance Manuals for Light Sport AircraftF2563 Practice for Kit Assembly Instructions of AircraftIntended Primarily for RecreationF2972 Specification for Light Sport Aircraft Manufa
6、cturersQuality Assurance System3. Terminology3.1 Definitions:3.1.1 airshipengine-driven lighter-than-air aircraft thatcan be steered.3.1.1.1 DiscussionThis definition can include “and thatsustains flight through the use of either gas buoyancy or anairborne heater, or both.”3.1.2 balloonlighter-than-
7、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 (other than structure, engine,enclosure, and systems) that a lighter-than-air aircraft can carrywhile achieving the design defining perfo
8、rmance requirements.3.1.4 gross weighttotal aircraft system weight(s) at take-off.3.1.5 lighter-than-air aircraftaircraft that can rise andremain suspended by using contained gas weighing less thanthe air that is displaced by the gas.3.1.5.1 DiscussionAirships may include dynamic lift thatderive as
9、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 aircraft as the not-to-exceed gross weight.3.1.7 thermal airshipairship using heated air for a portionof it
10、s lift, incorporating design features to prevent nosecollapse due to dynamic pressure and exempt from specificpressurized envelope requirements.3.1.8 vectored thrust balloonthermal balloon with thrustcapability that does not have design features to prevent forwardenvelope collapse due to dynamic pre
11、ssure and is thereforelimited in its lateral speed capability.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 Requirements4.1 Performance Requirement
12、s 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 flight, these compo-nents will be
13、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 Aviation1This specification is under the jurisdiction of ASTM Committee F37 on Ligh
14、tSport Aircraft and is the direct responsibility of Subcommittee F37.60 on Lighterthan Air.Current edition approved Nov. 1, 2014. Published November 2014. Originallyapproved in 2005. Last previous edition approved in 2013 as F2355 13. DOI:10.1520/F2355-14.2For referenced ASTM standards, visit the AS
15、TM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unite
16、d States1Organization (ICAO) defined standard atmosphere in still airconditions at sea level. Speeds shall be given in indicated (IAS)and calibrated (CAS) airspeeds in knots.4.1.3 Flight PerformanceFor all flight operations it shallbe shown that control sufficient to safely maneuver or land theairsh
17、ip, 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 altitude and ambient temperature for which a
18、pproval 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, level flight (cruise), approach, and lan
19、ding.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 controls, 4.5 kg (10 lb) prolonged opera
20、tion.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 captive gas airship, or (4) themaximum per
21、mitted 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 LandingIt must be shown that a pilot of n
22、ormal 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 for:(1) Maximum duration of envelope va
23、lve 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 StabilityLongitudinal stability of theair
24、craft 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 turbulence. The three conditions areascent, de
25、scent, 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-down deck angle, and(3) Longitudinal up
26、set 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 will initially givean unaccelerated leve
27、l 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 demonstrated by a separateand full deflection
28、 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 shall not be less than6/s (60 s for a
29、 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 International Civil AviationAssociatio
30、n Organization (ICAO) defined standard atmospherein still air conditions at sea level.4.2.3 Flight PerformanceFor level flight, climbs,descents, and landing, it shall be shown that control sufficientto safely land the balloon can be maintained.4.2.3.1 ClimbEach balloon must be capable of climbing at
31、least 300 ft in the first minute after takeoff with a steady rate ofclimb. Compliance with the requirements of this section mustbe shown at each altitude and ambient temperature for whichapproval is sought.4.2.3.2 ControllabilityThe balloon shall be controllableduring takeoff, climb, level flight, a
32、pproach, 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) themaximum permitted envelope failure as speci
33、fied 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 pilot canachieve a landing sink rate of not
34、 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 into a dangerousdescent.4.2.4.2 Minimum
35、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.F2355 1425. Structure Requirements5.1 Structure for Airships and Thermal Airships (except asnoted):5.1.1 LoadsUnless otherwise specified, all requirementsare specified in
36、 terms of limit load.5.1.1.1 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 following:5.1.2.1 3.0 on castings,5.1.2.2 1
37、.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 effect of tempera-ture and other operating
38、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 loadswithout permanent deformation of the struct
39、ure.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. Whendynamic tests are used to demonstrate
40、 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 requirementshall be investigated either by conservat
41、ive 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 tear resistance testing for theenvelope.5.
42、1.6 Load Factor:5.1.6.1 Positive n = 1.5 (comprised of a maneuvering loadmultiplied by a gust load factor).5.1.6.2 Negative n =0.5.1.6.3 Additional load considerations shall be evaluated forselected design airspeeds and resultant dynamic pressures.5.1.7 Design AirspeedsThe selected design airspeeds
43、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 maximum speed obtainable in level flight w
44、ith 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 maximum forcesthat can be generated by
45、 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 surface loads on theairship shall be evalu
46、ated 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 allow the airship to swing around the
47、 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 damage.5.1.10 Control System and Supportin
48、g 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 ConditionsDesign features shall limitthe l
49、anding sink rate to less than or equal to 1 m/s (3.3 ft/s).Testing by drop test will use a drop height to achievea1m/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 s are considered to have passed.5.1.13
