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1 N l USAAVSCOM TR 89-o-11 FILE COPYNVUS ARMYI AVIATIONSYSTEMS COMMANDADVANCED TECHNOLOGY landing GEARV olume I SenMcDonnell Douglas Helicopter Company DTIC5000 East McDowell RoadMesa, AZ 85205 ELECTEA ugust 1990 Report for Period September 1985 -December 1989 Approved for public release; distribution Is forAVIATION APPLIED TECHNOLOGY DIRECTORATEUS ARMY AVIATION SYSTEMS COMMANDFORT EUSTIS, VA 23604-5577 AVIATION APPLIED TECHNOLOGY DIRECTORATE POSITION STATEMENTThe objective of the Advanced Technology landing gear (ATLG) Programwas to design, fabricate, and test a crashworthy retractable main landinggear system suitable for an 8500-pound utility helicopter.

2 Among thetechnical issues addressed and resolved as a result of the ATLG develop-ment effort were landing gear system integration and structural compati-bility in a limited space airframe, MIL-STD-1290 crashworthiness fora compact landing gear configuration, hydraulic/electrical supportsystems redundancy, and extention/retraction reliability and gear testing was accomplished using conventional platform droptests, as well as "iron bird" drop tests. Test results were comparedwith KRASH analytical predictions to evaluate landing gear performanceand characterize system dynamic behavior. The results of the ATLG demonstration effort will be used to guide the development of futureArmy helicopter landing gear Ned Chase of the Aeronautical Technology Division served as ProjectEngineer for this names cited in this report do not constitute an official endorsement or approval ofthe use of such commercial hardware or INSTRUCTIONSD estroy this report by any method which precludes reconstruction of the document.

3 Do not return it to DOCUMENTATION PAGE Form Approvedf 0MB No. 0704-0188 Publc reprtingll burden for this comlaiti'lOof nforiaiion S e rtiiated to average hour oaf resoonse, including the time for reviewing instructions, searching existing data maitainin the data needed, and ; om;4 eting nd reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of thiscollection of information, including suggistions for reducing this burden to Washington -iHeadcquarters Serviceis, Directorate for information Operations and Reports. 1215 jefferscnOavis Highway. Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget.

4 Paperwork Reduction Prolect (0704-0 188). Washington. DC 205031. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND OATES COVEREDIA ugust 1990 Final Seotembe- 1985 -flA;ember 19894. TITLE AND SUBTITLE S. FUNDING NUMBERSA dvanced Technology landing gear (C) DAAJ02-85-C-0049 Volume I -Design6. AUTHOR(S) Sen7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) S. PERFORMING ORGANIZATIONREPORT NUMBERMcDonnell Douglas Helicopter Company5000 East McDowell Road MDHC 89-17 Mesa, AZ 852059. SPONSORING/ MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/ MONITORINGAGENCY REPORT NUMBERA viation Applied Technology Army Aviation Systems Command USAAVSCOM TR 89-D-13 AFort Eustis, VA 23604-557711.

5 SUPPLEMENTARY NOTESV olume I of a two-volume report12a. DISTRIBUTION/ AVAILABILITY STATEMENT 12b. DISTRIBUTION CODEA pproved for public release; distribution is ABSTRACT (Maximum 200 words)This report describes the development of a retractable, crashworthy, main landing gear system for anLHX-size utility helicopter. The landing gear is of a tricycle configuration and is designed to absorb60 percent of the energy from a 42 fps level impact condition. The landing gear extends automaticallyin less than two seconds in an emergency. In the event that the hydraulic and electrical systems fail,the gear is extended with the hydraulic accumulator that primarily supports the helicopter APU.

6 Fivesets of landing gears were fabricated in the program. The tests included single- gear platform droptests with level and simulated roll and pitch conditions, and combined pitch (+15*) and roll (100)conditions with an iron-bird fixture simulating a helicopter. The tests were conducted for five impactvelocities from 10 to 42 fps. The crashworthiness analyses were conducted using program KRASH. Thecorrelation between test and crashworthiness analysis results was very good and demonstrated howanalyes can be used to predict the response of landing gears without utilizing expensive tests. Thecost of 5000 shipsets over a 13-year production cycle has been projected from the cost of landing gearsfabricated in this program.

7 /14. SUBJECT TERMS 15. NUMBER OF PAGESL anding gear , Helicopter, Crashworthiness, Drop tests, Energy absorption. 17116. PRICE CODE17. SECURITY CLASSIFICATION 1. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACTOF REPORT OF THIS PAGE OF ABSTRACTUNCLASSI FIED UNCLASSI FIED UNCLASSI FIEDNSN 7540-01-280-5500 Staidard Form 298 (Rev 2-89)0,'cr be by ANSI Sid .3i- '294-102 FOREWORDThis Design report is Volume I of the final report of the Advanced TechnologyLanding gear Program; the final report covers the work performed under ContractDAAJ02-85-C-0049 from 20 September 1985 to 31 May 1989.

8 This contract withMcDonnell Douglas Helicopter Company was conducted for the Aviation AppliedTechnology Directorate, Army Aviation Research and Technology Activity(AVSCOM), Fort Eustis, Virginia. The program was under the direction of Mr. volume describes the design and analysis in the development of the advancedtechnology landing gear . Volume II, "Test," includes the results of all thetests conducted in the program and the correlation with analytical predictionof crash-impact program was accomplished by the Structures Department of McDonnell DouglasHelicopter Company, Mesa, Arizona, with Dr.

9 Sen as Program Manager andProject Engineer. Subcontracting to McDonnell Douglas Helicopter Company wasMenasco California Division, Burbank, California. The Program Manager atMenasco was Mr. key personnel associated with the program and their areas of responsibilitywere:McDonnell Douglas Helicopter Sen Project EngineerL. Bohorquez DesignM. Jones StructuresA. Bolukbasi CrashworthinessR. March WeightsL. Richmond Requirements & Systems AnalysisE. Murgia MaintainabilityJ. Williams ReliabilityMenasco California DivisionD. Martin Project Engineer and DesignH. Kawada Stress AnalysisC. Wilson TestThe contract was performed under the general direction of Mr.

10 Widmann,Manager, Research NTIS GRA&I( ~DTIC TAB 0<2w!Unannounced or JustiflcationBy -- .Distribution/Avallability CodesAvail md/orDit Specialiii:This program was undertaken to develop a retractable, crashworthy landing gearsystem for an LHX-size utility helicopter with extensive energy absorptiontrade-off study and crashworthiness analysis to verify the design concepts. Thedesign and crashworthiness analysis have been verified by single- gear platformdrop tests, and by tests for combined roll and pitch impact attitude with aniron-bird test fixture simulating a helicopter. This program has demonstratedthe differences in the behavior of landing gears in platform and iron-bird droptests, and the close correlation that can be achieved between crashworthinessanalysis and impact tests for OF CONTENTSFOREWORD.)