instrument integration

8/14/2019 Instrument Integration

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NASA Student Airborne Research

Program (SARP)Instrument Integration Session

Adam Webster

July 20, 2009


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SARP Instrument Integration Session

ARCTAS Instrument Floorplan, 2008


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Instrument Installation Detail DesignOnce a basic instrument floorplan is finalized, detailed design of newinstrument installations beginsMost instruments consist of standard (19 rackmount equipment) andone or more non-standard installationsDocumentation is an integral part of all facets of aircraft operations andthe experimental installation design is no exception

Typical instrument installation documentation requirementsInstallation drawings of non-standard installations (i.e., anything besidesrackmount equipment)Structural analysis of non-standard installationsModal (vibration) analysis for installations external to the aircraft cabinEquipment rack loading calculation sheetsElectrical schematics for heater circuitsFlow diagrams for pressurized systems

Batteries/UPS datasheetsMSDSs for all chemicals, etc. in the instrument or used for maintenance

Provide input to the detailed hazard analysis performed by DFRC safetygroup

Types and controlsBasic hazards include lasers, radioactive materials, radio frequency emitters,pressure vessels, compressed gasses, chemicals, cryogens, motors/pumps,heaters, chillers, batteries/uninterruptible power supplies (UPS)


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General Integration ConsiderationsInstrument Integration Design

Requires intimate knowledge of aircraft grade fasteners, materials,processes, etc.

National Aerospace Standards Mil-Spec Standards Air Force-Navy Standards

Corrosion preventionmaterial selection and surface finishesWeld design and inspectionwhen necessaryNew electrical wiringnon-flammable (usually Teflon-based Mil-Specwire)Optical window selection based on instrument requirements: fusedsilica, BK7 (borosilicate crown glass), Pyrex, etc.

Optical window usage is tightly controlledwindows periodically undergoenvironmental (temperature and pressure) testing to verify structural

integrityPerform EMI test of aircraft and experimenter systems to seepotential interference issues

Known EMI issues are kept in mind in the floorplan developmentphase

Antenna locations (i.e., conflicts between GPS antennas andInmarsat/Iridium satellite communications systems)

General familiarity with aircraft systems and their potential useto experimenters


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3D Design ToolsExtensive 3D geometrymodeling is used in newinstallation design

Facilitates the ability toanticipate issues in the

componentmanufacture/fabrication/installation processes tostreamline the actualinstrument integrationprocessModels are directly linked to2D CAD installation

drawings which arerequired to documentinstallationsModels are directly linked tonumerical finite elementmodels used in structuraland dynamic analysesUsed to generate various

electronic files usedextensively in themanufacturin rocess


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Stress AnalysisStress analysis is performedutilizing the applicable loadscases for the installation

Aero loading (i.e., lift and drag)Inertial loading

Operational loads Emergency landing loads

Cabin pressure load

3D geometry models are directlylinked to numerical finiteelement models used in thestress analyses to verify

structural integrity of theinstallation underUtilize engineering calculationsoftware to tie analysisdocuments together withapplicable hand calculations,explanation, and discussion


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Modal AnalysisModal analysis is typicallyperformed on installationsexternal to the aircraft

Many of the externalinstallations on the DC-8

can be relatively blunt-shaped (non-aerodynamic)objects which, in general,create significant vortexshedding in their wakes

Performed in conjunctionwith a basic vortexshedding analysis to verify

that there will be nosignificant detrimentaldynamic loading due toairflow-induced vibrationSometimes also performedon internal installations ifvibration is a significant

concern to an instrumentsfunctionality, alignment,


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Legacy DocumentationDC-8 is a relatively oldaircraft platform andtherefore much of thedocumentation is legacy

hand drawingsDesigned in mid-late1950s

Built in 1969

Majority of permanentexperimental

modifications performed~1987

Literally thousands ofdrawings (tens ofthousands of pages) oflegacy hand drawings inarchive


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Instrument Integration ProcessIntegration process requires continual communicationand coordination with various groups

Instrument principle investigators, instrument engineers,technicians, etc.Aircraft operations engineer, ground/maintenance crew,program manager, flight crew

Scheduling instrument team arrivals, componentprocurement and manufacture, etc so that everything comestogether in a timely fashion during the actual upload

Various presentations to review boards to acquireapproval for flightEngineering Check Flightperformed with minimal

aircraft crew onboardAircraft is flown through its normal flight envelope limitsVerify structural integrity of installationsVerify there are no adverse dynamic effects on variousinstallations

Also work with potential experiment groups in the

development phase of instruments prior to flight selection


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ARCTAS Instrument Upload, Spring 2008


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instrument integration

Documents