Presentation on theme: "Dynamometer Test Stand for Aircraft Air Turbine Starter Testing"— Presentation transcript:
1 Dynamometer Test Stand for Aircraft Air Turbine Starter Testing David Cardenas Kevin Goldvarg Carol MorenoDepartment of Mechanical and Materials EngineeringAdvisor:Brian Reding, Ph.D.Benjamin Boesl, Ph.D.
2 IntroductionAir turbine starters (ATS) performance tested after repair/overhaulTypical ATS test stand consists of flywheel to simulate aircraft engines’ inertiaTurbine Controls, Inc. (TCI): Federal Aviation Administration (FAA) approved repair station, desiring to replace current ATS test standDesired feature: match wide range of inertia to simulate various enginesCurrent test stand: limited by 2 flywheelsPurpose: investigate use of dynamometer or absorber that can simulate inertia range for ATSImpact TCI’s testing capacity expansion by adapting to range of starters on the market
3 Problem StatementTest system equipped for variable inertia simulation would allow continuous load adjustmentsRepeatability plays an important role for dynamometersResults for torque and speed measurement expected to be same within system tolerance levelEstablishing repeatability is a complex aspect that must be considered in designData acquisition, system control, and performance diagnosis would allow data management, analyzing and graphing required parameters J. S. Killedar, Dynamometer, Theory and Application to Engine Testing, Xlibris Corporation, 2012. National Instruments Corporation, "Achieve Flexibility in Your Automotive Dynamometer Applications," 07 August [Online]. Available: DTec Devices, "Dynertia Users Manual: Inertia Dynamometer Control System," [Online]. Available:
4 Main Design Components Air Turbine StarterTurns engine’s main compressor to provide airflowAs engine accelerates it will reach self-sustaining speed and starter is disengagedDynamometerKey device measuring rotating speed, torque, power outputAbsorption type: absorbs available power doing work against frictional resistanceData Acquisition (DAQ)Sampling signals measure real world physical phenomenon and are converted into digital numeric values U.S. Department of Transportation - Federal Aviation Administration, "Aviation Maintenance Technician Handbook - General," 03 April [Online]. Available: https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_handbook/. A. G. Ambekar, Mechanism and Machine Theory, New Delhi: Prentice-Hall of India Private Limited, 2007. W. Tong, "Motor Testing," in Mechanical Design of Electric Motors, CRC Press, 2014. National Instruments Corporation, "What is Data Acquisition," [Online]. Available:
5 Design Selection for Dynamometer Test Stand HydraulicEddy CurrentInertia Dyne Systems, Inc., "Dynamometer Comparison," [Online]. Available:
6 Design Parameters Testing Procedure Starter coupled to known polar moment of inertia [slug-ft2]Air supplied to starter inlet at specified pressure and temperatureConditions maintained constant throughout operating cyclesBrake held until inlet conditions stabilizedBrake releasedAcceleration time measured 0 - cutoff RPMPassing criterionAcceleration time to cutoff speed must be within OEM-defined valuesHamilton Sundstrand, "Component Maintenance Manual: ATA ," in Pneumatic Starter: PN , 2010.
7 Preliminary Design Analysis The following parameters must be identified for ATS to be testedMaximum power and corresponding speedMinimum power and corresponding speedMaximum torque and corresponding speedMinimum torque and corresponding speedATS manuals provide certain parameter specifications, including speed, however power and torque are not know at corresponding speedUsing torque relationships, average torque can be found; not MAX or MIN𝑃𝑜𝑤𝑒𝑟 ℎ𝑝 = 𝑇)(2𝜋)(𝑁𝑃𝑜𝑤𝑒𝑟 𝑘𝑊 = 𝑇)(2𝜋)(𝑁𝑇= 𝐹 𝑡 𝑙= (𝐹𝑐𝑜𝑠𝛽)𝑙𝑇 =𝐼𝛼 J. S. Killedar, Dynamometer, Theory and Application to Engine Testing, Xlibris Corporation, 2012. W. Tong, "Motor Testing," in Mechanical Design of Electric Motors, CRC Press, 2014.
8 Preliminary Design Analysis TCI technicians have experience with main plot characteristics of an ATS test curveCommon characteristics shared by ATSTo find out ATS peak torque and corresponding speed, ATS test will be conducting using TCI’s current system to use as baseline for new design
9 Flywheel intertia = I (slug-ft2) Min stall torque T = Iα (lbf-ft) Design Selection15 different manuals corresponding to sample ATS population used to extract parameterscutoff speed range: RPMSince eddy current dynamometer provides wider inertia range, it would be most desirable design for TCIBudget is additional restraint in designAs the most immediate solution, proposed design is: a flywheel dynamometer that provides wide speed range through a variable flywheel mechanismSample no.Flywheel intertia = I (slug-ft2)Cutoff speed RPMt (s)ω (rad/s)Max const α (rad/s2)Min stall torque T = Iα (lbf-ft)T inlet (F)P inlet (psig)Smallest I3.326FROM0.044.5148.082.554…35008.2366.595.0(+/ F)(+/- 1psia)TO700016.5733.050.0Largest I / Largest Cutoff RPM69.042.4168.075875023.3916.3(+/- 15 F)(+/- 2.7 psia)Smallest Cutoff RPM21.410.5225.56033.6330032.8345.6(+/- 10F)(+/- 1 psi)
10 Design InspirationIdea derived from system used in variable weight dumbbellsOne-piece dumbbell: handle bar fixedly attached to a pair of end-weights at opposingEach end-weight may have 1 to 3 axially- aligned, inwardly-opening, threaded socketsEach insert weight has a protruding, threaded memberInsert weights are capable of attaching to the socketed end-weightsA lock-socketed structure may provide locking mechanismV. K. Zarecky, "Variable Weight Dumbbell". United States Patent US A, 7 November 1995.
15 Elements of Global Design Aviation regulationsComplies with FAA and EASA regulationsTransportation regulationsMust comply with international authoritiesOil-draining systemEnvironmental regulationsThe device does not cause environmental damagePlumbing system sealedUnits & parametersTest stand provides outputs according to country’s unit systemUsable with different countries’ input voltagesUser manualInstructions to setup testshttps://goglobal.fiu.edu/
16 Engineering Standards Electric motor testing standardsIEEE, IEC, ANSI/NEMA and EASAInsulation resistance of rotating machineInsulation testingMethods that enable the user to determine efficiency and energy lossesMethods that help to determine causes of temperature riseMachine guarding standardsOSHAAssure safe and healthful working conditions
17 Conclusion Eddy current would be best solution Complex Expensive ConsiderationsCoolingProgrammingProposed solution: Variable flywheel dynamometerSimplerInexpensiveSolve real problemEngineering analysis focusing on vibrationsMultidisciplinary conceptsTeamwork