Dynamometer Test Stand for Aircraft

Air Turbine Starter Testing

David Cardenas

Kevin Goldvarg

Carol Moreno

Department of Mechanical and Materials Engineering

Advisor:

Brian Reding, Ph.D.

Benjamin Boesl, Ph.D.

Introduction Air turbine starters (ATS) performance tested

after repair/overhaul Typical ATS test stand consists of flywheel to

simulate aircraft engines’ inertia

Turbine Controls, Inc. (TCI): Federal Aviation Administration (FAA) approved repair station, desiring to replace current ATS test stand Desired feature: match wide range of inertia to

simulate various engines Current test stand: limited by 2 flywheels Purpose: investigate use of dynamometer or

absorber that can simulate inertia range for ATS

Impact TCI’s testing capacity expansion by adapting to range of starters on the market

Problem StatementTest system equipped for variable inertia simulation

would allow continuous load adjustments

Repeatability plays an important role for dynamometers Results for torque and speed measurement expected to be

same within system tolerance level Establishing repeatability is a complex aspect that must be

considered in design

Data acquisition, system control, and performance diagnosis would allow data management, analyzing and graphing required parameters

[1] J. S. Killedar, Dynamometer, Theory and Application to Engine Testing, Xlibris Corporation, 2012. [2] National Instruments Corporation, "Achieve Flexibility in Your Automotive Dynamometer Applications," 07 August 2013. [Online]. Available: http://www.ni.com/white-paper/2974/en/.[3] DTec Devices, "Dynertia Users Manual: Inertia Dynamometer Control System," 2009. [Online]. Available: http://dtec.net.au/Downloads/DYNertia%20Manual.pdf.

[1] U.S. Department of Transportation - Federal Aviation Administration, "Aviation Maintenance Technician Handbook - General," 03 April 2013. [Online]. Available: https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_handbook/.[2] A. G. Ambekar, Mechanism and Machine Theory, New Delhi: Prentice-Hall of India Private Limited, 2007. [4] W. Tong, "Motor Testing," in Mechanical Design of Electric Motors, CRC Press, 2014. [3] National Instruments Corporation, "What is Data Acquisition," [Online]. Available: http://www.ni.com/data-acquisition/what-is/.

Main Design Components Air Turbine Starter

Turns engine’s main compressor to provide airflow

As engine accelerates it will reach self-sustaining speed and starter is disengaged

Dynamometer Key device measuring rotating speed, torque,

power output Absorption type: absorbs available

power doing work against frictional resistance

Data Acquisition (DAQ) Sampling signals measure real world physical

phenomenon and are converted into digital numeric values

Design Selection for Dynamometer Test Stand

[1] Dyne Systems, Inc., "Dynamometer Comparison," [Online]. Available: http://www.dynesystems.com/what-is-a-dynamometer.htm

Dynamometer Type Inertia Cost MaintenanceHydraulic Low High High

Eddy current High Very High LowInertia Variable (adjustable) Low Low

Hydraulic

Eddy Current

Inertia

Design Parameters Testing Procedure

Starter coupled to known polar moment of inertia [slug-ft2] Air supplied to starter inlet at specified pressure and temperature

Conditions maintained constant throughout operating cycles Brake held until inlet conditions stabilized Brake released

Acceleration time measured 0 - cutoff RPM Passing criterion

Acceleration time to cutoff speed must be within OEM-defined values

Hamilton Sundstrand, "Component Maintenance Manual: ATA 80-11-01," in Pneumatic Starter: PN 811050, 2010.

Preliminary Design Analysis The following parameters must be identified for ATS to be tested

Maximum power and corresponding speed Minimum power and corresponding speed Maximum torque and corresponding speed Minimum torque and corresponding speed

ATS manuals provide certain parameter specifications, including speed, however power and torque are not know at corresponding speed

Using torque relationships, average torque can be found; not MAX or MIN

[1] J. S. Killedar, Dynamometer, Theory and Application to Engine Testing, Xlibris Corporation, 2012. [2] W. Tong, "Motor Testing," in Mechanical Design of Electric Motors, CRC Press, 2014.

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Preliminary Design Analysis

TCI technicians have experience with main plot characteristics of an ATS test curve Common characteristics shared by ATS

To 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

Design Selection 15 different manuals corresponding to sample ATS population used to

extract parameters cutoff speed range: 3300 - 8750 RPM

Since eddy current dynamometer provides wider inertia range, it would be most desirable design for TCI Budget is additional restraint in design

As the most immediate solution, proposed design is: a flywheel dynamometer that provides wide speed range through a variable flywheel mechanism

Sample no. Flywheel intertia = I (slug-ft2) Cutoff speed RPM t (s) ω (rad/s) Max const α

(rad/s2)Min stall torque

T = Iα (lbf-ft) T inlet (F) P inlet (psig)

Smallest I

3.326 FROM 0 0.0 0.0 44.5 148.0 82.5 54

… 3500 8.2 366.5 95.0 (+/- 22.5 F) (+/- 1psia)

TO 7000 16.5 733.0 50.0 Largest I /

Largest Cutoff RPM

69.04 FROM 0 0.0 0.0 2.4 168.0 75 54

TO 8750 23.3 916.3 (+/- 15 F) (+/- 2.7 psia)

Smallest Cutoff RPM

21.4 FROM 0 0.0 0.0 10.5 225.5 60 33.6

TO 3300 32.8 345.6 (+/- 10F) (+/- 1 psi)

Design Inspiration Idea derived from system used in

variable weight dumbbells One-piece dumbbell: handle bar

fixedly attached to a pair of end-weights at opposing

Each end-weight may have 1 to 3 axially-aligned, inwardly-opening, threaded sockets

Each insert weight has a protruding, threaded member Insert weights are capable of

attaching to the socketed end-weights

A lock-socketed structure may provide locking mechanism

V. K. Zarecky, "Variable Weight Dumbbell". United States Patent US5464379 A, 7 November 1995.

Scaled Prototype

Design Aspects

Project Timeline

Tasks & Responsibilities

TASK DESCRIPTION TASK LEADER DURATION1 Preliminary meetings All 8 weeks2 Literature survey Carol Moreno 8 weeks3 Determine parameters Kevin Goldvarg 4 weeks4 Analysis of parameters All 2 weeks5 Test current test stand Kevin Goldvarg 8 week 6 Consolidate design Carol Moreno 2 weeks7 Mechanical element selection David Cardenas 8 week 8 Model & prototype testing All 8 weeks9 Data acquisition David Cardenas 4 weeks

10 User manual & training All 12 weeks11 Engineering analysis All 3 weeks12 Report completion All 32 weeks

Elements of Global Design Aviation regulations

Complies with FAA and EASA regulations

Transportation regulations Must comply with international authorities Oil-draining system

Environmental regulations The device does not cause environmental damage Plumbing system sealed

Units & parameters Test stand provides outputs according to country’s unit system Usable with different countries’ input voltages

User manual Instructions to setup tests

https://goglobal.fiu.edu/

Engineering Standards

Electric motor testing standards IEEE, IEC, ANSI/NEMA and EASA

Insulation resistance of rotating machine Insulation testing Methods that enable the user to determine efficiency

and energy losses Methods that help to determine causes of temperature

rise

Machine guarding standards OSHA Assure safe and healthful working conditions

Conclusion Eddy current would be best solution

Complex Expensive Considerations

Cooling Programming

Proposed solution: Variable flywheel dynamometer Simpler Inexpensive Solve real problem Engineering analysis focusing on vibrations Multidisciplinary concepts Teamwork

http://www.airliners.nethttp://corporate.airfrance.com/

Questions