Browse Topic: Turboprop engines

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The Impact of Powerplant on Stall Characteristics of Propeller Aircraft2026-99-18377/17/2026
This study focuses on a compact-layout propeller aircraft, investigating how its powerplant influences stall characteristics via combined theoretical analysis of aerodynamic principles and validation with flight test data. Special attention is paid to the effects of propeller slipstream, appropriate evaluation criteria are selected to assess the aircraft’s high-angle-of-attack performance and stall behavior, and the Weissman chart criteria are further adopted to analyze its lateral-directional departure tendencies. A theoretical analysis of the stall characteristics of compact-layout propeller aircraft is conducted. Through flight test data analysis, the stall characteristics of compact-layout propeller aircraft are studied, with an emphasis on understanding how slipstream effects influence their longitudinal and lateral-directional stall characteristics.
Fang, Shengyou, Yang, Xiaoli, Jiang, Tianjun, Fu, Yi
Design Considerations for Enclosed Turboprop Engine Test CellsAIR5295B (Current)11/19/2025
This document is offered to provide state-of-the-art information about design factors that must be considered in the design of new or significantly modified engine test cells used to test propeller equipped turboprop engines in either QEC or bare engine configurations. The report does not address design considerations for test cells designed to test turboprop engines with dynamometer type load absorption devices because they are essentially tested as turboshaft engines. Design considerations for those test cells are presented in AIR4989, Reference 2.1.
EG-1E Gas Turbine Test Facilities and Equipment
Prediction and Estimation of Propeller Drag01-16-02-000911/30/2022
Turboprop aircraft have the capability of reversing thrust to provide extra stopping power during landing. Reverse thrust helps save the wear and tear on the brakes and reduces the landing distance under various conditions. The article explains a methodology to predict the disking drag (reverse thrust) from the Computational Fluid Dynamics (CFD) technique using Blade Element Momentum (BEM) theory and estimation of the same from high-speed taxiing trial (HSTT) and ground roll data for a turboprop aircraft using system identification techniques. One-dimensional kinematic equation was used for modeling the aircraft dynamics, and the error between measured and estimated responses was optimized using the Output Error Optimization Method (OEOM). The estimated propeller drag was matched with CFD predictions to arrive at a relation between the propeller blade pitch angle and throttle position. The present study also investigates the estimation of the braking friction coefficient from the taxiing data and the change in braking distance using different runway conditions and reverse thrust. The exact prediction and usage of the reverse thrust can mitigate the possibility of using extra landing aids like spoilers for a similar prototype under design and development.
Nusrath T. K., Khadeeja, Kaliyari, Dushyant, Puttam, Jyothi Kumar, Madhu Babu, K., Arshad Shameem, C., Jaiswal A, Shikhar, Sajjan, Sharanappa V., Venkatesh, T. N., Pashilkar, Abhay A.
Exergetic Investigation of a Turboshaft Helicopter Engine Related to Engine Power01-13-02-001910/19/2020
Turboshaft engines, one of the classifications of the helicopters, combine the core engine and fan and consume fossil fuels. Emissions, produced by the fossil fuels, cause global warming and environmental pollution, such as ecological, human health. To improve helicopter capability, energy is the first point of improvement. High-energy efficient helicopter engines help decrease the environmental damage. Exergy should be applied to the system to determine the maximum available energy. In this study, energy analysis and exergy analysis have been applied to a turboshaft helicopter engine. According to the result of this study, the maximum energy and exergy efficiencies are found to be 21.99% and 15.87%, respectively, at 1500 Shaft Horsepower (SHP). It is seen that the efficiencies increase with the increase of the engine power. Besides, exergy destructions and exergy loss values are presented by calculating different powers.
Koruyucu, Elif, Altuntas, Onder, Karakoc, T. Hikmet
Advanced Exergy Analysis of an Air Craft Gas Turbine Engine at Different Power Loading Operations2019-01-18639/16/2019
The innovations in aircraft propulsion have been identified as the key parameter towards the progress in transportation. Continuous advancement in the performance and efficiency of propulsion has enabled aircraft to travel over larger distances with higher speed. Aviation is also responsible for approximately 2% of total greenhouse gas emission and is expected to grow around 3% by 2050. The present article aims to use the exergetic analysis of a turboprop engine which should be helpful in designing of such engines and also helps these engine users to regulate and select the operation modes. A gas turbine with film air cooling of turbine blades has been proposed to be the turboprop engine. The engine is analyzed on exergy point of view at different power loading operation modes and the performance is studied. Selected exergetic measures under consideration are Exergy Efficiency, Fuel Exergy Depletion Ratio, Relative Exergy Consumption Ratio, Exergetic Improvement potential and Productivity Lack ratio. The total fuel exergy depletion ratio of the turboprop engine is estimated to be around 64.7 % at 100% loading. Also, among the identified cycle components, combustion chamber is identified as the main source (~ 35%) of the exergy destruction and, thus is the biggest contributor to the overall irreversibility of the system. The exergy efficiency is observed to be minimum at 75 % mode and maximum for Take-off. The exergetic improvement potential of the thermodynamic inefficiencies increases with increase in fuel-air ratio from 75%-mode to Take-off mode. The combustor section of the engine has been identified as the greatest source of relative exergy consumption ratio (63 %) and productivity lack ratio (51 %) followed by the turbine and compressor sections (at take off mode).
Mohapatra, Alok Kumar, Hotta, Tapano, Choudhary, Tushar
Design Considerations for Enclosed Turboprop Engine Test CellsAIR5295A (Historical)11/21/2018
This document is offered to provide state-of-the-art information about design factors that must be considered in the design of new or significantly modified engine test cells used to test propeller equipped turboprop engines in either QEC or bare engine configurations. The report does not address design considerations for test cells designed to test turboprop engines with dynamometer type load absorption devices because they are essentially tested as turboshaft engines. Design considerations for those test cells are presented in AIR4989, Reference 2.1.
EG-1E Gas Turbine Test Facilities and Equipment
Aviation Oxygen Safety Management System Analysis2018-01-60014/15/2018
Oxygen has been a significant variable in flight operations for nearly 60 years. Today, the use of oxygen is almost synonymous with rocket, jet and turbo-prop operations affecting more than 45,000 aircraft worldwide. Today’s pilot flies farther, higher and longer than ever before, and does so at an ever increasing frequency. While the past 60 years have yielded tremendous advances in propulsion, avionics, materials and many other areas, oxygen and its role in aviation has remained largely stagnant. Although considered a major aircraft system and an essential component in high altitude operations, the orthodox mantra of ‘engineering it better’ has produced only limited results, most of them in the area of dispensation equipment (masks). In recent years Aeronautical Data Systems and collaborative entities have begun working to create a standardized and comprehensive aviation oxygen safety management system. This paper includes a general examination of what a new aviation oxygen doctrine would entail, how it would diverge from existing industry policies, and how it would improve industry safety. This analysis is derived from work produced in an earlier collaboration with the University of North Dakota Aerospace Foundation. This study was initially created in an attempt to improve the oxygen safety training offered to its aeronautics/human factors students. This document is an evolution of the initial study intended to create discussion among industry leaders and specialists in order to generate broader feedback and consensus regarding aviation oxygen safety. The ultimate objective of this paper is to lead into a final and standardized method of implementing an Oxygen SMS Module. This paper diverges from traditional thinking in that it applies an information and skill based solution to a system that has otherwise been viewed as a hardware problem. To put it simply: Aircraft oxygen systems have possessed the capacity for substantial operational flexibility for a very long time. What has been absent is the ability to synthesize oxygen data into a legible format and the education to utilize this information to its greatest effect. Over the past decade advances in software, electronics, telecommunications and physiological research have provided the components necessary for a true modernization of aviation oxygen. We assert that these advances can collectively yield a new system of oxygen safety that delivers to aviators an unprecedented level of capability in planning for, reacting to, and surviving an oxygen contingency.
Stabile, Jim
Thermoeconomic, Sustainability and Environmental Damage Cost Analysis of Air Cooled CT7-7A Turboprop Engine2018-01-07744/3/2018
The aim of this study is to investigate the overall performance (exergetic, exergoeconomic and exergoenvironmental) of CT7-7A turboprop engine manufactured by General Electric Aviation (GE Aviation) and currently used to power CN-235, a medium range transport aircraft. The investigation has been carried out using the thermoeconomic, sustainability and environmental damage cost analysis methods. The adopted turboprop engine has been investigated to observe the behaviour of various performance parameters, sustainability, emission parameters as well as cost parameters of engine. Due to ever increasing demand in air transport systems, focus has been on developing efficient and sustainable systems with lowest possible cost. In order to reduce cost & environmental effects of engine and at same time to acquire higher performance, it is necessary to understand the mechanism that can offer improvements in the engine operating and design parameters so that higher performance can be obtained. Exergetic sustainability parameters such as exergetic efficiency, exergy loss and destruction ratio, environmental damage cost, sustainability index and sustainability cost index play an important role on choice of suitable aircraft engine for operation. The methodology includes working with energy, exergy and cost balance equations and sustainability index for component-wise modelling of the whole system. The presented work analyses CT7-7A engine from all three (thermoeconomic, sustainability and environmental analysis) perspectives.
Sahu, Mithilesh Kumar, Choudhary, Tushar, Kumari, Anupam, R, Sanjay
Thermodynamic Modeling of Blade Cooled Turboprop Engine Integrated to Solid Oxide Fuel Cell: A Concept2018-01-13084/3/2018
In modern turboprop engines, reduction in emission and fuel consumption is the primary goals during the development of gas turbine aero engines. In this paper, a concept has been proposed for hybridizing the air blade cooled turboprop engines by integrating it with a fuel cell. The proposed study focuses on thermodynamic analysis of a turboprop engine integrated to a solid oxide fuel cell (SOFC) system. A solid oxide fuel cell is the perfect candidate for utilizing waste heat available at turboprop engine exhaust, through recuperation process. Integration of SOFC is ultimately leads to enhancement the overall performance of the turboprop-SOFC hybrid system. Power generated by the SOFC system can be utilized by the aircraft and in can complement the auxillary-power-unit (APU) and may even supplement it. On the basis of 1st and 2nd law of thermodynamic modeling analysis of a turboprop-SOFC system has been presented in this article. The adopted turboprop engine has operated under a wide range of operating conditions. Parametric analysis has been performed, to investigate the influence of various parameters such as compressor pressure ratio, turbine inlet temperature, air flow rate on the turboprop-SOFC hybrid system. The thermodynamic losses within each component of the hybrid system have been evaluated by the energy and exergy analysis. From the parametric analysis, it has been observed that the performance of a hybrid turboprop-SOFC system can be increased significantly by about 12-13%, when TIT increases. Moreover, the exergy destruction within the fuel cell eventually decreases as air flow rate increases, whereas in combustor the exergy destruction linearly increases with increase in air flow rate. The integration of SOFC with turboprop engine has immense potential in advancing turboprop technology, which results in developing efficient and sustainable hybrid systems for long-range transport aircraft.
Choudhary, Tushar, Sahu, Mithilesh Kumar, R, Sanjay, Kumari, Anupam, Mohapatra, Alok
Test Facility Shakedown and CommissioningAIR6364 (Current)11/29/2017
The paper discusses in general terms the activities required to be undertaken or demonstrated during the establishment of the facility such as: the assessment checks prior to forwarding to the end users site for embodiment into the facility system the establishment of the facility such as trial installations of hardware, functionality checking of lifting transportation and access systems, centerline pull checks, pressure testing of fuel and air start systems, flushing of wet systems and electrical continuity checking. the commissioning of the facility such as instrumentation calibrations, engine starts, engine running, assessment of command and control system, assessment of DAS system, aerodynamic and acoustic surveys. The paper will concentrate on the main engineering engine related aspects of the facility and will not necessarily contain information on the construction validation activities such as HVAC, electrical, facility fire system, waste water etc. Risk analysis may be performed during the design phase whose results could lead to pay particular attention to some specific equipment / functionalities during the commissioning phase. If identified, these risks should be translated to specific tests and integrated into the validation plan, either at the factory or on site or both. If the test cell is designed to test several engine types, the acceptance process should validate upon which engine the test cell will be commissioned ➔ these discussions should take place at the early stage of the design process if not during the bidding phase. Moreover, an agreement between the Contractor and the Customer may have to be reached in order to clearly define how the scaling will be demonstrated in the case of the available engine types for commissioning are not representative of the full capacity upon which the facility is designed (e.g. the requirements are assessed based on future engine types). It is particularly relevant to air flow and acoustic levels and tones where effects aren’t only linear. Correlation activities are outside the scope of this document. Document is primary intended for typical overhaul (MRO) test cells. Development/Production facilities may include additional and specific equipment that requires dedicated shakedown and commissioning processes and procedures issued directly from the OEMs. Outdoor test cell specifics are not covered by this document.
EG-1E Gas Turbine Test Facilities and Equipment
Installed Outdoor Engine TestingAIR5301A (Historical)11/29/2017
This SAE Aerospace Information Report (AIR) was written because of the growing interest in aircraft installed outdoor engine testing by the Federal Aviation Administration, airlines, charter/commercial operators, cargo carriers, engine manufacturers and overhaul and repair stations. This document was developed by a broad cross section of personnel from the aviation industry and government agencies and includes information obtained from a survey of a variety of operators of fixed and rotary wing aircraft and research of aircraft and engine maintenance manuals.
EG-1E Gas Turbine Test Facilities and Equipment
Exergoeconomic Analysis of Air Cooled Turboprop Engine: Air Craft Application2017-01-20449/19/2017
Aircraft engines powering propulsion of the aircraft is the key component of the system. In aircraft industry it is desirable that an aircraft engines should supply high speeds (for military fighters) with low maintenance (for civil airplanes). In this regard an integration of gas turbine engines with traditional propeller has been introduced and termed as turboprop engine. In present work, a gas turbine with cooled blading has been proposed to be the turboprop engine which has been exergoeconomically analyzed to assess the performance and economics related to the proposed turboprop engine. Exergo-economic analysis is a tool which combines thermodynamic analysis and economic principles to provide information that is helpful to predict thermodynamic performance and total cost of the engine (thermal system). The methodology includes energy, exergy and cost balance equations for component-wise modelling of whole system. “Average Cost Theory” (Levelized cost) approach has been adopted to analyze the entire system exergoeconomically. The work represents the characteristics curves for exergoeconomic parameters that show graphical relationship between the engine operating parameters and exergoeconomic parameters. Present study also compares the proposed turboprop engine with the well-known T56 turboprop engine and CT7-9C turboprop engine on exergoeconomic basis.
Sahu, Mithilesh Kumar, Choudhary, Tushar, Y, Sanjay
GE's clean-sheet turboprop engine to launch with Textron Aviation16MEIP03_083/1/2016
Textron Aviation has opted for GE Aviation's all-new turboprop engine to power its single engine turboprop (SETP). The 1300 shaft horsepower (SHP)-rated turboprop engine will be the first entry in GE's new family of turboprop engines designed specifically for business and general aviation aircraft in the 850- to 1600-SHP range. Brad Mottier, Vice President and General Manager of GE Aviation's Business & General Aviation and Integrated Systems division, said during the recent announcement that “this new engine features an industry-best 16:1 overall pressure ratio (OPR), enabling the engine to achieve up to 20% less fuel consumption and 10% more cruise power compared to competitor offerings in the same size class, which usually feature an OPR of 9:1. It also has 4000-6000 hour MTBO,” or mean time between overhauls, which is about 30% longer than with existing engines.
Broge, Jean L.
MOBILITY ENGINEERING: March 201616MEIP033/1/2016
Autonomous vehicles: impact on society Self-driving technology offers plenty of promise, but not everything about autonomous vehicles will be a panacea. Crankshaft reliability by integrated design, simulation, and testing This testing method is proven and beneficial for the design and development of the crankshaft and could be applied to other critical engine components, thereby extending to system reliability. New Engines 2016 Highlighting the design, engineering, and technologies inside some of the most competitive gasoline and light-duty diesel ICEs. Touch and go Avionics developments are changing life in the cockpit and at airborne work stations. Improving heavy-duty engine component efficiencies Cylinder deactivation can improve fuel economy by using a reduced number of cylinders that operate at higher loads and thermal efficiency, while other cylinders are turned off, when the engine operates at partial load conditions. A switching roller finger follower is one of the technologies that help make it work. Low-friction techniques push advanced city-car project toward 84-mpg target Clean-sheet design for Proterra's all-electric city bus GE's clean-sheet turboprop engine to launch with Textron Aviation OTA reflashing: the challenges and solutions Clamoring for a connection HMIs offer something for everyone Secondary loop and heat pump climate control under evaluation once more SABIC showcases customizable sheet, 3D seat for aircraft interiors Ford looks to spread Corning's new lightweight Gorilla Glass beyond the 2017 GT 2016 Civic structure employs 'first' partial in-die soft zones UCLA researchers develop new strong and lightweight metal nanocomposite GT350 Mustang features novel composite structural component Crash testing advances on many fronts Evaluating new forestry machines in a fraction of the time Aurora Flight Sciences, Stratasys debut at Dubai jet-powered, 3D printed UAV Surface Generation speeds composites throughput with one-shot stamp-forming process GE scanner enhances defect detection for industrial CT Hot-stamping process from Schuler employs flexible 'pressure controlled hardening' BUDD-e concept forecasts what VW zero-emission van could be in 2019 Airbus looks to expand military product lines
Fanjet Evolution — the Next StepsTBMG-218854/1/2015
The global aerospace sector has always represented the cutting edge of practical technology advancement. When the first military jet engines emerged in the post-war 1940s it was clear that commercial applications would soon follow. The leap in performance, payload capability, maintainability, and speed compared to the best that turbo-supercharged piston-engines could offer was truly revolutionary.
Propulsion15AERP04_014/1/2015
Fanjet Evolution - the Next Steps Rolls-Royce is on a determined path to equip commercial airplanes over the coming decades with new engines that take advantage of engineering breakthroughs in materials and core architectures. The global aerospace sector has always represented the cutting edge of practical technology advancement. When the first military jet engines emerged in the post-war 1940s it was clear that commercial applications would soon follow. The leap in performance, payload capability, maintainability, and speed compared to the best that turbo-supercharged piston-engines could offer was truly revolutionary.
Gardner, Richard
Europe's Aerospace Industry Looking ConfidentTBMG-197556/1/2014
Talk of further consolidation within Europe’s dynamic aerospace sector has been on the lips of industry watchers for several years, but although the major European-based global players have not progressed toward further mergers, the continent’s biggest aerospace company, the former EADS, has achieved a very significant business restructuring, sweeping all its diverse companies into one giant, three-division entity, and adopting the new corporate identity of the Airbus Group.
Europe's Aerospace Industry Looking Confident14AERP06_016/1/2014
Apart from Airbus's highly visible presence in defense and commercial aircraft, Europe also has successful capabilities in helicopters, business jets, and aero engines, and in all these areas their global market share is growing. Talk of further consolidation within Europe's dynamic aerospace sector has been on the lips of industry watchers for several years, but although the major European-based global players have not progressed toward further mergers, the continent's biggest aerospace company, the former EADS, has achieved a very significant business restructuring, sweeping all its diverse companies into one giant, three-division entity, and adopting the new corporate identity of the Airbus Group. At one stage it looked as if a proposed merger between EADS and BAE Systems might create the world's largest combined aerospace and defense company, but a German political veto put an end to this plan, largely because of sensitivity over the defense aspects of such a deal.
Gardner, Richard
The Preparation and Use of Chromel-Alumel Thermocouples for Aircraft Gas Turbine EnginesAIR46B (Historical)5/1/2014
This SAE Aerospace Information Report (AIR) reviews the precautions that must be taken and the corrections which must be evaluated and applied if the experimental error in measuring the temperature of a hot gas stream with a thermocouple is to be kept to a practicable minimum. Discussions will focus on Type K thermocouples. These are defined in NBS Monograph 125 as nickel-chromium alloy versus nickel-aluminum alloy thermocouples.
E-32 Aerospace Propulsion Systems Health Management
Guide to Engine Lubrication System MonitoringAIR1828B (Historical)5/1/2014
The purpose of this SAE Aerospace Information Report (AIR) is to provide information and guidance for the selection and use of lubrication system monitoring methods. This AIR is intended to be used as a technical guide. It is not intended to be used as a legal document or standard. The scope of this document is limited to those inspection and analysis methods and devices that can be considered appropriate for routine maintenance.
E-32 Aerospace Propulsion Systems Health Management
Turboshaft/Turboprop Gas Turbine Engine Test Cell CorrelationARP4755B (Historical)12/19/2013
This paper describes a recommended practice and procedure for the correlation of test cells that are used for the performance testing of turboprop and turboshaft engines. This Aerospace Recommended Practice (ARP) shall apply to both dynamometer and propeller based testing. Test cell correlation is performed to determine the effect of any given test cell enclosure and equipment on the performance of an engine relative to the baseline performance of that engine.
EG-1E Gas Turbine Test Facilities and Equipment
The big boys go for plastic12AERD0613_016/13/2012
While it is true that the latest developments in advanced alloy manufacturing techniques can deliver structures and components that meet all the product requirements that aerospace primes need for new aircraft, there can be no escaping the fact that there is now an unstoppable momentum building up for the plastic airplane. Composites have been around for many decades, but the promise of lighter and stronger structures has taken far longer to translate into significant mainstream civil aircraft production, beyond the general aviation, business jet, and defense communities. In the May 16 issue of Aerospace Engineering, we looked at the impact of composites on how large turbofan engines are built, but in the airframe sector, the shift has been gradual, with composites first replacing metal components on a one-to-one basis for simple structures, and where large angular sections could be molded in one piece, replacing the need for large numbers of separate sheets, strengthening fillets, and rivets.
Gardner, Richard
Guide to Limited Engine Monitoring Systems for Aircraft Gas Turbine EnginesAIR1873 (Historical)3/28/2012
E-32 Aerospace Propulsion Systems Health Management
Test Cell InstrumentationAIR5026A (Historical)8/1/2011
This document discusses, in broad general terms, typical present instrumentation practice for post-overhaul gas turbine engine testing. Production engine testing and engine development work are outside the scope of this document as they will typically use many more channels of instrumentation, and in most cases will have requirements for measurements that are never made in post-overhaul testing, such as fan airflow measurements, or strain measurements on compressor blades. The specifications for each parameter to be measured, in terms of measurement range and measurement accuracy, are established by the engine manufacturers. Each test cell instrument system should meet or exceed those requirements. Furthermore, each instrument system should be recalibrated regularly, to ensure that it is still performing correctly.
EG-1E Gas Turbine Test Facilities and Equipment
Innovation Fuels the Future of Air TravelTBMG-101126/1/2011
Aircraft of the future may not look significantly different from today’s aircraft, but a peek “under the hood” will reveal technologies that are vastly different. Commercial aviation giants such as Boeing and Airbus — in addition to NASA and academia — are developing breakthrough airframe, propulsion, materials, and cabin designs that will help aircraft of the future fly quieter, cleaner, and more fuel-efficiently, with enhanced passenger comfort.
Turboshaft/Turboprop Gas Turbine Engine Test Cell CorrelationARP4755A (Historical)11/15/2007
This paper describes a recommended practice and procedure for the correlation of test cells that are used for the performance testing of turboprop and turboshaft engines. This Aerospace Recommended Practice (ARP) shall apply to both dynamometer and propeller based testing. Test cell correlation is performed to determine the effect of any given test cell enclosure and equipment on the performance of an engine relative to the baseline performance of that engine.
EG-1E Gas Turbine Test Facilities and Equipment
Design Considerations for Enclosed Turboprop Engine Test CellsAIR5295 (Historical)11/15/2007
This document is offered to provide state-of-the-art information about design factors that must be considered in the design of new or significantly modified engine test cells used to test propeller equipped turboprop engines in either QEC or bare engine configurations. The report does not address design considerations for test cells designed to test turboprop engines with dynamometer type load absorption devices because they are essentially tested as turboshaft engines. Design considerations for those test cells are presented in AIR4989, Reference 2.1.
EG-1E Gas Turbine Test Facilities and Equipment
Installed Outdoor Engine TestingAIR5301 (Historical)11/15/2007
This SAE Aerospace Information Report (AIR) was written because of the growing interest in aircraft installed outdoor engine testing by the Federal Aviation Administration, airlines, charter/commercial operators, cargo carriers, engine manufacturers and overhaul and repair stations. This document was developed by a broad cross section of personnel from the aviation industry and government agencies and includes information obtained from a survey of a variety of operators of fixed and rotary wing aircraft and research of aircraft and engine maintenance manuals.
EG-1E Gas Turbine Test Facilities and Equipment
Aircraft Hydraulic Starter/PumpsAS838 (Historical)4/26/2005
This specification established (1) the common requirements for hydraulic units capable of functioning as starters and as pumps suitable for use in aircraft and missiles and (2) the methods to be used for demonstrating compliance with these requirements.
A-6C4 Power Sources Committee
Turbomachinery Blade Modal Analysis Using Contact Elements2004-01-314111/2/2004
This paper presents a new methodology for analytically evaluating the natural frequencies and mode shape of a turbomachinery blade in an environment where friction phenomenon occurs. The blades analyzed in this study are unshrouded and located in the high-pressure turbine found in turbofan engines, and in the compressor turbine found in turboprop engines. The goal of this method is to correctly predict the modal parameters of the blade in order to determine whether there will be any resonance in the running range of the turbomachinery, and to more accurately predict the stresses at the blade-disc interface. This study was performed using ANSYS® contact elements. After comparison, the analytical results were found to agree with the experimental results. A convergence study was also performed, and it was found that only the friction coefficient and the surface contact stiffness had a considerable effect on the natural frequencies and mode shape convergence.
Guerra, Mario, Thomas, Marc, St-Georges, Lyne
Dynamic Modal Analysis and Optimization of a Mechanical Sensor Arm Deployment System for a C-130 Aircraft2004-01-312911/2/2004
During structural engineering design two of the most overlooked design facets of a finished product is understanding the behavior characteristics of how the product will react when resonated at its natural frequencies and actually defining and understanding the overall vibration profile responsible for the excitation of the structure. A C-130 mechanical arm/pod system has been developed to accommodate 1,000-pounds of sensor payload deployable in flight from a C-130 Hercules military aircraft (variants B thru J). The mechanical arm/pod system will be subjected to a profile of vibration from numerous sources during deployment and while in the final operating position. A general vibration profile for the mechanical arm/pod will be compiled from the plane’s four T-56-A-15 turboprop engines, the atmospheric turbulence and random gust loads. A pitot-accelerometer sensor probe was used to obtain vibration data of the C-130 ramp during a zero-light turbulence category flight for indicated airspeeds of 130 knots and 150 knots. The mid/low frequency values with worse case scenario magnitudes induced by buffeting, flutter and gust loads were computed. A formal vibration analysis was conducted utilizing the Finite Element Approach and Modal Analysis using Pro/ENGINEER and Pro/MECHANICA software packages. The natural frequency modes for the mechanical arm/pod system was computed in the x, y and z directions with three different geometrical configurations of the structural cross-member supports.
Wowczuk, Zenovy S., Means, Kenneth H., Mucino, Victor H., Thompson, Gregory J., Feragotti, Lawrence, Smith, James E., Naternicola, Adam, Corso, Bruce J.
Engine Bleed Air Systems for AircraftARP1796 (Historical)6/22/2004
This ARP discusses design philosophy, system and equipment requirements, installation environment and design considerations for systems within the ATA 100 specification, Chapter 36, Pneumatic (reference 1). This ATA system/chapter covers equipment used to deliver compressed air from a power source to connecting points for other systems such as air conditioning, pressurization, anti-icing, cross-engine starting, air turbine motors, air driven hydraulic pumps, and other pneumatic demands. The engine bleed air system includes components for preconditioning the compressed air (temperature, pressure or flow regulation), ducting to distribute high or low pressure air to the using systems, and sensors/instruments to indicate temperature and pressure levels within the system. The engine bleed air system interfaces with the following ATA 100 systems: The interface with these systems/chapters is at the inlet of the shutoff/control valve of each associated system. This boundary definition aligns with that in the ATA 100 specification. The primary emphasis of this ARP is on systems which use the aircraft engine as the source of the pneumatic supply. Alternate supply systems are discussed in Section 7.0.
AC-9 Aircraft Environmental Systems Committee
Simulating safetyAEROJAN04_031/1/2004
Bombardier Aerospace simulates airflow in nacelles to prevent engine foreign-object damage. The potential for objects to be ingested into an aircraft's engine through the nacelle and possibly force the engine to be taken out of service for repairs is a concern with all airplane operators. Bombardier Aerospace has performed many physical experiments on its Q Series Dash 8 regional aircraft in an effort to eliminate foreign-object damage (FOD). The Q Series Dash 8 family of turboprop regional airliners includes the 37- passenger Q100 and Q200, the 50- to 56- passenger Q300, and the 68- to 78-passenger Q400, which had its first flight in 1998 and entered commercial service in February 2000. Two PW150A turboprop engines supplied by Pratt & Whitney Canada power the Bombardier Q400 aircraft. Each engine develops 5070 hp.
An eye on UAVsAEROAUG03_048/1/2003
Electronics play an important role in unmanned aerial vehicles designated for intelligence, surveillance, and reconnaissance mission areas, as well as for combat. Roadmaps seem to be everywhere these days. Earlier this year, Dyke Weatherington, Deputy, Office of the Secretary of Defense, Unmanned Aerial Vehicle Planning Task Force, announced the release of the 2002 Unmanned Aerial Vehicle Roadmap. According to Weatherington, one of the specific purposes of the document, which looks out to 2027, is to identify “those near-term mission areas that can be impacted significantly by emerging UAV technology.” Another goal for the roadmap is its use as “a guide to our industry and allies, identifying the highest value areas for independent investment and areas for international cooperation,” said Weatherington. Ironically, it is international uncooperation that has made UAVs increasingly important for a wide range of armed forces mission scenarios-particularly ISR, or intelligence, surveillance, and reconnaissance-proving especially useful because they can be launched from secure positions to perform military tasks in a dangerous environment.
Broge, Jean L.
Boundary Layer Control System; PressureAS81366 (Historical)2/13/2002
This specification covers pressure boundary layer control systems of turbo-jet and turbo-prop aircraft for increasing the aerodynamic lift of the wings and flaps during approach, landing, and takeoff.
Aerospace Council
Evaluation of an Unconventional Diesel Engine as a General Aviation Powerplant2000-01-16855/9/2000
A novel two stroke cycle diesel engine is evaluated as a general aviation aircraft powerplant. Two certificated spark-ignited gasoline reciprocating engines are also evaluated in the same aircraft. The evaluation of aircraft propulsion performance considered only the effects of altered powerplant parameters on the range of an aircraft having a fixed gross weight and payload cruising at a given lift/drag ratio. Thermodynamic analysis finds the diesel engine can have a sea level power rating exceeding the 10,000 foot cruise power requirement by 55% with nearly equal specific fuel consumption, a low engine speed and a modest cylinder pressure. It uses a single-stage, radial turbocharger without intercooling or auxiliary mechanical scavenging. The diesel engine can significantly increase the range of a particular airplane now powered by a certificated turboprop engine. The candidate gasoline engines could not equal the turboprop-powered aircraft performance.
Addoms, Robert
AC Starting Demonstration with Allison AE2100 Turboprop Engine9712246/18/1997
During the month of October 1995, Auxilec successfully demonstrated its newly developped AC engine start concept on the Allison AE2100 turboprop engine. This demonstration took place at the AE2100 engine development test cell, which is located in Indianapolis, Indiana. The Auxilec AC engine start system included an off-the-shelf 3OkVA brushless generator, which was derived from an existing helicopter application, together with a vector-controlled power inverter, which was derived from an existing automotive application. The engine start system was powered either by an 80 VDC conventional power supply, or by four NiCad 24VDC/42Ah batteries connected in series and kept at ambient temperature conditions. During this engine start demonstration, which lasted two days, Auxilec managed to perform forty-four (44) successive starts. Of these forty-four (44) engine starts, seven (7) were powered by batteries, while the rest were powered by the 80 VDC power source. As part of this engine start demonstration, Auxilec also performed a sequence of four (4) successive engine starts using only battery power. During this test, the average engine start time was measured at approximately 40 seconds.
Devred, Hervé, Besnard, Jean Philippe, Martinez, Mario
TEST CELL INSTRUMENTATIONAIR5026 (Historical)11/1/1996
This document discusses, in broad general terms, typical present instrumentation practice for post-overhaul gas turbine engine testing. Production engine testing and engine development work are outside the scope of this document; they will use many more channels of instrumentation, and in most cases will have requirements for measurements that are never made in post-overhaul testing, such as fan airflow measurements, or strain measurements on compressor blades. The specifications for each parameter to be measured, in terms of measurement range and measurement accuracy, are established by the engine manufacturers. Each test cell instrument system should meet or exceed those requirements. Furthermore, each instrument system should be recalibrated regularly, to ensure that it is still performing correctly.
EG-1E Gas Turbine Test Facilities and Equipment
REPORT ON AIRCRAFT ENGINE CONTAINMENTAIR1537A (Current)8/1/1996
The study shall be directed to commercial aircraft service and include engine experience in both fixed wing aircraft and helicopters covering the time period from 1962 to the present.
Engine Containment Ad Hoc Committee
GUIDE FOR DETERMINING ENGINE STARTER DRIVE TORQUE REQUIREMENTSAIR781 (Current)9/1/1994
A general discussion is presented herein, to outline the starter functions which are necessary for a successful engine start. In addition, sample calculations are included to illustrate an accepted method of determining the engine starting time from known data. Further consideration is then given to the relationship between starter torque output and engine pad strength and a generalized formula is presented for calculating the theoretical transient torque peaks for a simplified starter-engine system. Sample calculations for actual tests are included, and the results of these calculations are compared with measured values.
AE-6 Starting Systems and Auxiliary Power Committee
Turboshaft/Turboprop Gas Turbine Engine Test Cell CorrelationARP4755 (Historical)3/1/1994
EG-1E Gas Turbine Test Facilities and Equipment
Philosophical Approach to the Basic Understanding of the Mechanics of Jet Propulsion9209604/1/1992
This paper attempts to bring home the philosophy which lies behind the practical application of air-breathing and rocket engines. The various types of practical engines namely rocket engine, ram jet engine, turbojet engine, turbofan engine (mixed and unmixed exhausts), turboprop engine appear to be principally different. However philosophically, they are all one and the same. To appreciate this philosophy, let us change our frame of interest from the fluid to the jet engine. This leads us to the very first principles of jet propulsion i.e. the generation of thrust from the pressure forces exerted by the fluid on the boundaries and components of the jet engine. Well established mathematical concepts and relationships are available for practically estimating the performance of these engines based on fluid parameters. However philosophically, thrust and propulsive efficiency are sufficient for the philosophical understanding of the generation of variety of aircraft engines. A fluid exerts pressure normal to the surface over which it flows. In a jet engine, the resultant of the fluid pressure forces in the direction of motion is the thrust. Hence for a surface whose outward normal subtends an angle in the first or fourth quadrant with the direction of motion will give positive thrust and that which subtends an angle in the second or third quadrant will give negative thrust. Hence a convergent nozzle will give negative thrust. Negative thrust may be viewed as a necessary evil to maintain the positive thrust which cannot be maintained by only combustion temperature due to limitation on its maximum value. An engine which can make maximum possible use of the fluid pressure profile for thrust would have the highest possible propulsive efficiency i.e. unity. The bypass concept is an attempt in this direction. The outward normal of the bypass disk subtends an angle of nearly 0° with the direction of motion thereby converting almost 100% of the pressure force acting on it for thrust. Mixing at low bypass ratios reduces the negative thrust by increasing the taper ratio of the combined nozzle when compared with individual cold and hot nozzles for separate jets. The core and bypass engines are together clubbed into a single theoretical model by means of an appropriate weighting parameter which takes limiting values for bypass ratio of zero and infinity.
Mahulikar, Shripad Prabhakar
GUIDE TO ENGINE OIL SYSTEM MONITORINGAIR1828A (Historical)1/22/1992
The purpose of this SAE Aerospace Information Report (AIR) is to provide information and guidance for the selection and use of oil system monitoring devices and methods. This AIR is intended to be used as a technical guide. It is not intended to be used as a legal document or standard. The scope of this document is limited to those inspection and analysis methods and devices that can be considered appropriate for routine maintenance. In agreement with industry usage, wear particle size ranges are given in micrometers (1 μm = 10-3 mm = 10-6 m).
E-32 Aerospace Propulsion Systems Health Management
Single Lever Power Management of Turboprop Engines9122009/1/1991
Historically, Turboprop engines have been controlled via two levers in the cockpit -- one adjusting engine speed and the other controlling engine power. Engine power was controlled by speed lever and fuel flow (a function of power lever angle). The pilot had to adjust the speed lever to obtain the desired engine speed setting, then he would “close the loop” on torque (his primary control parameter) by watching a gage and moving the power lever angle (PLA). This resulted in significant pilot effort in readjusting the engine to different power levels/operating modes. The control system for the TPF351-20 engine, as applied to the Embraer CBA123 aircraft, is designed to reduce pilot workload by providing a single lever system that controls the engine to a torque commanded by the power lever position. This was made possible by the use of a Full-Authority Digital Engine Control (FADEC). In order to maximize the use of the FADEC in the reduction of pilot workload, it is tied via various serial data busses on the aircraft to the Air Data Computer, the Autopilot, and Engine Indication and Crew Alerting System (EICAS). These inputs allow the FADEC to schedule torque linearly versus power lever command, and to hold each engine to within 1 percent torque of each other which prevents undesirable power lever splits or aircraft yaw. The FADEC also uses the Autopilot inputs to adjust engine power during approach to keep the aircraft on the specified glide slope. Pilot workload, aircraft performance, and maintainability are significantly improved by the state-of-the-art advances made in control of turboprop engines on the TPF351-20.
Prevallet, L.C.
THE PREPARATION AND USE OF CHROMEL-ALUMEL THERMOCOUPLES FOR AIRCRAFT GAS TURBINE ENGINESAIR46A (Historical)1/25/1990
E-32 Aerospace Propulsion Systems Health Management
Evolution of Light Gas Turbine Engine During the Last-30 Years8710535/1/1987
When comparing the turboshaft and piston engine advantages from the technical and economic point of view, we are led to the conclusion that the turboshaft engine, with its regular improvement in performance, will quickly replace the piston engine in the power range from 300 to 500 shp, just as it has already done in the rest of field. Similarly, what happened with helicopters, where the piston engine has been completely abandoned when the Aerospatiale Alouette II - fitted with a Turbomeca Artouste II - showed the indisputable superiority of the turboshaft engine, will happen again with light aircraft as soon as operators have the opportunity to see for themselves the undeniable advantages - hereunder highlighted - which the turboprop engine offers.
Faury, M., Mazoyer, J.P.
Advanced Allison Small Turboprop Engines8710555/1/1987
To offer turboprop engines in power classes that support a variety of aircraft applications. Allison is developing two new turboprop engines in the Model 250 series engine line. The Model 250-B17C/D engines, rated at 420 shaft horsepower
Pegors, Douglas E.
Garrett TPE331-12 Engine Provides Improved Altitude Performance for High-Speed Executive Turboprop Aircraft8509084/1/1985
This paper describes the program objectives of the TPE331-12 engine and outlines how these objectives were met with a combination of proven design features from the TPE331-10 engine, from which the TPE331-12 is derived, and with the advanced technology of the new, recently certified TPE331-14 engine. The Garrett Turbine Engine Company (GTEC) TPE331-12 turboprop engine was conceived as an uprated version of the existing TPE331-10 model. In 1981, it became apparent that a commercial interest existed for the uprated −10 engine if it could offer at least a 10 percent gain in thermodynamic shaft horsepower with no specific fuel consumption (SFC) penalty. This paper will describe how these improvements were achieved.
Krasnow, Howard J.
An Electronic Limiter for Aircraft Engines8509104/1/1985
All engines have limits to the maximum power which may be obtained. This may be dictated by the power transmission capability of the engine and gearbox or physical limits on rotational velocity and temperature to restrict turbine blade creep to an acceptable level. To accommodate this requirement it is customary to use mechanical governors or a Full Authority Digital Electronic Control. However, the mechanical solution suffers from eventual deterioration due to wear, while the electronic approach requires certification to FAA Critical Levels. A solution has been to develop an electronic limiter, which controls the fuel control governing pressure (Py) of a conventional mechanical fuel control in order to meet the design limits of the engine. This paper will describe one such limiter developed by Avelex for aerobatic turboprop engines.
Brown, A.
Prop Jet Singles Have Arrived8508824/1/1985
PROP JET SINGLES HAVE ARRIVED documents the development of the Allison Model 250 Series turboprop engine. The history of the engine development as well as early flight test work by the engine manufacturer and the findings of aircraft manufactures who flight tested the engine are covered in some detail A general discussion on the operation of the engine systems and the development of those systems to include the miscellaneous tests to assure engine operation are included. Development and certification of the Model 225-B10 low cost turboprop engine is also discussed.
Schweibold, J. A., Molish, M.
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