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1 THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS 345 E. 47th St, New York, N.Y GT-325 The Society shall not be responsible for statements or opinions advanced In papers or discussion at meetings of the Society or of its Divisions or, Sections. or printed In Its publications. Discussion Is printed only if the paper is published in an ASME Journal. Authorization to photocopy - material for internal or personal use under circumstance not falling within the fair use provisions of the Copyright Act is granted by ASME to libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service provided that the base fee of $0.30 per page is paid directly to the CCC, 27 Congress %TOOL SaJem MA Requests for special permission or bulk reprodoztion should be addressed to the ASME Technical Raftslikig Department Copyright by ASME NI Rights Reserved Printed In U.S.A. USING AN AUXILIARY POWER UNIT (APU) GAS TURBINE ENGINE TO START THE LSD-41 CLASS DIESEL ENGINES Jeffrey S. Patterson Naval Surface Warfare Center, Carderock Division Philadelphia, PA iii ABSTRACT The LSD-4I Whidbey Island Class of Amphibious dock landing ships are powered by two Colt-Pielstick PC2.5V Block 16 cylinder Main Propulsion Diesel engines. These engines represent the largest diesels in the U.S. Navy. Currently, they are started without the use of a mechanical starter, by injecting 100 cfm [47.2 LPs] of 3,000 psig [206.9 barr] high pressure air, reduced to 425 psig [29.3 barr] directly into one block of eight engine cylinders. Naval Surface Warfare Center, Carderock Division (NSWCCD) was tasked to perform a proof of concept test that would demonstrate the capability of an Auxiliary Power Unit (APU) gas turbine engine to start these large, medium speed diesel engines. This paper will present the background, installation and initial testing for this proof of concept test. The background section will discuss the test philosophy, the LSD-41 Land Based Engineering Site (LBES) and initial prototype testing. The installation section will discuss the modifications made to the LBES for this test and the characteristics and specifications of the test hardware. The testing section will discuss the test plan and the test procedures. This paper will not present any results or data analysis from this proof of concept test. Test site availability and equipment procurement delays postponed the start of this test until March, Therefore, the test results will be discussed at the upcoming Turbo Exposition conference. clutches, brakes and related support system. The power produced by these engines is absorbed by two tandem mounted waterbrakes. The goals of this proof of concept test were as follows: To investigate the possibility of starting a large diesel engine with the bleed air from an APU gas turbine engine. To identify an alternate starting system that would eliminate the need for the existing high pressure bottled air system. To reduce operating and maintenance costs and the safety risk to ship personnel. To increase system reliability. To determine the maximum distance the APU units could be located from the main diesel engines. [for the LPD-17 (LX) Class shipboard impact] INTRODUCTION The LSD-41 LBES, as shown in Figure 01, is located at the NSWCCD in Philadelphia, PA. This site duplicates the starboard propulsion plant on the LSD-41 Class ships. The facility contains two Colt-Pielstick PC2.5V Block 16 cylinder medium speed Main Propulsion Diesel engines rated at 8,500 brake horsepower each, twin turbochargers, a twin-pinion reduction gear, associated couplings, FIGURE 01. LSD-41 LBES. The APU unit selected for this test was an AlliedSignal Model FtST 184 jet air starter. This APU supplied bleed air to two AlliedSignal Model B Air Turbine Starters (ATS), which were coupled to two Preiented at the International Gas Turbine and Aeroengine Congress & Exhibition Birmingham, UK June 10-13, 1996

2 Ingersoll-Rand Model ATS700 intermediate gear cases. The ATS and gear case assemblies, as shown in Figure 02, provided the necessary breakaway torque required to rotate the engine's flywheel. The flywheel, in turn rotated the engine's crankshaft, camshafts and pistons, which compressed the fuel within the cylinders, causing combustion and power output. To facilitate this test, one test site engine was modified by adding a ring gear assembly, mounted to the front face of the existing flywheel at the drive end of the engine. The ring gear, as shown in Figure 03, provided the means to translate the breakaway torque from the ATS and gear case assemblies to the engine's flywheel. The two ATS and gear case assemblies were mounted perpendicular to the flywheel, to engage the ring gear. The APU was located 30 feet [91.4 m] from the engine, at the 22 foot [67.1 m] platform level of the LEES. It was connected to the starters and gear cases through an thin walled 304 stainless steel piping system, which included a pressure regulating valve and a Y-pipe flow divider, as shown in Figure 04. data was critical for determining the maximum distance between the API/ and the engines. This information was required for the LPD-17 (LX) Class shipboard impact study. FIGURE 04. APU Piping Arrangement,t FIGURE 02. ATS and Gear Case Assembly. FIGURE 03. Ring Gear Assembly. To simulate increased piping distances, an Enertroic Model SA1195C air cooler was used to decrease bleed air temperature. This BACKGROUND The following section will discuss the proof of concept test philosophy, the LSD-41 LEES and a discussion of initial prototype testing. Proof of Concept Test Philosophy The LSD-41 Main Propulsion Diesel engines are currently started with 3,000 psig [206.9 barr] high pressure air, reduced to 425 psig [29.3 barn. This high pressure bottle air system is both costly to operate and to maintain, as well as inherently dangerous to ship personnel. To address these concerns, the Navy expressed an interest in developing a lower cost and lower risk start system, to replace the high pressure system. This system would be proposed as a forward fit for the new LPD-I 7 (LX) Class, as well as possible backfit installation on the LSD- 41 Whidbey Island Class. To this end, Naval Sea Systems Command (NAVSEA) tasked NSWCCD Philadelphia, through NSWCCD Annapolis, to perform this proof of concept test, using the LSD-41 LEES. LSD-41 Land Based Engineering Site The LSD-41 LEES is the only large, medium speed Diesel engine hot plant available to the U.S. Navy. The site duplicates the starboard propulsion plant of the LSD-41 Class of amphibious dock landing ships. To date, the LEES has completed the following operating accomplishments: Development and acceptance testing which included 350 engineering changes applied to lead ships and incorporation of lessons learned. Engine power component investigation following initial ship delivery. Crew familiarization training using hot plant. The LSD-41 Class are designed to transport both personnel and the Navy's Landing Craft, Air Cushion (LCAC) Class of amphibious landing craft. The LSD-41 Class specifications are listed below in Table 01. 2

3 Table 01. LSD-41 Class Design Specifications Description Overall Displacement Design Specification 11,275 tons std [1.02x10 7 kg] 15,704 tons full [I.42x10' kg) Length. 610 ft [185.8 m] Beam 84 ft [25.6 m] Draft 20 ft [6.1 m] Propulsion Speed 4 Colt-Pielstick PC2.5V diesels 34,000 bhp total, 2 shafts [25,353 kw total] 20 + knots [10.29 m/s] The LBES was designed and constructed during the early 1980s, in response to significant developments in large diesel engines and machinery control systems. Prior to fleet implementation, construction techniques, diesel system modifications and operational procedures were evaluated at the site. The site contains two Colt-Pielstick PC2.5V Block 16 cylinder Diesel engines with twin turbochargers, a twin pinion reduction gear, two facility waterbrakes for load absorption, an enclosed operating station, local operating station and associated propulsion supponsystems. The engine specifications are listed below in Table 02. Table 02. Colt-Pielstick PC2.5V Engine Specifications Initial Prototype Testing As a precursor to this proof of concept testing, NAVSEA sponsored an APU start demonstration test at Hawthorne Power Systems in San Diego, CA on March The purpose of this test was to prove that the low pressure bleed air from an APU could be used to start large diesel engines. To facilitate this test, a Caterpillar Model 3608 diesel generator set was used. The idea of this test was to replace the two existing high pressure vane motor type starters with one air turbine starter. This test involved the efforts of several organizations, including AlliedSignal Engines, Ingersoll-Rand, Naval Air Warfare Center, Aircraft Division (NAWCAD) Patuxent River, MI) and NSWCCD Philadelphia, PA and Annapolis, MD. The following section will describe the equipment used, the test plan and a discussion of the results. Equipment Description. The following equipment was used for this start system demonstration test:' Caterpillar Model 3608 diesel generator set, with a continuous rating of 2350 kw at 1000 rpm. AlliedSignal Model M32A-60A start cart with an 85-Series APU gas turbine engine. One AlliedSignal Model ATS air turbine starter. One Ingersoll-Rand Model ATS700 intermediate gear case with a2.18:1 reduction gear. Assorted hardware including a start/regulation valve, a portable data logger and a calibrated flow measurement section. Description Design Specification Teat Plan. Testing was accomplished in a three phase process: 2 Number of Cylinders 16 Rated Engine Power 8,500 bhp [6,338 kw] Motor the engine with the high pressure air system and the existing vane motor starters, and record the maximum speed of the engine, in rpms. Rated Engine Speed Engine Dimensions Engine Weight Operating Cycle Bore Piston Stroke Compression Ratio Displacement 520 rpm 28 ft [91.8 m] long x 13 ft [42.6 m] high x 12 ft [39.3 m] wide 100 tons [90,718 kg] 4-stroke, turbocharged inches [400mrn] inches [460 mm] 11.5 to I 3,527.3 inches' [57.8 liters] Motor the engine with the low pressure air system and the AlliedSignal and Ingersoll-Rand hybrid air turbine starter, and record the maximum speed of the engine, in rpms. Start diesel generator set with the low pressure air system and air turbine starter, and record the engine data. The purpose of this three phase testing was to develop comparison data for start times and cranking power between the high and low pressure air start systems. ' Updike, J., 1995, "APU/ATS Low Pressure Diesel Pneumatic Starting System Test Report", Technical Report , AlliedSignal Engines, Phoenix, AZ, page 9. 'Updike, 1, 1995, page II. 3

4 Test Results. The results of this test indicated that the Caterpillar Model 3608 diesel generator set could be successfully started with a low pressure air system, using an APU and air turbine starter.' The test data revealed that: The starting torque for the air turbine starter was at a level between one and two of the vane motor starters. The engine start time was less than 5 seconds. Based on the results of this test, it was decided to apply this low pressure air start system concept on the LSD-41 large, medium speed diesel engine. INSTALLATION The following section will discuss both the modifications made to the LSD-41 LBES and the test hardware including the APU.unit, the air regulator valve, the ATS, the intermediate gear case and the bleed air cooler. Modifications to LSD-41 LBES In preparation for this alternate starting test, several modifications were made to the LSD-41 test site. These modifications included the removal of the flywheel guard, the addition of a machined ring gear assembly to the flywheel, the addition of a support foundation for the air turbine starter and intermediate gear case assemblies, and changes to the engine electronic control system. To translate the starting torque from the air turbine starters and intermediate gear cases to the engine's flywheel, a machined ring gear was required. This ring gear was designed and constructed by Coltec Industries, Fairbanks Morse Engine Division, the manufacturer of the PC2.5V diesel engine. The design was similar to a ring gear assembly Coltec designed for their Model PC2.6V diesel engine. Prior to installation of the ring gear, the engine's flywheel was removed and shipped back to Coltec. While there, the front face of the flywheel was machined to accept the ring gear. The ring gear, shown in Figure 03, is of one piece AISI 1040 carbon steel construction, and is bolted directly to the front face of the flywheel. It measures 64 inches [162.6 cm] in diameter), 2.0 inches [50.82 mm] thick and consists of 384 gear teeth. These teeth are designed to mesh with the pinions on the intermediate gear cases. With a pinion pitch diameter of 2.0 inches [50.82 nun], the overall ratio between the ring gear and gear case pinion is 32 to I. Following construction, the ring gear and flywheel assembly was shipped back and reinstalled on the test site. To accommodate the ring gear, the flywheel guard was removed. For safety reasons, the guard was temporarily modified and reinstalled in place. To secure the air turbine starter and intermediate gear case assemblies, a support foundation was designed and constructed. This foundation was designed to withstand the torque created by the starter assemblies. The foundation was constructed of one inch thick [25.4 'Updike, J., 1995, page 18. mm] plate steel, and offset to permit proper pinion and ring gear tooth engagement. The starter and gear case assemblies were bolted directly to the foundation, at equal distances above and below the centerline of the flywheel. The ATS foundation was bolted to the engine support foundation, directly aft of the flywheel. Aft looking forward, the starter assemblies engage the right hand side of the flywheel. To permit the alternate starting method, several modifications were made to the LSD-41 engine control system. These modifications included the addition of a on/off switch for the air regulator valve, a valve position gage, lock out of the existing high pressure air system, changes to the start time and fuel ramp logic and the addition of key APU and bleed air, temperature and pressure parameters. These modifications will be discussed in a later section. Test Hardware The following section will discuss the hardware used for this test, including the APU unit, air regulator valve, Y-pipe flow divider, intermediate gear case, air turbine starters and bleed air cooler. APU Unit The APU cart selected for this test was an AlliedSignal Model RST 184 jet air starter, as shown in Figure 05. This cart contained an series gas turbine engine, which was mounted to a rigid frame within a removable sound attenuated enclosure cover, to provide the pneumatic power in the form of compressed bleed air. Pneumatic engine power was developed with the compression of ambient air through the two stage centrifugal compressor. This compressed air was mixed with fuel and ignited, which in turn drove the ingle stage radial turbine wheel. FIGURE 05. Model RST 184 Jet Air Starter The cart is a self contained power source that requires only a source of JP-5 jet fuel for operation. The integrated control system for the cart, controls the starting, acceleration and operation of the engine. The specifications for the cart and engine are outlined in Table 03. 4

5 Table 03. APU Cart and 85 Series Engine Specifications Description Design Specification Cart Dimensions 56 inches [142.3 cm] high x 78 inches [198.2 cm] long x 32 inches [81.3 cm] wide Cart Weight (dry) Fuel Tank Capacity Electrical System Maximum Mass Air Flowrate 1200 lbs [544.3 kg] 79 gal [300 I]) 24 VDC 155 lbs/min [1.18 kg/s] Maximum Air Pressure 51 psia [3.6 kg/cm 2] Bleed Air Temperature Maximum Inlet Air Temperature Exhaust Gas Temperature (Rated) 400 F [205 C] 130 F [54 C] 1200 F 1649 C] The engine contains an accessory assembly, which consists of a reduction gearbox and cooling air fan. The accessory assembly provides mounting provisions for the Aid control unit, electrical starter, oil pump and centrifugal switch assembly. The accessory assembly is driven by a torsion shaft that couples the compressor turbine main shaft to a planetary and ring gear assembly. rotation of the turbine wheel. The engine continues to accelerate to a point where first the starter disengages and then the ignitor plug ceases to fire. At this point, combustion and the engine is self sustaining. Once engine speed stabilizes at 100%, the bleed air panel light illuminates, and the unit is ready to supply bleed air. This entire start process, including fuel ramp, acceleration, ignition, and engine speed and exhaust temperature monitoring are controlled by the engine's control logic.' Although the unit was built and delivered back in 1988, it had never been operated by NSWCCD personnel. Prior to testing, it was necessary to calibrate the unit, to determine the maximum mass air flowrate, and temperature and pressure of its bleed air supply. Performance and calibration testing was conducted at NAWCAD, Patuxent River, MD. Prior to testing, the unit was inspected, cleaned and deprtserved. In addition, the start batteries were serviced and charged. Following this maintenance, the unit was then attached to a calibrated 3 inch [7.62 cm] flow measurement section with a 2 inch [5.08 cm] American Society of Mechanical Engineers (ASME) nozzle. The purpose of the so-called "bazooka tube", was to measure the pneumatic output capability of the APU. The tube, as shown in Figure 06, was instrumented with pressure and temperature transducers to measure the flow characteristics of the bleed air supply, at the end of the 30 foot [9.14 ml of flexible hose. These values were then combined with the ambient conditions, to determine the unit's maximum mass air flowrate. The engine assembly contains a two stage centrifugal compressor and a single stage radial turbine wheel, rotating on a common shaft. Pneumatic and shaft power is developed by the compression and ignition of an air and fuel mixture. A liner assembly provides a combustion area and is perforated to ensure the proper burning rate and correct air to fuel ratio. The engine operates in a very simple manner. After the starter is energized, it engages a jaw in the accessory assembly, which starts to drive the gear train. The gear train in turn, drives the common compressor and turbine wheel shaft, as well as the accessory assembly components. As the rotating shaft increases in speed, ambient air is drawn into the two stages of the compressor assembly and is compressed. After compression, the air enters the combustion chamber, from the turbine plenum. As the engine speed increases, rising oil pressure activates both the fuel solenoid valve and ignition unit. This causes fuel to flow through the atomizer assembly into the combustion chamber, where it mixes with the compressed air. The ignition unit causes the ignitor plug to fire and ignite the air and fuel mixture. The hot gases flow into the torrus assembly and through the nozzle section, where they impact the blades of the turbine wheel. The energy of the hot gases is absorbed by the FIGURE 06. Calibrated Bazooka Tube. The resultant performance numbers, corrected to Standard Day Conditions, were then compared to the acceptance test data, as outlined in Table 04, to determine the overall health of the unit. 'AlliedSignal Aerospace GmbH, 1978, "Operations and Maintenance Manual Parts Breakdown", Technical Report , AlliedSignal Aerospace, Raunheim, Germany, pages

6 Table 04. APU Performance Data Description Mass Air Flovmite (Design) Mass Air Flowrate (Actual) Maximum Air Pressure (Design) Design Specification 155 lbs/min [1.18 kg/s] 142 lbs/min [0.93 kg/s] 51 psia [3.6 kg/cm 2] Maximum Air Pressure (Actual) 54.8 psia [3.8 kg/cm 2] cases was to act as a transition between the ATS units and the flywheel. In addition to the slip clutch, these cases contained a 2.53:1 reduction gear and a 12 tooth pinion gear. This pinion gear was designed to mesh with the teeth of the ring gear. For this application, the gear case pinions were fixed and were always in contact with the ring gear. Based on information provided by Coltec, the breakaway and cranking torque valves for the PC2.5V diesel engines were as follows: Breakaway Torque = 10,100 lb-ft [44,927 N] Cranking Torque = 8,300 lb-ft [36,920 N] Bleed Air Temperature (Design) Bleed Air Temperature (Actual) 400 F [205 C] 397 F [203 C] Based on calculations provided by AlliedSignal, the two air turbine starter and intermediate gear case assemblies will provide the following torque values: The overall assessment of the APU, was that it was a healthy unit. This conclusion was based on the results of the performance tests, as compared to the baseline data Factoring in the losses due to the enclosure, flexible hose and the quick disconnect coupling, the mass air flowrate and pressure measurements were nearly identical. Air Regulator Valve. An air regulator valve was installed in the system, to regulate the flow of bleed air going to the air turbine starters. For this application, an AlliedSignal Model inch (10.1 cm) regulator valve was chosen, as shown in Figure 07. This normally closed valve is the same one used for the LM2500 gas turbine engine bleed air system. During operations, the valve was closed until the APU accelerated to 100% engine speed and stabilized, and the system piping was pressurized. At that point, an electrical signal was sent to open the valve, which took approximately 6 seconds. This permitted the bleed air to flow and to engage the air turbine starter and gear case assemblies. Once the PC2.5V diesel engine accelerated to idle (200 rpm), a signal was sent back to close the valve, which disengaged the starter assemblies. Torque = Torque = Torquis(rotor) x 8.4 x Gear Ratio x Pinion/Ring Ratio 15.5 lb-ft x 8.4 x 2.53 x 32 10, lb-ft [46,888.7 N] (per assembly) Therefore, the two starter and intermediate gear case assemblies (with the C-ratio gear reduction of 2.53:1) will provide approximately 21, lb-ft [93,777.3 N] of breakaway torque. This amount should be ample torque to start the diesel engine. Air Turbine Starter and Intermediate Gear Case Assembly. For this test, two AlliedSignal Model B air turbine starters were used These starters were sonically flow calibrated to act as sonic flowmeters. During calibration, the corrected airflow rates for the two units was determined to be: ATS Number 01 (S/N 169) = psia [2.02 kg/cm'] ATS Number 02 (S/N Mod B) psia [2.11 kg/cm 2] The starter splines on these units were modified by AlliedSignal to remain in a fixed, or engaged position. The means to engage and disengage the spline was handled by the slip clutch located inside the intermediate gear case The ATS units were located between the Y-pipe flow divider and engine flywheel. The starters were attached to both the Y-pipe and intermediate gear cases by means of Marrnan clamps. The purpose of these starters was to provide the breakaway torque required to turn the engine over. As mentioned, the starters were coupled directly to two Ingersoll- Rand Model AT 5700 intermediate gear cases. The purpose of these gear FIGURE 07. Air Regulator Valve. Bleed Air Cooler. The purpose of the bleed air cooler was to cool down the bleed air leaving the APU cart. This piece of equipment, borrowed from the DDG-51 LBES, Was a rather late addition to the test. This unit was added to assist in the determination of the maximum distance between the APU and the diesel engine. This information was needed for the LPD-17 (LX) Class shipboard impact study. 6

7 It The cooler was located in the flow stream, where the bleed air exits the APLI enclosure. The Enertroic Model SA1195C cooler, was a dual pass seawater heat exchanger, with a divided shell. The bleed air will be systematically cooled to the point where it no longer has the energy to start the diesel engine. Using this data, along with the pressure and temperature data, the maximum distanoe could be calculated. This testing will be completed during the second phase of this proof of concept test. V-Pipe Flow DIVIder, The Y-pipe flow divider, as shown in Figure 04, was required to uniformly split the bleed air exiting from the regulator valve. This Y-pipe was constructed from 4 inch [10.2 cm] diameter II gauge 304 stainless steel. It was designed to provide both starter assemblies with equal amounts of bleed air. This was critical to ensure that the starter assemblies provided equal breakaway torque levels to the engine's flywheel. TESTING The following section will discuss the testing phase of the project. This will include a discussion of the test plan and the test procedures. piscusslon of Test Plan A test plan was developed to define the objectives, major tasks, responsibilities, schedule, and general and administrative aspects of this proof of concept test program. In addition to reviewing the test approach, this plan specifically outlined the tasks and responsibilities of all participating activities. These tasks and responsibilities were as follows: NAVSEA 03R1 - Responsible for funding and sponsorship of the AK! proof of concept test NSWCCD, Annapolis, MD - Responsible for project management of the APU test. Primary interface with project sponsor. NSWCCD, Philadelphia, PA - Responsible for test program coordination, budget development and tracking, and coordination with the mission readiness panel. Responsible for development of the test plan and test procedures, on-site LBES management, coordination of design, construction and operation of LBES, and design, procurement and installation of APU, ATS, ring gear, gear case and assorted hardware. Also responsible for testing, test data analysis and final test report. NAWCAD, Patuxent River, MD - Responsible for providing APU operational protest support, and APU and instrumentation support at LBES during testing. AlliedSignal Engines Division - Responsible, under the applicable contract, to provide the ATS components and accessories. Provide project engineer for APU/ATS technical support during design, testing and data analysis phases of Project Colt= Industries - Responsible, under the applicable contract, to design and procure a ring gear. Provide project engineer during removal and installation of flywheel and ring gear assembly, and testing phase of project. Ingersoll-Rand Inc. - Responsible, under the applicable contract, to provide and modify two intermediate gear cases. Provide project engineer during testing phase of project Discussion of Test Procedures Operational testing will be divided into two phases; hot start and cold start testing. The individual test cycle will be performed in the following manner One cold start test, followed by 9 hot start tests. For repeatability, the above test cycle will be performed at least twice. The test will be conducted in accordance with the Diesel Engine Test Specification MIL-E Each test will require the services of two test engineers, four test site operators and three outside contractors Coltec and Ingersoll-Rand). Each test cycle should be completed in one manday. During testing, the data points outlined in Table 05 will be recorded by the computer based data acquisition system. Table 05. Operational Data Points Data Point APU Bleed Air Temperature API.! Bleed Air Pressure PC2.5V Engine Speed Delta Pressure Across Air Regulating Valve Unit op rpm psig ATS 1 Inlet Temperature F ATS 1 Inlet Total Static Pressure ATS 1 Inlet Pressure Psig psia ATS 2 Inlet Temperature F ATS 2 Inlet Total Static Pressure ATS 2 Inlet Pressure PC2.5V Diesel Fuel Rack psig psia lbs./min Time and Date - Ambient Temperature In addition to the above test parameters, the test site operator will record the ambient barometric pressure (in hg) and relative humidity (%). Prior to testing, the PC2.5V diesel engine and all subsystems will be aligned in accordance with the LSD-41 LBES EOSS. The APU will be op 7

8 checked out and aligned in accordance with the operating manual. After the PC2.5V and APU are aligned, the data acquisition system will be started. For hot start testing, the diesel engine will be operated for 40 minutes prior to attempting an APU start. After the engine is shutdown, the APU will be started, with the air regulator valve in the closed position. At the end of the start cycle, the READY light on the local control panel will be illuminated, the engine RPM will stabilize at 100% and the EGT will stabilized at appradmately 500 F (260 C). At this point, the APU will be loaded and the piping system allowed top. The regulator valve will then be opened and bleed air will be permitted to flow to the starter assemblies, causing the diesel engine to start. After the PC2.5V engine reaches idle (200 rpm), the air turbine starters will be disengaged and following a one minute cool down period, the APU will be secured. This cycle will be repeated a total of 9 times. As required in MIL-E-23457, the engine must be started within five seconds to be considered a successful start. For test purposes, the start time begins after the air regulator valve is fully opened. Francis, George W., "Testing an APU for Potential Service Aboard a U.S. Naval Destroyer", ASME paper 94-GT-119, (1994). Military Specification, "Engines, Diesel, Propulsion and Auxiliary Naval Shipboard", MIL-E Updike, Jan, "APU/ATS Low Pressure Diesel Pneumatic Starting System Test Report", Technical Report , AlliedSignal Engines, The cold start testing will be performed in the same above manner, except the engine will be cooled prior to the attempted APU atria This will be accomplished by circulating approximately 35 F [2 C] river water through the main engine water jacket. The engine will not be operated prior to cold start testing. As required in MIL-E-23457, the engine must be started within ten seconds to be considered a successful start For test purposes, the start time begins after the air regulator valve is fully opened. At the conclusion of testing, the data collected will be analyzed and a final test report will be issued. RESULTS Unfortunately, due to design, equipment and facility related delays, testing is not scheduled to start until March, Initially, testing was planned to start in August, However, due to asbestos contamination of the test site facility, testing was delayed until November, Testing was further delayed, due to equipment procurement delays. In addition, delays were encountered due to changes in the scope of testing by NAVSEA 03R1. These changes in scope centered around the addition of a bleed air cooler. The cooler was added to assist in the determination of the maximum distance between the APU and the diesel engine. The results of this testing will be discussed at the upcoming Turbo Exposition. CONCLUSIONS AND FUTURE PLANS It is the belief of the author that PC2.5V diesel engine will be successfully started with the bleed air of the Model RST 184 APU cart. The successful completion of this test will hopefully impact the design of the LPD-17 (LX) Class. This impact should result in the deletion of the high pressure bottled air system, which should reduce operating and maintenance costs, increase reliability and reduce risk to ship personnel. REFERENCES AlliedSignal Aerospace GmbH, "Operations and Maintenance Manual Parts Breakdown", Technical Report , AlliedSignal Aerospace,