machinery system information 2009-10-29

1DISTRIBUTION STATEMENT A:

Approved for public release; distribution is unlimited.

MACHINERY SYSTEM INFORMATION EXCHANGE

29 OCTOBER 2009



Content

• Machinery Architecture

• Machinery Module Structure (Port Module)

• Engine Compartment

• Engine Maintenance & Removal Concept

• Lift Fan System

• Propulsor

• Electric Plant

• Reliability Information



Machinery Architecture

NOTE: Main engine starter will be pneumatic

•4 Propulsion and lift gas turbines•2 Reduction gearboxes•4 Shaft lines•2 Centrifugal lift fans•2 Nozzle bow thrusters•2 Shrouded propellers•2 Craft service generators•2 Auxiliary Power Unit (APU)



Port Machinery Module

Outboard Bulkhead Looking Outboard




Inboard Bulkhead Looking Outboard



Port Machinery Module showing opening for Gearbox Removal

1.3 m

1.6 m

Opening for GBX Removal

Inboard Bulkhead Looking Outboard




Machinery Module Top Plan View




Machinery Platform




Forward Bulkhead Looking Aft




Plenum Bulkhead Looking Aft




Gearbox Bulkhead (BHD2) Looking Aft




BHD2 Looking Aft




BHD3 Looking Aft



Engine Compartment

• Starboard and port engine compartments identical (mirrored)

• Required firewall between engines not shown in this brief

– 50 mm Nominal thickness

– Centered between engines

• Forward bulkhead removable to allow engine removal

• Engine inboard and outboard accesses may be relocated to improveaccessibility to LRUs using the following rules as much as possible:

– One access that cuts three stiffeners, or two accesses that cut two stiffeners each with at least two stiffeners in between

– Bulkhead (side) accesses should be inline with top accesses

• If an off-engine FADEC is considered, potential locations available for FADEC mounting would be any area accessible from the quick access hatches (not on the firewall between the engine compartments)



Engine Compartment Machinery Arrangement

Machinery Arrangement

Engine Compartment Structure

FWD



Engine Compartment Structural Openings

(4) Engine Access Hatches on Engine Compartment Overhead

(2) Structural Openings for Engine Intake Ducting/Plenum on Engine Compartment Deck

(2) Structural Openings for Engine Exhaust on Forward Bulkhead

(1) Engine Access Hatch on Inboard and

Outboard Bulkheads

(2) Structural Openings for Engine Output Shaft on Aft Bulkhead

(Hidden)

(2) Structural Reservations for Cooling Fan on Aft Bulkhead (Hidden)



Engine Maintenance and Removal Concept

• Engine replacement may be performed at the ACU (IMF) or in the welldeck of the amphibious “mother” ship

• Routine maintenance tasks relative to the installed engines includes: check lube oil level, waterwash, and clean compartment & drains

• Non-routine maintenance tasks relative to the installed engines includes engine removals and LRU replacement



Engine Maintenance and Removal Concept

Engine Compartment Configuration – Main Engine Shown in Installed/Operating Position

• Engine rolls forward, on permanently installed rails, through a BERP in the plenum bulkhead

• Temporary rails and grating are installed between the engine module and lift fan bearing structure

• Exhaust is translated forward in similar fashion (prior to BERP removal)



Engine Maintenance and Removal Concept Overview (cont.)

Engine Compartment Configuration – GT Shown In Installed/Operating Position




Engine Compartment Configuration – GT Shown In Maintenance/Removal Position





Engine Positioned For Non-Routine Maintenance And/Or

Staged For Removal




Engine Compartment Configuration – GT Shown In Installed/Operating Position




Transmission

Transmission System – STBD Machinery Arrangement (Lkg inboard)

To Lift Fan

To Propulsor

Gearbox



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General Transmission Requirements

• Dual input, dual output reduction gearbox

• Gearbox must fit within the dimensions of the gearbox compartment.

• Shall be modular to enable removal through the inboard compartment access (Slide 11)

• Shall be interchangeable between port and stbd transmission systems (reconfiguring is permitted)

• The lift fan output direction shall be reversible from port to stbd. The port lift fan shaft rotates clockwise looking forward; the starboard lift fan shaft rotates counter-clockwise looking forward. Direction shall be selected prior to installation and not accessible after installation.

• Clutches and disconnects

– Overrunning clutches on the inputs are required

– Manual disconnects are required on each output somewhere in the drive train

• Propulsor output shall have a spline coupling that permits 150 mm of axial movement of the propeller shafting

• Gearbox oil sump shall be a stand-alone unit



25

General Transmission Requirements

• Gearbox must be protected from over-torque conditions resulting from water and foreign object ingestion at the propeller and lift fan.

• 4500 hour / 30 year design life

• K-Factor = 625

• Lightweight

• Compact

• Lubrication Oil = MIL-PRF-23699 Revision E

• Pressure fed lubrication oil nozzles at the gear meshes and bearings

• Gearbox must incorporate oil temperature sensors and wear metal chip detectors

• Gear elements to be designed for infinite life in bending (>107 hours) and >104 hours pitting resistance

• Gearbox to be composed of high speed helical gear units, all gear elements to be AGMA quality level 13 minimum for high speed marine gearing

• All gearbox bearing elements to be American Bearing Engineering Committee (ABEC) level 5 minimum

• Gearbox to be designed in accordance with MIL-G-17859 Rev D and ANSI/AGMA 6011-I03 (Specification of High Speed Helical Gear Units)

• Gearboxes must incorporate access points for borescope inspection of gear and bearing elements



26

Gearbox Parasitic Loads

– Lube oil pump: 15 kW

– Hydraulic pump: 112 kW

– Craft service generator: 100% Speed = 15,000 RPM; 100 kW

• Width = 10 in (255 mm)

• Length = 15 in (380 mm)

• Weight = 150 lb (68 kg)

– Quick disconnect attachments for the parasitic loads are not required



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Miscellaneous Transmission Requirements

• GBX shall function normally with only one engine on-line (operating at 4,500 kW)

• Load/Speed spectrum not defined. Craft will operate at sustained speeds from 80-100% (50% time each). GBX should be able to operate at 4,500 kW for 5% of the time and 3,500 kW for 95% of the time.

• Casing material shall be high-strength aluminum alloy compatible with marine environment.

• Distance between the engine compressor flange and the gearbox can be varied, but is a function of the airflow (and plenum dimensions) required by the engine OEMs.

• Shafting/Couplings and alignment procedures will be used to maintain alignment limits.

• Chip detectors should have a zapping capability.

• Vibration monitoring suite will monitor gearbox vibration.



Installation Requirements

• Gearbox is hard mounted to the bulkhead (Aft side of BHD1)

• Gearbox must fit within the dimensions of the gearbox compartment

• Gearbox cannot interfere with blow-in doors and cooling fans

• Scavenge duct angles down toward the deck. Gearbox cannot interfere with the duct.

• Air temperature in gearbox room during operating = 120 F



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Navy Gearbox Concept

• Three modules to enable removal– Input module

– Lift module

– Propulsor module (reconfigured from port to stbd)

• Single Parallel Axis Main Reduction Gear– Dual Input / Double Reduction Gearbox

• 1st Reduction - 5.03:1

• 2nd Reduction– Lift - 1.73:1

– Prop - 2.37:1

• Weight estimate: 1694 kg without clutches



30


Lift System Module

Propulsor Module

Input Module

Gearbox Concept – Stbd Side, Aft Looking Forward



31


Gearbox Concept – Isometric view

Lift System Disconnect Clutch (Hidden)

PropulsorDisconnect Clutch

Craft Service Generator

Lift Fan Shaft Reversing

Mechanism (Epicyclic)

Engine Input Shaft



32


Gearbox Concept – Isometric Showing Internals


Approved for public release; distribution is unlimited.33


Gearbox Concept – Looking Forward, Showing Internals

Gearbox Concept – Looking Aft, Showing Internals



Lift Fan System

• Centrifugal fan• Double width, double inlet impeller with

26 cambered blades• One lift fan per drive train• Impeller materials

– Center Disc: AA6061-T6 Aluminum plate

– Shroud: Formed AA5083 Aluminum– Blades: Extruded AA6061-T6 Aluminum– Spinner: Composite– Volute: Composite– Bearing/Shaft support structure:

AA6061-T6 Aluminum extrusions and plate

• 95% operating speed (N2): 1715 RPM



Lift Fan System General Requirements

• Individual impeller blade rapidly replaceable onboard craft

• Blade attachment bolts shall not exceed 102 mm in length

• The volute shall have a horizontal bolt joint split below the shaft

• Volute local reinforcing elements may be used to maintain a 2772mm longitudinal fan width (maximum)

• Two accesses shall be provided on the inboard side of the volute– One above the bolt joint to access blades for removal

– One below the bolt joint to access the top of the cushion vanes

• Structural requirement for lift-fan hull opening to house below-the-deck volute diffuser



Lift Fan Loads

• Impeller shall be structurally designed at a nominal speed of 1715 RPM and shall survive a water ingestion of 300 liters/sec without effecting its performance.

• Impeller shall be designed for 30 minute overspeed at 2092 RPM.

• Volute and transitional duct designed at an internal air pressure of 8.3 kPa at 100% N2 and a simultaneous external wave slap load of 51.7 kPa.

• BT nozzle designed at 17.3 kN thrust normal to its exit plane, 11.7 kPa internal air pressure, 17.2 kPa peak internal pressure, 16.7 kNhorizontal and 22.3 kN vertical reactions at the nozzle base.

• Cyclic loads used for fatigue design shall be calculated based on both:

– The impeller operating for the life of the craft at ANSI/AMCA Standard 204-05 “Balance Quality and Vibration Levels for Fans” seismic vibration velocity limits.

– The impeller operating with an imbalance of 90,000 g.mm for 240 minutes.



Lift Fan Structural Concept

• Above deck lift fan structure design– BT maintenance stand with the

electric actuator installed below the stand

– Transition duct between the lift fan volute and BT - Composite

– T-shape bearing support (exploring alternative designs)



Navy Concept for Lift Fan Blade Attachment

• Blade root to center disc– Eight 14mm bolts

• Blade tip to shroud– Four 10mm bolts

• Non-extruded sections (caps) welded to extruded section

Non-extruded blade root section, welded to blade and used to attach blade to the center disc



Structural Design Concept

• Rotors, stators, shroud and rudders shall all be constructed using a carbon fiber composite

• The shroud concept is designed with a focus on minimizing axial stiffeners, especially in the region of the rotating propeller. This focus is intended to minimize the mechanical stresses that are induced in the shroud by the unsteady pressure pulses that exist about the propeller blade tip.

• The shroud is constructed from a corrugated style carbon web that is continuous from leading edge to trailing edge.

• The shroud is attached to the deck of the craft through two feet that mate to the shroud corrugated structural web.

• All thrust must be transferred to the hull through the shroud mounting feet.



Structural Design (Conceptual)

• The stators are constructed from a corrugated carbon core. Aerodynamically shaped leading and trailing edges are manufactured separately and are mechanically attached, to facilitate later removal. The pressure and suction skins are manufactured from carbon and are also mechanically attached. This manufacturing approach makes interior space available for running cables, hydraulic lines, etc.

• Individual stators shall be removable.

Stator Interior

Assembled Stator



Foreign Object Damage (FOD)

– The Foreign Object Damage (FOD) screen consists of a conical support frame and a net.

– The FOD screen shall protect the propeller, stator and shroud leading edge against ingestion of objects from the forward direction.

– The FOD screen shall protect the propeller, stator and shroud leading edge from objects with kinetic energies of up to 200 N-m/s at forward speeds, including masses up to 30 kgs.

– The FOD net shall stop objects greater than 100 mm in diameter.

– The FOD frame shall consist of nine equal sections, with no opening greater than 0.4m^2. The FOD frame shall be constructed of a composite material.

– The shroud shall have provisions for the attachment of a forward Foreign Object Damage (FOD) screen. There shall be no less than nine attachment points. Each attachment shall be capable of supporting a 2.5 kN load in any direction. The attachment points shall be on the outside surface of the shroud at least 180 mm aft of the shroud leading edge.

– The support structure of the FOD screen shall withstand point loads of 1 kN in any direction.

– The conical frame shall be approximately 1.2 m deep.

– The conical frame shall include a section that opens to permit personnel access to the propeller.



Anti-icing

• The propulsor shall be protected from icing damage by the use of an electric thermal anti-icing system.

• The icing system shall operate on the leading edge of the shroud as shown in the figure.

• Currently, the anti-icing system is required on the shroud leading edge only. We're reluctant to add anti-icing capabilities in the propeller sweep area because of the pressure pulses in that region. Our proposed philosophy –anti-icing on the shroud leading edge only – is similar to LCAC which has functioned adequately. We would be interested in opinions from the structural design standpoint.

• The ultimate purpose of the anti-icing system is to prevent damage to the propeller. Ice cannot be allowed to build up on the shroud leading edge because it can break off and impact the spinning propeller.

• Power assumed for each anti-icing system (one port, one starboard) is 1.5kW at 28Vdc

• The machinery system components shall start and continue operating with ambient air temperatures between -12.2 and 37.8 degrees C and relative humidity up to 100 percent – the anti-icing system must prevent ice within this range.

Anti-icing region



Shroud void (for rotor blade removal)

• Access void at bottom (6 o’clock) of shroud (conceptual)

• Void is large enough to allow removal of one de-pitched rotor blade

• Void is not larger than necessary for single blade removal

• Void does not disrupt structural ribs within the shroud

• Void is filled by a plug during operation

Void/Plug concept



Electrical Plant One-Line Diagram



Reliability Block Diagram

A

1B



Reliability Information

Navy Assumptions:

machinery system information 2009-10-29

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