CH-53K Heavy Lift Helicopter

A Survivability Focused Design

Presented at the American Helicopter Society 67th Annual Forum Virginia Beach, VA

May 3-5, 2011

This is a work of the U.S. Government and is not subject to copyright protection in the U.S.

Kathy Russellkathy.russell@navy.milVulnerability Analyst

NAVAIRChina Lake, California

Martin Krammermartin.krammer@navy.milVulnerability Test Engineer

NAVAIRChina Lake, California

Richard Gardnerrichard.gardner@navy.mil

Survivability LeadNAVAIR

Patuxent River, Maryland

Nicholas Gerstnernick.gerstner@survice.com

Survivability AnalystSURVICE Engineering

Dayton, Ohio

Introduction

Next Generation

Heavy Lift Helicopter for the US Marine Corps

• Operational

Requirements

More Survivable Design

CH-53ECH-53K

• Survivability

Key Performance

Parameters

• Air Vehicle

Specification

Background

Balanced Survivability Approach

•Susceptibility - the inability of an aircraft to avoid being hitSusceptibility Reduction - missile warning and missile jamming or decoying further enhance the survivability capabilities of the platform

•Vulnerability - the inability of an aircraft to sustain damage once hitVulnerability Reduction – threat tolerant design

Susceptibility and Vulnerability Reduction Verification• Analysis • Flight Test • Live Fire Test

Susceptibility Reduction

Threat Avoidance

Susceptibility reduction for the CH-53K consists of an integrated Aircraft Survivability Equipment (ASE) suite

Radar Warning Receiver AN/APR-39B(V)2 (RWR)/Electronic Warfare Management System Directional Infrared Countermeasures System (DIRCM) AN/AAQ-24(V)

 Missile Warning System (MWS) *update – Laser Detection incorporated with MWS Countermeasure Dispenser System (CMDS) AN/ALE-47

Analysis and Flight Test will assess the ASE system effectiveness against AVS threats

SusceptibilityVerification

Susceptibility Analysis•Incorporates threat systems•Aircraft performance data•Various models and simulations

– Moderate Transmittance (MODTRAN)– Modeling System for Advanced Investigation of

Countermeasures (MOSAIC)– Future Operational Combat Unified Simulation

(FOCUS)– Multi-Service Electro-Optics Signature

(MuSES)

Survivability Requirements

CH-53K Key Performance Parameters

Two of the seven system KPP’s are Survivability Requirements

•Fly Away Capability – Ballistic Tolerant Design•Force Protection – Cockpit and Cabin Armor

Meeting the KPP requirements

•Challenging yet achievable Air Vehicle Specification (AVS)•Continuous Survivability Analyses•Early Ballistic Tests•Early involvement and a coordinated survivability team

Vulnerability Reduction

VulnerabilityVerification

Analysis and Test

MODEL TEST

VulnerabilityVerification

Vulnerability Analysis – Critical Data Sets

Geometry Conversion Techniques• SAC CATIA to BRL-CAD format• Streamlines the modeling effort • Ensures precise and accurate component representation

Traditional Data Sets• DMEA• Pd/h and Pk/d• FALT

VulnerabilityVerification

Vulnerability Analysis – Critical Data Sets

Low and Slow(L&S)

High and Fast(H&F)

0 40 80 Vmax

Helicopter Speed (kts)

0

100

Amax

Alt

itu

de

AG

L (

ft)

Low and Slow(L&S)

High and Fast(H&F)

0 40 80 Vmax

Helicopter Speed (kts)

0

100

Amax

Alt

itu

de

AG

L (

ft)

Traditional Flight RegimesDiscrete Mission Points• Define specific flight conditions

• Correlate to susceptibility analyses

Mission Points

Design ImpactInitial Assessment – Not compliant

Assessment Updates• Updated preliminary designs

• Integrated CH-53E JLF results

Design Enhancements• MGB redundant lube system

• Supplemental fuel feed system

• Main rotor actuator redesign

• Tail rotor drive shaft growth

Risk Reduction Testing• Identified components for testing to refine design and analysis

• Tail rotor drive shaft and Flexbeam successfully tested

• Additional items identified for testing

VulnerabilityVerification

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Analysis Update Reference No.

Status Spec

Initial assessment

RR testing

CDR

Risks From CDR Design Challenges

PDR

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Analysis Update Reference No.

Status Spec

Initial assessment

RR testing

CDR

Risks From CDR Design Challenges

PDR

VulnerabilityVerification

Assessment ProgressionMilestone Assessments – Compliant

Force Protection Verification

Design ImpactInitial and Milestone Assessments – Compliant

Assessment Progression• KPP requirements addressed cockpit and cabin occupant protection

• Weight optimization studies conducted to minimizeineffective armor and maximize protection

• Design changes assessed for impact on protection levels

Initial PDR Design Current CDR DesignInitial PDR Design Current CDR DesignCDR Cockpit Armor

CDR Cabin Armor

CH-53K Survivability

• Risk Reduction Tests─Tail Rotor Flex Beam

─Tail Rotor Drive Shaft

─ Sponson Material - Fuel Cell Interaction

─ Fuel Line Leak Containment

• Live Fire Tests

Risk Reduction Test

Tail Rotor Flex Beam Test

Test Damage

Ballistic Impact

Test ConclusionTest articles were able to maintain

the loads after damage

Test ConclusionTest articles were able to maintain

the loads after damage

Risk Reduction Test

Tail Rotor Drive Shaft Test

Ballistic Impact

Test Damage

Test ConclusionTail Rotor Drive Shaft is tolerant to the AVS

ballistic threat

Test ConclusionTail Rotor Drive Shaft is tolerant to the AVS

ballistic threat

Test Set-up

Demonstrates structural capability to respond to hydrodynamic ram

• Sponson composite wall construction• Self sealing performance of candidate fuel bladder

Risk Reduction Test

Sponson Material – Fuel Cell Interaction

Proposed solutions tested for leak mitigation / fire suppression initiated by ballistic impacts on fuel feed lines

Fuel Line Leak Containment

• CH-53K is designated as a covered LFT&E system– U.S. Code Title 10, Section 2366 (10USC2366)

• Alternative LFT&E (ALFT&E) strategy uses analysis to aid in

identification of critical components and viable test shots

• Key Focus Areas– Collateral and cascading effects

– Assess potential crew and passenger casualty

– Assess CH-53K Battle Damage Assessment and Repair procedures

– Provide survivability comparison of CH-53K with legacy CH-53E

– What modifications can be made to reduce the vulnerability of the CH-53K?

LFT&E

• MRGB• IGB & TGB• TR Drive Shaft• TR Flex Couplings• TR Disconnect Couplings

Main and Tail Rotor Servos

Stationary and Rotating Scissors

TR Pitch Beam Pitch Control Link

• TR Blade, Flex Beam• TR Pitch Link• TR Pitch Change Shaft• TR Shaft• TR Pitch Beam• Armor – Crew, Cabin• Propulsion – GE 38

Component Level Ballistic Tests

• TR Hangar Bearings & Mounts• Stationary Scissors• Swash Plate• MR & TR Servos• Sponson structure & cell

•Drive System Tests– MRGB Rear Module– TR Gearbox– Intermediate Gearbox– TR Drive Shaft – TR Flex Coupling– TR Disconnect Coupling– TR Hanger Bearing and

Bracket– NGB-MRGB Shaft, Coupling

Hanger Bearing– Rotor Brake– NGB & Mounts

•Armor Tests– Cabin floor / wall– Cockpit seat & wing

•Structure Tests– Transition and Tail

•Fire Tests– Engine Nacelle

• Fire detection / ext. system

– Fuel System• Sponson / SEFS• Feed (Engine)• Dump & Refuel • Fuel line Sleeves

– Hydraulic System

•Flight Control Tests– Control boxes & wiring– MR Servo Actuator– TR Servo Actuator– TR Blade

– TR Hub

– TR Pitch Beam

– TR Control Link– TR Pitch Change Shaft– Swashplate

GTV System Level Tests

CH-53E(mounted on a hover stand at WSL during JLF Tests)

Model - Test - Model

MODEL TEST

Initial A

ssessment/

Model

PDR Update

CDR Update

MS - C / OTRR

Trade Studies

Trade Studies

Lessons learned

from previous

programs

e.g. CH-53E

Risk Reduction Test results

Data from formal live fire

test program

ENSURES SURVIVABLE DESIGN

Questions ?