Overview of the CTOL and STOVL Full Scale Static Tests on ...

F-35 Program Information

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© 2009 Lockheed Martin Corporation

Overview of the CTOL and STOVL Full Scale Static Tests on F-35 Lightning II

Program

Marguerite E. Christian

Technical Lead, Full Scale Static Test

F-35 Structures Development

Lockheed Martin Aeronautics Company

2009 Aircraft Structural Integrity Program (ASIP) Conference

December 1-3, 2009

Jacksonville, FL

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

2

Non-Technical Information

Use or disclosure of the information contained herein is subject to the restrictions on the Cover Page© 2009 Lockheed Martin Corporation

Acknowledgements

• Bob Burt, Director, F-35 Structures Development

Team

• Phil Gross, Deputy Director and Chief Structures

Engineer, F-35 Structures Development Team

• Joe Yates, Senior Manager, F-35 Structures Test

• Don Whiteley, STOVL Variant Chief, F-35 Full Scale

Static Test

• John Bradley, CTOL Variant Chief, F-35 Full Scale

Static Test

• Keith Jackson, Test Coordinator, F-35 Full Scale

Component Tests

3



Tri-Variant Joint Strike Fighter (JSF)

F-35C CV

Span . . . . . . . . . . . . . . . . . . . . . . . . 43 ft / 13.11 m

Length . . . . . . . . . . . . . . . . . . . . . 51.4 ft / 15.67 m

Wing area . . . . . . . . . . . . . . . . . . 668 ft2 / 62.06 m2

Combat radius (internal fuel) >600 n.mi / 1,111 km

Range (internal fuel) . . . . . >1,200 n.mi / 2,222 km

F-35B STOVL

Span . . . . . . . . . . . . . . . . . . . . . . . 35 ft / 10.67 m

Length . . . . . . . . . . . . . . . . . . . . 51.2 ft / 15.61 m

Wing area . . . . . . . . . . . . . . . . . . 460 ft2 / 42.7 m2

Combat radius (internal fuel) >450 n.mi / 833 km

Range (internal fuel) . . . . . . ~900 n.mi / 1,667 km

F-35A CTOL

Span . . . . . . . . . . . . . . . . . . . . . . . . 35 ft / 10.67 m

Length . . . . . . . . . . . . . . . . . . . . . 51.4 ft / 15.67 m

Wing area . . . . . . . . . . . . . . . . . . 460 ft2 / 42.7 m2

Combat radius (internal fuel) >590 n.mi / 1,093 km

Range (internal fuel) . . . . . ~1,200 n.mi / 2,222 km

Conventional

Take-

Off and

Landing

Short

Take-

Off and

Vertical

Landing

Carrier

Variant

4



F-35 Full Scale TestsLocations & Fixture Sharing

STOVL Static STOVL DurabilityCTOL Static

CTOL Durability

CV Durability

CV Static

CV Drop

Vought Aircraft Industries,

Grand Prairie TX, US

Lockheed Martin

Fort Worth, US

British Aerospace Systems

Brough, UK

5



Requirements Comparisonof AG-1 and BG-1

AG-1 (CTOL) BG-1 (STOVL)

159 Load Rams 164

3335Strain and Deflection

Channels3711

163 Test Runs 211

6



Full Airframe Test Conditions for AG-1 and BG-1

AG-1 (CTOL) BG-1 (STOVL)

No. Maneuver Description No. Maneuver Description

1 9g Abrupt Pull-up, 0.60/SL 1 -3g Right Trim WB Door Opening Event, 1.05/7K

2 1g Yaw Gust, 1.05/SL 2 5.6g Right Rolling Pull-Out, Full Command/Rate, 1.05/20K

3 4g 360 Deg Roll to Right, 1.50/40K 3 -1g 180 Deg Roll To Left, 1.05/7K

4 1g 360 Deg Roll to Left, 1.05/SL 4 -1g 180 Deg Roll To Right, 1.05/7K

5 7.2g 360 Deg Roll to Right, 0.60/5K 5 7g Abrupt Pull-Up, 1.05/7K

6 -3g Push Over, 0.95/SL 6 -3g Push-Over, 0.90/SL

7 7g Wind-up Turn, 1.20/20K 7 7g Wind-Up-Turn, WB Door Opening Event, 0.90/SL

8 -3g Push Over, WB Door Opening Event, 0.90/SL 8 -3g Push-Over, WB Door Opening Event, 0.95/SL

9 9g Wind-up Turn, 0.95/SL 9 7g Wind-Up-Turn, WB Door Opening Event, 0.95/10K

10 1g 180 Deg Roll to Left, 1.50/22K 10 7g Abrupt Pull-Up, 0.60/10K

11 9g Abrupt Pull-up, 0.80/SL 11 0g 180 Deg Roll To Left, 0.80/SL

12 9g Wind-up Turn, 0.90/SL 12 0g 180 Deg Roll To Right, 0.80/SL

13 -3g Push-over, 1.05/SL 13 1g Steady Sideslip To Left, 0.95/SL

14 9g Wind-up Turn, Hammer Shock Event, 1.05/SL 14 4g Rolling Pull-Out To Left, 1.50/28K

15 2g Rolling Pull-out to Right, 0.90/SL 15 2g Rolling Pull-Out To Left, 1.50/40K

16 0g 180 Deg Roll to Right, 0.95/SL 16 0g 180 Deg Roll To Right, 0.95/5K

17 1g 360 Deg Roll to Left, 0.95/5K 17 1g Steady Sideslip To Right, 1.05/15K

18 1g 360 Deg Roll to Right, 0.95/5K 18 4.8g Abrupt Pull-Up, 0.60/SL

19 5g 360 Deg Roll to Right, 0.80/SL 19 2g Rolling Pull-Out To Right, 0.95/SL

20 0g 180 Deg Roll to Left, 0.95/SL 20 4.5g Rolling Pull-Out To Left, 1.05/12K

21 2g 360 Deg Roll to Left, 1.05/12K 21 2g Rolling Pull-Out To Right, 0.90/SL

22 -1g 180 Deg Roll to Left, 1.50/22K 22 3.8g Rolling Pull-Out To Left, 0.90/SL

23 1g Steady State Sideslip, 1.05/SL 23 Brake Left

24 4g Rolling Pull-out to Left, 1.05/SL 24 Tiedown - Heavy Weather

25 9g Symmetric Trim with WBD Open, 1.05/SL 25 Tiedown - Moderate Weather

26 9g Symmetric Trim with WBD Open, 0.95/SL 26 0.5g Selective Stores Jettison, 0.95/SL

27 9g Abrupt Pull-up with Buffet, 0.60/5K 27 7g Wind-Up Turn, WB Door Opening Event, 1.05/7K

28 5.5g 360 Deg Roll to Right, 1.05/SL 28 Hybrid: 7g Right Pull-up, 0.60/15K + 7g Wind-Up Turn, Hammer Shock Event

29 Hybrid: Towing, Right Turn + 0g 180 Deg Roll, 1.50/22K 29 Hybrid: 7g Wind-Up-Turn, WB Door Opening Event + 7g Wind-Up Turn

30 Hybrid: Taxi + 9g Pull-up/Push-over 0.60/SL 30 Hybrid: 1g 180 Deg Roll To Right + 1g Steady Sideslip to Right, 1.05/7K

31 9g Wind-up Turn, 0.95/SL – STRAIN SURVEY

32 9g Abrupt Pull-up, 0.80/SL – STRAIN SURVEY

7



STOVL Local Static Tests

Refuel Probe Back-up

Structure and Mechanism

Outboard Weapons Bay Door (WBD)

Inboard WBD and Cradle

Fwd Main Landing Gear (MLG) Door

MLG Inboard Trunnion Support Structure

MLG Drag Brace Interface at FS450

MLG Outboard Trunnion Support Structure

Nose Landing Gear

(NLG) Doors

Fwd Fuse Side Skin

* Weapons Bay Sta 8 Hardpoints

Jacking

Hoist

Cockpit Pressure

Fuel Tank PressureEngine Thrust Mount

Engine Mount-Fwd Upper

Vane Box

Lift Fan Exhaust

Lift Fan Mounts

Boarding Ladder Door

Aux Air Inlet

Lift Fan Inlet

RCN Door Attach

Structure

Nose Landing

Gear (NLG)

Backup

Structure

* Wing-Pylon Sta 9

* Wing-Pylon Sta 10

* Wing-Pylon Sta 11

Completed Tests

102 Local Test Runs

50 Local-Global Test Runs

* Sta 6Performed airframe capability

testing at in support of future

weapon systems

*

8



CTOL Local Static Tests

Completed Tests

53 Local Test Runs

43 Local-Global Test Runs

Cockpit

Pressure

In-Flight Refuel

Receptacle

Backup StructureHoist

Engine

Thrust

Mount

Weapons Bay

Sta 8 Hardpoints

MLG

Backup

Structure

Wing – Pylon Sta 9



Jacking

Fuel Tank

Pressure

Inboard WBD, Sta 5,

and Backup Structure

Outboard WBD and

Backup Structure

Arresting

Gear Backup

Structure

MLG Uplock

Backup

Structure

Vertical

Tail

Hinge 3

Vertical Tail

Shear

Fitting

Engine

Mount, Fwd

Upper

Engine

Mount,

Fwd Side

Airframe capability testing

planned in support of future

weapon systems

Airframe capability testing

planned in support of future

weapon systems

9



AG-1’s Journey Across the Atlantic

Transport from FW to Houston, TX

Secured in hull of

shipping vessel

Transfer to barge for trip

down Humber River

Ocean

journey took

18 days

Reported UFO

sighting in Dallas, TX

10



AG-1 Arrival at BAES April 25, 2009

Arrival at Brough at 6:30 AM

Largest

crane in UK

used to lift

AG-1 from

barge.

Maneuvering around BAES site Delivered at BAES

test facility

11



Achieved Unprecedented Test Rates

0

50

100

150

200

250

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Days from Test Start

Test Runs

Legacy ALegacy CLegacy E - Less unit loads Legacy F - Less calibrationsLegacy TF-35 BG-1 Orig PlanF-35 BG-1 Current PlanF-35 BG-1 Execution

Calendar Days from Test Start

12



Still Improving……

• AG-1 Schedule Revised Based Upon BG-1 Test Performance

• Testing Continues to Outpace Flight Test Need Dates

• Current Pace Indicates Test Completion 6 Months Ahead of Baseline

• BG-1 Static Tests Remained Well Ahead of Flight Test Need Dates

• Completed Test Program Despite Delayed Test Start and Addition of 27 Expanded Capability Tests

0

25

50

75

100

125

150

175

200

225

Jan-08

Feb-08

Mar-08

Apr-08

May-08

Jun-08

Jul-08

Aug-08

Sep-08

Oct-08

Nov-08

Dec-08

Jan-09

Feb-09

Mar-09

Apr-09

May-09

Jun-09

Jul-09

Aug-09

Sep-09

Oct-09

Nov-09

Dec-09

Jan-10

Feb-10

Mar-10

Apr-10

May-10

Test Runs

Actual

Baseline Plan

Flight Clearance Dates

Expanded Testing

STOVL Doors

? Planned Delivery 01/11/08

? Actual Delivery 05/28/08

�Test Completion 11/12/09

First Flight

80%/64%

100%/80% Need

Date 5/26/2011

Phase 0

Phase 1

Phases 2 & 3

Phase 4

Phase 5

Phases

6, 7 & 8

NLG Door

STOVL Static Test (BG-1)

CTOL Static Test (AG-1)

Projected Test

Completion

0

25

50

75

100

125

150

175

200

225

Nov-08

Dec-08

Dec-08

Jan-09

Mar-09

Mar-09

Apr-09

May-09

Jun-09

Jul-09

Aug-09

Sep-09

Oct-09

Nov-09

Dec-09

Jan-10

Feb-10

Mar-10

Apr-10

May-10

Jun-10

Jul-10

Aug-10

Sep-10

Oct-10

Nov-10

Dec-10

Jan-11

Feb-11

Test Runs

AG-1 ActualAG-1 Baseline PlanAG-1 Revised Plan (BG-1 Rate Incorp)AG-1 Extended TestsFlight Clearance DatesAG-1 Extended Testing

80%/64%

100%/80%

Need date

01/26/201

1

Phase 0

Jan-09

Feb-09

Apr-09

May-09

Jun-09

Jul-09

Aug-09

Sep-09

Oct-09

Nov-09

Dec-09

Jan-10

Feb-10

Mar-10

Apr-10

May-10

Jun-10

Jul-10

Aug-10

Sep-10

Oct-10

Nov-10

Dec-10

Jan-11

Feb-11

Mar-11

Phase 1

Phase 2

Phase 3

Phase 4

First Flight

Transport

13



Test Rate Enablers

• Well Organized and Documented Planning

• Efficiency of Test Fixture Required Minimal Set-up Changes

Between Test Conditions

• Robustness in Data Acquisition System Eliminated Channel

“Swap-out”

• Efficiency of Team Protocol for Test Preparation Tasks

• Flexibility to Adjust Test Sequence to Maximize Efficiency

• Inherent Structural Integrity of Test Article

Test Data Agrees Very Well With Predictions – Full Correlation in Work

TCN 29966, Test Values vs. Strain Predictions at 150% DLL

-12500

-7500

-2500

2500

7500

12500

-12500 -7500 -2500 2500 7500 12500

Strain Prediction (micro strain)

Test Value (micro strain) .

Above Prediction

Above Prediction

Below Prediction

Below Prediction

Reversal

Reversal

Linear FEM Prediction

RHS Wingbox Rib - Vesette

Measured strain

@ 150% DLL

Non-Linear

FEM Prediction

14



Test Findings

• STOVL – Very Few Issues and No “Real” Structural Failures

• CTOL – Only Test Finding Thus Far is Slight Damage to Rudder Blade Seals

STOVL (BG-1)

Cracks at Fwd Chevron Root on LHS and

RHS Lift Fan Exhaust Doors

Cracks occurred above 115% DLL; DUL

test completed without failure

Interference Between Inboard Weapon Bay

Door and Fuselage at 50% DLL

Required door and fuselage trim

Aft Downlock Mechanism on LHS Auxiliary

Air Intake (AAI) Door failed at 129% DLL of

applied test loads

Mechanism Redesigned - added door

lock stops; replaced LHS AAI Door and

Aft Downlock Mechanism; successfully

completed DUL test without rupture

TEF and Rudder Blade Seal damage during

Control Proof of Operations Test

Presented on following charts

CTOL (AG-1)Rudder Blade Seal damage during Control

Proof of Operations Test

Presented on following charts

15



Blade Seals Damaged During BG-1 Control Proof of Operations Tests

• Trailing Edge Flap and Rudder Blade Seals Slipped off of

Bullnose at Full Deployment and Were Damaged as

Control Surface Returned to Faired Position– Defined Trim for All Development Aircraft and Modified Seal

Design for Production Aircraft

LHS Aft Door Hinge

RHS Vertical Tail and Rudder View Lkg Inbd & Fwd

Bullnose Seal Cut-out

for Rudder Hinge Bullnose

Seal

Blade

Seal

16



AG-1 Control Proof of Operations Tests

• Incorporated Lessons Learned From BG-1 CPO Test Results– Surface Deployment Angle Consistent with Expected Load Levels

– Bullnose Seals Trimmed Based Upon BG-1 Finding

• No Damage to Wingbox Control Surface Blade Seals

• Minor Damage to Rudder Blade Seals – Study On-going

AftLower

Blade Seal

View Looking Inboard and

Down at RHS VT

Middle

Blade Seal

Chafing of upper edge on

outboard lower blade seal

Down

Aft

IML of Outboard Middle Blade Seal

at Bullnose cut-out for RH VT Hinge 3

Surface delamination on

IML of middle blade seal

17



CTOL Horizontal Tail Component Test

• Testing Performed at BAES Test Facility in Brough, UK

• Seven Test Cases to 115% and 150% DLL

• 197 Channels of Strain/Deflection Data and 12 Load Rams

• Reduced Test Schedule by 40% and Completed Testing

Approximately One Month Early

View of Upper Surface

Inbd

Aft

• Successfully Completed

Maximum Up and Down

Bending Tests to 200% Limit

Load in May 2009

– No Structural Failures

– Test Level Limited by Fixture

Capability

• Note: STOVL Horizontal Tail

Testing Completed in 2008

Ahead of Schedule

– Tested Specimen to Failure;

Maximum Load Level Achieved

224% DLL

HT installed in fixture with upper

surface facing downward.

18



Test Finding for CTOL Horizontal Tail Test

• Bearing Installed in Inboard Test Fixture Lug Migrated

During 115% Limit Load Side Load Test

– Resulted in Modification to Bearing Design and Retention Method

for Production Aircraft

• Installed Retainer Ring Upon Completion of 200% Limit

Load Test and Successfully Completed 150% Limit Side

Load TestInbd

Aft

View

Looking Up

Horizontal Tail Hinge Spar

Lower Cap

Exposed Bearing

Outer Race

Fixture

Inboard

Lug

19



BG-1 Testing Supports Flight Test Envelope Expansion

BG-1 Phase 0 – 1st Flt & Out-of-fixture Conditions

• NLG Door Open & VAVBN Vane Loads

• Cockpit & Fuel Tank Pressure Tests to DUL

BG-1 Phase 1 – Initial STOVL Mode & Air Refuel

• LFI, LFE, AAI Doors

• Air Refuel Probe Backup Structure, Lift Fan Mounts

BG-1 Phase 2 – Doors / 115 & 150% DLL

• NLG Doors & FF Side Skin Hammershock

BG-1 Phase 3 – CPO and Doors/115 & 150% DLL

• Control Proof of Operations Tests

• AAI Doors w/ Hammershock & Weapons Bay Doors

BG-1 Phase 4 – Initial Full AF Conditions to 115% DLL

• 7 FAF Test Conditions (Includes Engine Hammershock)

BG-1 Phase 5 – Full AF Conditions to 150% DLL

•Wing Up/Down Bending, Max/Min Fuselage Bending

• 7g Maneuver w/ Hammershock Pressure

BG-1 Phase 6 – Local Tests #1

• Fwd MLG Door & RCN Door & Backup

BG-1 Phase 7 – Local & Global/Local Tests

• MLG Backup, Taxi & Tow, Wing Hardpoints* & Ladder Door

•Weapons Bay Hardpoints* & Sta 5/7 ASRAAM Hangfire

BG-1 Phase 8 – Final Tests

• Engine & Lift Fan Mounts, Jacking, Hoist & Tie-down, Sta 6*

Jun ‘08

Oct ‘09

Nov ‘09

Test Completion

NLG Test Supports BF-1

Initial Flight Clearance

CTOL Flight w/ open

STOVL Doors

Hover Pit Entry

Limited STOVL Mode

Clearance

Air Refuel

80/64% Allowable

Load Envelope Flight

Clearance Support

Weapons

Separation

Ship Suitability &

Final Certification

Clearance Event

100% Allowable Load

Envelope Pursuit for

Loads Aircraft

May ‘09

Jun ‘09

Oct ‘09

Dec ‘09

Feb ‘09

BF-1 1st Flight

Sep ‘08

* Includes Extended Capability Tests

20



AG-1 Test Phases & Flight Test Support

Test Completion Clearance Event

AG-1 Phase 0 – 1st Flight

• Cockpit/Canopy and Fuel Tank Pressure Tests to DUL

AG-1 Phase 1 – In-Flight Opening of WBD

•WBD Open and Closed Tests to 150% DLL

AG-1 Phase 2 – In-Flight Refuel and CPoO

• In-Flight Refuel Receptacle Tests to DUL

• Control Proof of Operations Tests

AG-1 Phase 3 – Initial Full Airframe Conditions to 115%

DLL

• 6 FAF Test Conditions (Including Hammershock)

AG-1 Phase 4 – Full Airframe Conditions to 150% DLL

•Wing Up/Down Bending, Fuselage Up/Down Bending

• Hammershock w/ 9g Maneuver

• Control Surface Max Hinge Moments

AG-1 Phase 5 – Local and Local/Global Tests to 150% DLL

• NLG Backup, MLG Trunnions, Jacking, Hoisting

• Engine Mounts Backup, Arrestor Gear Backup

•Weapons Stations Expanded Capability

Supports Initial Flight

Clearance

In-Flight Opening Door

Clearance

Aerial Refueling

80/64% Allowable

Load Envelope

Flight Clearance

100/80% Allowable

Load Envelope Flight

Clearance Support

Feb ‘09

Aug ‘09

Oct ‘09

Oct ‘09

Dec ‘09

100/80% ALE Flight

Clearance

Weapons Separation

Arresting Gear 100%

Max Take-Off Gross

Weight

May ‘10

• 46% of Testing Completed to Date

AF-1 1st Flight

21



Summary

• Test Progress Unprecedented

– BG-1 Completed Per Baseline Schedule Despite Delayed Test Start and Limited Number of Test Anomalies/Findings

– Schedule Savings Allowed Incorporation of Expanded Capability Tests Without Impact to Flight Clearance Support

– CTOL and STOVL Horizontal Tail Component Tests Completed One Month Ahead of Schedule; Reduction of About 40%

• Demonstrated Strength Capacity Above 150% Limit Load for CTOL and STOVL Horizontal Tails and STOVL Weapons Hardpoints

• Lessons Learned Implemented for Remaining Static and Durability Test Articles

• CTOL Test In-Progress and Keeping Pace with BG-1 Performance

– AG-1 Test Started per Baseline and Expected to Finish 6 Months Earlier Than Planned

• What’s Next?

– CV Drop Test to Begin in Jan. 2009

– First Full Scale Durability Test (CTOL) to Begin in Feb. 2010

– CV Full Scale Static Test Scheduled to Begin Sept. 2010

Static Test Results Verifying Outstanding Structural Integrity

of F-35 Lightning II Design

22



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