c-130 structural changes through its life

1

© 2011. LOCKHEED MARTIN CORPORATION. ALL RIGHTS RESERVED

Positive Changes to a

Classic Design: Structural Changes

Through the Life of the C-130

Frank McElwain Dept Mgr, C-130 Structural Analysis

Aircraft Airworthiness & Sustainment 2011

April 21, 2011

2 © 2011. LOCKHEED MARTIN CORPORATION. ALL RIGHTS RESERVED

C-130 History, Variants, Missions

Outline

Changes, Prior to the C-130J

Closing Remarks

Call for the C-130J, C-130J Changes

C-130J Features and Benefits

The ESL Wing


The Year:

1951

The Current Platform:

Fairchild C-119 Flying Boxcar

The Problem:

As The US Entered The Korean War, The USAF Realized It Lacked A True Military Transport Capable Of Airlifting Combat Troops Over Medium Distances And Delivering Them To Short, Austere Airports.

Initial Aircraft Requirement


Initial Aircraft Requirement

• The Solution: A New Medium Cargo Transport

• USAF Requirements:

– Carry Ninety-two Infantrymen Or Sixty-four Paratroopers On A

Mission With A Combat Radius Of 1,100 Nautical Miles, Or,

Alternatively, A Thirty-Thousand Pound Cargo Over 960 Miles,

– Operate From Short Unprepared Airstrips Of Clay, Sand Or

Humus Soil,

– Slow Down To 125 Knots For Paradrops And Even Slower For

Assault Landings,

– Have Both A Rear Ramp Operable In Flight For Heavy-

Equipment And Side Doors For Paratroop Drops,

– Handle Bulky And Heavy Equipment Including Bulldozers,

Artillery Pieces And Trucks, And

– Fly With One Engine Out.


The Model 82

• Kelly Johnson‟s Purported Assessment:

Design Team Lead:

Willis Hawkins, Chief Of Preliminary Design

Aesthetics Weren’t The #1 Priority

"It's a pretty good design, but you won't sell

more than a hundred of them."


Contract Awarded To Lockheed

• The Competitors:

► Boeing

► Douglas

► Lockheed

► Fairchild

• The Winner: Lockheed‟s Model 82

– On July 2, 1951 Lockheed Awarded Contract To Produce Two Prototype YC-130 Aircraft


Key Design Characteristics

– The Model 82 Was The First Tactical Airlifter And Featured:

• Large, Unobstructed, Fully-Pressurized Cargo Hold

• High-Wing Design To Place Cargo Floor At Truck-bed Height

• Integral Roll On/Roll Off Rear Loading Ramp

• Low Landing Speeds, Short-Field Capability, And Previously

Unavailable Austere Landing Field Capabilities

• Ability To Be Quickly Reconfigured For Carriage Of Troops,

Stretchers, Passenger Box, Or Support Or Airdrops Of Troops

And/Or Equipment Into Forward Battle Zones.

• Tremendous Lift Capacity, Range, 365 Mph Cruising Speed,

And Flight Handling Characteristics


First Flight August 23, 1954

“She’s a real flying machine. I could land it crossways on the runway if I had to.” Stan Beltz, Test Pilot


YC-130 Flight Test Performance

Maximum Payload Of 40,000 Pounds

Exceeded All Air Force Specifications

Shortly After The Successful First Flight, The Air Force

Increased Its Order From Seven C-130As To Seventy-Five

Weight Control Measures Kept Airframe

Weight At 108,000 Pounds:

5,000 Less Than Estimated

Cruised Faster, Climbed Higher, And Landed

In 20% - 40% Less Distance Than Required


Lockheed In Georgia

Air Force “GOCO” Plant 6

„The Bomber Plant‟

Lockheed Moves To GA ,

Re-Opens Air Force Plant 6

1942: Ground Broken in March

1943: Bell Begins B-29 Production in April

1945: 28,000 Bell Aircraft Company

Employees Turning Out 50+ B-29s/Month

When WWII Ends And Plant Closes

1950: USAF Invites Lockheed To Re-Open

AF Plant 6 And Refurbish B-29s For Korean

Conflict

1951: 275 Key Lockheed Engineers And

Managers Move To Georgia from California

1952: Lockheed Wins B-47 Co-Production

Contract & Decision Made To Move C-130

Production To Georgia


Initial Production

Building B-1, Position #1

Final Check-Out

The First Lady Now Resides At Eglin AFB Armament Museum

“The First Lady” (a/c 3001)

First Flight – April 7, 1955

C-130A Production Begins in 1953 At

Air Force Plant 6, In Marietta, GA

First C-130A delivered to 463rd Troop

Carrier Wing at Ardmore AFB, Oklahoma

in December 1956


Longest Running Military A/C

Production Line • 2,370 Aircraft Produced In Five Major Versions Since

1953 And Delivered to 61 Different Nations:

– C-130A Entered Service Dec 1956

• 231 Delivered; ~17 Still in Service

– C-130B Entered Service Nov 1958

• 230 Delivered; 100+ Still in Service

– C-130J Entered Service Jun 1998

• 217 Delivered; Current Production Model

– C-130E Entered Service Jun 1961

• 488 Delivered; 300+ Still in Service

– C-130H Entered Service Mar 1965

• 1,205 Delivered; 950+ Still in Service


Variants, 70 and Climbing

• Aerial Delivery

• Aerial Fire Fighting

• Aerial Photography And Mapping

• Aerial Refueling

• Airborne Drone Launch And Control

• Airborne Hospital

• Airlift

• Commercial Airline Passenger Service

• Electronic Surveillance/ Communication/ Battlefield Control

• Gunship / Close Air Support

• Hurricane Hunter

• Maritime Patrol

• Missile Tracking And Satellite Recovery

• NASA Research

• Oil Spill Control / Dispersal

• Personnel Transport

• Rapid Ground Refueling – Tanker

• Search And Rescue

• Ski Bird

• Special Ops

• Special Accommodations / VIP Module

• Weather Observation And Research

One Of The Most Versatile Airframes In The World:


Missions

Air Dropped Insecticides, Fire Retardants, And Oil Dispersing Agents

Hauled Killer Whales, Camels, Cows, Chickens, And Horses

Been Flying Hospitals, Commercial Airliners, And VIP Quarters

Performed Solo And Formation Aerial Demonstrations

Carried As Many As 452 Passengers, Despite Being Designed To Carry Only 90

Landed And Launched Off Of A US Navy Aircraft Carrier

Landed And Taken Off From The Icy North And South Poles

Participated In All Major US Military Operation Since Korea

Responded To Major Disasters Around The World

Air Dropped Everything From Leaflets To 15,000 Pound Bombs

Supported Special Forces As Gunships And For Search And Rescue, Deep Insertion, Surveillance, And Electronic Combat Missions

Tracked Icebergs In The North Atlantic And Drug Traffickers In The Caribbean

Flown Into Hurricanes, Forest Fires, And Mapped The Earth

Since Its First Flight Over 50 Years Ago, C-130s Have:






The ESL Wing

Closing Remarks

Outline


Major Structural Components


Assy Techniques and Material Material Technology Evolution C-130 Materials

Assembly Techniques C-130 Assembly Techniques

1950’s 1960’s 1970’s 1980’s 1990’s -

2011

C-130A/B C-130E* (1) C-130H1(3) C-130H2 (2) C-130H3/J

Low Durability High Durability

Minimal Corrosion Protection Enhanced Corrosion Protection

High Corrosion Susceptibility Low Corrosion Susceptibility

(1) Includes: C-130E (61-72), MC-130E, MC-130P, HC-30P, HC-130N

(69), AC-130H

(2) Includes: C-130H2 (78-91), MC-130H, HC-130N (88-92), AC-130U

(3) Includes: C-130H1(73-74) and EC-130H

A/B E H1 H2 H3/J

Surface Treatment &

Paint Limited More Improved

Fay Surface Sealing Limited Yes Improved

Wet Installed

Fasteners Limited Yes Improved

Interference Fit

Fasteners Limited Limited Yes

Automatic Hole

Drilling Limited Limited Yes

• Original C-130A/B/E Used Best Materials

Available in 1950‟s/1960‟s

• Durability not a Requirement in C-130A/B/E

Design. Major Design Changes Incorporated

Improved Materials in Late 1960‟s Through

1990‟s and Increased Durability:

- Center Wing Redesign (FY ‟68, SOF)

- Outer Wing Redesign (FY ‟73, FY ‟84)

• Corrosion Prevention Designed into C-130H/J:

- Increased Use of Anodizing and Paint

System Upgrades

- Increase Use of Corrosion Inhibiting

Sealant in Joints and Fastener Installation

• Interference Fit Fasteners Improve Durability

• Automatic Hole Drilling Improves Fastener

Hole Quality and Enhances Durability


C-130H1 Durability Improvements

STRUCTURAL MEMBERS

PRE 1973

PRODUCTION IMPROVEMENT LMAS S/N

Cargo compartment floor beam

end ftg at FS 577 7075-T6 4340 steel assembly 3884

Engine mount drag angles, O/W 7075-T6 forging 7075-T73 forging 4542

Nose landing gear 4340 steel 300M forging, re-profiled 4638

Windshield doublers 7075-T6 clad 2024-T42 clad, increase t 3667

Flap track ribs, rear beam stiffener 7075-T6 7075-T73

3501-

4541

Center wing upper skin panels 7178-T6 or 7075-T73 * 7075-T73 4303

Center wing lower skin panels 7075-T6 or 7075-T73 * 7075-T73 4325

Outer wing skin panels 7075-T6 7075-T73 4542

Center wing beam caps 7075-T6 7075-T73 4359

Outer wing beam caps 7075-T6 7075-T73 4542

Wing corner fittings 7075-T6 7075-T73 4331-4515

Fuselage lower (sloping) longeron 7075-T6 7049-T73 4587

end fittings at FS 737 & FS 1041.5

* Used on production aircraft LASC

4301 and LASC 4303 (1968) and up.

USAF C-130E USAF C-130H1

S/S 3651 – 4527 S/S 4544 – 4735

1964 - 1972 1973 – 1974


Airframe Changes, Overview New Center Wing Design (1968):

• Increased Front & Rear Beam Web Thickness

• Upgraded Wing Panels, Beam Caps, & Corner Fittings

• Reduced-Stress Access Doors & Openings To

• Operating Stress Levels In Critical Areas Reduced 20%

• Upgraded Fatigue Life & Fail Safe Characteristics

• Increased Corrosion Resistance

New Outer Wing Design (1973): • Upgraded Wing Panel & Beam Caps Materials

• Increased Upper & Lower Rainbow Fitting Thickness

• Upgraded Rainbow Fitting Material

• Reduced-Stress Access Doors & Openings

• Operating Stress Levels In Critical Areas Reduced

18%

• Upgraded Fatigue Life & Fail Safe Characteristics

• Increased Corrosion Resistance

New Main Gear Design

(1988): • One Piece Forged Main

Landing Gear Piston

Incorporated

Upgraded Outer Wing

Design (1984): • Stronger Outer Wing

Box Rib Caps and Rib

Braces

• Skin Min-Thickness

Doubled • More Structural

Capability

• Improved Lightning

Protection

• Hi-Tigue Pins Used In

Majority of Wing

Structure

New Nose Gear Design (1975 & 80): • Redesigned NLG Cylinder & Cylinder

Fulcrum to Fulcrum Shaft Joint

• New Steering System Components

• Improved Corrosion Resistance

Upgraded Center Wing Design (1990): • Hi-Tigue Pins Used In Majority of Wing Structure


• Re-design of Lower Forward Beam Cap – New design extended previous tapered thickness run-out at WS 174

further outboard. Front beam web splice moved from WS174 to WS168.

• Re-design of WS 178 Bulkhead – Sheet metal web with fastened stiffeners to monolithic machined web

made from plate material.

• Re-design of Front and Rear Beam Webs – Increased material thickness and fewer splices. The new front beam

thickness = 25% greater in critical locations. The new rear beam web also increased in thickness and replaced 3 webs and 2 splices with one web.

• Re-design of Wing to Fuselage Attach Angle at WS 61.625 – Vertical and horizontal leg thicknesses increases.

• Re-design of Upper Forward and Aft Beam Caps: – Change from 1 row to 2 rows of fasteners at the cap to panel splice

outboard from WS140 to the corner fitting. New upper corner fittings with wider flanges to accommodate the increased beam width were also required for this change.

Center Wing Design Improvements


Outer Wing Design Improvements

•Major Redesign of Outer Wing occurred in

1973 at the first USAF C-130H (SN 4542)

incorporated the following improvements:

–Thicker Surface Panels for reduced Operating Stresses

(Increased Durability)

– Improved Materials to reduce Corrosion and Stress

Corrosion Cracking

–Eliminated riser “weep” holes which were prone to fatigue

cracking


Outer Wing Design Improvements

•Current Production Outer Wing Box based on

the 1984 Improved Outer Wing

– Incorporated Externally Mounted Fuel Probes for Improved

Maintenance Access

–Thickened the Outer Wing Surface Panels for Improved

Lightning Protection

– Improved Fastening System for Increased Durability


• Many Design Improvements incorporated during

C-130E and C-130H production

• Design Improvements addressed both Fatigue

and Corrosion Problems encountered in Service

by:

– Improved Detailed Design

– Thickness/Area Increases

– Material Changes to Improve Fatigue and

Corrosion Resistance

Fuselage Design Improvements


• Designed for Torsional and Bending Stiffness, Operating

Stress Levels are very low

• Very few reported service problems, relatively minor

design changes since C-130B: – SN 4426 Horizontal Stabilizer Tip Attachment, added Steel Straps and Angles

– SN 4471 Added Bearing Retainers for the Rudder Hinges

– SN 4515 Increased Thickness of H-Stab Leading Edge Formers

– SN 4653 Eliminated Spot-welds and cut-outs from Rudder and Elevator Control

Access Doors

– SN 4809 FS 946 V-Stab Attach Fittings changed to 7075-T73

– SN 4992:

• Added provision for Aft-Body Ventral Strakes to H-Stab

• Changed V-Stab to Dorsal Fin Leading Edge Assy to Kevlar/Epoxy and Foam Core

construction (for flush mount HF Antenna)

Empennage Design Improvements






The ESL Wing

Closing Remarks

Outline


The C-130J Super Hercules • The Year:

– 1988

• The Current Platform:

– C-130A-H Models

• The Problem:

– C-130A-H Fleet Reaching The End Of Its Product Life. US And

International Operators Facing Early Replacement Decisions

And Looking For New Systems With Digital Technology,

Lower Cost Of Ownership, Improved Readiness, And That

Need Fewer Personnel To Maintain.

I Need A Digital Cockpit For My Digital Kids. . .Call It A C-130J Gen. Duane Cassidy, CINCMAC, 1988

• The Solution = The C-130J


C-130 Main Instrument Panel

C-130J


C-130J Super Hercules

Key Features And Enhancements

The C-130J Is Nearly A Complete Reinvention Of The Hercules

World‟s Most Advanced Airlifter


C-130J Super Hercules

Propulsion System And Performance

38,000 lb Payload

C-130H

260 nm

C-130J

1300 nm

Sea Level

45°C Range Comparison

Engine: Allison AE 2100D3

Flat Rated At 4591 SHP

Twin Spool Design

Full Authority Digital Electronic

Control (FADEC)

29% More Static Thrust

15% More Fuel Efficiency

Automatic Thrust Control System

Engine Monitoring System

Early Component Fault Detection

Reduces MMH/FH And MTTR

Prop: Dowty R391

All Composite – Six-Bladed

Propeller

50% Fewer Parts

15% Weight Reduction

(1,032 lbs)

Performance:


C-130J Airframe Changes

New Nacelle (1996): • Enlarged Oil Cooler

• Redesigned To New

FAA Cert. Standards

New Forward Fuselage Design (1996): • Integral IFR Probe Prov.

• Modular Avionics Racks & Wire Harnesses

• New Bird Strike Option

Other Improvements (1996): • Longeron & Bulkhead Beef-Ups

• Eliminated Magnesium

• Extensive Use of White

Polyurethane In Trapped Areas

New Wing Components

(1996): • Composite Flaps &

Trailing Edges


C-130J Airframe Changes,

Fuselage: C-130H to C-130J






The ESL Wing

Closing Remarks

Outline


Sorties

Required

Flight

Hours

Crew

Hours

Comparison of

C-130H & C-130J-30


Troop Deployment, High and Hot


C-130J Program,

Flying Hours Experience


Superior Performance






The ESL Wing

Closing Remarks

Outline


• ESL Center Wing Developed as Special Operations Forces (SOF)

Center Wing, Severe Missions, early 1990‟s as a retrofit kit for

SOF C-130E derivative aircraft

• Provides 2 to 3 Times The Life of Standard CW

• ESL CW Increases Aircraft Weight by 725 lbs

• Minimal Performance Penalty For 725 lbs Weight Increase

– Range Impact Less Than 1% for C-130H

– Payload Impact Less Than 3% for C-130H

• The First C-130J Production Aircraft to Receive an ESL Center

Wing is LM Ship Serial # 5619 – Delivered in 2009.

Enhanced Service Life (ESL)

Center Wing


First C-130J

Enhanced Service Life Center Wing


Upper and Lower Surfaces Changed from the C-130H

• Upper Stringer Extrusions Changed From 7075-T6 to 7075-T73511

• Most Taper-Loks Changed to Hi-Tigues (Some Blinds Still Used)

• Stringer Area Increase (20% Upper Surface, 30% Lower Surface)

Upper Surface Lower Surface

Area

Increase

Area

Increase

ESL CW, Surface Changes


• Upper Cap Horizontal Flange Width Increased for Added Row of Fasteners

– Front Beam - WS 142 to WS 206

– Rear Beam - WS 151 to WS 215

• Web-to-Cap Lockbolts Changed to Hi-Tigues

• Front Beam Webs – Added Web Splice at WS 84.3

– WS 174 Web Splice Relocated to WS 168.3

– WS 61.6 to WS 84.3, 0.112 in 7075-T6 Changed to 0.1 in Ti-6Al-4V

– WS 84.3 to WS 168.3, 7075-T6 Increased from 0.112 in to 0.140 in

– WS 168.3 to WS 219.8, 301-H Increased from 0.063 in to 0.071 in

• Rear Beam Webs – WS 61.5 – WS 206, 7075-T6 Increased from 0.112 in to 0.125 in

BL 0.0

ESL CW, Box Changes


• Machined from 7075-T73511

Extrusion (was 7075-T6511 Ext.)

• Area Increased – Upper Fitting Approx. 20%

– Lower Fitting Approx. 30%

• Tangs Increased in Length and Width to Accommodate Additional Fasteners

• Node Counterbore Eliminated – Nodes Thickened

– Radius Washer Added

Area Increase Inner Tang

Increase

Outer Tang Increase Fitting Node

(Typ)

ESL CW, Joint Changes

“Rainbow Fittings”


• Fitting-to-Stringer Splice Straps – Reconfigured

– Material Changed from 7075-T7351 Plate to 7075-T73 Forging

• Splice Angle Cross-Sectional Area Increased

• Most Taper-Loks Replaced with Hi-Tigues (Some Blinds Still Used)

Stringer Splice Angle Rainbow

Fitting WS 220

Splice Strap

Profile Increase

Splice Strap

ESL CW, Joint Changes

“Rainbow Fittings”


• WS 61.6 Rib – Lower Cap Cross Sectional Area

Increased by Approx. 20%

– Skin Flange of Lower Cap Increased in Width to Accommodate New Wing Attach (Drag) Angle Fastener Pattern

– Thickness of Forward Web Increased From 0.063 in to 0.071 in

– Thickness of Aft Web Increased From 0.190 in to 0.236 in

– Door Assembly in Aft Web Removed BL 0.0

Door Assy

(Removed)

– Web-to-Cap Lockbolts Replaced With Hi-Tigues

• WS 178.8 Rib – Upper Cap Cross Sectional Area Increased by Approx. 20%

ESL CW Changes,

Ribs


• Truss Forging Upper, Lower, Vertical, and Diagonal Member Cross Sectional Areas Increased by Approx. 25%

• Truss Flanges Common to Front Beam Increased in Thickness by Approx. 25%

• Diagonal Brace Attach Lug Increased From 0.36 in to 0.60 in thick

• Diagonal Brace Tube Attach Bolts Increased in Diameter From 0.375 in to 0.500 in

• Hi-Loks and Lockbolts Replaced With Hi-Tigues

Upper Member

Lower Member

Vertical Member

Diagonal Member

Front Beam

Attach Upper

Tang

Front Beam

Attach Lower

Tang

Diagonal

Brace Tube

ESL CW Changes,

Engine Support Structure


Closing Remarks

The C-130 was unique at inception.

Program pride has never been greater.

With a long and distinguished past, the C-130 continues to be a unique part of aviation history.

Program leadership has not allowed the design to become stagnant.

Structural changes, both small and large, have played a pivotal role in keeping the aircraft current, effective, and affordable - while increasing its capabilities.

The future has never been brighter.

c-130 structural changes through its life

Documents

operating stress levels

lockheed martin corporation

initial aircraft requirement

t6 increased

area increase

wing structure

increased durability

130j features