BCA PROPIETARY INFORMATION 17/08/2015 1 BARRY CONTROLS AEROSPACE TECHNICAL PRESENTATION ON VIBRATION...

1BCA PROPIETARY INFORMATION21/04/23

BARRY CONTROLS AEROSPACETECHNICAL PRESENTATION ON

VIBRATION AND VIBRATION ISOLATION


Introduction

David Posavec

Eastern Regional Sales Manager

Barry Controls Aerospace

Responsibilities Include:

•OEMs

•Regional & Major Airlines

•Cargo Airlines

•GA & Distribution

•Trade Shows & IA renewals



• Over 55 years developing and manufacturing aviation vibration and noise control solutions

• World’s leading supplier of Engine and APU Vibration Isolators

– Jet, turboprop, and general aviation aircraft products

– Manufacture over 5,000 products and hold over 350 PMA’s

– Applications on virtually every commercial jet aircraft

• Three locations:

– Burbank, California (pictured)– Toulouse, France– Hersham, England



• Proven Supplier– World’s leader in the design, development, production and support

of state of the art vibration isolation systems.

– Over 55 years of experience in providing main engine and APU isolation systems for a majority of the world’s commercial and business aircraft manufacturers.

– Issued first firm order in the industry to outfit a jet carrier’s entire fleet with an active cabin noise reduction system.

– Service Center direct product support

– ISO-9000 and D1-9000 approved

– Factory direct, product support engineers, field support personnel and warranty processing.


Product Line

• Vibration Isolation

– Fixed Wing

– Rotary Wing

• Tuned Mass Absorber

– Passive

– Active (ATMA)

• Other products include: anti-vibration mounts, avionics

trays and racking systems



• Quality System Approvals– FAA - PMA/TSO - F.A.R. Part 21

– FAA - Organizational Designated Airworthiness Representative (ODAR) F.A.R. Part 21.303

– FAA - F.A.R. 145 Repair Station

– FAA - J.A.R. 145 Repair Station

– CAAC - China CCAR 145 Repair Station

– Government - MIL-I-45208A and MIL-Q-9858A

– Boeing - Advanced Quality System AQS/D1-9000A

– Coordinating Agency for Supplier Evaluation (CASE)

– ISO 9001 Compliance



• Quality System Approvals by Major OEM’s– Aerospatiale– Airbus – Agusta– B.F. Goodrich– Boeing– British Aerospace– Cessna– Fairchild/Dornier– Fokker– Gulfstream– Lockheed-Martin– Nordam– Northrop– Raytheon Aircraft– Westland Aerospace


General Aviation Experience

• General Aviation Isolation Systems

– Beech Bonanza, King Air, Queen Air, Musketeer, Travel Air

– Cessna Skyhawk, Stationair, Centurion, Eagle, Conquest

– Maule M4, 5, 6, & 7 series -Mooney Mark, Ranger, Statesman

– Pilatus PC-6, -7, -9, -12

– Piper Aerostar, Apache, Arrow Series, Aztec, Cherokee,

Cheyenne, Comanche, Dakota, Navajo

– Robin, Socata, Transavia, Wassmer, Xian and Zlin


Business Jet Experience

• Business Jet Engine Isolation Systems– All Gulfstream Applications, G-II, G-III, & G-IV

– Raytheon Jayhawk, Premier I, 400A, and Hawker Horizon 4000

– Cessna Citation 1, 2, & 3

– Israel Aircraft Industries 1121 & 1123

– Sabreliner NA-265-65 & NA-265-75A

– Rockwell NA-265-40 & NA-265-60

– Lockheed Jetstar

– Sino-Swearingen SJ30-2


Regional Aircraft Experience

• Regional Transport Engine Isolation Systems– All ATR Applications - ATR42 & ATR72 Series

– All BAe/Jetstream Applications - J31, J41, & ATP

– All Fokker Applications F50 & F60

– Fairchild/Dornier Applications - Metro, Do228, Do328 Turboprop and Do328 Jet

– deHavilland Dash 8 Series 400

– Lockheed C-27J

– Saab 340

– Xian Y7-200A & Harbin Y11-100

– CASA C212 & C295

– IPTN N250


Commercial Jet Experience

• Large Commercial Jet Engine Isolation Systems– Boeing 717

– Boeing 727 Series

– Boeing 737 Series

– Douglas DC-9 Series

– Douglas MD-80 Series

– Fokker 70 and 100


Product Experience

1. MD-80 Aft Isolator

2. MD-80 Fwd Isolator

3. 727 Aft Isolator Side & Center Engines

4. DC-9 Fwd Isolator

5. DC-9 Aft Isolator

6. DC-9 Conebolts

7. MD-80 Conebolts

8. 727 Aft Isolator

9. 737 Fwd Isolator

10. 737 Aft Isolator

11. 727 Fwd Isolator

12. A-320 APU Isolator

13. A-300 APU Isolator

14. 747-400 APU Isolator

213

4

5

8

9

11

10

13

12

6

7

14


Auxiliary Power Unit Experience

• APU Isolation Systems– Airbus A300, A310, A319, A320, and A340

– Boeing 727, 737, 747, 757, 767, and 777

– Embraer ERJ-170 and ERJ-190

– deHavilland Dash 8-400

– Fokker 50 and 100

– Lockheed 1011 and C-27

– SAAB 340 and 2000


VibrationWhat Causes It?

Vibration in aircraft is caused by asymmetry in:

Rotating mass

Aerodynamics

Power output


Examples of a Rotating Mass :

Crankshaft

Propeller

Turbine Disk

Tire/Wheel Assembly

VibrationRotating Mass Examples


Causes Of Asymmetry In A Rotating Mass:

Imbalance of mass about the axis of rotation

Eccentricity about the axis of rotation

Misalignment from the plane of rotation (such as a bent propeller flange), etc…

VibrationRotating Mass Asymmetry


Aerodynamic:

Asymmetry in an aerodynamic structure that results in animbalance of aerodynamic forces can be a source of vibration.

These imbalances can be caused by:

Dimensional differences as a result of manufacturing tolerancesor repairs

Asymmetrical airflow to the structure (“P” factor would be anexample)

VibrationAerodynamic Asymmetry


Power Output

Asymmetry in power output is most applicable toreciprocating engines and would refer to the differencesin power output by each cylinder.

These differences could be attributed:

Differences in compression Uneven fuel delivery Weak or non-existent ignition, etc…

VibrationPower Output Asymmetry


Vibration in an aircraft is undesirable due to its detrimental effects on the aircraft and its occupants. Some of these effects are:

• High noise level

• Metal Fatigue

• Adhesive Disbond

• Reduced Avionics Life

VibrationEffects of Vibration


Various steps can be taken to reduce engine vibration.

• Dynamic balancing of the engine and propeller• Tighter manufacturing tolerances• Match balancing of engine components

In reality, the total elimination of vibration is an almost impossible task.

• Vibration Isolation is a cost-effective alternative

VibrationEngine Vibration Reduction


A simple form of vibration isolator is illustrated in Fig. 1. It consistsof a mass (M), a spring (K), and a viscous damper (C). The springdeflects to prevent a outside force from disturbing the mass, thedamper works to reduce the number of oscillations the spring willundergo before the system returns to equilibrium.

VibrationVibration Isolator


Benefit of Engine Isolators

• Offer optimum distribution of engine casing and airframe

loads by design of isolator stiffness and snubbing.

• Thermal expansion of the engine can be taken by

deflection of isolator

• Offer broad-band vibration isolation for high frequency

vibration.


Benefits of Engine Isolators

• Improves engine blade-out loading and flutter conditions.

• Facilitates engine installation and removal.

• Allows for increased airframe and engine tolerances

using the allowance gained from isolator flexibility.

• Reduces possibility of damage to engine and airframe.


There are two important terms that describe anisolator’s characteristics:

Transmissibility

Damping

VibrationVibration Isolator Terminology


Transmissibility is defined as the ratio of the dynamic output (vibration applied to the airframe) to the dynamic input (powerplant vibration).

A typical transmissibility curve is shown in Fig. 2.

Figure 2

VibrationTransmissibility


• Damping refers to the phenomenon by which energy is dissipated in a vibratory system.

• It is an important property in aircraft engine isolators because aircraft engines operate over a wide range of rpm’s.

• As a transmissibility curve shows, when the engine RPM goes down, the amount of vibration transferred to the airframe can go up.

VibrationDamping


The damping properties of theelastomers used in aircraft engineisolators reduce the amount ofamplification that can occur astransmissibility increases.(Ref Fig.3).

However, the degree of isolationprovided is also reduced.

Figure 3

VibrationDamping


• Focuses the centerlines of the isolators at a point slightly ahead of but in the same plane as the engine’s center of gravity.

•Flight loads are applied equally to each isolator.

Typical Dynafocal Mount Installation

VibrationIsolator Installation


Figure A: Semi-focalized Bed Mount Figure B: Focalized Bed Mount

Typical Bed Mount Installations

VibrationIsolator Installation


ISOLATOR SELECTION

A matter of compromise:

Softer Elastomer: Better Isolation, More EngineDeflection

Stiffer Elastomer: Less Isolation, Less Engine Deflection

VibrationIsolator Selection


Tuned Mass Absorption

• In addition to isolating vibration, it is possible to “absorb” vibration:

• Absorption is accomplished using a mass and a spring.

• The spring is tuned to resonate at same frequency as disturbing frequency

• Resonation is out of phase with disturbing frequency, resulting in cancellation

VibrationAbsorption


DC-9/MD-80 Tuned Vibration Absorber

VibrationTuned Vibration Absorber


Benefits of Tuned Mass Absorbers

• Effectively attenuates vibration up to 90%.• Dramatically reduces vibration/noise levels.• Self-contained units, ready for installation, low

maintenance.• Relatively low cost, light weight solution in comparison

with other cabin noise reduction solutions.• Reduces structure displacement and stress, improving

structural fatigue life.• Improves isolation system performance.


ATMA® System

Noise Reduction

System Components4 N1 Absorbers4 N2 AbsorbersController Box

HarnessesSensor Assemblies

Power consumption

5 Amps maximum

30 Watts (or less during cruise)

Health monitoring function


No engine removal required

Overnight installation

No interior modifications

No special tools required

Installed ATMA® System

Noise Reduction


Aircraft Vibration IsolatorsDescription and Operation

Typical General Aviation Vibration Isolator


Aircraft Vibration IsolatorsWhy bother with Cure Dates?

Elastomers used in Aircraft Vibration Isolators continue tocure (release chemicals & oils) long after they aremanufactured.

This can lead to stiffening of the elastomer Excessive stiffening can cause the elastomer to be

outside of tolerable spring limits based on design criteria. Cure dates ensure elastomers are within tolerable limits

before being installed on aircraft.


Aircraft Vibration IsolatorsDeciphering Cure Dates

Cure Dates are printed on the outside of each BarryMountpackage adjacent to the part #

Sample Cure Date: CD 0230

Was manufactured the 30th week of 2002.

Since the elastomer composition may not be readily knownplease call Barry Controls Technical Engineering Dept. @818-973-2524 to determine shelf life or if you have furtherquestions


Aircraft Vibration IsolatorsIsolator Materials & Cure Dates

Molded assemblies can be made of several materialsdepending on their installed environment: Natural Rubber (usually black) –5yr Cure Date Butyl –10yr Cure Date EPDM – 10yr Cure Date Chlorylbutyl – 10yr Cure Date Chlorylprene –10yr Cure Date Nitrile –10yr Cure Date Silicone (colors, hi-heat resistant) –20yr Cure Date Fluorocarbon –20yr Cure Date Metal Mesh – Cure Date N/A


Aircraft Vibration IsolatorsSelection & Replacement Criteria

Do not assume the vibration isolators removed from the aircraftare the correct part #for that aircraft or that they werepreviously installed properly. Verify by using updated Barry applicability charts to ensure

FAA/PMA approval for your particular application. New FAA/PMAs are granted all the time. Do not rely on cross-reference charts. Follow the specific installation directions on BCA’s Application

Sheets for the Isolator(s) you are replacing The same Barry part # may have different installation

instructions (direction of the shimmed molded assembly) fordifferent aircraft applications.


Aircraft Vibration IsolatorsMaintenance

Maintenance of Engine Vibration Isolators

Cleaning: Wipe Down With A Clean Rag Soap and Water Wash Isopropyl Alcohol No Other Solvents Should Be Used

If Lubricants Or Solvents Are Spilled Onto Isolators,They Should Be Removed As Quickly As Possible.


An on-aircraft inspection should be performed during:

Annual or 100 Hour Inspection

The inspection can be accomplished with the isolatorsmounted on the aircraft.

Aircraft Vibration IsolatorsOn-Aircraft Inspection


The criteria for inspection should include:

Elastomer Condition

Elastomer-to-Metal Bond Integrity

Metal washers (as visible) for corrosion or damagesuch as nicks, dings, etc.

Surrounding structure (such as the cowling, propspinner) for damage caused by excessive drift of theengine.

Aircraft Vibration IsolatorsOn-Aircraft Inspection


Aircraft Vibration IsolatorsBench Inspection

Engine vibration isolators should be removed and inspected under thefollowing circumstances:

When an engine is removed for overhaul.

When sudden stoppage of the propeller or engine occurs.

When the nacelle engine bay has been exposed to excessive heat (i.e.engine fire).

When excessive vibration is experienced or reported.

Any circumstance not identified above that would indicate theairworthiness of the isolator(s) may have been compromised (ageweathering, deterioration, etc.).



Removed isolators should be inspected to the samecriteria as installed mounts.

Two additional checks of the molded assemblies shouldalso be performed.

Free height of the molded assembly

Eccentricity.



Free Height Eccentricity



An additional item to check when inspecting disassembledisolators is the spacer.

Spacer Types:

Tubular Metal

Molded With Tubular Metal Core



The spacer should be inspected for:

Distortion Due to Overtorquing

Snubbing Marks

Condition of Elastomer (if applicable)


Aircraft Vibration IsolatorsReplacement

Whenever the above inspections cause a rejection of acomponent of an isolator, the isolator must be replaced as anassembly. Mixing of new and used components is not allowed.

Barry Controls Aerospace also recommends that isolators bereplaced as a set, rather than mixing old and new isolators on anengine


Aircraft Vibration IsolatorsReplace vs. Overhaul

Piston Engine isolators are replaceable items due to the relativeinexpensive nature of their metallic components

Most Turboprop, Business Jet, Regional Airline &Commercial Aircraft Engine & APU isolators are candidatesfor Repair or Overhaul by our FAA Repair Station #UT3R905L due to the relatively high value of their metalliccomponents.

BCA offers Repair & Overhaul of BCA & NON-BCA components in our Repair Station directly to operators &via our Distributor network.

Please see our Repair Station Capabilities Brochure


Conebolt Inspection Criteria Service LettersIssued May 2004

EFFECTIVITY:

CONEBOLT PART#S APPLICATIONR18423-53 & R18424-54 Boeing727 with Fedex Hush Kit with

95803-1 isolatorsR18423-53 & R18423-54 Boeing 727 with 7350000 isolators

R18207-51 & R18206-52 Boeing 727 with K2223 isolators

R18423-2, R18423-49, R18424-2 & Boeing 737 with BCA 5467-1 isolatorsR18424-50

R18210-2 & R18211-2 DC-9 Series (Excluding DC-9-80 & MD-80 Series with BCA K2219-7 isolators

K2219-9SA3, K2219-9SA7, & DC-9 & MD-80 with BCA K2219-9 isolatorsK2219-9SA9



REFERENCES:

a) Barry Controls Aerospace Component Maintenance Manual 71-20-01 for Type # 7350000

b) Military Specification MIL-S-8879

c) SAE Specification AS8879 (Supersedes MIL-S-8879C)

d) ANSI/ASME Specification B1.3M

e) Federal Standard FED-STD-H28/20B



BACKGROUND:Barry Controls Aerospace (BCA) has received powerplant mounting conebolts used on the JT-8D series of engines back from operators with complaints that the conebolt does not pass the minimum run-on torque requirement for the self-locking attach nut. Multiple tries with different attach nuts yielded similar results.

Inspection of the conebolt’s 0.625-18 UNJF-3A threads found that the parts had worn and no longer met the requirements of MIL-S-8879C (or it’s replacement SAE AS8879), which prevented the attach nut meeting it’s minimum run-on torque. The wear to the threads is a result of loss of material due to friction from contact with the nut, rework of the threads with a thread chaser or file, or bolt “stretch” due to repeated torquing.

BCA would like to clarify the inspection requirements outlined in MIL-S-8879C (& SAE AS8879) to ensure that the conebolts are properly inspected and overhauled in accordance with the BCA Component Maintenance Manual 71-20-01 for Type # 7350000.



Paragraph 4.4.2 of MIL-S-8879 (& paragraph 4.1, System 22, of SAE AS8879) outlines the thread’s characteristics that must be inspected to ensure compliance (Note: Application category for conebolts is “Other Thread”).

They are:

a) “GO” functional diameter

b) Pitch diameter size

c) Major diameter size

d) Minor diameter size

e) Root radius

The acceptable methods and tools used to inspect these characteristics are presented in FED-STD-H28/20 (or ANSI/ASME B1.3M). Please note that a “GO/NO-GO” ring gage set is not capable of measuring all of the dimensions listed above.



OPERATOR ACTION:

Due to the critical function of the conebolt, Barry Controls Aerospace recommends that operators take the following actions:

• Operators performing their own conebolt overhauls and repairs should review the MIL-S-8879C (or SAE AS8879) specification to ensure that the conebolts threads characteristics listed in this specification are being inspected using the methods prescribed by FED-STDH28/20 (or ANSI/ASME B1.3M).

• Operators procuring overhauled conebolts from third-party agencies or having third-party repair agencies perform their conebolt overhauls and inspections should verify that the conebolt’s threads characteristics outlined in MIL-S-8879C (or SAE AS8879) are being inspected using the methods prescribed by FED-STD-H28/20 (or ANSI/ASME B1.3M).



Barry Controls can also perform overhauls or provide rebuild/exchanges of conebolts with all units having the threads inspected to the requirements of MIL-S-8879 (or SAE AS8879) and using the methods prescribed by FED-STD-H28/20 (or ANSI/ASME B1.3M).

For any questions, contact:


4510 Vanowen Street

Burbank, California 91505 USA

(818) 843-1000

FAX: (818) 845-6978

SITA: BURBCCR


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BCA PROPIETARY INFORMATION 17/08/2015 1 BARRY CONTROLS AEROSPACE TECHNICAL PRESENTATION ON VIBRATION...

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