THE GLIDING FEDERATION OF AUSTRALIA INC
Lubrication Theory Work Book
Student Name: ________________
Mentor/Tutor Name: ________________
UNCONTROLLED WHEN PRINTED
Revision 1.0
This issue of Lubrication Theory Workbook is the first issue of this document.
GFA Document ID: TWB011
Copyright © The Gliding Federation of Australia Inc, 31/08/16
Lubrication Theory workbook
REVISION RECORD
Prepared
Approved
Version
Date
Peter Cesco
Vice President
1.0
31/08/16
Précis of changes – New
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Date of Issue: 31/08/16
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Lubrication Theory workbook
ABOUT THIS WORKBOOK
This workbook is intended to be used to enable improved understanding of specific theory aspects of
Sailplane maintenance delivered by experienced sailplane inspectors. It is intended that this manual will
be completed after theory training has been presented as part of an airworthiness training course.
It should be used in conjunction with the Gliding Federation of Australia’s Manual Of Standard
Procedures (MOSP) and any relevant aircraft documentation.
This workbook is a working document, reinforcing the information presented. Each student has their own
copy of the workbook.
This THEORY workbook is not intended to be a pass/fail document, but is intended to be used as part of
a knowledge and skill building exercise in a specific topic area
This unit has been designed to provide you with some of the necessary skills and knowledge to be able to
operate and think your way through the technical skills of identifying and selecting the correct fastener or
fastening systems used in sailplanes.
The module is not exhaustive and is should not be used instead of correct technical documentation or
better knowledge. The module is designed to be done by you in your own time.
You are encouraged to seek information from more experienced sailplane inspectors, aircraft LAME
sources and/or specialist knowledge where it can be found.
Sailplane maintenance requires effective human intervention to places the aircraft back on the flight line
in a serviceable and useable manner after maintenance, and should not be rushed.
You will also be issued with an assessment feedback document to allow you to give your feedback on
both the module applicability and improvements, and your mentor/tutor/trainer. Please complete this
honestly as it is your chance to assist us in maintaining the standards necessary.
The single best thing you can bring to ensure a quality airworthiness system is an enquiring mind.
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Lubrication Theory workbook
LUBRICATION
INTRODUCTION
Sailplanes have many areas that need to be lubricated, with a variety of greases and oils. It is important
that the correct lubricants are used and that you do not use incorrect products because of their ease of
use or because of the difficulty getting the correct lubricant into a confined area.
Lubricants need to meet a number of requirements, depending on where they are used. Generally a
maintenance manual for the aircraft will assist, however if no information is available discussing with other
form 2 inspectors will often help. Before discussing with someone else you will need to review the
requirements for the lubricant. The following criteria may help:

Environment it will be used in (eg in hangar most of time, trailered).

The heat range needed to be covered (eg in sunlight in the tropics).

Will it come into contact with moisture, or be in a moisture rich environment (eg near the sea,
high rainfall area).

Dust.

Load carrying ability.

Impact it will take.

Speed it will be moving.

Cyclic nature of the load.

Material compatability.

Access for lubrication.

Maintenance intervals.

Sealed or open bearing.
There are many other criteria; it is your role as a Form 2 inspector to ensure the best lubricant for the job
is selected.
REFERENCE GFA BASIC SAILPLANE ENGINEERING
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Lubrication Theory workbook
ACTIVITY 1 –LUBRICATION INTRODUCTION.
Answer the following:
1.
Describe three places that need lubrication on a sailplane, and the criteria for the lubrication in
these areas.
_____________________________________________________________________
_____________________________________________________________________
2.
Where or how would you find the information on the correct lubricant to use on your sailplane?.
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
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Lubrication Theory workbook
TYPES OF LUBRICANTS.
INTRODUCTION
There are four main types of lubricants used on sailplane, they are:

Oil

Grease

Solid Film

Silicon
OIL
Rarely used in sailplanes except motors and hydraulic systems. Normally liquid at room temperature, oil suffers
from evaporation losses and so has a shorter service interval compared to other forms, it also attracts dirt and dust. It
can also move into unprotected composite fibers if used too heavily.
GREASE
Grease is oil with a thickener added, and is semi solid at normal operating temperatures.
There are three main thickeners, they are:

Metal soaps

Urea (organic)

Inorganic
While the lubrication is still done by the oil, the thickener add useful properties such as allowing a greater
temperature range for operation, rust prevention, anti-oxidants and extreme pressure usage.
SOLID FILM
These non oil based coatings are used where normal oils and grease would not last for any reasonable time. PTFE
(teflon) and graphite are considered soft examples and Chrome and Titanium nitrides or Titanium carbides are
considered hard examples.
Other than PTFE and graphite a form 2 inspector will not normally apply these coatings as they require specialist
skills and knowledge.
SILICON
Silicon should be used sparingly around paint or fiberglass as it often renders the area where it is used almost
impossible to repair or paint.
Silicon is a synthetic lubricant and is used where rubber in a sliding environment is required and dirt pickup is not
desired. It is mostly supplied in pressure pack cans and need to be carefully used because of the previous reason..
Don’t use around water systems (normal grease is generally better), but good for the sliding rails of a clear view
panel.
SHELF LIFE OF LUBRICANTS
Historically oils and greases are very stable and if left in their containers, unopened, will be able to be used when
opened. Synthetics oils will generally last for over 10 years in this condition. Sometimes greases will appear to
separate, generally mixing the liquid and the thickener by brisk stirring will restore it to its original state.
Check the original containers for any use by dates, this is especially important on items such as brake fluids, which
will be affected by water if left opened.
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Lubrication Theory workbook
REFERENCE GFA BASIC SAILPLANE ENGINEERING
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ACTIVITY 2 – TYPES OF LUBRICANTS
Discuss the following items:
1.
What are the four main types of lubricants used in sailplanes?.
______________________________________________________________________
______________________________________________________________________
2.
Explain why grease is sometimes used instead of oil.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
3.
Discuss the following statement “I just splash silicon grease everywhere on bearing
surfaces, it’s so easy to spray”
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
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Lubrication Theory workbook
LUBRICATION TECHNIQUES
INTRODUCTION
The very first thing required for lubrication is a clean surface. If solvents are used to clean off old grease,
dust and grime the inspector must ensure that the solvent will not affect the surface being cleaned.
When the item is clean it is a good practice to review the underlying surface for cracks, wear and
deterioration.
Often it is a good idea to test the operation once with no lubrication to check freeplay, grease should not
be used to compensate for play in a system.
GREASE GUN
Most lubrication on a sailplane can be performed using a finger or a rag.
There are some places that may need a grease gun, and it is important when it is being used that it has a
good connection to the grease nipple. Hand grease guns are common in automotive workshops and are
readily sourced.
GREASE NIPPLES
As part of the import of gliders the grease nipples should be changed to standard Australian items, this is
because the incorrect nozzle will mean that correct lubrication does not happen and excessive wear will
result.
Blanik L13’s and other older European sailplanes were/are produced with different grease nipples that are
incompatible with Australian grease guns. The sailplane log book should identify if the grease nipples
have been changed.
PRESSURE PACK LUBRICANTS
Most pressure pack lubricants are not designed for long term lubrication. Reviews of the use of pressure
cans in maintenance has found that spray cans such as WD-40 have been used and resulted in the
application of the thin film of oil being sprayed on with such force that it has removed the original
manufacturers grease. This has been seen to remove the protection provided by the grease and
contributing to the ultimate failure of the part.
REFERENCE GFA BASIC SAILPLANE ENGINEERING
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Lubrication Theory workbook
ACTIVITY 3 – LUBRICATION TECHNIQUES
1.
“When I clean an item prior to lubricating it is a good idea to have a close look at it”.
Discuss.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
2.
What happens if the wrong grease nipple is used in a sailplane?.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
3.
“Spray can lubricant should never be used”. Comment.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
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