GDMMBi²13-1G
Version 0010
16
5
Standard Practices
– Airframe
5.1
Torque and Safety procedures
This chapter provides standard torque and safety procedures that are to be used in all
areas of the aircraft unless otherwise specified. The use of these procedures will ensure
the security of installation and prevent overstressing the components.
5.1.1
Torque Procedures
Correct Torque of fasteners is critical. If a bolt or fastener is too loose it may cause
unnecessary movement resulting in wear or fatigue damage, while over tightening may
cause tensile failure of the bolt, or crush components.
Definition of “Just Not Loose”
A definition of torque has been established for the assembly of this wing that is called
“just not loose”, a setting which is used to achieve the best combination of strength
characteristics of the tubing while not allowing any vibration or relative movement of the
bolt in the axial direction. In practice this means that the nut shall be tightened adequately
to ensure that each of the components that are held by it are in contact with each other,
and then approximately ¼ turn more should be made. The resulting fit should not allow
any axial movement of the bolt in its location, but will allow rotation (using fingers) of a
held component to be achieved with approximately 20mm of lever arm (e.g. A wire
tang).
The correct torque of the bolts for the wing section of the airframe is especially
important for the safety and longevity of the wing. In general standard torque values
will not be applicable, because of the nature of the thin wall aluminum tubing that
has been used to construct the majority of the wing structure.
Never tighten nuts so that the aluminum tubing is deformed from its circular cross
sectional shape.
Always have at least one full thread showing past any Nylok nut that is used.
Where stainless steel washers are used, the rounded edge should be placed
towards the aluminum tube, if any, or towards other aluminum part, if not.
5.1.2
Safety Procedures
Nylstop Nuts
Nylstop nuts are used throughout the airframe. Nylstop nuts may not be reused.
Loctite
On any bolt that does have or not a Nylstop type locking mechanism, Loctite 243 should be used
to prevent premature loosening.
Do not fit the plastic nut caps until the airframe has been inspected.
Summary of Contents for BioniX2 13
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