GDMMTA582-1G
Version 0010
15
6
Standard Practices
– Airframe
6.1
Torque & Safety
This chapter provides standard torque values and safety procedures that are to be used in
all areas of the aircraft unless otherwise specified. The use of these standard values and
procedures will ensure the security of installation and prevent overstressing of
components.
6.1.1
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, while over tightening may cause
tensile failure of the bolt, or crushing of components.
General Torque Procedures
Definition of “Just not loose”
A definition of torque has been made for the assembly of this trike which has been 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.
In general, standard torque values will not be applicable, because of the nature of
the thin wall aluminum and steel tubing that is used to construct the majority of the
trike structure. Never tighten nuts so that the 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.
General Torque Exceptions
1. Joints with hinges or bearings, where free operation is necessary.
2. Bolts, nuts and screws that attach plastic or fiberglass or aluminum tube components, where the
softer material would be damaged by high torques.
3. Engine bolts are to be torqued to the engine manufacturer’s specifications, and may need to be
sequenced.
6.1.2
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.
Summary of Contents for Skypper 582 S
Page 44: ......
