Savage Cub Australian Flight Manual © X-Air Australia 2008 Release 1.2 Page 37 of 40
due to centrifugal forces acting on the object-forces which tend to pull the object away from
the centre of the circle and keeps it moving in a straight line. You have increased the pull on
the string to overcome these forces thus creating the centripetal forces noted above-forces
which tend to push the object toward the centre of the circle and produce a curved path of
travel. In our case, the airplane is the object and the pull on the string is replaced by the lift of
the wing.
Thus, we can see that whenever the airplane is in a curved flight path an excess load factor
is imposed on the wings. The airplane has one load factor in level flight and extra load factors
are added to produce the curved flight path. When an airplane is in a dive, the load factor is
approaching zero because the wings are not lifting the airplane. An abrupt pull-up after a dive
will "load up" the wings with a factor of 3 or even more very quickly. During a steep turn, it is
necessary to add extra load factors on the wing in order to produce a centripetal force to
overcome the centrifugal forces tending to produce straight and level flight. This load must be
great enough to overcome the pull of gravity as well as the centrifugal force.
The load factors required to hold a given bank without slipping or skidding are given in the
following table. A slip is produced when you bank too steeply for the amount of rudder
applied. The extra lift produced centripetal force by the excess bank tends to push the
airplane toward the inside of the turn. A skid is produced when you do not bank steeply
enough for the amount of rudder applied. The centrifugal forces, in this case, are tending to
pull the airplanes to the outside of the turn.
From the table on the next page, it can be seen that a 70 degree bank is within the assumed
load factor limit of 3. This degree of bank is usually considered a "vertical" bank in small
commercial airplanes. Note how much the load factor has increased from 70 degrees to 80
degrees. It is very important that the angle of bank be held below 70 degrees in order to
avoid the possibility of exceeding a safe load factor.
Angle of wings to
Horizontal
Example
Load Factor Required
0 degrees
(Gentle 10 degrees
Blank)
20 degrees
30 degrees
1
1.01
1.06
1.15
40 degrees
(Medium Blank)
50 degrees
1.31
1.56
60 degrees
70 degrees
2.0
2.92
80 degrees
5.75
