19
A NOTE ABOUT CABLES AND CABLE MAINTENANCE
The cables which support the wing’s airframe are critical components of the wing’s structure, and must be
maintained in an airworthy condition. It is a general practice in the design of aircraft structures to design
to an ultimate strength of 1.5 times the highest expected load in normal service.
The wing’s cables, like other structural components on the wing, are typically designed with a structural
safety factor of only about 50% above the expected maximum load. No significant loss in cable strength
can be tolerated.
A cable with even a single broken strand must be replaced before the wing is flown again. A cable which
has been bent sharply enough to have taken a permanent set must also be replaced immediately.
Some degree of fatigue due to repeated bending of cables is almost unavoidable in an aircraft that is
assembled and disassembled regularly. Bottom side wires are subject to the highest loads in flight, and
are therefore the most critical. This is why we recommend that these wires be replaced annually, even if
there is no known damage.
Replace washout wires, all bottom wires, cross bar tensioning wires every 4 years regardless of their conditions.
CHECKING THE SAIL WASHOUT
Sail washout is determined by the length of the washout cables and angles of the outer sprogs. When
replacing the upper cables, it is helpful to measure the sail washout to make sure it remains unchanged.
The sprog angles, provided the outer sprog tubes are not bent, will always be constant. Therefore we will
be measuring the sail washout which is created by using washout cables.
1. Fully set up the wing on a reasonably level surface with the keel tube extension installed in the keel.
2. Place three equal supports, about 1,7 m (5.5 ft) tall, under the each leading edge tube / cross tube
junction and under the keel tube between the control frame and nose plates.
3. Tie one lightweight string or sawing thread tightly across the wing between battens #3 and #3 and
another string between battens #4 and #4.
4. Measure the height of each thread in relation to the top of the keel tube extension. The results should
be as follows:
Batten number
Sail height above the keel tube, mm
3 – 3
225
4 – 4
270
Tolerance is ± 20 mm.
If measured distances are less than those of written in the table above, the wing should not be flown until
re-adjusted. If measured distances are differ from those of written in the table for 20 mm per side, the
wing should not be flown. In such case consult your local dealer.
11. IN CLOSING - A FEW WORDS ON YOUR SAFETY
- Flying nanolight trikes is a grate fun but it is, as any form of flying, associated with risks. Your safety can
be greatly enhanced by following a few simple rules:
- Your wing is delivered to you ready to fly. Do not make any adjustments, which are not described in this
manual.
- If you are in doubt about any aspect of your wing, you should consult your dealer or Aeros for advice.
- Fly a wing suited to your level of ability. A new risk may arise when you first fly a new type of the wing.
