27
6. If you fly regularly at the coast in windy conditions, be aware that the sea mist spray can
cause corrosion. Hose down your wing after such flights, and keep a special lookout for
corrosion.
7. Keeping your sail clean will extend the life of the sail cloth. When cleaning the entire sail you
should generally use only water and a soft brush. You may clean small spots or stains with any
commercial spot remover that is labeled for use on polyester.
10.1.7. SPROG MEASUREMENT
Profi TL uses inboard and outboard sprogs in combination with one transverse batten on each
sprog. Each transverse batten spans two top surface battens, so a total of eight top surface
battens are supported. The sprog system is the primary component of the system, which
provides pitch stability.
The function of the system is to support the trailing edge of the sail at low angles of attack, and
thus provide a nose-up pitching moment. The inner and outer sprogs are adjusted at the factory
to their proper settings.
The sprog angles should be checked regularly. This can be done with any digital electronic
angle meter as described below:
Figure 63
1. Fully set up the wing on a reasonably level
surface.
2. Rest the keel tube on a support with the
keel tube horizontal. Attach the keel extension
to the keel tube. Using the angle meter, as
shown on fig. 63 and fig. 64, check that the
keel extension is set to horizontal position.
Maintain this keel tube angle during further
measurements. Set the angle meter to zero.
Figure 64
Figure 65
3. Place the worktop of the angle meter under the middle part of the sprog close enough to the
sprog wire attachment point so that the entire worktop surface of the angle meter touches the
sprog (Fig. 65).
The scale of the angle meter will show the sprog angle.
