SCHEMPP-HIRTH FLUGZEUGBAU GmbH., KIRCHHEIM/TECK
Arcus M
Water ballast fin tank
To ensure optimum performance in circling flight, a forward centre of gravity,
caused by water ballast in the wing nose and/or by a crew member in the rear
seat, may be compensated by carrying water ballast in the fin tank.
For details concerning the quantities to be filled refer to page 6.2.8.
The water ballast tank is an integral compartment in the fin with a capacity of
11.0 kg/Litres (2.91 US Gal., 2.42 IMP Gal.). This tank is filled as follows (with
the horizontal tailplane in place or removed):
Set elevator trim to the rear.
Insert one end of a flexible plastic hose (outer diameter 8.0 mm/0.31 in.) into the
tube (internal diameter 10.0 mm/0.39 in.) protruding from the rudder gap at the
top of the fin on the left hand side. The other end of this hose is then connected
to a suitable container which is to be filled with the required amount of clean
water.
The fin tank has eleven (11) spill holes, all properly marked, on the right hand
side of the fin, which indicate the water level – see accompanying sketch.
The venting of the tank is through the uppermost 11.0 kg/Litres hole (which
always remains open – even with a full tank).
The ballast quantity to be filled depends on the water load in the wing tanks
and/or on the load on the aft seat – see loading table on page 6.2.8.
Before filling the tank always tape closed one hole less than the load required,
measured in kg/Litres.
If, for instance, a fin ballast load of 3.0 kg /Liters is required, only the lower two
holes (1 and 2) are taped closed, any excessive water then escapes through
the third spill hole, thus preventing overloading.
October 2011
Revision –
FLIGHT MANUAL
The tank label is on the right hand side of the fin.
1 kg/Ltr.
2
3
4
5
6
7
8
9
10
11
appr. 4.5.6.3
