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Document No.: 304S/MM
Date of Issue:
08/14
5-2
H
P
H
Ltd.
The C.G. of the empty sailplane with normal loading between 154 and 275 Ibs,
(70 - 125kg) should fall into the crosshatched area of a diagram in 5.2.
Should the sailplane, in particular cases, be trimmed so that the C.G. falls
above or below the crosshatched area, and the maximum loading is lower than
275 lbs, (125kg) or the minimum loading is higher than 154lbs.,(70kg) *), these
loading should be placarded in the cockpit (e.g. minimum loading on seat
176lbs.,(80kg)). This modification should be approved and recorded into the
operating documents and the maximum as well as minimum load must be
placarded in the cockpit, as well (see Flight Manual ch. 6.2)
*) depends on the empty weight
Using of permanent tail water ballast allows to pilot maintain the flight cg
position at optimum range. Adding this ballast limits the minimum pilot’s weight.
Minimum pilot’s weights relevant to the added permanent water ballast should
be approved and recorded into the operating documents (see Flight Manual ch.
6.3) on the base of the minimum pilot weight without ballast.
1 kg (2.2 lbs) of the water ballast increases the minimum pilot weight for 4.8 kg
(10 lbs). (i.e. if the minimum pilot weight for empty sailplane is 75 kg than
minimum pilot weight for 4 kg of the permanent tail water ballast is 94.2 kg
…..75 + 4 x 4.8 = 94.2).
The establishment of the empty C.G. is also necessary after installation of
additional equipment, after repairs, new surface finishing or other modifications
which may change the weight of the sailplane. Weights and C.G. should be
entered into the accompanying documentation (Sailplane Flight manual).
For high performance and competition flying, it is recommended to establish the
flight C.G. for the individual pilots, as performance of the sailplane deteriorates
outside the optimum C.G. range.
The optimum C.G. range is between 35 and 43% MAC (Mean Aerodynamic
Chord).
