PIK-20 E Service manual
5.3 Calculations for actual empty weight and moment
To calculate the actual empty weight and moment after a change in
equipment or ballast use the Sample Problem 5.5 as follows:
1. Write down the empty weight and moment according to the last
weighing document in approbate columns.
2. Put the weight, arm and moment of every single changed equipment
or fixed ballast weight down in proper columns. Put + sign for ad
ded and — sign for removed equipment. The moment you get by
multiplying arm (m) x weight (kg) = moment (kgm)
3. Add all weights and moments taking the signs into account and thus
you get the actual empty weight and moment which can be recorded
in the Flight Manual 6.4.
5.4 Calculations for minimum and maximum pilot weight
(See sample Problem 5.5)
Corresponding to the backmost allowed C. of G. limit the minimum
pilot weight can be calculated as follows:
mpmin = 1.017 Mo — 2,485 mo
mp = pilot weight including parachute (kg)
mo = sailplane actual empty weight (kg)
Mo = sailplane actual moment engine retracted (kgm)
Empty weight and moment must not include fuel or water ballast be
cause the C. of G. of the sailplane must be within the limits also with
empty tanks (both move the C. of G. backwards when emptying).
Note 1:
If the sailplane's C. of G. is adjusted to be at the back limit with
a pilot heavier than 70 kg, the minimum pilot weight on the main placard
must be changed accordingly.
Corresponding to the foremost allowed C. of G. limit the maximum
pilot weight can be calculated as follows:
mpmax = 1.271 Mo — 2,881 mo — 32,1
The effect of the maximum fuel amount and extending of the engine
has been corrected in the formula. The amount of the water ballast does
not affect the foremost C. of G. location.
EIRI KY -
Kisällinkatu 8
SF-15170 Lahti 17
page II-35
