sin αst

The following assumptions are made when using the above calculation principle:
� The rotor plane is perpendicular to the direction of the wind
� Friction in the tail pivot is neglected
� The mass of welds in the tail is neglected
� The tail vane is parallel to the air flow
FURLING AND YAW ANALYSIS
The gain height Δh of the tail is analysed in SolidWorks as a function of the furling angle �f
in the range of 0-5�, using 1� steps.
Furling angle, �f [�] Height gained, Δh [mm]
Table I.2: Results of the tail motion analysis
0 0
1 9.28
2 18.8
3 28.4
4 38.3
5 48.3
The rotor thrust Ftf is calculated for wind speeds 13 m/s, 14 m/s and 15 m/s as shown in
table I.3.
Wind speed V [m/s] 13 14 15
Thrust force Ftf [N] 718 872 1050
Table I.3: Rotor thrust force as different wind speeds
The work performed by during furling Wr may now be calculated as a function of the furl-
ing angle �f at the three wind speeds of table I.3. Correspondingly the potential energy of
the tail may be calculated as a function of the furling angle �f. The result is illustrated on
figure I.5 below.
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