sin αst

LIST OF ATTACHMENTSFURLING AND YAW ANALYSIS
For the first scenario of CW rotation the equilibrium equation is:
Which yields a yaw error � of 3.50°.
For the second scenario of CCW rotation the equilibrium equation is:
Which yields a yaw error � of 2.24°.
The largest yaw error of 3.50° occurs during CW rotation for alignment. The error is con-
sidered low enough to be acceptable.
208
I.2 Furling mechanism
The present calculation verifies the overall functionality of the furling mechanism, by
checking that furling is initiated at a wind speed of 14 m/s.
The calculation is based on the principle of energy conservation. It is assumed that the
amount of work performed by the furling rotor is translated into an increased potential
energy of the tail, see description in section 8.2. The energy conversion is expressed
mathematically by:
Mv � Mr � Mfr.tot � 0
Mfr.tot � Mr � Mv � 0
Where Wr is the work performed by the rotor:
Wr
And Ev is the potential energy of the tail:
Ev � Wr
� Ftf Lr.y�f
Ev �
mv g h
Ftf is the rotor thrust force, which is found using the rotor calculation tool calculated. Lr.y is
the moment arm of 107.5 mm shown on figure I.3 and �f is the furling angle of figure 8.6.
mv is the tail mass of 17.5 kg and Δh is the gained height of the tail’s mass centre.
(I.24)
(I.25)
(I.26)
(I.27)
(I.28)