DESIGN: Dragonfly ~ Control - Flight -Assembly - Phase Lag
Delta-3 is currently 0º. This is an option, which may be included in the future. It involves putting a slight twist in the slider spline. OTHER: Flight Dynamics - General - Pitch-Flap Coupling ~ Method C
Due toFlapping Hinge Offset:
Due to Gyroscopic Precession:
Due to Forward Velocity: ? Active
Total phase lag should be:
0º [delta3 contribution], + (90-65)º [flap hinge offset contribution], -?º [gyro contribution], = 25º.
Flapping Hinge Offset:To establish the amount of phase lag required to work with the rotor's offset.
Damping ratio = damping / critical damping =
Frequency ratio = RRPM / natural frequency of blade flapping (undampened) =Ω/ωN undamped
Ω= 68 rad/sec
Assuming a constant mass distribution in the blade;ωn /Ω = root( 1 + (((3/2) * (e/R)) / (1 -(e/R)))) = root( 1 + ((1.5 * (13.5/96)) / (1 -(13.5/96)))) = root( 1 + (0.211/ 0.859 )) = 1.116
ForΩ/ωNundamped I think that the value will be 1/1.116 = 0.8960
c/cc= ( γ / 16) * (1 - (e/R)4 * ((1 + ((1/3) * (e/R)))/(1 - (e/R))) * (1 / (ωn /Ω)) = ( 6.54 / 16) * (1 - (0.141)4 * ((1 + ((1/3) * (0.141)))/(1 - (0.141))) * (1 / 1.116) =0.409 * 0.544 * 1.219 * 0.896 = 0.243
The value used above for' γ ' [blade Lock nbr.] is the SynchroLite's value of 6.54
From figure 7.3[Source ~ RWP1 p.447] the phase angle will be 65º. This is certainly low ~ recalculate to check.
This should give good clearance between the swashplate and the pinion.
See drawing on;DESIGN: Dragonfly ~ Control - Flight - Mixer - Overview
DESIGN: Dragonfly ~ Control - Flight - Cyclic - Overview
MAKE: Dragonfly ~ Control - Flight - Spider - Stick
OTHER: Flight Dynamics - General - Phase Lag
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Last Revised: December 4, 2003