Item 0936
DESIGN:
UniCopter ~ PT - Reduction - Primary - Gear - Engine Vertical
Drawing:
Notes:
For use on assembly 0845
Works with Hirth engine(s) only.
Calculations Related to Location of Primary Gears:
Knowns:
Distance between centers of secondary ring gears = 25".
Angle between masts [Yα] * 2 = 18º
The axis of the secondary pinion gear is horizontal.
At pinion axis of azimuth 0º the angle between a crown gear and the pinion is 90º.
At pinion axis of azimuth 90º & 270º the angle between a crown gear and the pinion is 90º + 9º = 99º.
Inputs:
Azimuth ψº of pinion axis on horizontal plane.
Calculations: Red is Azimuth ψº = 45º. | Pink is Azimuth ψº = 43º . | Green is Azimuth ψº = 42º .
The elevation of the center of the primary gears above the plane of the secondary gears [E] ; (1/2 * stagger) * tan(1/2 * V)
tan(9) = 0.1584 | 12.5 * 0.15838 = 1.9798" | tan(9) = 0.1584 | 12.5 * 0.15838 = 1.9798" | tan(9) = 0.1584 | 12.5 * 0.15838 = 1.9798"The distance between the center of secondary and primary gears (in the horizontal plane) [H] ; (1/2 * stagger) / cos( * (90 -
ψ ) cos(45) = 0.7071 | 12.5 / 0.7071 = 17.6778" | cos(43) = 0.7314 | 12.5 / 0.7314 = 17.0905" | cos(42) = 0.7431 | 12.5 / 0.7431 = 16.8214"The angle between the primary-secondary center axis (shaft) and the horizontal is [Angle] ; Inv (sin(E/H))
=6.4302º | = 6.6522º | = 6.7591ºResults:
The angle between the crown and pinion gear faces is; 90º - Angleº = 83.5698º | = 83.3478º | = 83.2409º
The angle between the two crown gear faces is;
2 * ψ º = 90º | = 86º | = 84º This calculation is not quit exact yet since it is the horizontal angle, ie. not in the plane of the shafts. Also the green calculation is only accurate to within 1/2 a degree.The two results must equal each other [Difference].
90 - 83.5689 = 6.4311º | 86 - 83.3478 = 2.6522º | 84 - 83.2409 = 0.7591º
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Last Revised: July 25, 2001