Propeller Owner's Manual
136
DESCRIPTION AND OPERATION
61-00-36
Page 2-14
Rev. 2 Feb/17
(6) Operation in beta range is at elevated pressures that are
considerably above oil pressures required for constant
speed operation as shown in Figure 2-3. The slope of the
line representing oil pressures required for beta range
operation is shown to be much steeper than for constant
speed operation.
Operation in constant speed only compresses a spring set
located in the propeller cylinder that pushes against the
piston. Operation in beta range requires that two spring
sets be compressed; one spring set is acting against the
piston (as in constant speed operation) and the second
spring set is in the barrel of the propeller hub (between the
blades and the engine flange) and identified as a reversing
spring in Figure 2-2. The reversing spring is compressed
by the moving the beta lockout unit when blade angle
movement below low pitch occurs.
Compression of one spring set (for constant speed
operation) versus compression of two spring sets (during
beta range operation) is why the slope of the operating oil
pressure line in constant speed operation is less that the
slope of the oil pressure line in beta range.
