Copyright of RotorSport UK Ltd
Document number RSUK0060
Page 94 of 101 Page issue 5.1, dated 10.06.14
9.
I
VO-PROP IN-FLIGHT VARIABLE PITCH PROPELLER
9.1. INTRODUCTION
A variable pitch propeller (VPP) manufactured by IVO Prop Corp of Long Beach
California, is available as optional equipment to optimise propeller efficiency, fuel
consumption and noise in all flight regimes and power settings. This is achieved by
changing the propeller pitch in flight.
The propeller is modified version of the IVO DL3-68, specifically designed for RotorSport
gyroplanes This means that there are internal design features that make the product
unique, and it must not be replaced by a propeller other than the part supplied by
RotorSport UK Ltd.
The propeller is electrically actuated via slip rings on the engine face.
WARNING! Cleanliness of this face is important, do NOT apply corrosion preventative
substance to the slip rings! It will prevent them from functioning!
9.2. FUNCTION
In this propeller the pitch change is obtained by twisting each blade along its length by
means of an internal torque tube. An electrical gear-motor mounted in the propeller hub
drives a spool which twists each torque tube simultaneously.
The propeller has two internal pitch limit stops, mechanically limiting the pitch angle at the
pre-determined FINE and COARSE limits. NB: These are different for 912ULS and 914UL
engine applications.
These pre-determined limits ensure that the aircraft will still climb at a minimum rate of
250fpm in the full-COARSE setting, and will not over-rev the engine in the climb in the full-
FINE setting.
However, it is the pilots responsibility to monitor engine rpm in the
cruise and descent to ensure rpms are kept within operational limits!
Note that the propeller requires up to 10secs to transit from full fine to full coarse pitch.
9.3. CONTROL
No constant speed controller is fitted in this application and the pilot must select the
appropriate power setting/manifold absolute pressure for the chosen propeller pitch.
The pitch is adjusted by means of a rocker switch, with two amber LED’s providing
information on the propeller pitch status. Full-FINE setting is always used for certain flight
regimes, but any intermediate COARSE setting may be selected at the pilots discretion.
The propeller controller will automatically switch-off power when the propeller reaches
either of the mechanical limit stops and will indicate this by means of the two LED
indicators