Feature 8 | ProPulsors
Propeller and rudder design for the
QE class carriers
The design and integration of the UK Royal Navy’s Queen Elizabeth (QE)
class aircraft carrier’s propellers and rudders has presented challenging
engineering issues due to the size and speed of the vessel, the propeller’s
high-load nature and the harsh environment in which the rudder operates*.
W
ith a displacement of over Artist’s impression
65,000tonnes the propulsion of the QE class
system for the QE Class carriers.
delivers approximately 40MW per
propeller requiring careful management
of cavitation and pressure pulses. The
rudder has been designed with a twisted
profile, a first in the Royal Navy, and flow
blockers to significantly reduce cavitation.
Rolls-Royce was chosen to supply both the
propeller and rudder, and working closely
with the Aircraft Carrier Alliance (ACA)
has used unique features to optimise the
hydrodynamic design of these critical
components.
Whilst the overall vessel design and
delivery is the responsibility of the ACA, consider the power density ratio (PDR) variation and shaft speed into account.
the ship’s Integrated Electric Propulsion on the propeller disc, PDR in kW/m
2
. This In the table, different PDR and DI
(IEP) system is being designed and method takes the propeller power and values are given for the QE class vessels
manufactured by the Power & Propulsion diameter into account but neglects the and for other similar demanding naval
Sub-Alliance of Thales, Rolls-Royce, vessel’s speed. It is a good method when or commercial propeller designs that
Converteam and L-3 Communications. comparing alternatives with similar speed Rolls-Royce have produced over the last
The hydrodynamic designs of the and wake field characteristics. years. In the table typical guideline limit
propellers and the semi-spade rudders Another commonly used method values for these parameters are also given.
have been developed by the Rolls-Royce that gives a more accurate comparison The difficulty of the QE class propeller
Hydrodynamic Research Centre in between different vessels is the Difficulty design is here confirmed and it is seen
Sweden in close co-operation with BMT Index (DI), defined by Keller, which takes that it is among the most difficult projects
SeaTech, QinetiQ, and the ACA. propeller power, diameter, wake field Rolls-Royce have been involved in during

Propeller loading
The maximum propulsive power generated
PDr DI
by the four Converteam propulsion roPax ferry 1 870 785
motors is 80MW, which means that each
roPax ferry 2 993 799
propeller after some shaftline losses has to
roPax ferry 3 609 651
absorb nearly 40MW. This is a significant
Cruise vessel 713 655
amount of power to be absorbed by a 6.7m
diameter propeller and together with the
Mega yacht 1222 725
high ship speed and strict performance
Navy destroyer 1076 696
requirements, the propeller design is
QE class (CVF) 1112 691
considered to be challenging. There are
limit values <1000 <600-700
several methods available to compare the
difficulty of a propeller design, the easiest
Propeller design difficulty measures for the QE class propeller in comparison to other
and most commonly used method is to
demanding rolls-royce propeller designs.
40 Warship Technology October 2009
p40-47_WT Propulsors-QE OCT09.indd 40 17/09/2009 17:03:03
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52