year, on January 3. Two days later, Naval Air
Systems Command (NAVAIR) announced the
helicopter, which carried the Sikorsky model
number S-95, would be designated CH-53K.ENGINES
A full $3.04bn SDD contract to produce ve
airframes, including a single ground test
vehicle (GTV) and four ying engineering
development models (EDM), along with static
and fatigue test articles, was issued on April
5, 2006. At that time, systems integration and
RDT&E were expected to run until 2015 and
cost up to $4.4bn.
Sikorsky announced its selection of the
General Electric GE38-1B turboshaft engine
to power the CH-53K in December 2006. It
was a derivative of the CFE738 commercial
turbofan and the T407 turboprop that was
originally developed for the cancelled
Lockheed P-7A maritime patrol aircraft.
Subsequently designated the T408-GE-400, it
is equipped with a dual-channel full-authority
digital electronic control (FADEC) system and
features advanced health-monitoring functions.
Due to shifting priorities, development
progressed slowly, but the CH-53K programme
completed preliminary and critical design
reviews (PDR and CDR) in September 2008
and July 2010.
Although the CH-53K was originally
expected to y in 2011, the SDD schedule
was adjusted in August 2011 and rst ight
was set for 2013 with initial operational
capability (IOC) moving from 2015 to 2018.
Another revision pushed the dates to 2014
and 2019 respectively.
Final assembly of the GTV and EDMsrespectively began in July and December
2011, and the former was delivered to
Sikorsky’s Development Flight Test Center in
Jupiter, Florida, on December 4, 2012. Testing
began in December 2013, then on January
24, 2014, the GTV’s engines were powered up
and the rotor head turned for the rst time.
In May 2013, Sikorsky received a
$435.3m modi cation to the SDD contract
for four production representative system
demonstration test article (SDTA) CH-53Ks
to support operational evaluation (OPEVAL).
The rst four SDTAs are being assembled
and test own at the Florida facility – the
initial example having made its maiden ight
in January this year. Final assembly and
ight testing of the SDTA ve and six and
production aircraft will take place at Sikorsky’s
Stratford, Connecticut, facility.
On April 4, 2017 the programme was
granted Milestone C approval for the start
of low-rate initial production (LRIP), and
Sikorsky received a $304m contract for two
Lot 1 LRIP CH-53Ks on August 30.
Subsequent purchases will include six
aircraft in LRIP Lot 2, eight in Lot 3 and 13 in
Lot 4 for a total of 25 CH-53Ks before full rate
production (FRP) begins. Initial deliveries from
the LRIP lots are expected to begin in 2020.
An FRP decision is expected in 2020
and 169 aircraft will follow by 2028. Planned
orders were increased as a result of a USMC
force structure review that was completed in
March 2011.
The current Acquisition Program Baseline
(APB) was approved on April 24, 2013 and
the programme of record (POR) totals 200
CH-53Ks, including the SDTAs.A Government Accountability Office (GAO)
review determined that since 2005 CH-53K
development expenditure had increased by
more than 46% to $7.3bn, and the price for a
single aircraft rose by 14%.
In March last year, the Marine Corps
con rmed that programme costs had
increased 21% over its original baseline.
The average recurring y-away cost is
$87.1m per aircraft, but when development
costs were included, the average price
increased to $138.5m each.DESIGN
Sharing only a family resemblance and
a similar con guration with the earlier
Super Stallion, the CH-53K is powered by
three 7,332shp (5,467kW) T408-GE-400
engines. With 63% fewer parts than the
General Electric T64 used on the CH-53E,
they provide a 57% increase in power over
CH-53E engines but with reduced fuel
consumption of about 18%.
The new main rotor hub design is based
on Sikorsky’s commercial S-92 helicopter
and its split-torque gearbox design was
developed for the US Army’s cancelled RAH-
66 Comanche. The 79ft (24.08m) and 20ft
(6.1m) diameter of the main and tail rotors
is unchanged from the CH-53E, but their
increased chord provides larger surface areas
that translate to additional lift.
Additionally, the high-efficiency composite
main rotor blades have an advanced airfoil
and swept tips that are optimised to increase
performance in hover and forward ight.
The CH-53K’s ‘hot and high’ performance
enables it to lift a 27,000lb (12,245kg)http://www.aviation-news.co.uk 29The rst of four Engineering Manufacturing
Development (EDM) YCH-53Ks conducts
its maiden ight from Sikorsky Aircraft’s
Development Flight Center at William
P Gwinn Airport in Jupiter, Florida, on
October 27, 2015. All photos Sikorsky Aircraft
unless stated28-32_ch53kDC.mf.indd 29 03/04/2018 17:25