TITLE:
MCDONNELL
DOUGLAS C-17A 'Globemaster III'
TYPE:
Long-range
and intra-theatre heavy cargo transport.
PROGRAMME:
US Air
Force selected McDonnell Douglas to develop C-X cargo aircraft 28 August 1981;
full-scale development called off January 1982 and replaced on 26 July 1982 by
slow-paced preliminary development order; development and three prototypes (one
flying) ordered 31 December 1985; fabrication of first C-17A (T1/87-0025) began
2 November 1987; first production C-17A contract 20 January 1988; assembly
started at Long Beach 24 August 1988; assembly of prototype completed 21
December 1990; first flight 15 September 1991 - also delivery to 6517th Test
Squadron/6510th TW, Edwards AFB (unit re-named 417th TS/412th TW on 2 October
1992); 100th hour/35th sortie 17 January 1992; first aerial refuelling 11 April
1992 during 51st sortie (155.8 hours); first stall testing 7 May 1992; 200th
hour/65 sorties 8 May 1992; achieved VNE (Mach 0.875/510 knots) May 1992; first
opening of cargo door in flight 17 June 1992; 300th hour/73 sorties 13 August
1992; 100th sortie/326 hours 29 August 1992; new software for expansion of flight
envelope flown 5 January 1993. 400th sortie, 25 May 1993 (by P5/89-1191); first
paratroop drop, 9 July 1993 (from T1/87-0025); two new payload-to-altitude
records established (by P1/88-0265) on 8 October 1993, increasing C-17's
records to 21. First overseas service flight (P11/92-3291) to Mildenhall, UK,
25 May 1994.
DESIGN
FEATURES:
Externally
blown flap system based on McDonnell Douglas YC-15 medium STOL transport
prototypes (see 1979-80 Jane's), with extended flaps in exhaust flow from
engines during take-off and landing; combines load-carrying capacity of C-5
with STOL performance of C-130; required to operate from 915 m (3000 ft) long
and 18.3 m (60 ft) wide runways, complete 180 degrees three-point turn in 25 m
(82 ft) and reverse up 1 in 50 gradient when fully loaded using thrust
reversers. Structure designed to survive battle damage and protect crew;
essential line-replaceable units (LRU) to be replaceable in flight;
rear-loading ramp. Supercritical wing with 25 degrees sweepback; 2.90 m (9.5
ft) high NASA winglets.
LANDING
GEAR:
Hydraulically
retractable tricycle type, with freefall emergency extension; designed for sink
rate of 4.57 m (15 ft)/s and suitable for operation from paved runways or
unpaved strips. Mainwheel units, each consisting of two legs in tandem with
three wheels on each leg, rotate 90 degrees to retract into fairings on lower
fuselage sides; tyre size 50 x 21-20; pressure 9.52 bars (138 lb/sq in);
maximum sink rate 4.6 m (15 ft)/s. Menasco twin-wheel nose leg retracts
forwards; tyre size 40 x 16-14; pressure 10.69 bars (155 lb/sq in). Allied
Signal (Bendix) wheels and carbon brakes. Min ground turning radius at outside
mainwheels 17.37 m (57 ft 0 in); min taxiway width for three-point turn 27.43 m
(90 ft 0 in); wingtip/tailplane clearance 74.24 m (237 ft 0 in).
POWER
PLANT:
Early
aircraft have four Pratt & Whitney F117-PW-100 (PW2040) turbofans, with
maximum flat rating of 181.0 kN (40,700 lb st), pylon-mounted in individual
underwing pods and each fitted with a directed-flow thrust reverser deployable
both in flight and on the ground. Power plant contract open to competition for
later C-17As. Provision for in-flight refuelling. Two outboard wing fuel tanks
of 21,210 litres (5603 US gallons; 4666 Imp gallons) each; two inboard wing fuel
tanks of 30,056 litres (7940 US gallons; 6612 Imp gallons) each; total capacity
102610 litres (27,086 US gallons; 22,572 Imp gallons). Plessey fuel pumps.
ACCOMMODATION:
Normal
flight crew of pilot and co-pilot, side by side on flight deck, two observer positions
and loadmaster station at forward end of main floor; access to flight deck via
downward opening airstair door on port side of lower forward fuselage. Bunks
for crew immediately aft of flight deck area; crew comfort station at forward
end of cargo hold. Main cargo hold able to accommodate US Army wheeled
vehicles, including five-ton expandable vans in two rows, or three Jeeps side
by side, or up to three AH-64A Apache attack helicopters, with straight-in
loading via hydraulically actuated rear-loading ramp which forms underside of
rear fuselage when retracted. Aircraft fitted with 27 stowable tip-up seats
along each sidewall and another 48 seats which can be erected along the
centreline; optionally up to 48 litters for medical evacuation mission or up to
100 passengers on 10-passenger pallets in addition to 54 sidewall seats.
AVIONICS:
Honeywell
dual air data computers, with advanced digital avionics and four full-colour
multi-function displays (MFDs), two GEC-Marconi full flight regime foldable
head-up displays, plus integrated mission and communications keyboards (MCKs)
and displays (MCDs). Primary flight data presented on HUD and a selectable mode
for the MFD. Horizontal navigation situation, computer-generated flight plan
and weather radar overlay selectable on MFD. Station keeping (SKE), engine and
flight control configuration data available on MFDs. All frequency tuning for
nav/com accomplished from glareshield control panel. MCDs have frequency and
channel pre-storage facility and provide for flight plan entry manually or by
pre-programmed cassette, permitting insertion of in-flight planning changes
without disturbing ongoing navigation. All MCD information for flight and
navigation monitoring is presented on the HUD and MFDs.
DIMENSIONS:
EXTERNAL:
Wingspan:
wings only: 50.29 m (165 ft 0 in)
between
winglet tips: 51.76 m (169 ft 10 in)
Wing
aspect ratio: 7.16
Length:
overall: 53.04 m (174 ft 0 in)
Height
overall: 16.79 m (55 ft 1 in)
Tailplane
span: 19.81 m (65 ft 0 in)
AREAS:
Wings,
gross: 353 m{2} (3800.0 sq ft)
Ailerons
(total): 11.83 m{2} (127.34 sq ft)
Tailplane:
79.2 m{2} (845.0 sq ft)
WEIGHTS
AND LOADINGS (target):
Operating
weight empty: 122016 kg (269,000 lb)
Max
payload (2.25g): 76657 kg (169,000 lb)
Max wing
loading: 751.71 kg/m{2}
(153.95
lb/sq ft)
Max
power loading: 366.51 kg/kN (3.59 lb/lb st)
PERFORMANCE:
(estimated; pending completion of
flight
test programme):
Normal
cruising speed at 8535 m (28,000 ft):
Mach
0.77
Max
cruising speed at low altitude:
350
knots (648 km/h; 403 mph) CAS
LENGTH
(m): 53.04
HEIGHT
(m): 16.79
WINGSPAN
(m): 50.29
MAX T-O
WEIGHT (kg): 265,352
MAX WING
LOAD (kg/m{2}): 751.71
MAX
LEVEL SPEED (knots): 350
MAX
RANGE (nm): 2800