The An-70 is a monoplane with a high-mounted wing design that features four distinctive propfan engines.
Designed by the Progress Design Bureau, each of the D-27 engines is rated at 13,800 shp, which is used to drive the SV-27 contra-rotating scimitar propellers designed by Aerosila, eight on the front propeller and six on the aft propeller.
The propfan engines deliver slipstream to the supercritical wings that feature double-slotted trailing edges to provide high lift coefficients at low speeds.
The modernization of the aircraft during 2010–12 saw upgrades to the engines, including the incorporation of FADEC, and the further separation of the two propellers.
The aircraft’s cruise speed is 750 km/h (405 kt) at an operational altitude of 8,600 to 9,600 m (28,200 to 31,500 ft); Antonov claimed in 1997 that the aircraft had a design maximum speed of 850 km/h (460 kt, or Mach 0.8), which would have compared favourably with Mach 0.77 of the larger turbofan-powered C-17.
According to DASA’s evaluation, the prop fan engines were 10 percent more efficient than conventional turboprops.
Similar to many aircraft designs of the Soviet Union, the An-70 was designed as an airlifter that could operate from unprepared fields.
In short take-off and landing (STOL) configuration, the aircraft could lift off from a 600 m (2,000 ft) dirt strip with 25 tonnes (55,000 lb) of cargo and fly for 3,000 km (1,900 mi).
Alternatively, it could fly the same distance with 35 t (77,000 lb) of cargo if it took off from a 1,800 m (5,900 ft) paved runway.
For a payload-heavy mission, the An-70 can haul 47 t (104,000 lb) of cargo for a range of 1,500 km (930 mi), but if range was essential, the aircraft can carry a load of 17 t (37,000 lb) over 8,000 km (5,000 mi).
In exceptional circumstances, the An-70 subjected to lower-G take-offs, can airlift a 47-tonne (104,000 lb) T-80U main battle tank and fly it for 3,000 km (1,900 mi).
The fully pressurized internal cabin measures 4 m (13 ft) wide and 4.1 m (13 ft) high, and has a length of 18.6 m (61 ft) from the front to the ramp, with the ramp included, the total cabin length is 22.4 m (73 ft).
In comparison, the turbofan-powered Il-76 has a lower cross-sectional cargo area, but exceeds the An-70 in payload capability and ramp length.
The An-70’s cargo hold is serviced by four electrical hoists that facilitate autonomous cargo loading.
A central floor can be rapidly installed for the accommodation of 300 soldiers or 200 injured personnel over two decks.
Similar to the An-124, the An-70 design makes extensive use of titanium and composites to keep weight to a minimum and increase damage resistance.
Approximately 25 percent of the airframe is made of carbon-fibre composites, which are primarily used on control surfaces and the tail assembly, while aluminium and steel alloys are used for the rest of the structure.
The An-70 has a designed life of 45,000 hours over 15,000 flights.
The prototypes had a fly-by-wire flight-control system that comprised three digital channels and six analogue channels, it was expected that production aircraft would have a four-channel digital fly-by-wire system.
Aircraft and system information are mainly relayed to the pilot and co-pilot via six large multi-function CRT displays, with secondary electro-mechanical instruments and head-up displays, a flight engineer position is also present on the prototypes.
Specifications
Crew
3-4
Capacity
300 troops or 206 stretcher cases / 47,000 kg (103,617 lb) max payload
Length
40.73 m (133 ft 8 in)
Wingspan
44.06 m (144 ft 7 in)
Height
16.38 m (53 ft 9 in)
Airfoil
TsAGI P-202
Empty weight
66,230 kg (146,012 lb)
Max take-off weight
145,000 kg (319,670 lb)
Powerplant
4 × Progress D-27 propfan,
10,350 kW (13,880 hp) each
Propellers
14-bladed Aerosyla Stupino SV-27,
4.5 m (14 ft 9 in) diameter contra-rotating propeller
(8-bladed forward; 6-bladed rear)
Performance
Maximum speed
780 km/h (480 mph, 420 kn)
Cruise speed
750 km/h (470 mph, 400 kn) at 9,100–11,000 m (29,856–36,089 ft)
800 km/h (500 mph; 430 kn) max
Stall speed
113 km/h (70 mph, 61 kn)
Range
1,350 km (840 mi, 730 nmi) with 47,000 kg (103,617 lb) payload from 1,800 m (5,906 ft) runway
3,800 km (2,400 mi; 2,100 nmi) with 38,000 kg (83,776 lb) payload from 1,800 m (5,906 ft) runway
5,000 km (3,100 mi; 2,700 nmi) with 30,000 kg (66,139 lb) payload from 1,800 m (5,906 ft) runway
7,400 km (4,600 mi; 4,000 nmi) with 20,000 kg (44,092 lb) payload from 1,800 m (5,906 ft) runway
8,000 km (5,000 mi; 4,300 nmi) with maximum fuel from 1,800 m (5,906 ft) runway
