MD Helicopters MD Explorer

Design and development

In January 1989, McDonnell Douglas Helicopters officially launched the development of the Explorer, initially referred to as MDX. The Explorer was the first McDonnell Douglas helicopter to incorporate the NOTAR system from its initial design. McDonnell Douglas partnered with Hawker de Havilland of Australia to manufacture the airframes. 10 prototypes were built with seven being used for ground tests. McDonnell Douglas Helicopters became a launch customer for Pratt & Whitney Canada's PW200 series of engines, with an exclusive agreement to power the first 128 Explorers with two PW206As. Meanwhile, plans to offer the Turbomeca Arrius as an option were dropped. The first flight of the Explorer took place on 18 December 1992, with ship #2 (N900MD). FAA certification for the Explorer was granted on 2 December 1994, with JAA certification following shortly after.

In September 1997, a range of improvements were introduced, including PW206E turboshafts with higher single engine inoperative ratings, revised engine air inlets, improved NOTAR inlet design and a more powerful stabiliser control system. Benefits include improved range and endurance and an increased maximum takeoff weight. This enhanced Explorer was unofficially designated the MD 902.

In September 2000, the Explorer has been delivered with the further improved PW207E turboshaft, with improved hot and high and one engine inoperative performance.

The MD Explorer features the NOTAR anti-torque system, with benefits including increased safety, far lower noise levels and performance and controllability enhancements. Instead of an anti-torque tail rotor, a fan exhaust is directed out of slots in the tail boom, using the Coandă effect for yaw control. Boeing retains the design rights to the NOTAR technology despite selling the former McDonnell Douglas civil helicopter line to MD Helicopters in early 1999. The Explorer also features an advanced bearingless five blade main rotor with composite blades, plus carbonfibre construction tail and fuselage.

Variants

MD 900 Explorer

Initial Production model, powered by two Pratt & Whitney Canada PW206A (or PW206E or PW207E) turboshaft engines.

MD 901 Explorer

Civil utility transport model, powered by two Turbomeca Arrius turboshaft engines and tri-angel landing gear. McDonnel Douglas Helicopters announced that this type was available from serial number 127 and upwards. By sale of civil helicopter variants to MD Helicopters the type was not further developed. None ordered.

MD 902

Marketing name for an enhanced version with Category A approval and powered by two Pratt & Whitney Canada PW206E or PW207E. Enhanced version has additional engine isolation features and changes to the Integrated Instrument Display System. Older helicopters (except for the first seven built) can be modified to the enhanced version.

MH-90 Enforcer

Armed version for the United States Coast Guard flown by the Helicopter Interdiction Tactical Squadron from 1998 to 2000.

Combat Explorer

One demonstrator helicopter displayed at the 1995 Paris Air Show.

Operators

 Belgium

Federal Police

 Germany

Landespolizei

 Hungary

Hungarian Police

 Hong Kong

Heliservices

 Luxembourg

Luxembourg Air Rescue

Luxembourg Police

 Mexico

Mexican Navy

 United Kingdom

Essex Air Ambulance

Greater Manchester Police

Humberside Police

London's Air Ambulance

South Yorkshire Police

West Yorkshire Police

Yorkshire Air Ambulance

Lincolnshire & Nottinghamshire Air Ambulance

 United States

Calstar

Drug Enforcement Administration

National Park Service

University of Missouri Hospital

Former operator

 United States

United States Coast Guard

Specifications

Data from Jane's All The World's Aircraft 2003–2004

General characteristics

Crew: 1–2

Capacity: 6 Passengers

Payload: 2,565 lb internal or 3,000 lb slung load (1,163 kg or 1,361 kg respectively)

Length: 32 ft 4 in (9.85 m)

Rotor diameter: 33 ft 10 in (10.31 m)

Height: 12 ft 0 in (3.66 m)

Disc area: 899.0 sq ft (83.52 m²)

Empty weight: 3,375 lb (1,531 kg)

Max. takeoff weight: 6,250 lb (2,835 kg) (internal load), 6,900 lb (3,129 kg) (slung load)

Powerplant: 2 × Pratt & Whitney Canada PW206E turboshaft, 550 shp (410 kW) (continuous) each

Performance

Never exceed speed: 140 knots (161 mph, 259 km/h)

Cruise speed: 134 knots (154 mph, 248 km/h) at sea level (max. cruise)

Range: 293 nmi (337 mi, 542 km) at 5,000 ft (1,500 m)

Endurance: 3 hr 12 min

Service ceiling: 17,500 ft (5,335 m)

Rate of climb: 1,000 ft/min (5.1 m/s)

Hover ceiling: 11,000 ft (3,400 m) (in ground effect, International Standard Atmosphere)