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MD 600N
MD
600N
SYSTEM DESCRIPTION
10

2.1. Overview.
The MD Helicopters MD 600N
®
is a single turbine-engine, rotary-wing aircraft. The fuselage is constructed
primarily of aluminum alloy while the NOTAR
®

anti-torque system components are primarily carbon epoxy
composite structure.
Simplicity, low operating cost and maximum commonality with MD 500
®

Series helicopters were the primary design
criteria for the MD 600N
®
development.
The main rotor is a fully articulated six-blade system with excellent control and maneuverability characteristics. It
shares many rotor system components with other MD 500
®

Series helicopters. The small diameter of the main rotor
also gives the MD 600N
®
the ability to land safely in tight or confined areas.
Power from the 808 shp Rolls-Royce 250-C47M turboshaft engine is transmitted through the engine drive shaft to the
main rotor transmission. The main rotor transmission, through a second drive shaft, drives a gearbox for the
NOTAR
®

system fan. An overrunning clutch between the engine and the main rotor transmission permits
freewheeling of the rotor system during autorotation. All drive shafts are fitted with fail-safe couplings at both ends.
The airframe consists of faired sections which provide extremely clean aerodynamic lines. This contributes to
excellent handling qualities, low vibration levels and high-speed capability. The air- frame structure is designed to be
energy-absorbing while maintaining rotor hub integrity. A rigid, three-dimensional truss-type structure increases crew
and passenger safety by means of its roll- over structure design and reduces the potential for airframe collapse into
the crew and passenger compartments. MD
600N
SYSTEM DESCRIPTION
11
2.2. Performance statistics.
The MD 600N
®
has a cruising speed of 134 knots (248 kph/154 mph). Useful internal load, at maximum gross
weight, is 907 kg (2,000 lb) or a mix of internal and external useful loads up to 1179 kg (2,600 lb). Hover Out of
Ground Effect (HOGE) at ISA is 1829 m (6,000 ft) and Hover In Ground Effect (HIGE) at ISA is 3383 m (11,100 ft).
The rate of climb, at maximum gross weight, is 6.9 m/sec (1,350 feet per minute).
The helicopter has a maximum operating altitude of 6097 m (20,000 ft) and a temperature operating range of -40
degrees C to +52 degrees C. Slope landings of up to 10 degrees are possible, due largely to the articulated rotor
system.
2.3. Airframe.
The MD 600N
®
fuselage is a semi-monocoque aluminum structure. The crew and passenger compartments are
protected by an A-frame truss that also acts as an integral seat structure. The aircraft forward belly is a double-
walled keel beam that supports the front landing gear struts and provides energy absorption in the event of a hard
landing.
The aft cabin belly is also a double- wall
design, providing space for a newly-
designed, two-cell, crash- resistant fuel
system.
The MD 600N
®
floor is rated at 1350
pounds (not to exceed 115 pounds per
square foot) and offers cargo tie down points
for virtually any shape of cargo.
The NOTAR
®

tailboom is carbon composite
structure with a horizontal stabilizer
constructed of carbon composite and
Kevlar. The vertical stabilizers are made of
fiberglass.
The forward canopy transparencies are
secured with screws, easing removal for
maintenance and access to the aft side of
the instrument panel. MD
600N
SYSTEM DESCRIPTION
12

2.4. Engine.
The engine used in the MD 600N
®
is the Rolls-Royce 250-C47M gas turbine engine. The 250-C47M produces
808 shaft horsepower, derated in the MD 600N
®


to 600 shaft horsepower for takeoff and 530 horsepower at
maximum continuous operation. Derating the engine extends its service life and reduces maintenance while
offering increased performance at higher-density altitudes.
The 250-C47M engine is equipped with a full authority digital engine control (FADEC) unit. This system greatly
enhances engine control and provides several features and benefits that reduce pilot workload, improve flight
safety and decrease maintenance requirements. A separate hydro-pneumatic fuel control system is provided for
manual backup in case of emergencies.
The engine control unit records all important engine parameters and provides maintenance information to the
customer through a system of maintenance lights. Also available is an optional maintenance package that
includes software and hardware to allow downloading of the recorded parameters from the ECU onto a standard
personal computer.
Pilot workload is simplified with automatic starting and turbine temperature limiting. Provisions for main rotor and
NOTAR
®

fan load anticipation provides stable rotor speed throughout the flight envelope.
Maintainability is enhanced by removing the requirement for PTG rigging, and by eliminating pneumatic control
lines, accumulators and connections. No field authorized adjustments are required. Control system features
allow temperature limiting, further reducing the potential for engine damage. The standard analog/digital TOT gauge
records one-time exceedances.
The engine compartment is located aft of the mid-compartment, separated by a firewall. Access to the engine
compartment is through two doors contoured to the aerodynamic lines of the fuselage. The engine arrangement
provides access for inspection and maintenance without the need for ladders or work platforms. An engine
compartment fire detection system is standard on the MD 600N
®
.
MD
600N
SYSTEM DESCRIPTION
13
2.5. Drive System.
The main transmission in the MD 600N
®
is a new design based on the proven concepts of the MD 500
®

Series
transmissions. The transmission power limit is 600 shaft horsepower for takeoff and 530 shaft horsepower
continuous. It has been designed to achieve a life of 3,000 hours before overhaul, and can be removed from the
aircraft without removing any of the main rotor components.
An overrunning clutch transmits power from the engine to the engine drive shaft. The clutch has no external
controls and disengages automatically during autorotation and engine shutdown. The engine oil cooler blower is
belt-driven off the main drive shaft and draws its cooling air from the air inlet fairing to supply ambient air to the
engine and transmission oil coolers and to the engine compartment.
This transmission is common with the MD 600N
®
and all other new MD 500
®

Series helicopters.



MD
600N
SYSTEM DESCRIPTION
14

2.6. Main Rotor System.
Unique to MD Helicopters products is the static mast-hub support system. This hub sup- port system uses a
static mast, rigidly attached to the fuselage. All dynamic loads are transmitted through this mast, rather than
through the transmission. A separate, inner drive shaft transmits engine torque to the main rotor hub.
This feature offers improved flight control integrity and helps retain rotor system components in the event of a
main rotor blade strike. Additionally, this approach allows for the design of a main transmission that is lighter
in weight, and can be removed without disturbing the hub or control systems.
The MD 600N
®
features a six-blade, fully
articulated main rotor assembly. The blade
retention system is a unique strap pack design
which provides restraint and allows all three
degrees of freedom for rotor blade travel. The
system has redundant load paths for an added
measure of safety.

Elastomeric lead/lag dampers are standard in
the MD 600N
®
main rotor system. The blades
are of all metal construction and utilize nickel
abrasion strips to minimize the effects of erosion
from airborne particulate matter. The blades are
secured to the hub with quick-release lever-type
pins that facilitate rapid blade removal without the need for tools.
The main rotor system of the MD 600N
®
provides excellent handling qualities with crisp control responses. In
addition, the six-blade design reduces vibrations, providing an exceptionally smooth ride. Transient positive
load factors of 3.5 gs and negative load factors of 0.0 gs are attainable in the MD 600N
®
. MD
600N
SYSTEM DESCRIPTION
15
2.7. Flight Controls
Primary flight controls in the MD 600N
®
are designed to be lightweight, simple to use and easy to maintain.
Equally important, they are designed to eliminate the need for hydraulic controls common in competitor
helicopters. Instead, all main rotor controls in the MD 600N
®
are of the push tube type. There are no grease
fittings in the controls and required maintenance is at an absolute minimum.
The anti-torque pedals control vertical stabilizer and rotating thruster motion using a combination of push rods and
push-pull cables. The anti-torque pedals are adjustable, fore and aft, through approximately 4 inches of travel to
accommodate the fifth through 95th percentile aviator.
Adjustable friction devices are incorporated in the cyclic, collective and throttle controls. In addition, electrical
cyclic trim actuators allow flight loads to be trimmed out.






MD
600N
SYSTEM DESCRIPTION
16

2.8. Landing Gear System.
The landing gear on the MD 600N
®
is of the skid type with replaceable shoes. The gear is fixed to the
fuselage and is not retractable. Aerodynamic fairings cover the struts. New, heavy duty, nitrogen-charged
landin