ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
5
MM-2-9
Nov
5/13
2-5. Landing
Gear
A. Main Landing Gear: The main landing gear consists of two tubular aluminum skids
attached to the airframe by means of the forward and aft cross tubes through four air-
oil oleo struts. The struts cushion ground contact during landing. Drag struts give the
gear stability and strength and prevent fore and aft movement during ground contact
maneuvers. Replaceable hardened steel skid shoes are installed on each skid to
resist skid wear on hard surfaces.
B. Tail Rotor Guard: A tubular aluminum tail rotor guard is installed on the aft end of the
tailcone. It acts as a warning to the pilot upon an inadvertent tail-low landing and aids
in protecting the tail rotor from damage.
WARNING
Ensure the locking pin is installed in ground handling wheel before
removing the wheel bar from the wheel assembly and moving the aircraft.
C. Ground Handling Wheels: Each landing gear skid tube has ground handling wheels or
provisions for installing removable ground handling wheel assemblies. Each assembly
has a manually operated over-centering device to lift the skids clear of the ground.
The ground handling wheels should be retracted for engine run-up. If the aircraft has
optional removable Brackett
®
wheels, they should be removed before engine run-up.
2-6. Engine
The F-28F/280F series helicopters are powered by a Textron-Lycoming HIO-360 series
piston engine. The Textron-Lycoming HIO-360 series engine is a four cylinder, direct
drive, horizontally opposed, air cooled, fuel injected engine. The F-28F/280F series
helicopters are equipped with an Enstrom installed turbocharger system which allows the
engine to produce its rated horsepower up to the certified altitude limit.
2-7. Engine
Cooling
A fan mounted on the engine crankshaft flange forces cooling air through a shroud
assembly and baffles onto the engine cylinders. A portion of the cooling air is diverted
through ducting to the engine oil cooler(s). If the optional cabin heating system is installed,
a portion of the cooling air is directed to the heater shroud.
2-8. Flight
Controls
The flight controls include three primary systems: the collective, cyclic, and anti-
torque/directional controls. The flight control systems are not hydraulically boosted. The
collective flight control system incorporates a spring capsule that balances the steady
collective forces from the main rotor system. The cyclic control system also incorporates
spring capsules used to trim out the control system forces produced by the mail rotor
system. The spring capsules are part of electrical trim assemblies that are controlled by a
switch located on the cyclic stick grip. The aircraft also has fixed horizontal and vertical
stabilizers mounted on the tailcone to provide additional stability during forward flight.
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