Pilot Operating Handbook
H3 Sport 135 HP
SECTION 9
SAFETY TIPS
Dynali_POH_H3 Sport 135 HP Rev. 3.3 – Issue date 15.01.2021 Page
81
Hovering above high-level grass
Do not take off in high level grass. There is a danger of fire. Do not perform hover flight
above high level grass. The ground effect may be lost.
Mechanical noise
All mechanical noises are propagated and amplified by the carbon fiber parts. The
cabin wall acts as a resonating membrane. Carbon also grinds on the tubes of the
frame. It is in the cabin that noise is amplified. Tough, an insulated carbon fiber reduces
noise but causes additional weight.
The origin of the transmission noise is erroneous.
The sound seems to come from
each of the elements that are listened
. The noise coming from the belts, at startup,
is inevitable because ribbed belts are noisier than smooth ones, but they are more
powerful. The pilot has to get used to the sounds of the helicopter but must remain
constantly attentive to other noises he could hear.
In the engine reduction gear, the damping system of instant torque claw is very noisy.
It is a noise like "bumping" or "scrap".
The rear rotor siren sound comes from the 4 blades but also the gear of the RTG that
resonates in the rear propeller shaft, and the tail pipe.
At intermediate regimes, or when the rotors are not driven, the transmission belts are
flapping, causing a mechanical noise flappement. That noise appears at deceleration.
A "tic-tic" or a “grunt” comes from the 15 drive wheels on the base of the mast. The
mast is never perfectly aligned and the rollers operate a mini longitudinal displacement.
This
sound
always
accompanies
a
blade
in
the
same
position.
The "roar" in the tail pipe comes from the pinions of the RTG. When the tail rotor turns
slowly, rear blades, one after the other, falls in its roots, causing a “knock”.
The main rotor blades, when they are about to stop, can let a metallic noise like "dwing
jump” be heard.
Vibration level
Horizontal vibration
Ø
Unproper rotor balancing
Vertical vibration
Ø
Rotor tracking
Ø
Worn tilt bearing
Shimmy (or vibration in the
cyclic)
Ø
A misaligned blade in his root
Ø
Blade bearing deteriorated
Summary of Contents for H3 Sport 135 HP
Page 85: ......
