Hamilton Jet HJ241, Manual

Page: 41 / 202

3.7
3 DESIGN BASICS
3.3 D
RIVELINES
HJ-241 / HSRX
3.3 DRIVELINES 3.3.1 Requirement of the Driveline
1. The Driveline must accommodate parallel and
angular misalignment plus allow axial
movement.
2. The Driveline must transmit the torque input to
the Jet Unit with an acceptable life expectancy. It
does not have to transmit thrust loads as these
are absorbed by the Jet Unit
3. Torsional flexibility will be required in the
Driveline. A torsional vibration analysis must
always be carried out. The resultant torque on
the Jet Unit must always be in the same direction.
This should be carefully checked at engine idle
speed.
3.3.2 Engineering Checks
All driveline component suppliers (including engine
and jet suppliers) must be consulted with full
driveline details to ensure suitability and
compatibility of components.
CHECKS MUST INCLUDE:
1. Critical speed check for whirling of the
Mainshaft: consult C.W.F. Hamilton & Co. Ltd.
2. Critical speed check for whirling of the
Driveshaft: Consult the driveline supplier. Engine
to Jet alignment: Consult C.W.F. Hamilton & Co.
Ltd.
3. Torsional Vibration Analysis: consult engine or
torsionally flexible coupling supplier.
NOTE: Critical speed checks should allow safe
operation up to the engine's "no load"
governor setting (or high idle).
C
AUTION
Loads on Jet Unit Thrust
Bearing
The jet unit thrust bearing accepts
thrust loads from the jet unit to
propel the craft. It should not be
subjected to excessive loads from
other sources as described below:
• The Jet Thrust Bearing will
not stand excessive radial
loads caused by Adapters
and Belt Pulleys Overhang-
ing the Jet Coupling Flange.
• The Jet Thrust Bearing will
not withstand excessive
loads produced by rigid
Drivelines which do not
accommodate misalignment
resulting from engine move-
ment.
• There is a limit to the Drive-
shaft weight that can be
supported at the jet unit.
Figure 14: Drive Line Component Description
TORSIONALLY FLEXIBLE COUPLING
FIXED LINESHAFT
MISALIGNMENT ABSORBING COUPLING
(OPTIONAL)
ENGINE
DIESEL
MARINE
JET UNIT COUPLING