1. You don't need overlap to
perform in fluid dynamics.
The THRUST is all that you need in a Personal Watercraft. The thrust
of an impeller is generated by the pressure difference between the pressure
side (which is the side of the blade facing the larger hub end) and the
de-pressure side (which is the side of the blade facing the smaller hub
end). The amount of overlap of impeller blades has nothing to do
with the suction effect or so-called vacuum. The volume of water flowing
into the impeller is only dependent on the volume of water flowing out.
The better the impeller controls the flow field the greater the volume
of water flowing out of the jet pump and the greater the THRUST.
Atmospheric pressure and personal watercraft dynamics control the delivery
of water to the inlet side of the pump. That means blade overlap can not
improve thrust because water is not vacuumed in by the impeller.
The amount of overlap is determined by blade geometry. Nujet is
the most efficient design in this business. Please keep in mind that
water enters the blade at a tangent to the blade at the leading edge of
blade, so it is independent to amount of overlap. Then thrust is
generated while water is pushed smoothly over the whole blade geometry.
The design philosophy of Nujet is controlling the impeller “FLOW FIELD”
and optimizing the “CHORD LENGTH”, “PITCH” and “CAMBER DISTRIBUTION”.
Overlap makes no sense relative to performance. The best design is
high thrust, cavitation free and without overlap. The Nujet 3D design
is the answer to this requirement.
2. Mirror polish pleases your eyes,
but does nothing for performance.
If manual buffing would improve the performance of an impeller, the leading
manufacturers of Personal Watercraft, and Nujet, would have been doing
it for a long time. An expert in the impeller improvement business
says an impeller could lose two pounds of thrust by polishing due to the
fact that water in the flow field doesn't bite a polished impeller as efficiently
as non polished impeller.
3. Why Nujet doesn't express its “Pitches” in 13/18,
14/19 or as most companies do.
Most people are familiar with so-called “variable” pitches such as 13/18
etc. These are marketing gimmicks only and they are just “numbers”.
The randomly picked numbers have nothing to do with any real design of
a blade or any performance of an impeller. Think about this, does
Brand S1’s 13/18 perform the same as S2’s. It does not. Check
this out with real experts. The Destroyer impeller's unique super
progressive pitch goes beyond “variable”. You will discover Nujet's
blade angles change radically from the hub to the outer edge. This
allows the impeller to efficiently force as much water through the jet
pump, per horsepower, as possible with freedom from cavitation.
Manufacturing:
Every Destroyer is precision investment-casts, using aerospace-grade stainless
steel. Each Destroyer impeller is then heat treated, passivated,
CNC machined to exact tolerances, and dynamically balanced. As a
result, every Nujet Destroyer impeller is designed and manufactured to
be more precise, more consistent, and more technologically advanced than
any other impeller on the market today.
