Super Jet Check out this Double Impeller

[Munkie]

There are a few stand up that run thoose..

 

[snowxr]

Cool, I'll take a 9-17/13-19 please. Next they'll come up with a custom driveshaft to mount a prop behind the stator in the reduction nozzle.

 

[GIL]

The downside would be a bunch more rotating mass which would hurt your bottom end. I wonder if the improved hookup would outweigh that?

IF I rememeber the story correctly they were building so much boost and Hp that they could not get any sort of conventional pump to hook up and had to resort to this type of prop and I THINK the housing was some one off stuff from R&D??? I think they were working with a Solas pump before the crazy setup and the prop was blowing loose at 70mph??? I was dumbfounded by the whole conversation because I could not believe the numbers I was hearing.

 

[Jetrace19]

Nicolas Rius supposidly runs these in his FZR's and they are suppose to virtually eliminate cavitation especially at take off in low speeds were these couches are just pushing some serious thrust numbers and the pump just not efficient enough yet. One of thses days, the pumps will catch up with the times a bitas we loose waaaayyyy to much in that department.

 

[DK-Freestyle]

Rius used it in his Off-Shore FZR.

 

[OCD Solutions]

I once read somewhere that a seadoo 155mm pump behind a 130hp 951cc engine, only puts 85hp to the water. I think we have a little room for improvement there.

I have been hearing about some big breakthru in pump efficiency for a few months now so i guess this is it? I was expecting a full pump/impeller redesign over a drop in impellor but if it's a simple thread in upgrade to a Mag then we are set. If the power gains are there then $700 is nothing.

 

[masterblaster]

why not just make a single prop twice as long with a slower transitioning pitch,and a second wear ring added to the pump,still seems like alot more weight to spin unless your in the 1000cc plus range wouldnt make sense

 

[Matt_E]

Because the two impellers are more for straightening and pressurizing flow.

 

[steve-uk]

everytime I see this thread pop up i keep thinking whats next... "the tri-fector......"

lol

 

[Matt_E]

Multi stage jet pumps aren't new technology. They are quite proven in other applications.

 

[RyanO]

if you put a prop behind the stator veins you will loose all the backwards thrust you have created because you have started cork screwing the water again (the purpose of the veins is the straighten it).

a longer single prop with more blade overlap will not work as it will act more lake a break then a prop.

These props are for boats pushing big HP numbers or people wanting top speed.

Maybe just Maybe a 1200cc ski could push one but still you would lose most of your bottom end.

So guys, unless your building a numbers only (mph) high HP race ski, or a boat forget about these coming to the freestyle/freeride world.

 

[chriselmore_1]

a little off topic, but what about running a reduction nozzle without the veins that match up to the stator veins. Just asking because I have a protec nozzle without em

 

[Matt_E]

I run a skat nozzle without vanes.

 

[chriselmore_1]

but a mag right?

 

[Matt_E]

Yes

 

[masterblaster]

wonder what there point was leaving them out,suppose the 12 veins are more than enough to get the job done in a mag

 

[Polish jet pilot]

The more veins/obstructions the less thrust we get. and multistage jet pumps are used in OZ and NZ in those crazy power boat races in really shallow water...the good thing is that you can suck stones/sand and it just goes through the pump without damage... but those engines put 600-800 hp...

 

[Waternut]

Aerodynamicist dont very well with liquids. They never have to deal with a liquids weight and the fact that it turns to gas at low pressure.

Aerodynamicist? :biggrin:
Have you heard of these newfangled water turbines they use in "hydroelectric dams" as of late?

Kevbo has a valid point. Sure air has weight but it's more like 0.01lb/gal instead of 8lb/gal. That's like redirecting a penny thrown at you instead of redirecting a bowling ball thrown at you.

Hydroelectric dams are opposite in function to a jet pump. The jet pump uses stagnant water and accelerates it up to produce thrust. The dam uses gravity and flow to extract power. Who cares if the water coming out the back side is a trickle in the dam.

All that said... You aren't straightening flow into the main impeller with the first impeller. If you want the benefit of two impellers, they need to be counter rotating or you need to have a stator between them. Let's not forget the power required to basically turn two propellers.

 

[T Curtis]

I have been testing the Skat -Trak inducer in the Rickter. Seems to work really well so far, No cavitation! Im still testing the right pitch for my setup.
I also have been testing this in my 2010 Yamaha HO in the surf. It seems to grab more water in the white wash.

 

[chriselmore_1]

really? What engine/pump setup are you running?