Gear Boxes

[Scale-Gas-Hydroboy]

I'm trying to find a company or somebody that might have a gearbox

with a 20% to 25% reduction. It would have to hold up to some pretty severe RPM's, as I would be attaching a gas turbine engine to it.

( 35000rpm idle - 120000rpm peak ). Please let me know if there

is such a beast of a gearbox out there. :-

Thanks: Steve

 

[Hurricane]

??? ???Don't know of any gerbox but would love some info on the tubine!!!

 

[Scale-Gas-Hydroboy]

In case anyone is curious. I'm going to try and install a turbine engine in a 1/6 scale hydro and set it up the same way as the full size guys.

This is why I'm looking for a gearbox. ;D

 

[Propjockey]

Something like this? (Jetcat USA heli-drive)

You might also try Wren-turbines.com

 

[Scale-Gas-Hydroboy]

Thanks for the help Prop. I've sent an e-mail to Jet-Cat USA,

now I'm just waiting to hear back from them. :

 

[Ian Inverarity]

Scale-Gas (Steve)

Sounds like a very interesting project, but have you considered what would happen to the turbine spinning at 120000rpm if the boat flipped and water got into the turbine? : Could get pretty expensive, possible dangerous!

But I think if it runs well it would be pretty cool! ;D

Ian.

 

[Twin_k90]

you need a gear box that has another set of nossle guid vaines and another turbine wheel, that bolts to the back of the turbine and you take the power from the gas,

1 bit of water in there and your up for some serious money, will need a compressor wheel and a miniminium,

BTW if you need turbine wheels my mate casts 66mm i think they are turbine wheels.

Dale

 

[TimD]

you need a gear box that has another set of nossle guid vaines and another turbine wheel, that bolts to the back of the turbine and you take the power from the gas,

Dale

That is the way to go with a turbine to drive connection - turboprop engine!

The output RPMs would be much more practical.

The heli unit pictured would have an output rpm range way too low. Heli rotorheads fall to pieces at high rpms.

 

[Propjockey]

Yeah, but imagine the size prop you could use!

 

[TimD]

bigger than the boat!!!!!!

Torque roll galore!

 

[Ian Inverarity]

Steve,

do you know the power output of the turbine? I would be aiming to have the prop shaft RPM at about 20 to 30k rpm, and if the power is quite a lot then look at the higher end of that range to keep the prop torque to manageable levels and enable you to use commercially available props!

Ian.

 

[Scale-Gas-Hydroboy]

The power output of the turbine ( after the 20% rpm reduction through a gearbox ) is about 8HP and 24000 rpm at the prop shaft. Not a whole lot of torque out of these turbines. I might even reduce the turbine rpm's by 25%, to gain more torque.

Steve

 

[Ian Inverarity]

8HP is quite a lot, you might want to be aiming for 26-28000 rpm to keep the prop size down. 8HP would be well ahead of the 67 nitro engines used in 1/8 scale boats. WHat size boat are you thinking of building? Also transmission losses through your gearbox will considerably reduce that 8 HP.

Ian.

 

[Scale-Gas-Hydroboy]

The boat we ( my dad and I ) are building is a 1/6 scale version of the Smokin' Joes unlimited hydro. It's 57" long, and a 29" beam.

www.angelfire.com/clone/oshawarcmodelboats/

goto Steve's new boat.

You can get an idea of the size.

I don't think we'll be to far off setting the boat up with a 4.5" pitch

prop turning at 20000+ rpm.

Steve

 

[Twin_k90]

Steve there is a bloke in far north Australia by the name of Mark Moon that is doing the same thing as you, shoot me a email [email protected] and ill shoot you his email address, he has had his running with the turbo prop etc. maybe you guys can swap ideas, i have spoken to mark on the phone and is a very nice bloke.

Dale