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Got Jet Fuel? Turbine Helicopters > Water injection & gearboxs
 
 
Guardian
Senior Heliman
Location: Sarasota, Florida

Hi all i will soon be getting plans and 2kits for the KJ-66, and I was wondering How would you install a water injection system on it ? What kind of gearing should it have ? all metal gears, or other ?
12-19-2002 Over year old.
 
 
Guardian
Senior Heliman
Location: Sarasota, Florida

What's this 97 viewings and no one know's a thing about my questions ? ( A & B )
12-26-2002 Over year old.
 
 
Phil Cole
Veteran
Location: Redwood City CA

Well, noone seems to be using water injection for model turbines, so noone knows about it. You could try asking Jesus Artes. If anyone knows, he would.

As for gearing, there are several turbo-shaft engines available. A bit of research would show that Jetcat use rubber belts, and Jakadofsky is using metal and some plastic in their gears. Others (Wren, SPS) have totally enclosed gearboxes, so your guess is a good as mine as to what's in them.

They all charge about as much for the turbo-shaft conversion as the core engine, so there is probably something non-trivial about it all. I'm sure there is more to it than extending the shaft and hanging some gears off it. At least there would be different turbine, to extract as much power from the gas flow as possible, rather than just enough to power the compressor.
12-26-2002 Over year old.
 
 
Guardian
Senior Heliman
Location: Sarasota, Florida

Thanks for the help phil
12-26-2002 Over year old.
 
 
Skydog222
Heliman
Location: Atlanta

Why would you want to install a water injection system on your turbine?? That is a very complicated system with very little effect in the flight envelope that you would fly in. I don't think you would be able to set one up properly on a helicopter.

We worked on exactly that last summer. We installed a water injection system on an AMT 450. At sea level, we did not really see much of an increase in performance. We did see about a pound increase in thrust, but, that is not a significant increase. You will not see much of an increase in the RC world, they don't fly fast enough to gain much from it. The only thing you really gain is a more complex system and more weight.

Well anyway....just wondering. =)

Michael
02-12-2003 Over year old.
 
 
Doug
Elite Veteran
Location: Naples Florida....

Well: I'll bite. Water injection on a Gas turbine can be accomplished three different ways.
1. Pre compressor cooling:
Injecting the water in front of the compressor lessens the heat of compression in a high pressure ratio compressor (the Jk66 at about 2/1 does not qualify).
2.) Diffuser injection:
This lowers combustion temp and increases mass flow. Not a good idea with a JK66 as it utilizes vaporizer fuel nozzles and the increased mass flow would cause surging in the compressor due to the low pressure ratio.
3.) exhaust heat recuperation.
This injects either water or live steam in the core engine exhaust to remove heat by converting the water to steam to drive a secondary low pressure turbine. Again at the low flows and low overall pressure ratio no benefit would be realized. as for gearing the jet cat system is at least "doable" other gearing methods would require a lot of R&D. Free turbines add a lot of weight and complexity on there own.

First member of Member of Bearings Anonymous
02-12-2003 Over year old.
 
 
Guardian
Senior Heliman
Location: Sarasota, Florida

Thanks for the help guys I guess water injection is out, is there any way to install an afterburner on the KJ-66 ? are there any sites for the conversion ?

thanks
02-17-2003 Over year old.
 
 
Doug
Elite Veteran
Location: Naples Florida....

Not much of a conversion. It needs a length of tailpipe (lose the nozzle). A round SS pipe with holes in the aft face can serve as a fuel nozzle and flame holder. You will need to line the tail pipe with another pipe with random hole's punched in it to serve as a anti screech liner. (You will know what screech is when you hear it) You need some form of ignition system (Hot streak works good just inject fuel in front of the turbine for a split second)

Why would you want to do that?

First member of Member of Bearings Anonymous
02-17-2003 Over year old.
 
 
Guardian
Senior Heliman
Location: Sarasota, Florida

you know the usual helicopter dog fighting, besides airwolf had a booster I figure Why can't mine as well ? I mean what could happen ? right
02-18-2003 Over year old.
 
 
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Got Jet Fuel? Turbine Helicopters > Water injection & gearboxs
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