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Jetcat third fuel pipe mystery

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Old 10-09-2017, 01:55 AM
  #1
HarryC
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Default Jetcat third fuel pipe mystery

I have a Jetcat 160sx internal kero start which i bought second hand. The front cover has 3 cut outs for fuel pipes. Two are used by the igniter and main fuel pipes. The third cut out doesn't have a pipe/festo coming out from the front cover but under the front cover there is a brass fuel pipe that goes down into the engine just like the main and igniter pipes do. What is that pipe for?
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Old 10-09-2017, 03:07 AM
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Bearing Lubrication pipe !?

Last edited by hmjets; 10-09-2017 at 08:05 AM.
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Old 10-09-2017, 03:15 AM
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Take a picture
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Old 10-09-2017, 04:19 AM
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HarryC
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Unused brass pipe nearest to camera, the main and igniter feeds with festos at rear. Cutout in purple cover looks like it was done by a previous owner not Jetcat
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Old 10-09-2017, 04:40 AM
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could it be a tube to pick up internal engine air pressure??!

Last edited by hmjets; 10-09-2017 at 08:08 AM.
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Old 10-09-2017, 04:44 AM
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Quote:
Originally Posted by HarryC View Post
Unused brass pipe nearest to camera, the main and igniter feeds with festos at rear. Cutout in purple cover looks like it was done by a previous owner not Jetcat
Harry was this engine converted to kero start as that could be the old gas injector?

regards

John.
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Old 10-09-2017, 05:02 AM
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None of my Jetcat engines have more than two fuel/gas connections.
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Old 10-09-2017, 06:01 AM
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From my experience with Jet Cat turbines, you are missing the bearing/lube regulator. This is a small aluminum fitting that attaches to the main fuel port with a tee fitting and is used to deliver fuel/oil to the bearing tunnel. If you run this turbine like this you will burn up the bearings.

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Old 10-09-2017, 06:34 AM
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I'm betting it's a old air start pipe line...I doubt it's the lube pipe.
take pictures of the other side.
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Old 10-09-2017, 07:18 AM
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Quote:
Originally Posted by Instructor View Post
From my experience with Jet Cat turbines, you are missing the bearing/lube regulator. This is a small aluminum fitting that attaches to the main fuel port with a tee fitting and is used to deliver fuel/oil to the bearing tunnel. If you run this turbine like this you will burn up the bearings.

Larry/Instructor
Correct, it's missing the T connector and regulator restrictor.
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Old 10-09-2017, 07:24 AM
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As this
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Old 10-09-2017, 07:40 AM
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I have put a lot of hours on this engine in the last 2 or 3 years, much of it at full throttle, so I don't think its a missing lube tube or that would have shown up long before now! I also happen to know that the other end of the tube just comes to an end behind the diffuser, it's not connected to anything inside the engine except open space, and that the lube is Tee'd off the main supply inside the engine rather than under the purple cover.
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Old 10-09-2017, 08:31 AM
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Quote:
Originally Posted by basimpsn View Post
I'm betting it's a old air start pipe line...I doubt it's the lube pipe.
take pictures of the other side.
I have ben flying Jet Cat turbines since 2000, and I don't recall them ever having an Air Start turbine. I don't have a Kero start turbine so If the lube system is different on a Kero start turbine, I wouldn't know. The original owner might have an external lube system he was using and did away with the setup the Jet Cat had.

Larry

Last edited by Instructor; 10-09-2017 at 08:33 AM.
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Old 10-09-2017, 09:35 AM
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Quote:
Originally Posted by Instructor View Post
I have ben flying Jet Cat turbines since 2000, and I don't recall them ever having an Air Start turbine. I don't have a Kero start turbine so If the lube system is different on a Kero start turbine, I wouldn't know. The original owner might have an external lube system he was using and did away with the setup the Jet Cat had.

Larry
Ok looking at the picture Dave Wilshere posted...I see your point thanks for the correction.
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Old 10-09-2017, 10:36 AM
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The pipe is definitely the one in Dave Wilshire's photo, thanks Dave. The problem is that the other end of the pipe stops in mid air inside the engine, whilst the Tee off for the lube is inside the engine. I am beginning to suspect that a previous owner has done his own modifications to the engine
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Old 10-09-2017, 10:53 AM
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Maybe JetCat updated it during a service or repair.
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Old 10-09-2017, 11:39 AM
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Quote:
Originally Posted by causeitflies View Post
Maybe JetCat updated it during a service or repair.
Yep... was thinking the same thing.

Todd at DreamWorks is the USA Jet Cat guy now. A few $$$ to ship it down to him to evaluate it, could save a lot of $$$ later.
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Old 10-09-2017, 11:42 AM
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Not JetCat's work. I would guess owner, could even be a university engine...
Harry is in the UK
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Old 10-09-2017, 01:14 PM
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Quote:
Originally Posted by Dr Honda View Post
Yep... was thinking the same thing.

Todd at DreamWorks is the USA Jet Cat guy now. A few $$$ to ship it down to him to evaluate it, could save a lot of $$$ later.
I guess that you were not aware Todd passed away a little while ago. There were several posts here on the Jet Forum including a very nice thank you from his wife who indicated that they were going to keep the business going.

The JetCat tech is named George and I cannot remember his last name. He's the one that got JetCat certified when Dreamworks picked up the importer/distributor rights.
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Old 10-11-2017, 11:32 AM
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just looks like it would have been used to either measure case pressure or maybe to pressurise retract tanks through a one way valve when people were experimenting with this a few years ago. Can't imagine the engine running particularly smoothly at low power unless its capped off.

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Old 10-12-2017, 04:27 AM
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I took the cover off one of my 160sx motors and it is plumbed just like the picture Dave posted. I was always told that line and restrictor assembly was metering fuel to lube the motor bearings. Harry...your motor must have a mod done to it, if you find out why it was done and how the bearings are being oiled please let us know.
Vin...
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Old 10-12-2017, 05:49 AM
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Quote:
Originally Posted by Vincent View Post
Harry...your motor must have a mod done to it, if you find out why it was done and how the bearings are being oiled please let us know.
Vin...
The Tee for oiling the bearings is further inside the engine.
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