Need some turbine help

jdlilfan

jdlilfan

Well-Known Member
I'm not sure if this is the correct thread for this or if it needs to be in technical?

Anyway, I have started to slowly restore a 1966 Garrett GTP70-52 turbine engine. All I have is a good working knowledge of turbines, working knowledge of this engine (from the shop that I bought it from), and a photocopied military MX manual that is missing some pages. I have no history of the engine other than it was crated from the US military and it looks to be pretty low time. Almost all the components are shiny and clean (other than some dust). The engine is missing the FCU, starter, and fuel nozzle. I have found a replacement fuel nozzle. I will most likely use diesel parts for the FCU and bypass the bleed air mixing. Not sure on a starter?

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There is little to no information out there on this particular engine and little to no resources for parts. Anyway I was hoping that someone on this board had some experience or could point me in the right direction on certain parts I need.

First off, I am starting with acquiring instrumentation. There is a Tach generator installed on the accessory drive. From that is a two plug connector. However the used/surplus tach gauges I have seen have 5 or 6 plug connectors. Are the two plugs just positive and negative?

Here is the tach gen:
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Here is the plug:

100_0195.jpg



Also the engine does not turn by hand. It will turn slightly then feel like it is caught. Like there is some shaft play? I am thinking this is because it is a direct drive to the gearbox and requires some force to get it to move? My grip doesn't seem to generate enough torque to twist the shaft and the hot side of the turbine is a little to small to get my fingers in there for grip. Am I correct in this assumption?

As for starting work on this, I was thinking about taking off the hot section and inspecting it. That way too I can get some leverage to turn the turbines and get a feel for the bearings. Also I will start cleaning out the oil system since there is white flaky goo in the oil tank (I'm thinking a preservative?). A friend said to clean it with Tranny fluid? I found some lucas oil treatment that looked suitable but was wondering what mechanics use to flush out a turbine oil system?

I was going to ask the shop I bought it from but they are not too eager to help due to liability issues I guess? Not sure, they just aren't eager.

Thanks for the help! This will be a long project. I'm in no hurry. Just something to tinker with.
 
First off, I have no experience fixing turbines. Second, you're nuts! Third, this is AWESOME and I wish you the best of luck with it!
 
Roger said:
First off, I have no experience fixing turbines. Second, you're nuts! Third, this is AWESOME and I wish you the best of luck with it!
Click to expand...
:yeahthat: this looks like a ton of fun and I wish you the best. Looks like it came out of a helo of somekind is that correct?
 
Actually I think it was from a generator or some type of APU. I had read on a website that mentioned briefly it was used as an APU on a few military aircraft in the late 1960's. There were tons of turbine generators that the military used so it was most likely from that application.

The engine puts out a max 160SHP @ 6,000 RPM on the gearbox. So it probably wasn't used on a helo.
 
Looks like fun. What do you plan on using it for when you get it up and running again?
 
Hello jdlilfan
I just did some custom work on that same model Garrett APU, destined to power a hovercraft. I think I can help point you in the right direction.

>The engine is missing the FCU, starter, and fuel nozzle.
I'd check with www.AvonAero.com as they would likely be able to provide those parts.

>There is a Tach generator installed on the accessory drive.
That's wired for a '2-pole' tachometer system (the Percent RPM indicator needs to be of the same type).

>Also the engine does not turn by hand. It will turn slightly then
>feel like it is caught. Like there is some shaft play?
Sounds like one of the accessories is binding.

>Also I will start cleaning out the oil system since there is white flaky
>goo in the oil tank (I'm thinking a preservative?).
The lube oil system will need to be completely cleaned out before you service with Mil Spec oil (either 7808 or 23699).

TurbineDood

My turbine powered boat:
www.TurbineFun.com
 
Thanks TurbineDood!

Actually I bought the engine from Avon Aero. They were going to scrap it along with a lot of other engines. I saved this one and they promised me it was in good condition. Other than that though they were not to keen on helping me in the right direction other than giving me a photo copied MX manual. It seemed like liability issues or something with them helping me because they kept putting me off. They also kept talking like I was going to blow myself up.

They did quote me a well used FCU for $700. That is 3 times more than I paid for the whole engine. I think I will use a different fuel pump instead....maybe electric. They recommended propane as a cheap alternative but diesel seems so much more cheaper and of course more fun...

I will look for a two pole tach and double check the accessories. Is the engine supposed to be easy to turn by hand? All of the gears on the accessory side have been really clean so far, no burrs or rounding of the gears. Nice and shiny.

Also do you have any recommendations on a cleaning agent for the oil lines? My diesel buddies keep telling me to use Tranny fluid.
 
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