Anyone familiar with the Isotov GTD-350?

[Johansson]

Hi guys!

A friend of a friend has an Isotov GTD-350 which he is going to fit to a veteran tractor and join us at the Speed Weekend event next year (the whole idea is insanely wonderful...) and he sort of talked me into starting the engine for him and tell him how it works.

No I wasn´t perfectly sober when I agreed.

Anyway, the guy has an engine support and supposedly everything needed to run the engine. He will build an oil tank as well so in theory I shouldn´t be missing any vital parts when it is time to kick her to life.

Is there anyone here with some first hand experience with these engines? Can they be started without a brake on the output shaft for example? I have found a complete set of manuals for it so I know what temps and revs to expect at startup and such.

Cheers!
/Anders

[racket]

Hi Anders

A freepower without load might over speed, I'd be trying to lock it solid just in case that first spoolup gets to high power.

Cheers
John

[Johansson]

All videos I have seen on youtube is with a free spinning output shaft, but it doesen´t feel right to start it so in case I manage to get it up higher in revs by mistake just like you pointed out John.

Making a female spline that fits the output shaft is another story, the guy says it is some non-european standard spline which isn´t that strange since the engine is made in russia. Perhaps I can get a friend to spark erode one out for him.

[racket]

Hi Anders

LOL.......... as its a russian "knockoff" of the Allison 250 , its probably an imperial spline size ;-)

Cheers
John

[turbochris]

I would definitely lock N2 somehow until i knew for sure the thing was tame. No load w a fuel control mishap could be bad. I can run my nimbus up to about 55% wo load before the N2 gov starts trimming the fuel.

[cursorkeys]

I have two, one is a friends ill one though

It is safe to start it up without a load on the output shaft. BUT, the fuel system is extremely complicated and seems to sequence wrong if the Np comes up too quickly (i.e. without a load) and the engine hangs at an intermediate speed rather than reaching idle. You can sort this hanging behavior out by placing a finger over the air metering port for the automatic starter on the FCU, it will then accelerate to idle and behave normally.

I would not advise moving the throttle at all without a load, for a start the Np governor will kick in pretty much at idle anyway and I've seen a malfunction of the over-speed protection on my engine which let Np exceed 115% with no sign of stopping.

It is also a right b**tard to start sometimes as it's very picky about the fuel supply pressure (10 PSI seems fine) and all the 4 fuel bleed points on the engine must be operated or it just won't start. I spent about a month trying to get the sodding thing to light off before a kind soul let me in on the secret.
It also seems to get flooded for lack of a better word, if you have a failed start with the HP cock open it will fill itself full of kero and refuse to start until thoroughly blown through. I have no idea why, maybe due to the shape of the combustion chamber any pooling fuel gets blown into the torch igniter of something along those lines.

The torch igniter can also be a sod and stop working but does come (very carefully, lots of parts!) apart for cleaning, I found all sorts of muck in mine.

The starter-generator is dyna-starter style and has a single external field connection this MUST be connected to the positive supply when energizing it and also MUST be disconnected again when you de-energise or you'll cook it and/or not reach minimum speed for the fuel crack valve in the FCU to open.
The original helicopter bits supplied 24V to the starter-genny first through a resistor and then direct with linear control of the field via a carbon pile. I've found that its a tough old thing and doesn't seem to care about 24v up it with no field control or soft-start but maybe 12V/24V soft-start would be a good idea.

I have some vids on YouTube under my 'Cursorkeys' account and if you would like to speak on the phone just give me a PM for the number.

It's a lovely engine; complex, grumpy and astonishingly loud for the size, but lovely.


edit: I also have a full set of manuals and the Russian training books as well if you need them. I have embarked on translating the Russian but I'm only maybe 25% complete...

[Johansson]

This was exactly what I wanted to hear, thank you very much! I haven´t got the engine shipped over yet but at least now I know what to expect.

I´ll get back to you as soon as the engine has arrived with more questions, since the engine was removed from an operative helicopter there is no starting panels or external gauges whatsoever but I hope I can be able to start it anyway, if not we are in trouble...

Cheers!
/Anders

[Vidar]

Hi, I'm new on this forum. I am planning to install a GTD 350 in front of a waterjet in a small boat. I have a manual but no start panels or instruments. I have never worked on turbines so I would realy like it if you kept this thread going. BR, Vidar

[cursorkeys]

Hey Vidar,

Sure, anything you want to know about the engine just ask

Cheers,

Jon

[moonpool]

Hello Vidar & Jon,

I'am planning to buy two GTD-350 engines :-)
Are there any spec. things I shoud look out for when buying these engines??

cheers
Rob

[turbochris]

is there a surplus of there engines over there?

[moonpool]

Hi Chris,

Thanks for the quick reply.
Yes one engine is complete, the other one is about 95% complete (so tells me the seller)
I'll find out what parts are missing when I check the engines next weekend.

[Vidar]

Hi Rob,
I'm just learning so I have no good advice so far other than checking that the major parts is there. Instrumentation like tachometers is good, I have trouble finding them and/or knowing if what I find is good.. Cursorkey has lots of info on his website. Good luck and keep us posted on your progress.

BR
Vidar

[moonpool]

Hi Vidar,

Thanks for the reply & info.
I'll look out for the pressure en tacho displays.
I'll share my findings when disassambling, re-assambling and starting these engines.

[cursorkeys]

Hi Rob,

Vidar's advice is pretty good wrt/ checking all the bits are there.

Apart from that I would make sure the free power and core turn smoothly without grating noises.
The core should be possible to turn by fingertips through the intake without a huge effort, although it takes a decent amount of force.

If possible I'd remove the oil filter and check for swarf.
First cut the locking wire then turn the to handle to release the locking bar.
Move the locking bar out of its recess and turn the handle the other way until the bar is above the locking points.
Then rotate the locking bar so it's resting on the top of the locking points and turn the handle the other way again to draw the filter out.
Small metal particles are fine. Anything longer than a few millimetres or of any significant thickness is bad.

Other than that you could check continuity on the starter-gen, but other than running it it's just down to general condition.

Spares have been impossible for me to find after months of looking and emailing. Found one chap with an oil tank but he wanted 400 euros....

Cheers,

Jon