FJK-1 & FJK-2 Gas Turbines

[nersut]

Dec 3, 2014 23:12:44 GMT -5 racket said:

Hi Erik

I'd go for the best quality #35 kart racing chain you can find , 15,000 rpm is a reasonable figure though, I did rev some to 22,000 "engine??" rpm with a 10 teeth engine sprocket once , its probably got the "best??" rpm vs power transmission capability for direct drive for a turbine build as it can be made any length and joined together ..................should be able to handle 30 hp easily .

Cheers
John

Thank you again John!

I will try to find some #35 sprockets & a length of chain plus master link.


Cheers
Erik

[mitch]

Been reading through your build thread, nice work!

[nersut]

Dec 4, 2014 11:16:56 GMT -5 mitch said:

Been reading through your build thread, nice work!

Hi Mitch

Thanks alot! I am also reading your ST-50 build, nice progress! I also have a ST-50 (actually three of them) & one VT-50.

My advice is to clean the turbocharger internal parts including the compressor- & turbine- wheel/shaft with an ultrasonic cleaner.
All the old & burned in oil deposits & gunk will easily be removed.
A cheap/small ultrasonic cleaner works just fine, just add some hot tap water & a little dishwash soap, after some cleaning the parts will look good as new.


Cheers
Erik

[nersut]

Hi everyone!

I won this nice Air Turbine Starter on eBay auction today, for just 49.99 USD. I was the only bidder & got it for the starting price!



Data: AiResearch 2995-00-914-1359, ATS140-44

• Air supply inlet pressure: 45 psi (3.1 bar)
• Air supply inlet temp. rating: 550 ºF (288 ºC)
• Air supply inlet flow rate: 107 lbs/min (1.78 lbs/sec.)
• Output torque rating: 975 foot-pounds! (1322 Nm) 
• Drive type: 24 tooth spline 1.2 inch output shaft

The air turbine starter have a turbine wheel, planetary reduction drive & output shaft.

I have an idea how to use it! 

My idea is to use it as the power turbine section for my gas turbine powered boat project.
Since the unit is very powerful, very compact, relatively lightweight, self containing, sturdy & powered by pressurized air via an air hose it should be perfect for my purpose.
(This is cheating, so I don't have to build a power turbine unit from scratch!) 

And since the air starter can easily handle one of my Cummins ST-50 turbocharger's  air compressor discharge at max rpm. it should be more effective than a sprocket's/chain driven power turbine section with limited rpm.

Here is my diagrammatic drawing of my idea.


The power turbine (air starter) will be powered by air compressor discharge from a big turbocharger (air producer) which is then driven by another DIY turbocharger gas turbine (gas producer).
The main idea is to separate the gas- & air- producer part & the power turbine by a flexible air hose.
The hot section will sitting at the lowest part of the boat (for stability & to lower the center of gravity) the power turbine will be at the back maybe on top of a outboard motor leg, only connection between will be an air hose.

Now to the practical part:

Will a Cummins ST-50 turbocharger (73.5 mm inducer) be suitable as the air producer part???
The ST-50 flows at maximum rpm. about 73 % (1.3 lbs/sec.) of the air starter's rating but with probably lower air pressure (don't know the maximum P2 for the ST-50).

How big/small (flowrate) should the gas producer be to run a ST-50 as the air producer to it's maximum rpm./flow???

---

Here is a YouTube video of an Air Turbine Starter made by AgentJayZ which makes very good videos anything about jet engines. 



Cheers
Erik

[madpatty]

Hi Erik,
The idea seems good....

I once tested my old can type gas producer in this sort of arrangement.....placed a large turbo downstream of the gas producer turbine.....even that turbo was screaming like anything........but unfortunately i didn have anything to use that compressed air....

Placing an industrial air starter will give good results....

Cheers,
Patty

[racket]

Hi Erik

The ST-50 "freepower" turbo will have a max horsepower output at the turbine wheel of probably 60 hp , if the comp wheel is 75% efficient you'll get ......60 X 0.75 = 45 hp of air energy, the turbine wheel in the starter if 80% effic will then drop the power output to ..........45 X 0.8 = 36 HP ..............the losses are compounding up and I'm using generous effic levels, they could be considerably lower, further reducing power output ..

Theres also one other consideration, the air stater will have its flow passageways designed for much denser flows with higher air speeds than your st-50 will produce , so there'll be a big reduction in flow compared to the starter specs.

Assuming your ST-50 is flowing only ~0.65 lbs/sec ( half max) at a lowish P2 of 2.5 :1 ( 22 psi gauge pressure) , you'll be absorbing ~ 45 hp .

As for the gas producer , probably a 2 inch -50 mm inducered turbo would be somewhere to start , but then "small" turbos have pretty poor turb stage efficiencies so there might not be 60 hp developed at the freepower turbo.

Lotsa unknowns unfortunately :-(

Good price on that starter though :-)

Cheers
John

[nersut]

Dec 18, 2014 3:07:06 GMT -5 racket said:

Hi Erik

The ST-50 "freepower" turbo will have a max horsepower output at the turbine wheel of probably 60 hp , if the comp wheel is 75% efficient you'll get ......60 X 0.75 = 45 hp of air energy, the turbine wheel in the starter if 80% effic will then drop the power output to ..........45 X 0.8 = 36 HP ..............the losses are compounding up and I'm using generous effic levels, they could be considerably lower, further reducing power output ..

Theres also one other consideration, the air stater will have its flow passageways designed for much denser flows with higher air speeds than your st-50 will produce , so there'll be a big reduction in flow compared to the starter specs.

Assuming your ST-50 is flowing only ~0.65 lbs/sec ( half max) at a lowish P2 of 2.5 :1 ( 22 psi gauge pressure) , you'll be absorbing ~ 45 hp .

As for the gas producer , probably a 2 inch -50 mm inducered turbo would be somewhere to start , but then "small" turbos have pretty poor turb stage efficiencies so there might not be 60 hp developed at the freepower turbo.

Lotsa unknowns unfortunately :-(

Good price on that starter though :-)

Cheers
John

Hi John

Thank you for the numbers, though there are a bit disappointing.
You always shoot my ideas down... Haha!

But, what if... I put two ST-50's as air producers to feed the air starter!?
Maybe a Holset HX55 (65 mm inducer) as the gas producer?
I have several turbochargers to choose from,
what size should the compressor inducer be on the gas producer to maximize the air output from the twin ST-50's?


This seems to be a lot of work, space & parts for "only" about 72 hp (but with a lot of torque).
Bulky, but still doable?


Cheers
Erik

[racket]

Hi Erik

LOL.......sorry about shooting down dreams ;-)

As for the torque output from the starter , thats mainly a function of the gearing as well as the horsepower , a 1 hp motor turns out 1 ft lb of torque at 5252 rpm , stick a 10:1 redux gearbox on it and you'll have 10 ft lbs of torque output but at only 525.2 rpm , if a 100:1 gearbox you'll have a 100 ft lbs but at only 52.52 rpm , we won't get going very fast with those sorta rpm.

Trying to "force" more air through the starter won't work unless the air is at a higher pressure/density , the turbine wheel in the starter can only "voluntarily" swallow a certain amount at a certain pressure/density , we can't force it to swallow more , all that will happen is the 2 supply comp wheels will surge.

The starter is designed for high pressure air and as such is "undersized" when we only feed it relatively low pressure air with limited velocity potential .

You'd be better off making two large gas producers and bleed off high pressure P2 air from each to feed the starter , you're losses will be lower.

Cheers
John

[nersut]

Hi folks

My new toy from eBay finally arrived!  It's the 140hp Air Turbine Starter unit I mentioned earlier.
Hmm, no wonder why I got it for only $49,99... (Sold as "removed") First there was a crack in the turbine scroll outlet pipe, should be an easy fix with my TIG-welder.
Secondly & more seriously... When I turned the shaft/turbine it spins freely but also made some crunching noises ...


I decided to take the starter unit apart for inspection & ultrasonic cleaning.
 

Luckily I didn't found any damage to the planetary reduction gears (about 16.5:1), turbine wheel, housing (apart from the crack).
The turbine wheel is a bit special, radial inflow "two-part" wheel, inducer 151 mm, exducer 100 mm. Air inlet diameter 72 mm.
 

Nice turbine & NGV, stainless? Inco? I found tiny metal particles inside the gear housing.

 

I found the fail parts, it was cracked springs for the pawls/ratchet clutch. Luckily almost all the broken pieces were contained in the clutch housing,
only tiny particles were spread around the gears, probably floating in the oil.
 

Here you can see the only remaining springs still attached (1 of 3) at 6 o'clock position.
 

I will clean all the part & try to repair/replace all the springs & reassemble the starter unit.

Does anyone knows if it possible to find replacement/service parts for this unit? It's a AiResearch 2995-00-914-1359, ATS140-44.

Cheers
Erik

[gidge348]

Hi Erik, for what you will be using this for I would think about throwing the ratchet & spring arrangement away and just locking it onto the shaft.

Ian...

[nersut]

Hi Folks

After couple of years of hibernation I took my old turbine for a spin! I have completely forgot how nice/scary the jet sound & roar was.



It fired up within 10 seconds & idled nicely. After a couple of minutes of idling to warm the oil I gave it slowly some fuel.
It spooled up nicely up to 650 °C TOT but the P2 pressure climbed only up to about 1 bar "increased idle", I haven't sealed her up sense last time so it did not go to the "usual" 1,6 bar P2 pressure.

I noticed something blew off the end cap & shut her down. It was one of the ceramic insulated igniters that was blown out from the aluminum holder.
After closer inspection I noticed some molted aluminum was deposited on one of the fuel lines. The gabs between the insulator & holder must have "some" blow by gasses.



I also took an old & small jumperstarter & took the old lead acid 12 V, 15 Ah battery out & put in my DIY powerbank made of 72 x 18650 Lithium batteries (sourced from laptops) = 14,8 V, 45 Ah 3 times more capacity & much lighter.
This runs the oil pump.



Here is some videoclips from yesterdays run. The sound is a bit muffled because of the cameras waterproof housing.

 

[nersut]

Hi folks!

Hopefully going bigger! With a "new" turbo, I was in East Greenland last year to upgrade data centers.
I took a little trek to the old airport & spotted a dumped Stewart and Stevenson Rolba airport snowblower.



As usual I did a quick check up in the engine compartment. It was a big 12.9L, two stroke, V8 Detroit Diesel @ 475 HP with supercharger and a turbocharger! I had a ratchet & some screwdrivers in my backpack, soo... after about an hour the turbo was out I carried the heavy turbocharger with me, about 30 kg's with the Y-manifold still attached & walked 3-4 km's through rough terrain & snow to the town, haha!  The turbo has no visual damage & spins freely.


...charging my iPhone with my laptop

I hope the turbo is a good candidate to a DIY gas turbine, here are the specs:

Garrett (Detroit) TV8513 part number: 23508800
Compressor wheel: Inducer 88 mm, exducer: 117,6 mm, 7+7 blades
Compressor scroll A/R 0.81
Turbine scroll with single inlet, A/R 1.39, trim 83, 11 blades

Maybe could John (again) be so nice & being an expert on numbers & gas turbines, and tell me if it's a go or no-go

Here is a screenshot of JetSpecs with the numbers from the turbo, the mass flow rate of 2+ lbs/sec. that's more than twice as much compared to my current FJK-2.

[racket]

Hi

The compressor has the same diameters as the one I had in my TV84 based bike engine , but your turbine stage looks bigger , its wheel appears to be clipped like the TV94 wheels we've been using , I'll be interested to know its inducer/exducer diameters , my TV84 had a 110 mm inducer, 17 mm tip height, with a 96mm exducer

I worked on a 1.8 lbs./sec flow for my TV84 , a 76 mm dia jetnozzle seemed OK.

If your turbine wheel is similar to our TV94 ones at 129/106mm , 19 mm tip height then your 1.39 A/R housing could be getting a tad large , though I ran my TV84 with the 110/96 wheel with a fat doughnut of a 1,84 A/R housing , but thankfully the wheels exducer ran choked and controlled the mass flow from the comp .

Yep , it'll make a good engine :-)

Cheers
John

[nersut]

Hi John

Sorry for the long delayed reply.
I took the scrolls of today to measure the turbine wheel.






Here are the dimensions:

Turbine inducer about 110 mm
Turbine exducer about 101 mm
Tip height about 19 mm

Here is the compressor wheel (compared to compressor from Cummins VT-50, the VT-50 has a smaller diameter inducer but the exducer diameter is larger)



Best regards
Erik

[racket]

Hi Erik

That should work very nicely :-)

I found with my slightly smaller turb wheel that it ran choked in the exducer , yours should be OK , and the 1.39 A/R housing is also just right .

A nice "find" ;-)

Cheers
John