FJK-1 & FJK-2 Gas Turbines

[nersut]

Hi John

That's good news & thanks again! I hope that I can start with a new build with that turbo, it will be called FJK-3!

Here are some pictures of the Rolba snowblower TRYING to clear an airport in East Greenland (Kulusuk)



Cheers
Erik

[racket]

Hi Erik

LOL, that poor machine has got a bit of work to do :-)

Cheers
John

[nersut]

I have an idea about making a nice compressor discharge & transition tube to the outer case of the combustor.
Is it possible to use fiberglass/epoxy as material? Instead of the usual metal parts, here I think of "lobster back" type delivery tubes with lots of cutting & TIG-welding or "thick" steel tubes etc.

I was thinking to make a nice polystyrene mold with nice flow & transition shape & use fiberglass/epoxy for the shell, and use acetone to dissolve the polystyrene afterwards.
It might need some reinforcement rings? to cope with the pressure.
Some epoxy resins have high Tg or Glass transition temperatures.

I was looking at the Allison 250 engine with nicely shaped transition parts & internal baffles agains tangential airflow an to get an even air distribution to the combustor liner.



Cheers
Erik

[racket]

Hi Erik

If you can find a material that can cope with 200 deg C and 3 Bar of pressure whilst still having a bit of safety margin , go for it .

The "good ol'" lobster back probably doesn't create too many losses as long as the air speeds have been reduced to lowish levels prior to entering it, those beautiful sweeping lines of the 250 can are a joy to behold, they're a great example of what we should aspire to if we want optimum air delivery .

Cheers
John

[mecarloschavez]

hello everyone im new at this blog and dont know exactly how to ask questions, im sorry if im doing something wrong, but  i want to know between the st50  and a ht3b wich one will produce more power for a turboshaft aplication.

thank you

Sept 19, 2013 22:19:10 GMT -5 nersut said:

Hi John

Ok, I think I can sacrifice a bit loss in power to make it more compact & stable.


I found the reason for the "siren" noise... I forgot to tighten the hose clamps at the compressor outlet.
The hose was letting some air out & made the siren/whistle sounds.

I made some thrust measurements today with a fish-scale.

• Thrust: about 16 kg or 36 lbs of thrust
• EGT: 540 degrees Celsius
• P2 pressure: 1.1 bar

It should make some more thrust when I fine-tune the size of the jet nozzle.

I decided to rebuilt the turbo because there was a bit of axial & side to side play after the fall.
The turbo cartridge was full of carbon deposits & the bushings was worn.



New rebuilt kit from Garrett: Model no. T45, part no. 468132-0000



I cleaned all the parts in the ultrasonic cleaner & they turn out very nice & clean.



Fully assembled cartridge, the rotor spins much much better now, almost like ball bearing turbo!   

More testing to do.


Cheers
Erik

[racket]

Hi

The ST50 is pretty old technology , so any modern turbo of a similar comp wheel inducer size should outperform the ST50 .

Cheers
John

[mecarloschavez]

THANK YOU:) ILL DO THAT.

[mecarloschavez]

Hello John, do you mean, a free power turbine wheel connected to the st 50  can produce about 60 HP?  im working on my setup using an HT3B   similar to ST50-  should i spect if i do things right to have that power at the free power turbine? 

thank you

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

[racket]

Possibly ............though lotsa unknowns , we should be able to get ~50 HP/lb/sec of mass flow

[mecarloschavez]

Hello I have a question about free power turbines and direct shaft , I saw different APUs that take shaft horsepower directly from the turbine / compressor shaft , other than needing a clutch or torque converter + gears to have useful rpm and torque numbers - which one should produce more power ? Or Is it the same ?

Sept 18, 2012 16:24:31 GMT -5 racket said:

Hi Erik

It looks like I missed your earlier posting about fitting a power turbine wheel to your engine , sorry about that .

Are you going to be powering a boat with it ??

Will you be constructing the turbine wheel yourself ??

Or will you be looking for a professionally produced turbocharger wheel ??

Do you have a thrust reading from your engine ??

If so , what thrust and what sized jet nozzle ??

These "numbers" will give me an idea of the available energy and mass flow you have available for processing by the freepower wheel .

Cheers
John

[racket]

Have a look at this Link jetandturbineowners.proboards.com/thread/1260/turbine-torque and click on the Link in thefirst article , it'll explain why we use 2 shaft engines for road use , one shaft engines are great for pumps and generators .

As for peak power output , they should be roughly the same, all other things being equal

[mecarloschavez]

thank you it helped a lot, im had just sent the turbocharger core to get a professional rebuild, and im going to design everything around it