DIY Turboshaft Kart build for the University of Kansas

[madpatty]

Hi...
Matte finish black looks cool with shiny bits...
I once coloured the turbo compressor housing of my jet engine matte black and it looked cool and powerful...

Cheers,
Patty

[ashpowers]

For the turbine profile I typically will cut a 60-45-30 angle step like a valve seat across the "curved" section of the turbine transition and then I use a die grinder with a 1" diameter sanding drum, ~100 grit, and then radius the corners of those cuts until I get the right clearance.. This "art work" is done to the part while it is still chucked in the lathe so it is spinning while you are performing this sanding process. From there I'll step up to 220 paper sheet, then 400 paper sheet, held by hand while the part is spinning to give it a nice smooth finish.

But as John said, you really need to get your gas producer built and running before you get to the freepower section. The design geometries of the FPT are dependent on the gas producer's final performance. You'll likely end up painting yourself into a corner if you do the FPT section first.

-Ash

[pulsedpropulsion]

Thanks for the advice! We just wanted to make sure we knew the process. We aren't working on the FPT yet! Although, the staff in charge of our machine shop would probably shoot us if they saw us using a die grinder on a lathe.. we'll just have to be sneaky!

[racket]

LOL.......what , not even a die grinder ..............heh heh , DIY Turbines often entail the use of a side grinder for "machining" in the lathe :-)

[ashpowers]

Without CNC machining, sometimes you have to get creative and as I call it, "become zee artiste'!" to produce more complex shapes on manual equipment.

-Ash

[pulsedpropulsion]

Just received the T50 turbo. Removed compressor housing, and the compressor is almost perfect. And there is no shaft play. Turbine housing has been sprayed with penetrating fluid and is soaking.
Pictures to come shortly!

[racket]

Hi Thomas

While you have the housings off could you measure the wheel sizes so we can get a rough idea of flows etc

Also if theres an A/R size on the housings , generally cast into the housings, on the scroll part for the comp housing but near the "foot" of the turb housing.

Cheers
John

[pulsedpropulsion]

It appears that the turbine housing is VERY stuck. Any suggestions on how to get it off? It already has about a quarter can of PB Blaster in it.

And Racket, I'll get you all the wheel specs as soon as I get that darn housing off.

[ashpowers]

Not uncommon for that to happen actually.. Its just oxidation between the CHRA and the housing. You'll need to use a little bit of force to get the housing loose. I would stand the turbo on its compressor inlet end so you can see the turbine wheel's exducer and then use a small hammer to tap the turbine housing loose from the CHRA. You'll need to work your way around the turbine housing and watching the turbine wheel, make sure you aren't causing the turbine housing to jam up against the turbine wheel. Go slow with it - tapping the housing upwards and working it up with light blows 180-degrees apart from each other. It would also help if you can heat the turbine housing up a little bit too.

[ozbooster]

Any time i have to remove a s/h exhaust housing it usually needs a lot of heat
also as your tapping ,keep finger tips on the compressor wheel or shaft and keep it moving so you get immediate notice if you contact the housing on the turbine

[enginewhisperer]

I usually leave the turbine housing bolts in, just backed off a turn or so, which lets you bash the housing pretty hard without fear of it moving far enough to contact the turbine when it moves
Once it loosens up you can remove the bolts fully and lift / lightly tap it off.

[pulsedpropulsion]

Unfortunately, the turbine housing is still not budging. We beat on the scroll for a while, nothing. We got dry ice to try to shrink the center housing off of the scroll. Nothing. Then while the center housing was cold, we heated the scroll. Still nothing. Finally we got the center housing so cold ice was forming on it, and got the scroll hot enough till it was just about to glow. And alas! Nothing still..
Through all of these heat treatments we were beating it with a hammer.

Is there anything left to try? I heard that automatic transmission fluid mixed 50-50 With acetone works wonders, but I've yet to try.

[Feathers]

Racket,

Compressor A/R unknown. Compressor inducer diameter is 2.9", hub diameter 1.16", exducer diameter 5". Exducer tip height 0.315".

Turbine A/R is 0.76. Turbine dimensions unknown until the scroll is separated from the core.

We're working on combustor designs right now.

[racket]

Hi Feathers

Could you post a few pics of the turbo , comp side and turb side including turb exducer blading so that we can get an idea of the exducer angles, some can be configured with fairly "open" blading .

Mass flow should be ~1.1 - 1.2 lbs/sec , but depending on the flow size of the turb stage it could change .

Cheers
John

[Feathers]

Here is the turbine exducer. There is some oil on the blades, but everything looks immaculate.

IMAG0218 by HighVoltageFeathers, on Flickr

I'm afraid it is "open" blading, without significant deflection at the exducer. Hopefully this won't effect the performance too severely.

Jetspecs gives 1.3 lbs/sec mass flow, which is probably a bit optimistic as you said.