Turboshaft minibike MRT-01

[miuge]

Glad to hear you John again
I used your housing as inspiration to build mine, bits between the scroll were obvious to have before welding the sheetmetal part, despite of it we still used quite big clearence.

Don't worry about the segmented scroll, it's still at the garage wall as decoration..

Anders, just use the steps seen at manufacturing video and you'll end up to something similar

[miuge]

Soon... First we'll try driving with propane and later make it run with diesel.

[Johansson]

Sweet!!

[racket]

Nice one guys :-)

[Richard OConnell]

Very cool!

[finiteparts]

Nice work!

Just a comment on your segmented scroll, which I really liked. Accelerating flows are much more tolerant of steps and it would be interesting to see the flow difference between the current scroll design and the segmented one. Rectangular flow passages develop corner losses, especially when transitioning from round to rectangular cross-sections, such that the mean flow will be more of a rounded cross-section. Additionally, the rectangular cross section has a larger internal surface area that will develop more scrubbing losses than a rounded cross-section.

I am sure both will work well, it would be interesting if there was some way to test both, because I am not sure that we could say which one is better without trying them out.

~ Chris

[gidge348]

Great job guys, I agree with Chris and like the segmented scroll, I know it probably does not look as cool (and that is a factor) but I have a feeling it will perform better? It would be great to see some back to back testing of the two.

Ian...

[miuge]

I'm a bit pissed I hadn't enough patience make it better Now it's hard to make comparison between two as the scroll is completely welded. I wish I had a flow analysis program to give any directional info of that.
Anyway this sheetmetal scroll has a lot bigger shape and internal surface area than the segmented scroll, as I kind of copied the shape of a S300 turbine housing. Segmented scroll had a more constantly tapered shape.
Remember that performance wasn't really the main point in this entire bike build, things are just going to get out of hand sometimes

[madpatty]

Hi Miuge,

You guys are doing a bit of very excellent work...

Actually i am also building a free power turbine almost just like yours...
Needed some details on the type of 6203 bearings you are using

1.Are they special high speed ones or the simple ones???

2.How have you locked them in the shaft tunnel so that they dont get displaced from their axial position??

Cheers,
Patty

[miuge]

Hi Patty,

Thank you!
They are simple FAG 6203 bearings, the one we use at turbinewheel side has C3 clearance due to higher temperature.
There's a sleeve between bearings and a retaining ring keeps them in place:



Yesterday we made spacers for both sprockets:

i187.photobucket.com/albums/x281/mice325/Project%20Jatkettu/IMG_3591_zpsc166cc10.jpg



Both mounted:
i187.photobucket.com/albums/x281/mice325/Project%20Jatkettu/IMG_3633_zpsea0047ee.jpg

We also ordered a cheap 12V oil pump and 2pcs #219 chains as we need approx. 170link


And then here's a short clip of the sheetmetal housing manufacturing:
vimeo.com/95577723

[madpatty]

Hi Miuge,

So that S500 turbine shaft had 17mm+ shaft diameter??

[madpatty]

Hi Guys,
The shaft i am using using for freepower is 14 mm in diameter...not able to find a bearing for that...dont want to get that shaft ground to a lower diameter...

Is there any way to use larger bore diameter bearing on a smaller dia. Shaft???

Moreover i needed some details on how to couple the small sprocket with the shaft..??

Thank you.

[Johansson]

You can make a sleeve for the turbine shaft that the bearings fit to, just make sure to get the tolerances right so you lock it in place with the nut. Wouldn´t be fun if the shaft starts spinning inside the sleeve.

[miuge]

Yes S500 shaft had a 17,4mm diameter which we ground to a 17mm.
Just make a sleeve something like this (14mm shaft, 6203 bearings, bearing distance X):

[madpatty]

Thanks a lot guys,
Thanks Miuge for such an elaborate expalnation...

I am not much into machining so getting a bit difficult for me....

I have understood the idea of using a sleeve with OD equal to bearing ID but didnt understood how to lock it into place over the shaft to prevent shaft spinning inside the sleeve??

And hopefully the separator between the bearings is free to rotate on the shaft???