"Fat Boy" 12/118 thrust engine

[miuge]

Nov 21, 2018 9:57:05 GMT -5 monty said:

While looking for a good price on the HX82 wheel.....

I found this by accident.....YIKE$$$!!!

The specs for the wheel are 150.3mm / 131.62mm (in/ex)
That could be the answer right? Too bad it's that pricey.. I'm quite sure Kinuqawa is not the only aftermarket supplier, just need more searching.

[racket]

Yep , it'd be big enough :-)

LOL............but I only spend half that much making a whole engine .

[racket]

Hi Ron

The Corrected Flow would be less than 150 lbs/min , the F Trim wheel goes 90 lbs Corrected with a 1.70A/R scroll , the G Trim will probably give another 12% , so ~100 lbs Corrected , but I don't know if it'd flow more with a bigger scroll/NGV .

The F Trim map "flat lines " past a 2:1 PR , so maybe the scroll is choking , don't know , I've never felt comfortable with how these turb maps are configured :-(

Cheers
John

[turboron]

John, thanks. The MHI has me drooling. Any ideas on a matching compressor?

Ron

[monty]

John,

I can sell you my turbine if you are having a hard time sourcing one. I can always get another one. PM me if interested to work out the details.

Right now I think the Holset would work better. For one thing it appears to have a left hand thread on the nut. That is important for my current PTO scheme. I actually may wind up doing something like Phil Heward's engines with a fabricated main shaft that the turbine pilots into. Trying to do everything with stock shaft is driving too much of my design at the moment.

I was thinking about your turbine/compressor matching problems. Have you considered a bypass valve? It seems you have constructed an APU that makes lots of bleed air with no outlet!!!

Monty

[racket]

Hi Ron

It'd depend on what diameter the quill is on that shaft , its a pretty big wheel with lotsa flow so the quill might be a bit bigger than the "usual" 7/16"dia

Rather than using a very expensive turbo wheel it might be easier to go with an axial wheel from Yilli Castings www.yilicasting.cn/productgrouplist-213221106/Turbine_wheel.html?spm=a2700.icbuShop.prup15aafb.11.e0993b3e4FxfZP which would be a lot cheaper option.

Cheers
John

[racket]

Hi Monty

I have considered using a standard turbine wheel and tighter NGV then bleeding off "excess" air , that was a last resort option , mainly because it'd be high pressure air which would complicate designing a freepower stage and extra combustor to use it.

Its looking like I'll take you up on your offer of selling your wheel, still no joy from any of the suppliers...........will send off a PM to you latter today.

Cheers
John

[turboron]

John, it looks like Yilli just furnishs raw castings. What is your experience machining these superalloys with our old lathes?

Thanks, Ron

[dieselguy86]

Ron,

Im an amateur machinist so dont take what i say as gospel, but ive had the best luck with low spindle speed and high feed rate.

Very hard to machine after they’ve been “ran”, they seem to get hard and you have to get below the hardened layer. Once below that its workable, but none the less its a pain all over.

-Joe

[CH3NO2]

^+1

Took me about 5 seconds to destroy a brand new carbide drill bit on Hastelloy X. Was too scared to feed in fast enough so I got punished for it.

[monty]

Nov 22, 2018 18:30:35 GMT -5 CH3NO2 said:

^+1

Took me about 5 seconds to destroy a brand new carbide drill bit on Hastelloy X. Was too scared to feed in fast enough so I got punished for it.

EDM....no dancing! It's your friend..

[monty]

Nov 22, 2018 16:01:54 GMT -5 racket said:

Hi Monty

I have considered using a standard turbine wheel and tighter NGV then bleeding off "excess" air , that was a last resort option , mainly because it'd be high pressure air which would complicate designing a freepower stage and extra combustor to use it.

Its looking like I'll take you up on your offer of selling your wheel, still no joy from any of the suppliers...........will send off a PM to you latter today.

Cheers
John

John,

It would be a win/win. After a lot of thinking and searching....I'm really leaning towards the Mitsu TD13.

It seems like it's becoming the aftermarket standard. A bit more expensive, but available online and the CHRA design is to my liking. I don't think the thrust bearing is quite as good as the Holset, but I don't have the parts in hand... The areas are about the same if a bit larger for the inducer and exducer compared to the Garrett and Holset. So I'd love to trade you my expensive paper weight for a down payment on the TD13 wheel.

Do you need bearings and such....I'd probably throw them in...

Monty

[racket]

Hi Monty

A pic of the 12 X 2.5mm dia bleed holes used to cool the turb hub as well as the seating for the piston ring seal , they're doing a good job as the stainless is still as shiny and silvery as when I machined it up



Also stops "gases" bypassing the seal and getting into the bearing cavity as well as heat transfering to the shaft tunnel from the NGV , the holes exiting onto the screw heads help spread the air "sideways" to cool the NGV wall bits

Cheers
John

[Chuks]

Nov 28, 2018 1:04:59 GMT -5 racket said:

Hi Monty

A pic of the 12 X 2.5mm dia bleed holes used to cool the turb hub as well as the seating for the piston ring seal , they're doing a good job as the stainless is still as shiny and silvery as when I machined it up



Also stops "gases" bypassing the seal and getting into the bearing cavity as well as heat transfering to the shaft tunnel from the NGV , the holes exiting onto the screw heads help spread the air "sideways" to cool the NGV wall bits

Cheers
John

It really worked for you John.
The turbine end bearing even looks newer compared to what's happening in turbochargers.
Another big lesson learnt.

[racket]

Hi Chuks

And theres no colouration back along the turbine shaft either , so less chance of coking .



Cheers
John