TV94 TurboFan Build

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Ash Powers
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Re: TV94 TurboFan Build

Post by Ash Powers » Wed Jul 22, 2009 12:08 am

Hi Johansson,

I have considered using a PBD as of recently - unfortunately when I designed this engine and built the comp diffuser I hadn't really entertained using one. I'm going to see how this approach works out first and then if it comes down to needing a PBD to make it work then I'll go with that. Fortuantely with the layout of this engine I can use a rather large diameter bearing housing. If push comes to shove, I can make up a new bearing housing that uses a PBD at mid-center of the shafting. That approach will require machining of quite a number of parts - not impossible but certainly more complicated. I'll just have to see how this approach works out and go from there. :)

Ainis
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Re: TV94 TurboFan Build

Post by Ainis » Sun Jul 26, 2009 9:06 pm

Ash, you wrote that minor diffuser radius was made by hand. How do you did that? With rasp?

Nick
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Re: TV94 TurboFan Build

Post by Nick » Sun Aug 23, 2009 7:52 am

Hi Ash,

fascinating build, i watch with keen interest!
just a quick note ref 303ss, I love the stuff personally, one more good thing about it is its really nice/easy to machine,every little bit helps! :D

Nick

Johansson
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Re: TV94 TurboFan Build

Post by Johansson » Fri Feb 12, 2010 11:53 am

Hi Ash!

Any progress on the engine?

I´ve bought a TV94 rotor myself and will start planning for the build this spring, I will keep the journal bearings to save me some trouble. It is a beautiful piece of art this rotor, I keep it in my book shelf and every time I pass it I have to stop and stare for a couple of seconds... :D

longjohn
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Re: TV94 TurboFan Build

Post by longjohn » Wed Nov 10, 2010 10:50 pm

Been Very quiet in here for a long time! Whats happening ?

Ash Powers
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Re: TV94 TurboFan Build

Post by Ash Powers » Mon Feb 14, 2011 1:46 am

Hi Guys,

I've been so busy the past year+ with the business - we've been growing and have moved into a 3600 sqft facility. All my equipment from the house is residing in the new building along with my turbine projects. They make great conversation pieces with customers. I've just had no time to work on this project, but I'm getting anxious about it and want to get back on it - even if for just a couple hours each week - just to keep it moving forward.

I've been looking around the web for suppliers of HastelloyX to build the combustion chamber from once I have developed it. Will also need this material to make a heat shield to go behind the turbine. Anyone know of a good source for sheets of this stuff?

Also, I've located an allison turbine wheel for the freepower section. :)

Looking forward to getting back on this engine - any help is appreciated, as always!

-Ash

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Re: TV94 TurboFan Build

Post by racketmotorman » Mon Feb 14, 2011 2:22 am

Hi Ash

Good to see you're back :-)

Have you checked out the new turbine Site http://jetandturbineowners.proboards.com/

Cheers
John

Ash Powers
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Re: TV94 TurboFan Build

Post by Ash Powers » Wed Feb 23, 2011 2:33 pm

Hi Guys,

I've been putting some time into this project and it is nice to see it moving forward again. Feels like the good ol days. :) I've obtained not just one, but TWO RR Allison 250 4th stage turbine wheels. Why buy one when you can get two for twice the price? :) I scored these babies for an awesome low of $150 each and came with documentation. Here's the pics:

The first picture almost makes it look like the blade edges are dinged up but that's a photographic effect caused by the reflection of the bubble wrap behind it shining back from the flash. These units are in really good shape. The wheel on the left has 2345 hours and 208 cycles remaining and the other has 1018 hours and 190 cycles remaining.

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I have also contacted several foundries with requests to have the nozzle guide vane section cast in 316SS - still waiting to hear back from them at the moment but I've only tried domestic companies. I dont know what kind of experience you guys have had with domestic companies as of the past few years but it seems like America has lost its drive - I can't seem to find anyone who actually wants to work to make a buck. I've even been feeling it in my business and have resorted to seeking manufacturing from offshore corporations. Seems like everyone else around the world will jump at an opportunity to manufacture products for us while I have to continually hound domestic companies just to get a response. Sorry to go all political/economics here, its just frustrating.... I digress..

So if I dont have any success finding one of my fellow americans to take my money for work I'm sure I can find someone abroad to do it. Out of a dozen companies I have emailed my request to last week I've only heard back from one and that was a short, simple, "We can't help you with what you need."

I've also been sorting out the bearings to use in the final setup. I've located an offshore company that builds full ceramic bearings and they are working on putting together a quote for a pair of duplex bearings, angular contact, full complement arrangement for use at the front end of the group (just behind the comp wheel) as well as a single full complement angular contact bearing for the rear. I've also inquired about a full ceramic roller bearing to use instead of a ball bearing for the turbine end of the group.

With a pair of duplex bearings for the front, the axial preload on the bearings is provided by the precision machining that is done to the inner and outer races of these two bearings such that when they are locked together it will properly preload the balls into the races. I've requested a quote for a pair of DB (back-to-back) bearings with a ball load configuration of "O" as seen below:

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DUPLEX bearings consist of an assembly of two PAIRED bearings which provide the following advantages:
● radial displacement reduced to a minimum
● increase of the radial and axial load capacity
● accurate axial positioning with axial loads
● extremely accurate functioning
● 0 arrangement called DB (back-to-back)
● X arrangement called DF (face-to-face)

These assembly configurations are used for applications where no bearing clearance can be tolerated and where a high degree of stiffness of the whole assembly is required.

Pairing is achieved with bearings of identical tolerance classes and by applying an axial preload to the inner rings for the O arrangement and on the outer rings for the X arrangement. Afterwards the inner or outer ring is ground in order to get both side faces in the same plane with minimum clearance.

Roller bearings tend to have better radial tightness as well as the ability to carry greater radial loads and do not require axial loading like ball bearing units which is why I'm entertaining the idea of using one of these at the turbine end of the assembly - it wont require any springs or spring washers in the assembly at all.

With the success John (racket) has had with his 9/94 turbine and incorporating the labyrinth seal behind the comp wheel to pressure balance the wheel and reduce axial loading on the bearings I'm pretty confident that this bearing assembly approach I'm taking is an overbuild, which I'm more than happy to do. With the $600 some-odd dollars invested into the compressor wheel and radial turbine in the gas producer I'm wanting to do everything I can to prevent a catastrophic failure. With the T04 engine I could get those parts for under $200 total which although not exactly cheap, was still within an immediate budget.

So we'll see how things come together for the NGV section - my focus right now is primarily on the hot section of this engine as I've pretty much finished with the cold side (minus getting a plate of rulon and machining the comp labyrinth seal).

Viv
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Re: TV94 TurboFan Build

Post by Viv » Wed Feb 23, 2011 2:45 pm

Hi Ash

Nice to see you back and continuing your projects build, Bon chance ;-)

Viv
"Sometimes the lies you tell are less frightening than the loneliness you might feel if you stopped telling them" Brock Clarke

Viv's blog

Monsieur le commentaire

Ash Powers
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Re: TV94 TurboFan Build

Post by Ash Powers » Wed Jan 25, 2012 5:01 pm

This is going to turn into a decade-long build at this rate, LOL! But at least I come with some good news!

I have been so busy building my business over the past couple of years and we have gone leaps and bounds from my garage. Recently I procured a seat for Solidworks and have been ramping up my skills with the product. This is a wonderful piece of CAD software and has made things a lot easier in my business - I will be using this product and newfound skills to further develop the TV94 turbofan engine. :) I've been working on putting together the NGV section of the engine - not 100% finalized at the moment but here is a sample of where I am at with it:

Image

I have my Garrett distributor tracking down a TV94 turbine heat shield which I will incorporate into the NGV design. Once I have that piece in hand I'll be able to refine the NGV and hand the drawing over to a local CNC shop to have them cut out a part in some billet aluminum and then later down the road I'll commit to a high temp alloy. :)

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Re: TV94 TurboFan Build

Post by racketmotorman » Wed Jan 25, 2012 10:10 pm

Hi Ash

Good to see the dream is still alive :-)

Cheers
John

Ash Powers
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Re: TV94 TurboFan Build

Post by Ash Powers » Thu Feb 02, 2012 8:29 pm

Been having more fun with SolidWorks and letting my imagination run free. :) Had to make several alterations to the NGV section parts - the original vane ring produced a bottleneck to flow so I had to shorten the vane chord and add a few vanes into the ring to maintain proper flow area into the turbine's inducer. I have also added axial swirl vanes to the exducer ring to get the combustion gases moving in the right direction upon entrance into the radial vane section. The idea with the axial vanes is simply to use some tubing and cut out sections of the wall and weld these vanes to the exducer ring. All of my dimensions are checking out for the flow areas and I've done my best to provide the smoothest flow transition from the combustor into the turbine. This hot section should work really well for this engine. I need to get ahold of Rossco and get the SW models he already put together for the rest of this engine so I can add this section to it - this is all it was previously missing and with the rest of the drawing I can get to play with the fluid dynamics package in SW to do some flow modeling and make any changes to improve the performance of these parts. :) So if anyone knows how to get ahold of him, please let him know I Am trying to get in touch with him!

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Mike Everman
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Re: TV94 TurboFan Build

Post by Mike Everman » Tue Mar 13, 2012 4:20 pm

Hi Ash, thanks so much for updating us on your build!
As to the duplex bearing discussion farther down the thread, something that may be of use to you:
I use universally ground angular contact bearings, SKF 620X BEGBP series for my spindles now (not jets. for reference, a 6204 has a 20mm bore). They allow you to assemble in either b-b or f-f and preload is achieved. They are a lot less expensive than matched pairs, like 1/5.
Mike
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Syler
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Re: TV94 TurboFan Build

Post by Syler » Sat Jan 18, 2014 5:05 pm

Very impressive machining! Is that what your business is? Your engine looks like a giant hollow point bullet. :D

I'm wondering; with all your machining capability, do you think you would be able to make your own axial flow compressor section? Or, perhaps fabricate another compressor stage to raise your overall compression ratio? Also, have you considered making those channels on your diffuser ring curved rather than straight angles? From the pictures, it looks as though the air coming from the compressor wheel should hit the flat surface, deflect, and cause a lot of turbulence.

Better yet, would you consider starting over on the compressor section and just make 3 or 4 axial compressor wheels?

racketmotorman
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Re: TV94 TurboFan Build

Post by racketmotorman » Sat Jan 18, 2014 10:24 pm

Hi

This Thread has been continued on the JATO Site http://jetandturbineowners.proboards.co ... ft-project

Cheers
John

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