"Fat Boy" 12/118 thrust engine

[racket]

Hi Guys

My Christmas presents have arrived early



Thank you Monty , you've made me a very happy fellow :-)

New development work for me in the New Year , can't wait to measure things up and crunch some numbers.

Cheers
John

[turboron]

John, Merry Christmas. Best wishes for exciting development in the New Year.

Thanks, Ron

[Johansson]

Hooray! The best present ever, thanks Monty for making sure that this awesome project keeps going!

[Deleted]

Very Nice.... Yep second that Anders, thank Monty.... need to see this beast at full throttle

[stoffe64]

Dec 6, 2018 17:51:28 GMT -5 racket said:

Hi Guys

My Christmas presents have arrived early



Thank you Monty , you've made me a very happy fellow :-)

New development work for me in the New Year , can't wait to measure things up and crunch some numbers.

Cheers
John

I jump in also and say thank you Monty for your offer that helps John to continue this engine project.
Cheers/Stephan

[racket]

Hi Guys

LOL.............an "OH SHIT " moment when I tried slipping the new wheel into the engine



seems its inducer is 130 mm compared to the old F Trim wheels at 129 mm , not a problem as I'll just skim out a millimeter from the NGV stub , but interesting as all the info I've read about the two wheels say they have the same 129 mm inducer, its just the exducer thats a different diameter, so much for all those "Auto Performance Sites".

I've measured up the rest of the shafting and alls well , the new quill is 2 mm shorter which isn't a problem , less thread hanging out the front , just a difference between the Rotomaster F Trim and the genuine Garrett G Trim .

Theres a variation in the curvature between the inducer and exducer from one wheel to the other so it looks like a new shroud section needs making for the exducer , might just make a whole new jetpipe rather than modify the current one .

Interesting times ahead :-)

Cheers
John

[monty]

DOH!!

John,

Glad everything got there safe and sound. Looking forward to seeing progress!! I just went and measured the Holset wheel relatively carefully and got 29.1mm for the inducer diameter. According to Euler, you should be ahead by a bit!!

Funny thing is I got my wheel from the UK last Friday. I think I ordered it the day before I shipped the Garrett off to you. Even stranger - I couldn't find anybody in the US who could beat the price of the wheel shipped from Andy's supplier in the UK....crazy!!

Monty

[racket]

Hi Monty

LOL........yep 0.7% better off, every bit helps :-)

Shipping times are crazy, I once received a book from the UK in 4 days , whereas things normally take a week or 10 days , I've given up trying to workout how they do things , the Garrett wheel went to Chicago , then Japan and on to Oz , then 3 days for the last 400kms to here , I was just about ready to go to my Post Office and make enquiries.

Those Holset wheels are a very good price , I think its because the British Pound has been devalued considerably in recent years , we now get 56p per $AU whereas it use to be 30 something p.

I'm looking forward to your Build Thread .

Cheers
John

[Chuks]

Congratulations JOHN.

I can't wait to have my own Garrett wheels....
Cheers.

[racket]

Hi Guys

I picked up the balanced rotor last Friday along with some hollow bar to make a new exducer shroud piece and the flange for mounting the jetpipe to the engine's NGV stubb pipe.

Shroud machined up fairly quickly and nicely



its a press fits into the 5" OD exhaust pipe which has its end squared off in the lathe , with some small tack welds to keep it in place and the mounting flange added , the new jetpipe is starting to take shape



The mounting flange has a small roll pin fitted into it so that the jetpipe orientation is easily maintained when assembling and disassembling the engine .

Just a couple of mounting pads for the jetpipe thermocouples and a pad for the P4t total pressure pitot and it'll be ready to use........tomorrows jobs.

Cheers
John

[Johansson]

Hi John,

I am really starting to appreciate the way you design the turbine shrouds, they are so elegant somehow compared to my thick chunks of steel.

Cheers!
/Anders

[racket]

Hi Guys

A new year has started , Christmas visitors gone home , the house put back into order , so back in the shed again

I was able to get the rotor balanced and reinstalled into the engine before Christmas , so time to check the compressor to front cover clearances and alignment.

First job was to fit 3 layers of masking tape to the inducer and exducer sections



Then fit the front cover and check for shaft freedom of movement , some slight restriction to movement , probably cased by the masking tape not sitting firmly against the blades , rocking of the comp wheel indicated plenty of "clearances" so engine turned over onto snout and turb wheel forced forward to remove endfloat in the "dry" thrust bearing , it previously having beenn checked with the dial indicator for ~0.004" endfloat , the restriction to movement increased initially but as the masking tape conformed closer to blade shape the rotor was moving freely .

Engine turned back over to sit on exhaust stub and front cover removed , another layer of masking tape installed , 4 layers amounted to ~0.014-0.015"



The front cover had 9 radial lines marked on the shroud surface with marking pen



Cover installed and rotor rotated , a bit firm when the comp wheel was turned , but much firmer when engine inverted and turb wheel forced forward , there wasn't much freedom of movement when the rotor rocked side to side .

Front cover removed to inspect marking pen lines




Things looked fairly even around the shroud , so an extra layer of masking tape added and the process repeated, but with 5 layers things were very tight to turn even from the comp end , 5 layers were ~0.018-0.019"




Checking my build journal indicates that things are roughly where they should be so I'll continue wit assembly ofthe engine

Cheers
jOHN

[turboron]

John, good to see you back in the saddle. I like your methodical compressor clearance check. All digits crossed for DIY Gas Turbine success in 2019.

Thanks, Ron

[Johansson]

Happy new year John!

I love the writeup for comp clearance, what a coincidence that I am just about to do the same and was trying to figure out how to best do it!😃

Cheers!
/Anders

[racket]

Happy New Year Anders

Yes, a fortuitous coincidence

All the best with yours

Cheers
John