Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on Nov 9, 2017 22:41:10 GMT -5
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Post by racket on Nov 10, 2017 0:43:21 GMT -5
Hi Chuks I used standard 20mm bore C3 bearings in FM-1 jetandturbineowners.proboards.com/thread/576/fat-lady-fm-1 up to ~30,000 rpm without problems, it was at higher rpms I started to run into difficulties when using minimal lube with bleed air , once I changed to full pressure jet lube and a better quality bearing the problems stopped. The same setup was used in the 9/94 engine jetandturbineowners.proboards.com/thread/385/gasturbine-second-quarter-drag-bike, but theres a need for some oil damping of the bearings mount to help with rotor dynamics, it gets complicated, thats why I went to "brass bush" bearings in the 10/98 and 12/118 engines, much simpler to setup and probably more reliable . Cheers John
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455
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Post by CH3NO2 on Nov 10, 2017 6:55:50 GMT -5
Hi Chucks, I like that Russian jet engine guy. I have no idea what he is saying but his videos are entertaining. Sometimes good ideas can come across even with a language barrier. Tony
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455
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Post by CH3NO2 on Nov 10, 2017 7:03:36 GMT -5
Hi John,
What is your nomenclature 9/94, 10/98, 12/118? I can guess the last number is the inducer diameter. Is the first number a tip height?
Tony
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Post by racket on Nov 10, 2017 15:07:07 GMT -5
Hi Tony
With the 10/98 and 12/118 engines the first number is the outer can diameter in inches , so 10" and 12" , the second number is the inducer diameter in millimetres so 98 mm for the TV94 comp and 118mm for the X831 comp wheel , the earlier 9/94 could have be called a 9/98 , 9 inch case , but instead I used a "94" to signify a TV94 comp , it was built with ball bearings so a different "class" of engines..............FM-1 could be a 12/94 , but with that first engine I really didn't think much about a "line" of engines needing their own numbers .
LOL...............if I'd only known back in the 1990s that I'd be making so many different engines and collecting so much info I'd have got myself a bit more "organised" ..........heh heh , its too late now to even try .
Cheers John
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Post by Johansson on May 1, 2018 12:31:30 GMT -5
Hi Chuks, You will need to rearrange the preload so that the spring force is acting against the front bearing pushing it forward, this way the engine thrust will compress the spring and push the shaft forward causing the turbine and compressor wheels to make contact with their housings. Cheers! /Anders
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Post by Johansson on May 1, 2018 12:35:28 GMT -5
Also, the part holding the front bearing inner race is a very critical part, especially since it needs to be perfectly flat where the compressor wheel touches it. Any misalignment and the nut torque will bend the shaft and cause massive vibrations.
If I have learned anything building turbine engines then it is not to mess with the rotating parts unless absolutely necessary, try to use the rotor in its original state and spend more work on designing a large enough combustor instead.
Cheers! /Anders
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Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on May 3, 2018 14:22:29 GMT -5
Hi Anders, Thanks alot... Lol, John already scared me with his FM 1 were he is always re balancing his rotor. Yes! that part pushing the compressor, as small as it looks it's one of the reason why I gave up...... Am sticking with standard.
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Post by Johansson on May 3, 2018 15:35:37 GMT -5
Go with the standard oil bearings, ball bearings are much less forgiving for imbalance and much more expensive as well.
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Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on Jun 26, 2018 11:31:57 GMT -5
Hi all, This place is worth taking a look at. This guy is doing amazing work on automation, don't know if I can leave the fate of my engine on electronics though. m.facebook.com/autoturbojet/
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Post by racket on Jun 26, 2018 16:48:09 GMT -5
Thats a nice job he's doing on that engine
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Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on Sept 2, 2018 17:00:43 GMT -5
Hi everyone, Am planning on another engine build, probably a better one.
But getting the right turbo parts is still on the way, though with other factors. Plan is building an engine with the capacity of 150 H.P for a two seater helicopter or maybe three depending on the outcome. Fuel efficiency is a must, so 5:1 PR will do. Massflow will be ~2.7lbs/sec. Tip speed ~1900ft./sec. The engine should be one engine with a single free power turbine but for the sake of cost, I decided to split the power and use twin engine to power a single freepower turbine.
Am looking at the Garrett GTX LINE.
So I need your help on this two wheels.
For the single engine; I need to find the tip height and hub diameter of the GTX5533R compressor wheel (91mm inducer diameter)
For the twin turbine I need the same information on the GTX4294R COMPRESSOR wheel 70mm inducer diameter.
Thanks for your help.
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Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on Sept 3, 2018 13:05:23 GMT -5
This wheel could fit into the GTX4294R turbine/shaft , it's GTA4594 compressor wheel, but I couldn't find the compressor map.
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Post by Johansson on Sept 3, 2018 15:54:08 GMT -5
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Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on Sept 3, 2018 17:43:02 GMT -5
Hi Anders, Yes, I think I will take after him, my rotor head might even rotate faster, who knows....the truth is that I don't want to be the first, I just want to get it don with your helps.
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