turbomarc
Junior Member
Joined: May 2015
Posts: 56 
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Post by turbomarc on Jun 10, 2015 5:20:06 GMT -5
Hi Marc Turbine wheel is a tad small for the sized compressor inducer ( mass flow) , we generally require a turb exducer with ~20% greater area than the comp inducer if we want to have adequate flow area out of the comp to allow the comp to flow at its best , you really need a turb exducer of ~64 mm to better match your 58.2mm inducer . Are those bits of "shrapnel" metalic ? Or are they carbon flakes from an oil leak from the turb seal forming coke behind the heat shield ? As for "comprehensive guide/rules" we had some "Rules of Thumb " in the Files Section over on the Yahoo DIY Turbines Group Cheers John John, i don't like my chances of getting a larger rear wheel or exhaust housing, would probably be cheaper to just buy a new turbo, i think i might just try and make the most of what i've got for now, while i cut my teeth on this and do my homework in preparation for maybe a larger frame turbo later down the track. There is a minor amount of the "shrapnel" that is metalic, that was the first thing i did was to get it all together then run a magnet thru it. Yahoo groups are still around??!?!?, Will endeavor to look them up and get reading.  Thank god for the semi wet weather in Sydney today, afforded me a early finish from work, got the reducer cone welded up, as well as the new combustion chamber, i'm pretty chuffed, no grinder, only finished both inside and out with a wire brush after welding   |
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Post by smithy1 on Jun 10, 2015 15:29:10 GMT -5
Now i know it might be a bit late in the game, but, majority of this build has been from rough guides i found online and some guess work, is there any comprehensive guide/rules to doing builds like this, as i'm really starting to think about perhaps another one, a bit more refined that i can try and make some thrust with, as opposed to just making noise and flames like i am now. Cheers, Marc. Mate....what you have done is something most people who try these things only dream of....your little machine runs and makes noise. Noise and flames are what it's all about... ....If I were yourself, I'd get your current setup running a well as possible, make it pretty and keep it as a garage queen/conversation piece for when your mates come round ...Then get yourself something a bit larger and make some serious noise....the guys on this forum are here to help if required, it's a great resource. I'm only a phone call or email away and I'm sure Andrew and John are contactable and likewise willing/able to help. Do we know if there are any other DIY guys in the general Sydney area?? We must organize to get together for a day with Andrew (and possibly get John down) to talk turbines and maybe make some noise, fire and corruption...I'm sure that between us four we can come up with some silly good ideas.  I'd love to bring the "Beast" and the little dragster along. I'm sure Andrew will have something interesting to look at and play with. If he is up to it and John comes along, he might even be able to bring his latest concoction as well, it'll be a pleasure just to have him present. Cheers, Smithy. |
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Post by racket on Jun 10, 2015 17:32:43 GMT -5
Hi Marc Yep , the Yahoo Group still exists though theres very little activity these days compared to just a few years ago when there'd be 20 emails a day , the large number of YouTube vids on how to build a turbine engine virtually killed off the Yahoo Group , the info in its Files can be found here groups.yahoo.com/neo/groups/DIYGasTurbines/files , I've tried to steal back my contributions to the Files but can't seem to be able to do it , if anyone can suggest how we could , it'd be appreciated as the info would be handy here on JATO . Metallic shrapnel doesn't sound good :-( You could "clip" your turbine exducer to increase its flow potential . Cheers John |
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Post by racket on Jun 10, 2015 17:38:43 GMT -5
Hi Smithy
LOL...........I'm always only a phone call away to anyone who wants to chat about their engines :-)
Mmmmm, not sure if I'd make it to Sydney and back these days , I don't travel very well due to some ongoing health issues ...........its a bummer getting old .
Cheers
John
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Post by smithy1 on Jun 10, 2015 19:25:52 GMT -5
Hi Smithy Mmmmm, not sure if I'd make it to Sydney and back these days , I don't travel very well due to some ongoing health issues ...........its a bummer getting old . Cheers John You don't have to do it all in one day.....you could bunk at my place overnight if you like, have a spare room with comfy double bed and white fluffy pussy-cat....you're always welcome. I can even disintegrate/incinerate something on the barbie for us...or I could ask Christine to cook it properly. Cheers, Smithy. |
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 10, 2015 20:10:26 GMT -5
Hey John, I found that page last night and joined, but I need to have my account approved by the people that run it before I can get access to the files and pictures. Yeah, not good having metallic flakes, but stuff it, I shall press on, I gave it a decent clean out, will still run it, and after a few fire ups pull it apart and keep an eye on the situation. Smithy, yeah with my extremely limited knowledge and near non-existent calcs, I'm extremely happy that it starts and runs. But as you said I'm happy to iron out as many issues and getting running as best I can while learning along the way. That way later on I will have some hands on experience and feel bit more confident to move on to a larger project later on. Just curious with the combustion chamber and where the air enters it, is there a optimum spot in relation to the flame tube that I should put it?? Closer to primary, secondary or tertiary?? Also I assume that it would be beneficial to make the air enter in such a way that it will swirl around the flame tube to help aid even flow?? Similar to a swirl pot for of design?  Yeah I'd be happy to meet up for a test and tune day once mine is back in action, be good to have someone have a close look and get some more feed back. Cheers, Marc. |
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Post by racket on Jun 10, 2015 20:45:16 GMT -5
Hi Smithy
Just getting to Sydney in one day is beyond me at present :-(
Cheers
John
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Post by enginewhisperer on Jun 10, 2015 20:59:48 GMT -5
I reckon that shrapnel is probably casting remnants from high quality construction methods If you want to change turbo I can donate a Mitsubishi TC06 turbo which has a smaller compressor and larger turbine than your ebay one - and is proven to work nicely as a DIY turbine. Otherwise I have a couple of larger truck turbos that could work nicely, but so far I found it difficult to provide enough starting air to spin them up! It always seems like a good idea to get the air to swirl around the combustor, but apparently it tends to cause uneven flow and more problems. Putting the inlet pipe away from the primary zone seems to help keep flow nice and even around there too. |
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Post by racket on Jun 10, 2015 21:14:04 GMT -5
Hi Marc Don't hold your breath waiting for the Yahoo OK , things are very slow there. As to where to place the delivery duct , I like to keep it well away from the combustion area , preferably below the main dilution holes so that theres minimal chance of uneven entry through the wall holes . On my "two shaft kart" jetandturbineowners.proboards.com/attachment/download/46 , the air discharged into a plenum surrounding the "funnel and snout" before making its way up the can to the Primary and Secondary holes by which time it should have been reasonably well distributed around the flametube OD . Similarly on the GT6041 kart jetandturbineowners.proboards.com/attachment/download/216 . I also had the delivery tube positioned in a similar spot on the TV84 powered bike (avatar) . As for having a tangential delivery to promote swirl , I'm not a great fan of that due to potentially extra losses from high speed air swirling around the walls , as well as possible combustion problems if theres too much vortex , better to promote swirl in the Primary Zone only by the use of suitable swirl vanes or FT wall holes being "tangentialised" by sticking a centre punch in them and twisting sideways . Ideally we need to have some diffusion ( funnel) at the combustor can wall to slow and spread the air prior to entering the space between flametube and outer can ,checkout pics of the Allison 250 turbine engine with its twin delivery tubes feeding into diffuser/plenums on each side of the combustor can before the air enters it , it is possible to have high losses at that position unless theres good aerodynamic shapes/areas , we can't simply weld a stub pipe onto the side of the combustor and hook the delivery tube to it , the high speed air travelling along the pipe suddenly needs to turn a corner at the flametube wall , it doesn't want to unless theres forces applied and those forces are losses that can't be recovered, turbine engines are "tuned" for performance by reducing losses as we can't spin them faster or run them hotter to gain power as they are already on their limits . Cheers John |
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 11, 2015 18:46:31 GMT -5
I reckon that shrapnel is probably casting remnants from high quality construction methods If you want to change turbo I can donate a Mitsubishi TC06 turbo which has a smaller compressor and larger turbine than your ebay one - and is proven to work nicely as a DIY turbine. Otherwise I have a couple of larger truck turbos that could work nicely, but so far I found it difficult to provide enough starting air to spin them up! It always seems like a good idea to get the air to swirl around the combustor, but apparently it tends to cause uneven flow and more problems. Putting the inlet pipe away from the primary zone seems to help keep flow nice and even around there too. Hi Andrew, Cheers for the offer, I'll see how things pan out with the current turbo. But with the larger truck turbos how much larger are we talking here? Not that I'd be jumping on them right away, but just curious, like I mentioned I would like to go bigger down the track. John, thanks for the pics of the CC entries I had a bit of a think about it but I should be able to come up with something, I'll get it down on paper, and see what you think. Cheers, Marc |
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Post by enginewhisperer on Jun 11, 2015 19:53:09 GMT -5
The truck turbo has a 75mm inducer (106mm wheel) so should be good for 60lbs thrust or so.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 16, 2015 6:10:33 GMT -5
The truck turbo has a 75mm inducer (106mm wheel) so should be good for 60lbs thrust or so. Sounds good, you wouldn't have two of them would you?? I made a small bit of progress today, it was for the inlet to the combustion chamber, after reading what Racket said, i checked out the Alison 250 and decided to take a leaf out of their playbook. With my flame tube i have 60mm separation between primary and the secondary, and the secondary to the tertiary.  Given that the outlet from the turbo is 2" (51mm) i am planning to position the inlet in between those holes so that im not pushing air directly thru the holes so that the flame tube can also be used to help aid flow around the chamber, well, that's my theory anyway, i'm sticking to it.    So all thats left is to scollop the big end of the inlet funnel for a neat fit on the combustion chamber, but what do you think John/Racket should do alright or am i barking up the wrong tree with this one?? Cheers, Marc. |
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Post by smithy1 on Jun 16, 2015 14:38:30 GMT -5
Hi Mark, Love your work and wish I had such welding skills....my welding looks like bird shite dropped from 100m:-/ I'm not real sure about the large "divergence" of the inlet to the outer CC...however.... I work with the Allison (RR) 250-C20B engines every day and their setup also has this "divergence" as the compressor discharge tubes enter the outer CC's inner plenum, see pic...so I suspect it will probably work. As can be seen, the C20B's have an "inner" plenum where the air is distributed evenly around the inner combustion chamber.  Cheers, Smithy. |
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 16, 2015 17:16:07 GMT -5
Well i made it a tad large as it's still got to be cut down, so i could go nearly as wide as the CC, or make it shorter which would also make it narrower.
I suspect it will be fairly short because i still have to put a 90 degree bend on the end of it towards the turbo outlet, the longer the funnel is, the more bend i will require to make it blend with the turbo outlet. Hopefully the mandrel bend i have is tight enough otherwise i have to get to work doing a heap of pieces to make a lobster back bend.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 16, 2015 21:22:54 GMT -5
I wouldn't say perfect fitment, but it has some penetration gaps that should be easy enough to take care of  |
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I'd love to bring the "Beast" and the little dragster along. I'm sure Andrew will have something interesting to look at and play with. If he is up to it and John comes along, he might even be able to bring his latest concoction as well, it'll be a pleasure just to have him present.
