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Post by turbojet atv on May 13, 2021 4:03:48 GMT -5
Hello everyone, I’m new here and new to to the turbojet community. This community is full of helpful people and ideas that are awesome. I’m currently building a turbojet with a free power wheel.
My idea starts with my combustion chamber. I’m using a 106mm turbo charger; the math for my combustion chamber is 10”x24” & my flame tube is 8”x24”. I had the idea of splitting the chambers and making 2 chambers feeding the one turbocharger. I’m only doing this to save space in the atv I plan on putting this jet in.
My idea is to build 2 combustion chambers; 6”x18” chambers w/ 4”x18” flame tubes. In my head it seemed like it would work as the two chambers would feed the single 106mm turbo. A 2 into 1 exhaust into the turbine housing & a 1-2 intake charge pipe from the compressor housing and into the combustion chambers.
The free power/turbo shaft part of the exhaust is the exciting part of the build as it will power two alternators that will power a 55kw electric motor. The electric motor will sending over 100hp & over 100lbft of torque to the rear wheels. Sounds exciting and insane.
For you experienced turbojet builders, how does the jet part of it sound? Does a 2 to 1 chamber sound like a interesting idea? I’d love to hear some feedback on that part of the build.
Thanks, Cullen.
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Post by racket on May 13, 2021 4:40:13 GMT -5
Hi Cullen Welcome to the Group :-) Checkout jetandturbineowners.proboards.com/thread/78/garrett-gt6041-powered-kart for ideas on your combustor needs . Our flametubes need ~3 times inducer area as their cross sectional area , the 106mm wheel inducer has an area of 13.67 sq inches , 3 times that is 41 sq ins or 7.2" diameter . Now if we divide our 41 sq ins by 2 we end up with 20.5 sq ins , or 5.1 inch dia flametube bores , 2 combustors could work but a lot of complication unless absolutely necessary , opt for a single one would be my advice . Why do you want to complicate your drive train with heavy electrics ..............remember "KISS" for drive trains jetandturbineowners.proboards.com/thread/40/2-shaft-turbine-kart-build or a tad more complicated www.youtube.com/watch?v=q7aNAhvMAao your 106 mm engine is capable of nearly 200 HP from a suitable freepower and gearbox Cheers John
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Post by turbojet atv on May 13, 2021 7:21:51 GMT -5
Thanks John, I’ll look into the links you sent.
The reason I looked into 2 chambers was to save some space in my frame. Reducing the area the chamber was taking up and allow me to have more useable space for all the other stuff I need to squeeze into it.
The idea for the electric drive; powered off the free power wheel, was because it would give me a incredible amount of power and torque right off the starting line. This is in a racing/drag application. Should’ve mentioned that. It needs to accelerate quick & have a lot of speed to get to the 1/8 mile mark.
That’s awesome to hear what a 106 engine can make. Also, I’m going to see if I can’t post a picture in here so you can get a small idea of my work area inside my frame.
-Cullen
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Post by racket on May 13, 2021 16:33:46 GMT -5
Hi Cullen A freepower turbine wheel has similar power characteristics as an electric motor , a freepower has twice the max rpm torque when stalled at nil rpm jetandturbineowners.proboards.com/thread/1260/turbine-torqueIf you checkout this dyno graph imgbb.com/gvg3ngV of this bike jetandturbineowners.proboards.com/thread/34/motorcycle-project you'll see some impressive torque numbers, then if you use a torque convertor in the drive train you'll get even better acceleration ...............no need for electrics , use their space for the large single combustor :-) Whatever you do , don't skimp on your flametube/s cross sectional area , anything less than 3 inducer areas and you can have big troubles. Cheers John
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Post by turbojet atv on May 14, 2021 5:38:45 GMT -5
Hey John, I’ll start out with the free turbine power and put the electrics on the back burner. The free power seems to be promising.
My free power wheel is a 9” turbine wheel from an old helicopter engine (not what model exactly. It says ge4128 on it). That should pick up a lot of exhaust and tune it into some pretty nice horsepower.
I made room in my frame by relocating my turbo so I will pick a big single over the twin combustion chambers. It should be less complicated from there on that side of things.
I’m now looking for a nice way to attach my turbine wheel to a “gearbox” or reduction box to power the rear wheels.
-Cullen
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Post by racket on May 14, 2021 17:09:56 GMT -5
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Post by turbojet atv on May 20, 2021 13:44:09 GMT -5
Here’s a small follow up on this crazy build.
I got a 10” x 24” piece of stainless steel for my combustion chamber. I’m getting that all mocked up in my frame and I’m about to order a 8” x 24” stainless steel tube for my flame tube. Stainless steel end caps & a fancy looking exhaust pipe going to the turbo.
I was skeptical about the 10” tube as I was think this is going to be a massive engine but the math called for a 8” flame tube and I read you need a minimum of 1” clearance around the flame tube so the combustion chamber is the correct size?
I wish I could upload pictures to show what everything looks like. I’m hoping to get big numbers out of this engine.
✌️ Cullen
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Post by racket on May 20, 2021 17:00:31 GMT -5
Hi Cullen
What are the numbers on your turbos specs tag ??
LOL, yah gotta remember the size of the diesel engine the turbo came off when considering your combustors size , its rather insignificant compared to the diesel .
Always better to go a bit bigger with the combustor than too small , your 8 and 10 inch tubing will provide generous proportions which should mean less chance of having any sort of combustion problems.
If you need numbers for your engine , I've got them already done for my build .
Cheers John
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Post by turbojet atv on May 21, 2021 9:05:28 GMT -5
Hi John, here are all the specs for my turbo charger Cold Side Details:
Anti Surge Compressor Cover Wheel Speed Sensor Port 5″ Inlet 3.0″ V-Band Outlet CNC Machined Billet Compressor Wheel 1/8″npt Port For Boost Reference
Exhaust Side:
Extremely Light Exhaust housing Cast From Stainless Steel 103mm Turbine 4.0″ V-band Outlet 3.5″ V-band Inlet flange 1.30ar
Compressor Wheel Details:
Inducer 107.5mm Exducer 140mm
Turbine Wheel Details:
Inducer 112mm Exducer 102mm
I’d like to get the number from your engine. It would help a ton, thank you.
✌️Cullen
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Post by racket on May 21, 2021 17:25:24 GMT -5
Hi Cullen
OH!!!!
Not the best matching of compressor and turbine wheels .................."performance ??" turbos might be OK on a piston engine but they need wastegates , we can't fit wastegates :-(
Your compressor inducer is ~11% greater in area than your turbine wheel exducer , ideally the turb exducer needs to be ~20% bigger than the comp inducer , you'll have problems getting your compressor flow through your turb stage .
What brand of turbo is it ??
Cheers John
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Post by racket on May 21, 2021 19:07:16 GMT -5
Hi Cullen If you checkout the Garrett maps www.garrettmotion.com/racing-and-performance/performance-catalog/turbo/gtx5544r-gen-ii-106mm/ you'll find that their turb stage Corrected Flow at a 2.5 PR is only ~69 lbs/min with a 1.40 A/R scroll , this corresponds to an Actual Flow of ~138 lbs/min if you run a 4:1 PR from the comp and theres a ~2.5:1 PR across the turb stage . Their 106mm comp flows ~200 lbs/min at 4:1 PR , but the turb stage can only "swallow" 138 lbs which puts the comp into surge :-( Great turbo for a piston engine but useless for a gas turbine conversion unless you want to bleed off ~70 lbs/min of compressed air Cheers John
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Post by turbojet atv on May 21, 2021 19:29:51 GMT -5
Hi John, Oh my, it sounds like I’ve ran into a dead end unless I can salvage what I’ve got already. I hope there’s a way to salvage it as I’m pretty committed to complete this project. My turbo is a On3 performance 106 turbo www.on3performance.com/shop/on-3-performance-107mm-cnc-billet-wheel-turbocharger-t6-stainless-v-band-exhaust-housing/These do work great on piston engines; they got cars making over 1500hp with these turbos. If I read what you said correctly, this turbo won’t work with a turbine engine? Honestly I’m not sure if I’ll be able to replace this turbo with a more suitable 106mm turbo from a Diesel engine. It would probably be a better fit if I could find one. Thanks, Cullen.
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Post by racket on May 21, 2021 22:11:54 GMT -5
Hi Cullen When you mentioned the size turbo you had I thought it was a Garrett GT6041 www.ebay.com/itm/333558250095?hash=item4da99efa6f:g:FlEAAOSwgd5ee7sk , it has a large 130/119 mm turbine wheel which is a better match for the compressor flow . You could use your turbo but you'd need to be "adaptable" , you could always bleed off P2 air and feed a freepower stage with just hot air , or feed the air through a small combustor to heat it up before going into the freepower for more power . Thats a very good price for your turbo though :-) Cheers John
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Post by turbojet atv on May 22, 2021 3:26:34 GMT -5
It was a decent buy for the size of turbo it is. I was quite surprised by it.
I had an idea; which you mentioned as well, which was to bleed off air pressure and divert it elsewhere. I figured I could route air from the comp side through a 1” or 1.5” tube to the free power wheel to add a little extra to it.
-Cullen
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Post by turbojet atv on May 22, 2021 5:01:12 GMT -5
I’m trying to post a pic of my project. Seeing if this works right here. ibb.co/TmdgpX0if not I’ll try another way -Cullen
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