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Post by rubenpeeters on Jun 8, 2020 8:17:35 GMT -5
Hello, I recently got a holset HX-82A turbo, it comes from a Cummins QST-30 which was in a fire. One bank of the engine was burned, the other side is in quite good condition. My turbo is from the 'good' side of the engine. Now i would like to build a turbine engine out of it. I started drawing some parts based on the video from colinfurze, and based on the link below. The inlet of the cold side is 130mm. The combustionchamber seems to be getting quite big(300mm diameter, 780 mm long). I don't think it should be that big. Does somebody have any idea how i should construct the combustionchamber? Thank's in advance Ruben Peeters The Netherlands www.instructables.com/id/How-to-build-your-own-Jet-Engine/
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Post by racket on Jun 8, 2020 17:02:55 GMT -5
Hi Ruben Welcome to the Group :-) Firstly , forget everything Colin Furze has ever said about jet engine builds . Secondly, ditto for Instructables Both have simply given their interpretations of whats been said on this Site . Jetspecs nuclearprojects.com/jetspecs/ will provide some guidence Better to have a look through the various builds here first Your drawing of the combustor has a couple of problems , firstly fit the air delivery tube at the other end (outlet) of the outer can , having it at the Primary Zone end can create combustion problems, also don't have it as a tangential entry , straight in with some sort of "funnel" at the outer can wall to spread the flow over a greater area to minimise losses as the air tries to enter and turn around the flametube . All the best with the build , the outer can will only need to be ~175 mm dia at most and maybe 450 mm long , but enter your comp wheel inducer size into Jetspecs and see what it produces . Cheers John
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Post by rubenpeeters on Jun 10, 2020 6:08:44 GMT -5
Thank you very much for your reply. I didn't use the right diameter for the inducer, that is why my measurements where not right. I put in the dimensions in the calculator, should i just guess the right diameters of the holes?
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slittlewing
Senior Member
Joined: November 2017
Posts: 458
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Post by slittlewing on Jun 10, 2020 17:04:35 GMT -5
HX60 - very nice big turbo!! I look forward to the build!
I am no combustor design expert but for reference, my engine has about 12 main primary holes, 8 secondary and 6 tertiary.
Cheers
Scott
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Post by racket on Jun 10, 2020 17:39:31 GMT -5
Hi Ruben
What fuel and fueling system will you be using , this will influence Primary hole size/number/position
Cheers John
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Post by rubenpeeters on Jun 11, 2020 2:37:12 GMT -5
Hello John,
We will probably be using diesel, combined with a pump and jet nozzle. The turbo turns out to be a Holset HX82-A
Ruben
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Post by racket on Jun 11, 2020 4:12:00 GMT -5
Hi Ruben
If using a spray nozzle for the fuel then less Primary holes , maybe 10 - 12 only and positioned down the side wall of the flametube at the theoretical impact point of your fuel spray , so you'll need to sort out the fuel nozzle spray angle first.
You can keep to similar numbers of Secondary and Tertiary holes .
Jetspecs recommends a generously proportioned combustor that doesn't require a lot of sophistication to work
Cheers John
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Post by rubenpeeters on Jun 16, 2020 5:10:53 GMT -5
After some searching we found 2 stainless steel tubes (Dia. 168 and 219). We cut the tubes at around 500mm, and drilled the holes according to what jetspecs told us. In the picture below you can see how it turned out. Now we will be having to make the rest of the combustionchamber. I have a few questions about that. 1. Where should we position the air intake? (as far down as possible?) 2. Should we put the ignition on top of the combustionchamber or close to the air intake? 3. What kind of oil and fuel system do you guys recommend? (what pump? what pressure? what nozzle?)(using diesel) 4. Should we widen the air intake where it connects to the combustionchamber? (the tube now is 88,9 mm) Thank's in advance Ruben Peeters
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Post by racket on Jun 16, 2020 22:31:57 GMT -5
Hi Ruben Yep , as far down the outer can as possible to keep the inlet air from disturbing the combustion. I like ignition on the side between Primary and Secondary zones. Guys use auto EFI fuel pumps with as much pressure as possible feeding an oil burner spray nozzle , and oil pumps like the Marco UP12 items.marco.it/en/up12-lo-bronze-gear-pump-for-light-oils.html. Some sort of diffusing funnel where the delivery tube meets the outer can helps to provide easier flow of air into the can Cheers John
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Post by rubenpeeters on Oct 16, 2020 5:05:58 GMT -5
After a little summerbrake we continued with the jet build. Now we have to finish welding to start building the ignition and fuel suply. We found an old oilpump with nozzle (see picture), which was used in an oilburner. We will try to use this system to spray diesel in the engine. Now for starting the jet we probably have to use propane? Where should we place the propane nozzle? Thanks in advance Ruben Peeters
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Post by racket on Oct 16, 2020 16:17:57 GMT -5
If you can use the "oil burner" ignition system , then no need for propane unless the "oil burner" also used propane .
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Post by rubenpeeters on Oct 30, 2020 4:22:08 GMT -5
Oh okay
I thought we would need the propane to heat up the engine in order to let it run on diesel. So that's not the case?
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Post by wannabebuilderuk on Oct 30, 2020 5:51:02 GMT -5
Those oil burners don't use a pilot light as far as I know, so just take the parts from it and reverse engineer the system into your purpose
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Post by racket on Oct 30, 2020 17:49:24 GMT -5
Nope , not the case , the propane pilot only provides for easy ignition and then positive ignition of the diesel which can be difficult with just a rudimentry ignition system
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Post by rubenpeeters on Apr 19, 2021 4:38:37 GMT -5
Hello, Yesterday we tried to start our Turbo jet with just the propane, to make sure it all works before we start installing the fuelsystem. To distribute the propane properly we bend a piece of tube and drilled some holes in it (just like in te picture). Without the turbo installed the ignition worked just fine. When we installed the turbo, the engine just would not start. We spooled up the turbo and added the propane, started the ignition but nothing happened. We are thinking that the ignition might not be in the right place. Does somebody have an idea what might cause it to not start? Or maybe explain how you start your turbo jets. Thanks in advance!
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