/diy/ - Do It Yourself

>>1166711
No body knows about this shit here? What a waste of thread

Make a pulse jet and be done with it.

Or this guy may have some information on more of a real jet engine and building one if i remember.
https://www.youtube.com/user/colinfurze

>>1166724

Calm your tits faggot...this is a slow board, and most of us work...check back tomorrow...

>>1166711
Here's the classic homebuilt model turbine design:
https://www.scribd.com/doc/3746230/Gasturbine-Engines-for-Model-Aircraft
Obviously if you have access to CNC, you can probably make something more elegant. But it still goes to show what you can get away with and still have a functional jet (wooden compressor wheel? No problem).

>I mean where does the combustion exactly happen why are there two tubes overlapong the other
I think the combustor in your picture is a basic form of annular combustor. Combustion is confined to a thin ring between the inner and outer tubes, and "cool" compressed air flows through both walls into this annulus to keep the flame confined and away from the walls.
>The placment of holes diameter of differrent holes and their number, why? Please explain, and give me a good source for this.
Dunno, most combustors I've seen have more holes and they're mostly the same size. Then again, Schreckling's burner has very few holes on the inner surface, and none on the outer surface. I'm sure you can get away with a lot more running low pressure ratios, especially if you don't particularly care how long the engine lasts.

>>1166711
>He didn't even wait an hour on one of the slowest boards on 4chan

Entitled much sweetheart?

>>1166711
john tom has some plans. there is a kid on youtube who made one out of literal scrap using only some simple hand tools.

shot sparks and made a horrendous grinding noise but it worked.

https://www.youtube.com/watch?v=trcnd7qs-S8

>>1166711
https://www.youtube.com/results?search_query=AgentJayz+Combustor

>>1166724
I know everything you want to know, but you're a cunt so I won't help you for a bit.

Air enters bigger intake, compresses and mixes with fuel, ignites, pushes rotors at back before exiting. Some jets are assisted initially

>>1167841
>I dont know anything
>op is cunt so i will be too

>>1166738
>>1166761
>>1166782
>>1168103
Thnx

They spray pattern from your fuel nozzle will dictate what sort of cool air slots you need. Melty spots on the can are just the engines way of telling you where it could use more holes

>>1166738
The metallurgy involved in axial flow engines is a bitch. That's why the ME-262 engines lasted something like 10 hours between overhauls and no working models remain. Meanwhile centrifugal designs used in the Gloster Meteor have a few functioning examples to this day.

The homebrew version of the centrifugal flow engine is one built around a turbocharger.

Search this code in amazon ISBN-10: 190037191X

It will tell you all you need. The main problems are the combustion chamber, it needs to be designed so it is cooled by the air coming from the compressor so it wont melt. The prop must be perfectly balanced because it spins at many rpm's and according to the above author the the drive turbine at the back can be fabbed from high temp Nickel Steel, you can do it with an angle grinder, care and lots of patience but it can be done.
Read about Frank Whittles work and study jet engine plans in general,one of Whittles big problems was the design of the combustion chambers, what did he do to solve them.
They are not very efficient a low altitudes though but I like the idea that you can burn just about any fuel in them.

>>1166724
irl jet engines operate on extremely tight tolerances. We're talking sub millimeter on those big fans, and possibly even tighter in the turbines, turbine shafts, etc. Engineered with materials designed to keep those tolerances over the full operating temperature.
Are you sure you're ready to go down this rabbit hole, OP?

>>1168643
Others did and it worked so why not?
Model jet engines are different than full scale ones, and have bigger chance of working if made at home, I do have a range if tools and materials to help me and the machine shop is close to my house I dont mind spending money and I doubt I need it because of the materials I got, here is a hope boost

https://youtu.be/jje0wV4l0tM

Looks like crap but self sustained

>>1168749
Because others haven't made axial flow engines from the ground up. If that's all you wanna do, pick up a shitty used turbocharger make a combustion chamber and then you're set

>turbine section glowing red hot
i'd call that a failure
what a joke

>>1166711
I built one out of a turbo.

It currently self sustains. Need to hook up thermocouples so I know I'm not hot starting... As well as redo some oil drain lines and make a nozzle.

I'm on mobile phone, so I'll let you look up how they work / fit together. There's a program called jet specs or something that helps you design the combustion chamber based off of compressor and turbine measurements.

I had to CNC plasma cut 2 plates and 2 rings for the combustion chamber. Rest was welding and some basic metalworking.

Do it. Super fun and rewarding project. I'll check back tomorrow to help out more with any questions / giving links

>>1169179
Great thank you, I will check out Jet Specs. Here is my idea, I want to make 4 combustion chambers outside the engines centre so heat doesnt build up on the shaft and gaps betwern them will allow outside air to cool down the shaft and it would be easier to hook oil lines to the bearings. I have a couple of centrifugal compressors I will use the better and lighter one to build the measurments around it. On the turbines side I will put a thick plate before the turbine with angled holes to drive the turbine (narrow holes would increase air velocity, correct me if I am wrong) and after the turbine I will put a strator so that air would go direct and smooth to create thrust. I can go and make a jet out of a car turbo like colin furze, but that will kill the challenge and I want a compact one to shove it on a glider.

>>1168978
Who built it from the ground up were experienced people with degres in the subject. Most DIY people didnt succeed to make it self sustain even with cnc machining, (check smartfilmprojects on youtube)
The guy in the video had one of the very feew engines that worked out, even if its crap but it works and he did it in a reasonable time.
It is harder than you think, the safest way to make one work is to get the plans of tested a engine and send them to a machine shop. But that kills the whole point of learning and kills the great smile on your face when your engine actually work

Kim Jong-Un, go to bed.

>>1166711
Reciprocating engines don't care about size. That's why you can make one as big or small as you wish and the physics won't change.

Jet engines are a different ballgame and don't work well when their dimensions change from the standard ones.

But it seems possible nonetheless. I would just do a reciprocating one and be done with it.

>>1169213
then stick to piston engines. There's literally no point to making a gas turbine if all its going to do is fail and throw red hot blades out the turbine section after a few mins of sustained running, unless that's your stepping stone to something better engineered

>>1169755
Thats the whole point for diy stuff, try make shit that might work and keep trying until it does, I want to build an rc jet from scratch

https://www.youtube.com/playlist?list=PLyyfwUFI3XU-CvGsSXnczu4p9AEobpAED

Russian guy making jet engine out of two car turbines

>>1170040
>dat precision
I like this guy already
way better than the janky shit I usually see
Hope his engine works out

>>1168217
>The metallurgy involved in axial flow engines is a bitch. That's why the ME-262 engines lasted something like 10 hours between overhauls and no working models remain.
No, the German engines had shit metallurgy because they decided to conserve strategic materials by forming the turbine blades from mild steel sheetmetal instead of casting them in nickel alloy. This had nothing to do with the multistage axial configuration of the compressor, though that did produce its own problems - cheifly vibration modes in the long, high-RPM shaft, as well as excessive labor demands. The Whittle, on the other hand, produced similar pressure ratios and efficiency using only a simple, single-stage, low-RPM compressor... but none of that has jack-shit to do with metallurgy.

>The homebrew version of the centrifugal flow engine is one built around a turbocharger.
Not necessarily. Read the PDF.

>>1171346
Thank you based president.

>>1171346
>forming the turbine blades from mild steel sheetmetal
proofs? i would be very impressed with stamped internals working at all

also what pdf

>>1171380
>proofs? i would be very impressed with stamped internals working at all
https://en.wikipedia.org/wiki/Junkers_Jumo_004#Technical_description_and_testing
>The initial 004A engines built to power the Me 262 prototypes had been built without restrictions on materials, and they used scarce raw materials such as nickel, cobalt, and molybdenum in quantities which were unacceptable in production. Franz realized that the Jumo 004 would have to be redesigned to incorporate a minimum of these strategic materials, and this was accomplished. All the hot metal parts, including the combustion chamber, were changed to mild steel protected by an aluminum coating, and the hollow turbine blades were produced from folded and welded Cromadur alloy (12% chromium, 18% manganese, and 70% iron) developed by Krupp, and cooled by compressed air "bled" from the compressor.
I was slightly mistaken, apparently it was stainless steel sheet for the turbine blades and mild steel for the combustor, etc., but still. That's a serious compromise in quality for strategic reasons.

>also what pdf
Schreckling's book: [>>1166738]
Bolting a combustor onto a manufactured turbocharger to make your own """homebrew""" turbine engine is certainly viable and will yield a more reliable engine than more crude and /diy/ish methods, but it's by no means the only way, nor the /diy/est way, to make a functional centrifugal turbine engine.

>>1166711
I built several based on turbochargers, this is where you want to start as the precision is already there for you. The hardest part about building your own jet from scratch is by far the turbine and compressor manufacturing, these have to be perfectly balanced all the way through the main shaft end to end.