Hi Folks,

This has been waiting for a while on my radar and finally I have decided to dive deep into this. This will be a build thread for turbine jet engine.

Little background about myself: I like meddling with things and built something that is interesting. I am a mechanical engineer and now an IT professional (damn, what are the odds  ). I have 4 years of professional experience turbine commissioning and operations at thermal power plant and three years of experience in model jet engines (not flying).

This built is going to be completely experimental in nature. It may succeed or it may fail depending upon many factors.

The proposed design specs are:

Diameter: 80 mm
length: ~200-240 mm
Thrust: ~50N-60N (5-6KG)

The design will be a scratch development and won't be a replica of any commercial product.

If there is sufficient interest I will continue with the thread.

5-6 kg? 
multiple rotors??

Oh yes, please make a thread ! Interested to learn more about it!

Subscribed!

Yes. 5 to 6Kg of thrust. One can use it in a heavy & big models.

I didn't get your point of multi rotor. It will be single rotor(single shaft) design. There are no multi rotor design in model jet engines.

Getting started !!!

I have drawn some rough drawings of the possible dimensions. Here are the raw parts now. All the parts are depicted and destined.

Work will start soon. Shaft would be the first candidate. (lucky he  !!!)

have you tried 3d printing prototype models sir?

  i'm sure you know what you are doing a lot better than most of us but still i thought of recommending something

Quote from: tonyStark on June 19, 2020, 08:28:28 PMThere are no multi rotor design in model jet engines.

thats why i had asked you

Quote from: tonyStark on June 19, 2020, 08:40:53 PM
Getting started !!!

I have drawn some rough drawings of the possible dimensions. Here are the raw parts now. All the parts are depicted and destined.

Work will start soon. Shaft would be the first candidate. (lucky he  !!!)

Would it be possible for you to mention material used and why and also what type of tooling used for achieving final product! It would be helpful I feel!

Sure.

Most of the parts are aluminium (6061 grade or Hindalium).
The shaft tunnel can be made out of aluminium or steel. I choose Aluminium given its easier machinability.
The shaft is EN24T simply for its high tensile properties and strength. You can also go for 12.9 grade allen bolt of this size.

3D printing won't help in such design given the amount of strength and pressure they come into.

subscribed and closely following

Quote from: tonyStark on June 19, 2020, 10:34:02 PM
Sure.

Most of the parts are aluminium (6061 grade or Hindalium).
The shaft tunnel can be made out of aluminium or steel. I choose Aluminium given its easier machinability.
The shaft is EN24T simply for its high tensile properties and strength. You can also go for 12.9 grade allen bolt of this size.

Good choice of materials. What about the blades, shaft, bearings etc?

Not much progress today.

The shaft round I got was of way bigger in Dia., cutting that much is a waste so I went to the market (10km from my place) but I had some problem in my bike midway. By the time I fixed and reached the market, it was close. Now it will open on Monday only. Will see, If I can machine this round tomorrow.

@sanjay Shaft is En24T. Bearing I will decide in due course,mostly GRW.

Interested, please continue posting!

Update:

last Saturday & Sunday went into designing & machining the shaft.

Shaft is one of the most important component. The turning has to be absolutely concentric and mating surfaces orthogonal to avoid shaft bending and vibrations. The first resonance is expected to be around 2400 to 2900 RPM.

I could not resist the temptation and turned down the 20mm round. En24T is not easy to machine, you can't take heavy cut in one go. There will be lots of heat and ample cooling fluid is need with speed around 400-450 rpm. It took 7-8 hours to get to this and still final fit and tolerances are yet to finish. The fit will depend on the mating component.

Wow !! Nice to know that you do have experience in TPP Turbine and Model Jet turbine . Else in most arguments with noobs, I had hard time convincing challenges in Material science, high temperature Lubrication, and extremely high tolerance machining.

Would you mind sharing where you got the chance to work on Model Jet Engines , because they are much rare opportunity than most Turbine types. Also, where you ot access to such machine tools, considering you too are a Software Professional like me, who had to build his Electronics lab from scratch - from Screwdrivers. Multi Meters to Signal Generators, Oscilloscope and RF Analyzer.

<Edit while you posted the Lathe Pics: Kudos : Keep the good work and heartiest well wishes and good luck for this project>

Which motor will you use for the edf sir?

I don't think he is trying to make an EDF. I recommend you do some research on Jet Turbines.

Regards,
Nitesh

yes, Nitesh is right. It is not an EDF.

It is a model jet engine very similar to what you see hanging under the wings of an aeroplane, just its very small and is for mostly RC purpose. If you have a RC plane which is quite big or you need a real jet flying experience, you install one of these. They run, sound and feel like real big jet engines.

@tonystark,

With your metal working skills and facilities, maybe you could build a ram jet like Dynajet, as a warm up exercise before building the turbine!

And I expect you'd have already considered turbochargers as a parts source...

Best wishes for your project.

BTW, I remember having seen videos of a (fairly large) working homemade jet turbine by someone somewhere in Punjab.
NOT an EDF  .
Will share if I can locate them.

Regards
Iyer

Quote from: ujjwaana on June 22, 2020, 11:40:02 PM
Else in most arguments with noobs, I had hard time convincing challenges in Material science, high temperature Lubrication, and extremely high tolerance machining.

Where you ot access to such machine tools, considering you too are a Software Professional like me, who had to build his Electronics lab from scratch - from Screwdrivers. Multi Meters to Signal Generators, Oscilloscope and RF Analyzer.

Indeed, metallurgy and machining process is with no doubt play a vital role in jet engines. The jet engine parts like the shaft, turbine blades and NGV come under very high temperature and pressure. Sustaining the mechanical properties at this elevated temperature needs special alloys. About tolerance,for example, the gap between the compressor and its shroud has to be 0.1mm for optimal efficiency. And the same goes for turbine and NGV.

The workshop is self built over the years, the way you have built from the scratch, as a part of the startup. Been into turbine for almost 7 years, initially big ones (TPP) and then shifted to model ones. I own a jetcat for like 3 years or more.

@KKIyer
There are many jet turbine prototypes in my closet worked upon over the last 4-5 years. All at different stages of development. I have been warming up a lot...

I have a running prototype TS 100 (10KG thrust) with 105mm dia. & 1.2kg weight. An upgrade to this size TS 120N is under development aimed at 120N thrust. The other one TS 80(80N) with a 91mm dia. is in early design stage.

The build I am sharing here is TS 60 with 80mm dia. is another one in the series aimed at creating something small with powerful thrust and reliable operation.

@tonystark,

I wonderered where you went after Nov 2016 

Yes,  .

meanwhile my caliper betrayed me and gave and 0.08mm error while machining the shaft. The compressor end was supposed to be 5.9. Caliper showed me 5.82. When i reached 5.82 and checked, damn, all in vain. There will be play in the mating component.

This is a scrap piece now. I will have to machine a new one from the beginning. It was such a beautiful piece coming out.