Discussion on the best fuel type.

[Bhuvan Aerospace]

Yes I have researched for a moth. I got the design I think that axial compressors are far more efficient than radial ones and they are very accurate. Its pretty simple.

[jetric]

This is getting tedious now! How do you expect to be able to make a axial compressor when you can't even afford a £25 membership fee!
First you started off with wanting to make a jet engine to power a supersonic drone, then said jet engine was going to be made out of a tiny turbocharger, then we have now seen said turbocharger that is a totally cobbled together bodge with no oil system? Now you've got no money to do anything and can not even get hold of any simple materials and now you want to make a multi stage axial compressor that will cost 1000s to make and to date there has only been two model jet engines ever made using an axial comp successfully.
John has given you multiple answers and advice to your questions that you have taken no notice off. Stop wasting people's time and effort and just wait until you are older and have sufficient funds and knowledge and parts to complete a simple turbocharger jet engine then go from there.

Nov 18, 2024 3:36:42 GMT -5 Bhuvan Aerospace said:

Yes I have researched for a moth. I got the design I think that axial compressors are far more efficient than radial ones and they are very accurate. Its pretty simple.

[enginewhisperer]

realistically you have zero chance of building an axial compressor based turbine engine.

Most smaller commercial engines use radial compressors because it is too hard to make an efficient axial compressor at that scale, and the cost is extreme.


By using turbocharger turbines and compressor wheels you benefit from a massive high volume industry and many millions of dollars of research paid for by automotive manufacturers.

The best technology and design methodology available in the size range you're talking is what's used in RC aircraft turbine engines.
You can build something with lower cost and performance using turbocharger parts and / or "kit" turbine and NGV castings, but it's still expensive and you need high precision tools.


Either way, I wouldn't be heading down the path of any custom turbine engine until you can get a basic turbocharger based unit working.

If you pay for GTBA membership you'll get more information than anyone here can tell you, and it'll be well worth the cost even if (especially if?) all it does is convince you not to build an axial engine.

[enginewhisperer]

BTW - there are plenty of things you can do for free that will be a massive help in getting your turbo based engine working.

1. Listen to the advice of people here, especially John!
2. Post clear detailed photos of your setup from different angles
3. Post videos of your startup attempts

[richardm]

I can only agree with the last 3 postings.

[Bhuvan Aerospace]

Nov 18, 2024 4:58:09 GMT -5 jetric said:

This is getting tedious now! How do you expect to be able to make an axial compressor when you can't even afford a £25 membership fee!
First you started off with wanting to make a jet engine to power a supersonic drone, then said jet engine was going to be made out of a tiny turbocharger, then we have now seen said turbocharger that is a totally cobbled together bodge with no oil system? Now you've got no money to do anything and can not even get hold of any simple materials and now you want to make a multi stage axial compressor that will cost 1000s to make and to date there has only been two model jet engines ever made using an axial comp successfully.
John has given you multiple answers and advice to your questions that you have taken no notice off. Stop wasting people's time and effort and just wait until you are older and have sufficient funds and knowledge and parts to complete a simple turbocharger jet engine then go from there.

Nov 18, 2024 3:36:42 GMT -5 Bhuvan Aerospace said:

Yes I have researched for a moth. I got the design I think that axial compressors are far more efficient than radial ones and they are very accurate. Its pretty simple.

Are you challenging me in making axial jet engine?
Currently my budget is £2000. And I accept the challenge.

[Bhuvan Aerospace]

Nov 18, 2024 5:14:01 GMT -5 enginewhisperer said:

BTW - there are plenty of things you can do for free that will be a massive help in getting your turbo based engine working.

1. Listen to the advice of people here, especially John!
2. Post clear detailed photos of your setup from different angles
3. Post videos of your startup attempts

I am sending.

[Bhuvan Aerospace]

Mainly I can't join GTBA cuz my parents haven't allowed me to join GTBA as I have my upcoming Class 10 boards exam. After March I will join.

[Bhuvan Aerospace]

I really thank John sir and Engine Whisperer for assisting me in making the engine and clarifying my doubts. But I have lost my hope on the tiny engine as it has extremely low efficiency as told by John Sir. BTW, my axial jet engine will be India's first 2kN afterburning micro axial jet engine. The calculation for the prototype/test version has been completed. After March I will continue work on it.

[Bhuvan Aerospace]

Currently I am trying my best to improve the tiny one and do errorless calculations for the upcoming jet engine!!

[racket]

have a look at these


youtu.be/ILN2-X-Gri8?si=SDQe5Kel4MhGBHwg

youtu.be/MObF8W2ZU1g?si=ip6qGhxQ08xkrBrC

[Bhuvan Aerospace]

Yes sir, I saw the videos. Thank you sir as they were very informative. The second video had a jet engine with centrifugal compressor powering a turbofan compressor to 3500 rpm. Good Idea.

[racket]

A 2kN engine is pretty large , and expensive , sourcing components will be rather difficult .

What mass flow of air are you designing for ??

[Bhuvan Aerospace]

3.5kg/s mass air flow with a 120mm turbofan stage. 2kn thrust is with afterburners.

[racket]

I think you might need to check your " numbers" , getting 3.5 kgs - 7.7 lbs/sec through a 120 mm "hole" at the front will be a challenge.

120mm hole = 17.53 sq ins , 0.1217 sq ft , 7.7 lbs of air = ~100 cubic feet , 100/0.1217 = 826 ft/sec , but we need to account for the fan hub area , so the velocity will be even higher , then we run into another problem because to accelerate the air to that velocity we need to convert some/a lot, of the ambient total pressure into dynamic pressure leaving little static pressure , this then increases the volume of that 7.7 lbs/sec with the result you'll need supersonic flow through the fan .........this will be awkward to achieve :-(

Its difficult to get much more than ~12 lbs/min/sq in through an ordinary radial comp inducer , 12x17.53= 210 , 210/60 = 3.5 lbs/sec , the high flowing latest Garrett comps might get 25% more , but thats still only 4.375 lbs/sec.

If you look at the numbers for my engine , its flowing ~4 lbs- 1.82 kgs /sec through a 127 mm comp inducer , and even with afterburn its only producing ~1.6kN .