Axial-Flow Turbojet
..Very nice work..my buddy NUNU is also doing a similar project. Could there be a problem with high CP to a single turbine wheel?
02-11-2014, 07:39 AM
#27
Junior Member
Thread Starter
Join Date: Oct 2013
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
Many Thanks!
The Diameter of my Engine is 100mm, but i dont know the Diameter of a 200N radial Engine...maybe 150mm?!
Yes, i think so. But the aerodynamic load of the Blades will be much higher, thus the risk of a complete Compressor Stall or even Rotating Stall.
The Diameter of my Engine is 100mm, but i dont know the Diameter of a 200N radial Engine...maybe 150mm?!
can this be done in 3 stages rather than 6 to reduce rotating mass?
02-11-2014, 07:46 AM
#28
Junior Member
Thread Starter
Join Date: Oct 2013
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
Could there be a problem with high CP to a single turbine wheel?
Otherwise, the fuel consumtion will rise or the Engine will not work.
02-16-2014, 01:32 AM
#32
Senior Member
Join Date: Jan 2002
Location: Southport, UNITED KINGDOM
Posts: 1,718
Likes: 0
Received 0 Likes
on
0 Posts
Fantastic work, well done, it's worth watching just to hear the axial compressor sound. It was not that long ago when self sustaining a homebuilt engine with a radial compressor was a major achievement.
Keep up the great work.
Rob.
Keep up the great work.
Rob.
02-16-2014, 02:54 PM
#34
Junior Member
Thread Starter
Join Date: Oct 2013
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
Close? To self sustaining? Believe me, the Engine really works!
http://www.youtube.com/watch?v=s8Oya2lLGLk
Yes, the development goes on..
But i don`t think, that an axial Microjet can be used to Power a Modelaircraft. Because there is a really big Problem: The axial Compressor is extemly sensitiv against Dust and Sand.
Even if you could filter out the "Sand Problem", the Dust would also cause Problems. The Oil of the forward Bearing gets atomized and flows through the Compressor and it will lay down together
with the Dust on the upper Side of the Stators... With the Time, the Layer grows, causing an inefficient Airflow... You will have to wash the Compressor regularly or borescope it.
No Modeljetpilot wants to do this! They want a Plug&Fly System without any Problems and the radial Compressor is a better Choice.
http://www.youtube.com/watch?v=s8Oya2lLGLk
It was not that long ago when self sustaining a homebuilt engine with a radial compressor was a major achievement.
But i don`t think, that an axial Microjet can be used to Power a Modelaircraft. Because there is a really big Problem: The axial Compressor is extemly sensitiv against Dust and Sand.
Even if you could filter out the "Sand Problem", the Dust would also cause Problems. The Oil of the forward Bearing gets atomized and flows through the Compressor and it will lay down together
with the Dust on the upper Side of the Stators... With the Time, the Layer grows, causing an inefficient Airflow... You will have to wash the Compressor regularly or borescope it.
No Modeljetpilot wants to do this! They want a Plug&Fly System without any Problems and the radial Compressor is a better Choice.
02-17-2014, 04:13 AM
#37
Senior Member
Join Date: Jan 2002
Location: Southport, UNITED KINGDOM
Posts: 1,718
Likes: 0
Received 0 Likes
on
0 Posts
Yes, the development goes on..
But i don`t think, that an axial Microjet can be used to Power a Modelaircraft. Because there is a really big Problem: The axial Compressor is extemly sensitiv against Dust and Sand.
Even if you could filter out the "Sand Problem", the Dust would also cause Problems. The Oil of the forward Bearing gets atomized and flows through the Compressor and it will lay down together
with the Dust on the upper Side of the Stators... With the Time, the Layer grows, causing an inefficient Airflow... You will have to wash the Compressor regularly or borescope it.
No Modeljetpilot wants to do this! They want a Plug&Fly System without any Problems and the radial Compressor is a better Choice.
But i don`t think, that an axial Microjet can be used to Power a Modelaircraft. Because there is a really big Problem: The axial Compressor is extemly sensitiv against Dust and Sand.
Even if you could filter out the "Sand Problem", the Dust would also cause Problems. The Oil of the forward Bearing gets atomized and flows through the Compressor and it will lay down together
with the Dust on the upper Side of the Stators... With the Time, the Layer grows, causing an inefficient Airflow... You will have to wash the Compressor regularly or borescope it.
No Modeljetpilot wants to do this! They want a Plug&Fly System without any Problems and the radial Compressor is a better Choice.
Regards
Rob.
02-17-2014, 12:52 PM
#38
Junior Member
Thread Starter
Join Date: Oct 2013
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
Thank you!
Yes, the next Step is a Test Stand with a lot of Sensors. I will show you the Instrumentation in a few days, its not finished yet.
(But be aware, its in german Language
)
The major achievement will be the variable Stator Vanes and to control them live!
More News soon!
Yes, the next Step is a Test Stand with a lot of Sensors. I will show you the Instrumentation in a few days, its not finished yet.
(But be aware, its in german Language
) The major achievement will be the variable Stator Vanes and to control them live!
More News soon!
02-17-2014, 02:14 PM
#39
Junior Member
Join Date: Dec 2013
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
This is very impressive, especially with the variable stator vanes , do they seal perfectly? Is there any leakage ? And what are the tolerances inside the engine referring to blade tip gap ?
Best regards
Juraj
Best regards
Juraj
02-17-2014, 03:08 PM
#40
Senior Member
Join Date: Jan 2002
Location: Southport, UNITED KINGDOM
Posts: 1,718
Likes: 0
Received 0 Likes
on
0 Posts
Thank you!
Yes, the next Step is a Test Stand with a lot of Sensors. I will show you the Instrumentation in a few days, its not finished yet.
(But be aware, its in german Language )
The major achievement will be the variable Stator Vanes and to control them live!
More News soon!
Yes, the next Step is a Test Stand with a lot of Sensors. I will show you the Instrumentation in a few days, its not finished yet.
(But be aware, its in german Language
) The major achievement will be the variable Stator Vanes and to control them live!
More News soon!
Rob.
02-18-2014, 05:14 PM
#41
Junior Member
Join Date: Dec 2013
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
one thing i noticed about the blades is they don't have the proper twist from root to tip , they are flat therefore this compressor is creating far more pressure at the case therefore much easier to stall the compressor because if the uneven compression.
That is the one thing i would definitely change.
Just my opinion.
That is the one thing i would definitely change.
Just my opinion.
02-19-2014, 01:50 AM
#42
Join Date: Jul 2006
Location: Norfolk , UNITED KINGDOM
Posts: 1,409
Likes: 0
Received 0 Likes
on
0 Posts
one thing i noticed about the blades is they don't have the proper twist from root to tip , they are flat therefore this compressor is creating far more pressure at the case therefore much easier to stall the compressor because if the uneven compression.
That is the one thing i would definitely change.
Just my opinion.
That is the one thing i would definitely change.
Just my opinion.
http://naca.central.cranfield.ac.uk/...rc/rm/2928.pdf
For model design like this the goal is to get the engine to run at all not to worry about small differences in efficiency. Having said that I cannot see the axial stages clearly enough to determine what their shape is.
This is a great engineering project and niffi should be congratulated in completing the design and machining and getting so close to what looks like a running engine. This has been a goal of many model engineers and I know of several projects that either were never completed or failed to self sustain. At least this engine has a chance of working with the help from Alfred Kittleberger in the design of the combustion chamber. I just hope that no more attempt are made to run on gas and that the proper engine mounts are attached rather than gripping it in a vice. I would be a shame to have it slip out and crash to the floor! I look forward to seeing more when the engine is ready to run on Kero.
John
02-19-2014, 05:52 AM
#43
My Feedback: (112)
Join Date: Jan 2002
Location: VICTORVILLE,
CA
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
In early axial turbine design the compressor stages often had similar or the same angles for several stages, and indeed had identical profiles rather than the theoretical best. The difference in compression between stages was adjusted by cropping the blades so they became shorter with pressure rise. They usually had strip blading with no twist. An early program of the UK National Gas Turbine Establishment in 1953 compared the results of untwisted blades with twisted ones. This study was coincidentally for a 6 stage compressor.
http://naca.central.cranfield.ac.uk/...rc/rm/2928.pdf
For model design like this the goal is to get the engine to run at all not to worry about small differences in efficiency. Having said that I cannot see the axial stages clearly enough to determine what their shape is.
This is a great engineering project and niffi should be congratulated in completing the design and machining and getting so close to what looks like a running engine. This has been a goal of many model engineers and I know of several projects that either were never completed or failed to self sustain. At least this engine has a chance of working with the help from Alfred Kittleberger in the design of the combustion chamber. I just hope that no more attempt are made to run on gas and that the proper engine mounts are attached rather than gripping it in a vice. I would be a shame to have it slip out and crash to the floor! I look forward to seeing more when the engine is ready to run on Kero.
John
http://naca.central.cranfield.ac.uk/...rc/rm/2928.pdf
For model design like this the goal is to get the engine to run at all not to worry about small differences in efficiency. Having said that I cannot see the axial stages clearly enough to determine what their shape is.
This is a great engineering project and niffi should be congratulated in completing the design and machining and getting so close to what looks like a running engine. This has been a goal of many model engineers and I know of several projects that either were never completed or failed to self sustain. At least this engine has a chance of working with the help from Alfred Kittleberger in the design of the combustion chamber. I just hope that no more attempt are made to run on gas and that the proper engine mounts are attached rather than gripping it in a vice. I would be a shame to have it slip out and crash to the floor! I look forward to seeing more when the engine is ready to run on Kero.
John
02-20-2014, 12:44 AM
#45
Junior Member
Thread Starter
Join Date: Oct 2013
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
First of all, many thanks for the nice words!
No, that is not correct. All six Stages have twisted Blades and i am convinced, that it is quite important. As you already said, you need every
percentage of efficiency.
The Picture shows some Compressor Blades which are not used because they are faulty at some point. But you see the Twist of
the Blades:
Mmh, i donīt know if i have misunderstood you, but the reason for cropping the blades is to maintain a constant dynamic Pressure (Air Speed and thereby Angle of Attack)
throughout the Compressor while the static Pressure rises.
The Test Stand is currently in Production togehter with the electronics and no, there will be no more Testruns in the old Vice...
More Videos and News soon!
one thing i noticed about the blades is they don't have the proper twist from root to tip
No, that is not correct. All six Stages have twisted Blades and i am convinced, that it is quite important. As you already said, you need every
percentage of efficiency.
The Picture shows some Compressor Blades which are not used because they are faulty at some point. But you see the Twist of
the Blades:
The difference in compression between stages was adjusted by cropping the blades so they became shorter with pressure rise.
throughout the Compressor while the static Pressure rises.
The Test Stand is currently in Production togehter with the electronics and no, there will be no more Testruns in the old Vice...
More Videos and News soon!
Last edited by niffi; 02-20-2014 at 12:46 AM.
02-20-2014, 01:18 AM
#46
Join Date: Jul 2006
Location: Norfolk , UNITED KINGDOM
Posts: 1,409
Likes: 0
Received 0 Likes
on
0 Posts
Niffi
Many thanks for posting the extra photos of the compressor blades, superb machining job. The more you post the more I am amazed at the effort you have put into this project. I look forward to seeing more test runs.
John
Many thanks for posting the extra photos of the compressor blades, superb machining job. The more you post the more I am amazed at the effort you have put into this project. I look forward to seeing more test runs.
John
02-20-2014, 03:27 PM
#48
Junior Member
Thread Starter
Join Date: Oct 2013
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
The E-Starter is finished now. The Motor is way to small for the Engine, but it has to fit into the Nosecone... So there is a temperature Sensor fitted onto the Motor
and it gives out a Warning at 70°Celsius. The Engine is ignited at around 3.000 RPM to support the Starter and idle Speed is reached at 17.000 RPM
(Yes, thats another big difference to radial Compressors, they need much higher RPM)
The Starter is equipped with an inertia coupling, so it uncouples automatically. A short Vdeo:
http://www.youtube.com/watch?v=y6HqY...ature=youtu.be
and it gives out a Warning at 70°Celsius. The Engine is ignited at around 3.000 RPM to support the Starter and idle Speed is reached at 17.000 RPM
(Yes, thats another big difference to radial Compressors, they need much higher RPM)
The Starter is equipped with an inertia coupling, so it uncouples automatically. A short Vdeo:
http://www.youtube.com/watch?v=y6HqY...ature=youtu.be
02-20-2014, 06:08 PM
#49
The E-Starter is finished now. The Motor is way to small for the Engine, but it has to fit into the Nosecone... So there is a temperature Sensor fitted onto the Motor
and it gives out a Warning at 70°Celsius. The Engine is ignited at around 3.000 RPM to support the Starter and idle Speed is reached at 17.000 RPM
(Yes, thats another big difference to radial Compressors, they need much higher RPM)
The Starter is equipped with an inertia coupling, so it uncouples automatically. A short Vdeo:
http://www.youtube.com/watch?v=y6HqY...ature=youtu.be
and it gives out a Warning at 70°Celsius. The Engine is ignited at around 3.000 RPM to support the Starter and idle Speed is reached at 17.000 RPM
(Yes, thats another big difference to radial Compressors, they need much higher RPM)
The Starter is equipped with an inertia coupling, so it uncouples automatically. A short Vdeo:
http://www.youtube.com/watch?v=y6HqY...ature=youtu.be