prototype RC turbofan, two-spool
#1
Thread Starter
Join Date: Sep 2002
Location: Nijmegen / Nederland
Posts: 628
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prototype RC turbofan, two-spool
Two-spool turbofan.
AgentJayZ also comments.
The fuel tank is 2.5liter (absinthe, grenadine??).
The designer/builder wrote that fuel consumption is high(er) because too much fuel was used to lubricate the bearings:
www.rc-network.de/forum/showthread.php/727090-Effizienteste-Turbine?p=4754549&viewfull=1#post4754549
Static thrust a little over 12kg, the core is KJ66 based (8kg):
translate...www.rc-network.de/forum/showthread.php/727090-Effizienteste-Turbine/p=4755001
Channel
www.youtube.com/channel/UCvdOgVvlsngJ9oTP4BVckfA
AgentJayZ also comments.
The fuel tank is 2.5liter (absinthe, grenadine??).
The designer/builder wrote that fuel consumption is high(er) because too much fuel was used to lubricate the bearings:
www.rc-network.de/forum/showthread.php/727090-Effizienteste-Turbine?p=4754549&viewfull=1#post4754549
Static thrust a little over 12kg, the core is KJ66 based (8kg):
translate...www.rc-network.de/forum/showthread.php/727090-Effizienteste-Turbine/p=4755001
Channel
www.youtube.com/channel/UCvdOgVvlsngJ9oTP4BVckfA
The following 4 users liked this post by ron_van_sommeren:
cetigershark (06-26-2021),
Desertlakesflying (06-26-2021),
DST-Engines (09-09-2023),
Viper1GJ (06-27-2021)
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DST-Engines (09-09-2023)
#3
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Vriendelijke groeten en wees voorzichtig, Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
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DST-Engines (09-09-2023)
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DST-Engines (09-19-2023)
#5
Strange that a 80 N turbine can produce 130 N running a fan. Considering the losses and running two turbine wheels and then some planetary gearbox or the like for the fan takeoff. Yet you are somehow able to almost double the original turbine core output.
I am assuming the TF-200 would have something to do with the inlet diameter, then if that is that case to get 130 N you would need around ~ 10K W of power to the fan just off the top of my head.
Pretty sure your going to get a lot less than that from a 66 core.
Regards,
I am assuming the TF-200 would have something to do with the inlet diameter, then if that is that case to get 130 N you would need around ~ 10K W of power to the fan just off the top of my head.
Pretty sure your going to get a lot less than that from a 66 core.
Regards,
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DST-Engines (09-09-2023)
#7
Actually as per the first rule you cannot get more out than actually went in initially. Yes the fan maybe be more efficient and the turbine use less fuel yet it would be difficult to get more thrust than you got in the first place. RC turbines are very inefficient due to the size, turbines do get more efficient as they get bigger. As per your comment you will have more thrust with less rpm, so your turbine output (KW) would be even lower than it was initially as igt is running a lower rpm.
So you for instance you have a shaft turbine that produces 10kw, then you have a generator connected to that. You could get 8~9KW or 80~90% efficiency back out, there are your losses. more parts, gears etc the losses increase.
So as above you would need at least 10+kw from the turbine in the first place to run a 200mm fan to get 150N, also you would have little residual thrust from the turbine as again it is all a closed loop.
It is also getting to the point whereas EDF's are getting to the point of mass power in a very efficient setup. Brushless motors at 90% running straight fans are putting out massive thrust, Vasyfan have a 570mm that is in the 150kg range which is amazing, 250mm fans running 55kg pretty awesome.
Regards,
So you for instance you have a shaft turbine that produces 10kw, then you have a generator connected to that. You could get 8~9KW or 80~90% efficiency back out, there are your losses. more parts, gears etc the losses increase.
So as above you would need at least 10+kw from the turbine in the first place to run a 200mm fan to get 150N, also you would have little residual thrust from the turbine as again it is all a closed loop.
It is also getting to the point whereas EDF's are getting to the point of mass power in a very efficient setup. Brushless motors at 90% running straight fans are putting out massive thrust, Vasyfan have a 570mm that is in the 150kg range which is amazing, 250mm fans running 55kg pretty awesome.
Regards,
Last edited by Halcyon66; 07-02-2021 at 02:30 PM.
#8
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Actually as per the first rule you cannot get more out than actually went in initially. Yes the fan maybe be more efficient and the turbine use less fuel yet it would be difficult to get more thrust than you got in the first place. RC turbines are very inefficient due to the size, turbines do get more efficient as they get bigger. As per your comment you will have more thrust with less rpm, so your turbine output (KW) would be even lower than it was initially as igt is running a lower rpm.
So you for instance you have a shaft turbine that produces 10kw, then you have a generator connected to that. You could get 8~9KW or 80~90% efficiency back out, there are your losses. more parts, gears etc the losses increase.
So as above you would need at least 10+kw from the turbine in the first place to run a 200mm fan to get 150N, also you would have little residual thrust from the turbine as again it is all a closed loop.
It is also getting to the point whereas EDF's are getting to the point of mass power in a very efficient setup. Brushless motors at 90% running straight fans are putting out massive thrust, Vasyfan have a 570mm that is in the 150kg range which is amazing, 250mm fans running 55kg pretty awesome.
Regards,
So you for instance you have a shaft turbine that produces 10kw, then you have a generator connected to that. You could get 8~9KW or 80~90% efficiency back out, there are your losses. more parts, gears etc the losses increase.
So as above you would need at least 10+kw from the turbine in the first place to run a 200mm fan to get 150N, also you would have little residual thrust from the turbine as again it is all a closed loop.
It is also getting to the point whereas EDF's are getting to the point of mass power in a very efficient setup. Brushless motors at 90% running straight fans are putting out massive thrust, Vasyfan have a 570mm that is in the 150kg range which is amazing, 250mm fans running 55kg pretty awesome.
Regards,
Turbine engine efficiency post combustion is all about recovering heat.
#9
Junior Member
Strange that a 80 N turbine can produce 130 N running a fan. Considering the losses and running two turbine wheels and then some planetary gearbox or the like for the fan takeoff. Yet you are somehow able to almost double the original turbine core output.
I am assuming the TF-200 would have something to do with the inlet diameter, then if that is that case to get 130 N you would need around ~ 10K W of power to the fan just off the top of my head.
Pretty sure your going to get a lot less than that from a 66 core.
Regards,
I am assuming the TF-200 would have something to do with the inlet diameter, then if that is that case to get 130 N you would need around ~ 10K W of power to the fan just off the top of my head.
Pretty sure your going to get a lot less than that from a 66 core.
Regards,
Think of it this way. Momentum is mass times velocity. Kinetic energy is 1/2 mass times velocity squared. So kinetic energy is 1/2 momentum times velocity. For the same momentum (the same thrust) your energy goes up in proportion to velocity. You are wasting more energy (and more fuel) just using a jet engine. Of course, there are trade-offs. The jet engine is simpler and cheaper and smaller for the same thrust. But it uses more fuel to produce the same amount of thrust.
This is why no modern full size aircraft relies on turbojets, because they're terribly inefficient compared to turbofans and produce much less thrust per unit of fuel.
The following users liked this post:
racedrvr (09-09-2023)
#10
My Feedback: (2)
Actually as per the first rule you cannot get more out than actually went in initially. Yes the fan maybe be more efficient and the turbine use less fuel yet it would be difficult to get more thrust than you got in the first place. RC turbines are very inefficient due to the size, turbines do get more efficient as they get bigger. As per your comment you will have more thrust with less rpm, so your turbine output (KW) would be even lower than it was initially as igt is running a lower rpm.
So you for instance you have a shaft turbine that produces 10kw, then you have a generator connected to that. You could get 8~9KW or 80~90% efficiency back out, there are your losses. more parts, gears etc the losses increase.
So as above you would need at least 10+kw from the turbine in the first place to run a 200mm fan to get 150N, also you would have little residual thrust from the turbine as again it is all a closed loop.
It is also getting to the point whereas EDF's are getting to the point of mass power in a very efficient setup. Brushless motors at 90% running straight fans are putting out massive thrust, Vasyfan have a 570mm that is in the 150kg range which is amazing, 250mm fans running 55kg pretty awesome.
Regards,
So you for instance you have a shaft turbine that produces 10kw, then you have a generator connected to that. You could get 8~9KW or 80~90% efficiency back out, there are your losses. more parts, gears etc the losses increase.
So as above you would need at least 10+kw from the turbine in the first place to run a 200mm fan to get 150N, also you would have little residual thrust from the turbine as again it is all a closed loop.
It is also getting to the point whereas EDF's are getting to the point of mass power in a very efficient setup. Brushless motors at 90% running straight fans are putting out massive thrust, Vasyfan have a 570mm that is in the 150kg range which is amazing, 250mm fans running 55kg pretty awesome.
Regards,
Last edited by highhorse; 07-03-2022 at 07:21 AM.
#11
My Feedback: (2)
Just a guess, but I think this will have primarily commercial applications (drones etc) vs any profitable market on the hobby end? The reason I say that is because the extra weight, diameter, complexity, cost etc are an excellent tradeoff in terms of fuel efficiency gains for longer flights where the monetary and weight savings become more significant? I hope that my guess is wrong though, because this concept is wayyyyy cool.
I just know that the A-10 fans must be dreaming of getting their hands on these motors!
I just know that the A-10 fans must be dreaming of getting their hands on these motors!
#13
Junior Member
Hello everyone, we have been working on a lager turbofan with thrust class 1 to 1.5kN for a few years now.
I recently uploaded a video, but I canīt post the YouTube link or any pictures.
I think it's because I'm still fairly new here.
Regards
Pascal
I recently uploaded a video, but I canīt post the YouTube link or any pictures.
I think it's because I'm still fairly new here.
Regards
Pascal
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DST-Engines (09-21-2023)