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GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 2:46 pm

Seems we know when the word's largest jet engine maker expects to release its next new jet enngine, in the mid 2030s.

NEWS: GE & Safran launch RISE (Revolutionary Innovation for Sustainable Engines) initiative to prepare for 20% lower engine emission tech ready for mid-2030s. Looking at 100% SAF and Hydrogen applications “including developing an open fan architecture.”

CFM JV extending to 2050.

The RISE name is a continuation of a naming convention that it started on the LEAP engine, which stands for Leading Edge Aviation Propulsion.

CFM putting its focus on open-rotor tech for SAF and H2, with an emphasis on aircraft intergration and improved passenger noise. First ground tests coming mid-decade.

Image
Ref: https://twitter.com/jonostrower/status/ ... 6064563201

We all know that open rotor means lower speed and more noise.

What we don't know is what the regulatory climate will be in the mid 30s especially with regard to emissions.

It seems this is CFM's way of telling us they know what they think it will be.
 
Northeast748
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 2:50 pm

Finally putting the UDF concept to better use, hopefully.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 2:56 pm

All I can say is... Go GE and Safran!
 
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BWIAirport
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 2:58 pm

What sort of performance implications would arise from adding an engine cowling around the propellers? Obviously there are a ton of open-prop aircraft flying every day but it seems like a cowling around the propellers would protect both the blades and any ground personnel around it
 
whiplash
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 2:59 pm

I love how it looks, though not very sure about the lower speeds and the noise.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:05 pm

BWIAirport wrote:
What sort of performance implications would arise from adding an engine cowling around the propellers? Obviously there are a ton of open-prop aircraft flying every day but it seems like a cowling around the propellers would protect both the blades and any ground personnel around it

The unducted fan blades limit cruise mach number. Just a little and a much faster cruise than today's turboprops.

I'm a fan of the GTF, so obviously I'm biased to a cowling. However being rational, one can design fan blades with enough blade out features to make for equivalent blade out safety.

Personel safety can be augmented by alarms and flashing lights.

It is a question of when the shroud benefits the mission and that is clearly on over 4 hour missions.

Lightsaber
 
Northeast748
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:15 pm

What is the general performance difference between rear “pusher” blades of the UDF36 vs. the apparent “puller” front ones of this engine?
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:17 pm

lightsaber wrote:
BWIAirport wrote:
What sort of performance implications would arise from adding an engine cowling around the propellers? Obviously there are a ton of open-prop aircraft flying every day but it seems like a cowling around the propellers would protect both the blades and any ground personnel around it

The unducted fan blades limit cruise mach number. Just a little and a much faster cruise than today's turboprops.

I'm a fan of the GTF, so obviously I'm biased to a cowling. However being rational, one can design fan blades with enough blade out features to make for equivalent blade out safety.

Personel safety can be augmented by alarms and flashing lights.

It is a question of when the shroud benefits the mission and that is clearly on over 4 hour missions.

Lightsaber

FG's article ( https://www.flightglobal.com/engines/cf ... 41.article ) agrees, speed is comparable to today's turbofans, design is simplified from previous efforts:

An open rotor architecture provides “huge propulsive efficiency” but which is able to “fly at the speed of today’s turbofans”, says Hegeman.

Fan diameter has been significantly reduced, to 144-156in (365-396cm) – in line with the external diameter of a current-generation single-aisle engine – enabling installation on a narrowbody-size aircraft.

In addition, the partners have chosen to “simplify” the overall architecture compared with previous open rotor engines, says Delphine Dijoud, executive manager, CFM RISE programme, systems engineering at Safran Aircraft Engines.

RISE features a single rotating fan, with variable pitch carbonfibre blades, behind which sits a row of static guide vanes. Safran’s earlier Sage2 demonstrator featured a contra-rotating second fan stage, but that required “complicated internal structures which were very heavy”, says Dijoud.

I think the elimination of contra-rotating is a big breakthrough. Less mass, less complexity, less opportunity for a rotating assembly to fail.

The picture in the thread starter shows the back row of blades are static guide vanes.
 
MIflyer12
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:30 pm

So, does this presage the timing for MAX and/or 320neo replacements?

Twenty years for a 20% improvement, and another 15-20 years to replace the prior-gen aircraft: this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:38 pm

MIflyer12 wrote:
So, does this presage the timing for MAX and/or 320neo replacements?

Twenty years for a 20% improvement, and another 15-20 years to replace the prior-gen aircraft: this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.

It sure does feel disruptive.

It suggests to me that assuming the post-2035 generation of airliners targeted at flights shorter than four hours or so is anything but an OR design with SAF and/or H2 as fuel is risky, as the biggest player is betting that this will be the way things go.

The FG article says these will need new airframes, trying to retrofit them on current airliners is a non-starter.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:45 pm

We see developments looking at piston engines up to around 2000HP, it makes sense that the turboprop/ open rotor then aims for the lower thrust turbofans.
 
mxaxai
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 3:55 pm

BWIAirport wrote:
What sort of performance implications would arise from adding an engine cowling around the propellers? Obviously there are a ton of open-prop aircraft flying every day but it seems like a cowling around the propellers would protect both the blades and any ground personnel around it

That's exactly what a regular turbofan is. The cowling adds cost, weight and drag.
 
Nnaeto87
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:02 pm

This is really cool and exciting from GE and Safran and would love to see this in operation some day.

Couple of questions from me:

1. How bad will the noise be? If it’s in-line with current engines like LEAP and GTF then that’s fine I think

2. With RISE (I like the way CFM name their engines) what stops Airbus and Boeing from yes building a clean sheet that’s just basically a composite 320/737. I.e. not putting that much effort into the frame and just harvesting the engine for the reduction. That’s what I expect.

3. Thé FG article says CFM say it has the flexibility to be upscaled to widebody use. Why is this good idea or why is it a bad idea?

Thanks!
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:04 pm

Revelation wrote:
We all know that open rotor means lower speed and more noise.

What we don't know is what the regulatory climate will be in the mid 30s especially with regard to emissions.

Well, ATR wouldn't be overly concerned about lower speed, especially if it would still be higher in cruise than their current offerings, given that target sectors would likely be under 3 hours.

Perhaps the elimination of counter rotation and substitution with the static guide vanes reduce external noise considerably...while engine rear-mounting helps with perceived cabin noise? The only major hurdle left is potential broken blade impact damage to the fuselage.


Revelation wrote:
The FG article says these will need new airframes, trying to retrofit them on current airliners is a non-starter.

I imagine the first iteration would be on a shorter version of this..... :airplane:

Image
https://leehamnews.com/wp-content/uploa ... roject.jpg
Last edited by Devilfish on Mon Jun 14, 2021 4:06 pm, edited 1 time in total.
 
planecane
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:04 pm

MIflyer12 wrote:
So, does this presage the timing for MAX and/or 320neo replacements?

Twenty years for a 20% improvement, and another 15-20 years to replace the prior-gen aircraft: this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.

That makes no sense at all. Adding a CO2 tax doesn't make anything carbon neutral. It may reduce the number of passenger miles flow and reduce overall CO2 emissions, but it doesn't neutralize anything.

Revelation wrote:
It sure does feel disruptive.

It suggests to me that assuming the post-2035 generation of airliners targeted at flights shorter than four hours or so is anything but an OR design with SAF and/or H2 as fuel is risky, as the biggest player is betting that this will be the way things go.

The FG article says these will need new airframes, trying to retrofit them on current airliners is a non-starter.


Targeting use of SAF is why there needs to be a leap in efficiency. SAF is very costly compared to fossil fuels.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:06 pm

Revelation wrote:
I think the elimination of contra-rotating is a big breakthrough. Less mass, less complexity, less opportunity for a rotating assembly to fail.

Also significantly less noise. Static guide vanes are still a source of noise but better than another rotating part.

Regarding SAF, note that SAF and fossile kerosene can be interchangable or mixed with each other. It's still a mix of hydrocarbons. Developing an engine for SAF is not a huge change compared to today.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:11 pm

Revelation wrote:
Seems we know when the word's largest jet engine maker expects to release its next new jet enngine, in the mid 2030s.

NEWS: GE & Safran launch RISE (Revolutionary Innovation for Sustainable Engines) initiative to prepare for 20% lower engine emission tech ready for mid-2030s. Looking at 100% SAF and Hydrogen applications “including developing an open fan architecture.”

CFM JV extending to 2050.

The RISE name is a continuation of a naming convention that it started on the LEAP engine, which stands for Leading Edge Aviation Propulsion.

CFM putting its focus on open-rotor tech for SAF and H2, with an emphasis on aircraft intergration and improved passenger noise. First ground tests coming mid-decade.

Image
Ref: https://twitter.com/jonostrower/status/ ... 6064563201

We all know that open rotor means lower speed and more noise.

What we don't know is what the regulatory climate will be in the mid 30s especially with regard to emissions.

It seems this is CFM's way of telling us they know what they think it will be.


"That plane has a propeller on it. It must be old and unsafe. I am not flying on it," says the general publuc. :duck:
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:27 pm

Even if you go to fully "green" fuels, it makes sense to improve efficiency as much as possible, because these green fuels will cost more money than current jet fuel, probably double current prices, even at large scale.
 
JayinKitsap
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:33 pm

The static guide vanes would allow for a shroud attached to them. I've always thought that having a shroud on the fan blades would be a nice concept but it would have lots of stress issues. Having a shroud or duct eliminates a lot of tip flow issues. I recall these issues increase radically the closer the tip velocity approaches Mach 1.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:54 pm

Revelation wrote:

I think the elimination of contra-rotating is a big breakthrough. Less mass, less complexity, less opportunity for a rotating assembly to fail.

The picture in the thread starter shows the back row of blades are static guide vanes.



It also leaves the door open for another engine manufacturer to compete with an engine using counter rotating blades which despite the gearbox complications, have superior propulsive efficiency.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 4:57 pm

This has more details about the "thrust" of the program.....

Image

https://www.geaviation.com/press-releas ... technology
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 5:08 pm

Aesma wrote:
Even if you go to fully "green" fuels, it makes sense to improve efficiency as much as possible, because these green fuels will cost more money than current jet fuel, probably double current prices, even at large scale.

It's also clever for the aviation industry to push the complicated issue of producing H2 and/or SAF at acceptable cost back onto the governments. They can say "we are ready to be green but the government is letting us down".

744SPX wrote:
Revelation wrote:
I think the elimination of contra-rotating is a big breakthrough. Less mass, less complexity, less opportunity for a rotating assembly to fail.

The picture in the thread starter shows the back row of blades are static guide vanes.

It also leaves the door open for another engine manufacturer to compete with an engine using counter rotating blades which despite the gearbox complications, have superior propulsive efficiency.

Could be, but CFM is saying in the FG article that whatever gain you get via better propulsive efficiency is not worth the pain of additional weight and noise, and presumably other issues such as manufacturing and maintenance cost.

Devilfish wrote:
This has more details about the "thrust" of the program.....

https://www.geaviation.com/press-releas ... technology

Seems they aren't holding back when it comes to building up expectations:

Technologies matured as part of the RISE Program will serve as the foundation for the next-generation CFM engine that could be available by the mid-2030s.
 
Noshow
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 5:19 pm

If engine programs get going aircraft programs get going as well. So this is good news for the industry and for engineering jobs that had been kept short for some years.
 
twaconnie
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 5:33 pm

Do you think Lockeed can bring back a new version of the Electra?
 
Noshow
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 5:43 pm

Lockheed could very well go back into the commercial business with blended wing bodies.
Not sure about UDF. However it might add a special touch to the Hercules and Orion.
Last edited by Noshow on Mon Jun 14, 2021 5:44 pm, edited 1 time in total.
 
kalvado
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 5:43 pm

744SPX wrote:
Revelation wrote:

I think the elimination of contra-rotating is a big breakthrough. Less mass, less complexity, less opportunity for a rotating assembly to fail.

The picture in the thread starter shows the back row of blades are static guide vanes.



It also leaves the door open for another engine manufacturer to compete with an engine using counter rotating blades which despite the gearbox complications, have superior propulsive efficiency.

This can certainly create several competing approaches. Someone would get burnt with their endeavor, someone else would win.
It may very well be that the ultimate engine would be something different from what is shown today. 2035 engine ready (2038 EIS, probably) means at least another decade before hard commitment to a certain design. Whatever is shown today may be a front-runner in development, or just the most fancy-looking option.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 5:45 pm

What does this roadmap mean for noise and for more sort of city center airports?
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 6:08 pm

I see the typical nonsense of listing hoped for efficiency of an engine 15 years in the future against one 20 years older and ignoring some pretty basic disadvantages.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 6:23 pm

Noshow wrote:
Not sure about UDF. However it might add a special touch to the Hercules and Orion.

Well...if they could mix puller/pusher configurations for wing and stab engines and build the TriStar airframe entirely out of composites with bleeding edge avionics, wing and wingtip designs -- they might be on to a winner..... :eyepopping:

Image
https://upload.wikimedia.org/wikipedia/ ... 009%29.jpg


Nomadd wrote:
I see the typical nonsense of listing hoped for efficiency of an engine 15 years in the future against one 20 years older and ignoring some pretty basic disadvantages.

Not totally nonsensical if it could get governments to pony up the money for further research and development. Of course, taxpayers may well raise their eyebrows :eyebrow: ...or a howl... :hissyfit:
Last edited by Devilfish on Mon Jun 14, 2021 6:39 pm, edited 1 time in total.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 6:23 pm

planecane wrote:
MIflyer12 wrote:
this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.

That makes no sense at all. Adding a CO2 tax doesn't make anything carbon neutral.

Thank you, because that makes ABSOLUTELY no sense from a technical standpoint...

...but this mentality is pervasive, and politicians love to take advantage of it; so I wouldn't be surprised if it (or something like it) comes to fruition.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 6:30 pm

Nice to finally see how this development looks. In recent years I read about the development of these large adjusting stators.

Goal is to get the swirl out of the rotor wake, which is of course a waste of energy.

The stators add weight & complexity, but way less than a counter rotating fan. And it enormously simplifies the engine pylon.

Of course this engine type prefers a high wing.
 
Nnaeto87
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 6:45 pm

Obviously this is also a clear answer to Boeing truss braced concept. If that’s where Boeing wants to place the narrow body replacement. This is obviously the engine that will power that?
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:00 pm

keesje wrote:
Of course this engine type prefers a high wing.

Such as a Transonic truss wing?
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:04 pm

keesje wrote:
Nice to finally see how this development looks. In recent years I read about the development of these large adjusting stators.

Goal is to get the swirl out of the rotor wake, which is of course a waste of energy.

The stators add weight & complexity, but way less than a counter rotating fan. And it enormously simplifies the engine pylon.

Of course this engine type prefers a high wing.

Just to be clear, current fans have vanes to deswirl the flow. Those do add drag without imparting energy.

Lightsaber
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:27 pm

lightsaber wrote:
keesje wrote:
Nice to finally see how this development looks. In recent years I read about the development of these large adjusting stators.

Goal is to get the swirl out of the rotor wake, which is of course a waste of energy.

The stators add weight & complexity, but way less than a counter rotating fan. And it enormously simplifies the engine pylon.

Of course this engine type prefers a high wing.

Just to be clear, current fans have vanes to deswirl the flow. Those do add drag without imparting energy.

Lightsaber


Indeed but not the unducted ones. I wonder about the drag factor also of this CFM design. But obviously new materials make them thinner, lighter and computer controlled, so adjustable every fraction of a second.

I assume (based on TP400) cruising speed will be M .8. Ages ago I did a high capacity, shorter range concept with Heny Lam.

Image
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:42 pm

keesje wrote:

I assume (based on TP400) cruising speed will be M .8. Ages ago I did a high capacity, shorter range concept with Heny Lam.

Image


M.8 is pretty good, what would be cruise altitude? Higher = less noisy to those on the ground
 
744SPX
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:45 pm

Nomadd wrote:
I see the typical nonsense of listing hoped for efficiency of an engine 15 years in the future against one 20 years older and ignoring some pretty basic disadvantages.



I wouldn't say hoped for by any stretch. In fact the numbers are low-balling if anything. NASA's ATP program along with the GE UDF and PW DX-578 proved that using nothing more than 1-for-1 current level turbine technology open rotor has a solid 15-20% advantage over a turbofan at speeds up to mach .9.

The only real disadvantage is having to choose between a more limited engine placement option and some extra required protection against blade out if using a traditional placement. But those factors cannot overcome the huge efficiency advantage of open rotor. The oft quoted speed disadvantage is all but nonexistent, especially for cruising speeds in the mach .85 range. Again, don't take my word for it. NASA demonstrated it and proved it.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:47 pm

I'm a bit underwhelmed at a 20% decrease in fuel burn and emissions not to be seen for another 15 years. I suspect a conventional turbofan will be able to show us that kind of continued improvement over the same time period. I think that GE/Safran are going to need to do a lot better than that if they are going to expect the OEMs to completely redesign their airframes around this new kind of engine.

JayinKitsap wrote:
The static guide vanes would allow for a shroud attached to them. I've always thought that having a shroud on the fan blades would be a nice concept but it would have lots of stress issues. Having a shroud or duct eliminates a lot of tip flow issues. I recall these issues increase radically the closer the tip velocity approaches Mach 1.


Congratulations! You have just designed...a turbofan.

744SPX wrote:
It also leaves the door open for another engine manufacturer to compete with an engine using counter rotating blades which despite the gearbox complications, have superior propulsive efficiency.


Perhaps, but if the last decade or so of commercial aviation has taught the industry anything, it's: "Don't bite off more than you can chew."
 
744SPX
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:49 pm

keesje wrote:
lightsaber wrote:
keesje wrote:
Nice to finally see how this development looks. In recent years I read about the development of these large adjusting stators.

Goal is to get the swirl out of the rotor wake, which is of course a waste of energy.

The stators add weight & complexity, but way less than a counter rotating fan. And it enormously simplifies the engine pylon.

Of course this engine type prefers a high wing.

Just to be clear, current fans have vanes to deswirl the flow. Those do add drag without imparting energy.

Lightsaber


Indeed but not the unducted ones. I wonder about the drag factor also of this CFM design. But obviously new materials make them thinner, lighter and computer controlled, so adjustable every fraction of a second.

I assume (based on TP400) cruising speed will be M .8. Ages ago I did a high capacity, shorter range concept with Heny Lam.

Image


The thing is, at even mach .8 it wouldn't need to be limited to short range. That's already faster than the 737 and A320 cruise speeds. Its a 1 for 1 replacement for both aircraft assuming similar seating.
 
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:51 pm

keesje wrote:
lightsaber wrote:
keesje wrote:
Nice to finally see how this development looks. In recent years I read about the development of these large adjusting stators.

Goal is to get the swirl out of the rotor wake, which is of course a waste of energy.

The stators add weight & complexity, but way less than a counter rotating fan. And it enormously simplifies the engine pylon.

Of course this engine type prefers a high wing.

Just to be clear, current fans have vanes to deswirl the flow. Those do add drag without imparting energy.

Lightsaber


Indeed but not the unducted ones. I wonder about the drag factor also of this CFM design. But obviously new materials make them thinner, lighter and computer controlled, so adjustable every fraction of a second.

I assume (based on TP400) cruising speed will be M .8. Ages ago I did a high capacity, shorter range concept with Heny Lam.

Image


I've got to say Keesje, I've enjoyed your work since I first saw it during the C-Series development. I may be new, but I've been on and off here as a spectator for quite a while.

What is there to keep Airbus to attach a UDF on a resigned A320 based airframe? Design a new wing, possibly elongate the landing gear for slightly more clearance, though I doubt that'd be needed. The SAAB 340 and 2000, as well as the Ilyushin Il-114, work well with a standard wing configuration and a decently low wing to the ground. Though I'm not an engineer. Is there a specific benefit to the shoulder mounting I'm missing?

Not that I mind it per se, but I think it would reinforce for ordinary passengers that the aircraft is "a dinky prop" if it looks like an ATR. A fine aircraft that I personally I love flying on, but from a public perspective that I gather is slightly more... negatively tinted... I think a low set wing would reinforce "same, but different"

Thinking about it... would the UDF impart the same blown surface benefit as an ordinary prop? Or would the airflow be negatively impacted by the peculiarities of the UDF?
 
JayinKitsap
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Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 7:59 pm

DocLightning wrote:
I'm a bit underwhelmed at a 20% decrease in fuel burn and emissions not to be seen for another 15 years. I suspect a conventional turbofan will be able to show us that kind of continued improvement over the same time period. I think that GE/Safran are going to need to do a lot better than that if they are going to expect the OEMs to completely redesign their airframes around this new kind of engine.

JayinKitsap wrote:
The static guide vanes would allow for a shroud attached to them. I've always thought that having a shroud on the fan blades would be a nice concept but it would have lots of stress issues. Having a shroud or duct eliminates a lot of tip flow issues. I recall these issues increase radically the closer the tip velocity approaches Mach 1.


Congratulations! You have just designed...a turbofan.


Yes, a turbofan if fixed as currently, I am envisioning a relatively thin shroud connected to the fixed vanes, or even better the rotating fan. Right now the case and nacelle are relatively thick. The thin shroud would be mostly a tension structure, too thin to take much bending. Right now a blade out case loads the shroud in bending to contain the blade, a thin element would work only in tension, it could contain the blade in a radial ejection but probably followed with all of the blades exiting rearward.
 
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JetBuddy
Posts: 2712
Joined: Wed Dec 25, 2013 1:04 am

Re: GE, Safran announce new airliner engine for the mid 2030s

Mon Jun 14, 2021 8:01 pm

This design seems less susceptible to bird ingestion. Presumably these blades can handle bird strikes like a regular turboprop. Unless the vanes are fragile?
 
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kitplane01
Posts: 2003
Joined: Thu Jun 16, 2016 5:58 am

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 2:00 am

Someone please help me with the blade-out requirements for open rotors.

I always assumed that open rotors would be certified as propellers, which do not require armor for the case of blade failure. But many posters assume they will be certified as turbo-fans, which do require such armor. Has the FAA or EASA spoken or written about which way they will certify open rotors?
 
CowAnon
Posts: 216
Joined: Fri Nov 03, 2017 12:03 am

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 3:48 am

kitplane01 wrote:
Someone please help me with the blade-out requirements for open rotors.

I always assumed that open rotors would be certified as propellers, which do not require armor for the case of blade failure. But many posters assume they will be certified as turbo-fans, which do require such armor. Has the FAA or EASA spoken or written about which way they will certify open rotors?


The source documents are hard to understand, but EASA has worked on that subject under rulemaking task RMT.0384(MDM.092). The rules don't appear to be finished, though.

https://www.easa.europa.eu/sites/default/files/dfu/ToR%20RMT.0384%20%28MDM.092%29%20Issue%203.pdf (9 pages - 2/20/2017)
https://www.easa.europa.eu/sites/default/files/dfu/NPA%202015-22.pdf (96 pages - 12/21/2015)

Leovinus wrote:
What is there to keep Airbus to attach a UDF on a resigned A320 based airframe? Design a new wing, possibly elongate the landing gear for slightly more clearance, though I doubt that'd be needed. The SAAB 340 and 2000, as well as the Ilyushin Il-114, work well with a standard wing configuration and a decently low wing to the ground. Though I'm not an engineer. Is there a specific benefit to the shoulder mounting I'm missing?

Not that I mind it per se, but I think it would reinforce for ordinary passengers that the aircraft is "a dinky prop" if it looks like an ATR. A fine aircraft that I personally I love flying on, but from a public perspective that I gather is slightly more... negatively tinted... I think a low set wing would reinforce "same, but different"

Thinking about it... would the UDF impart the same blown surface benefit as an ordinary prop? Or would the airflow be negatively impacted by the peculiarities of the UDF?


WRT re-engining an A320, I asked about turboprop wing-mounting issues in the Embraer New Turboprop Aircraft News and Discussion Thread. The helpful responses from mxaxai and LucaDiMontanari explain how there's more practical flexibility in where you mount the engine onto the wing (top/bottom/in between) for a turboprop/open rotor compared with a turbofan. So I don't think wing-mounting and ground clearance are the biggest issues with an A320 open rotor. I'm guessing the main problem might be aerodynamics; the airflow effects of a large open rotor on the wing might not be compatible with the existing empennage. So maybe the A320 would have to have major changes to the tail (like making it a T-tail), which might mean that an open rotor A320 couldn't be certified as a plain old derivative. (Updating the A320 wing to a top-mounted open rotor may break the grandfathering by itself, for that matter. I don't know - I gave up trying to follow the changes in the post-MAX regulatory landscape a long time ago.)

I think the open rotor does help with airflow above and below the wings. The variable pitch fans by themselves reduce the takeoff distances and short-range fuel consumption by large double-digit percentages.
 
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keesje
Posts: 14603
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Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 11:29 am

Leovinus wrote:
keesje wrote:
lightsaber wrote:
Just to be clear, current fans have vanes to deswirl the flow. Those do add drag without imparting energy.

Lightsaber


Indeed but not the unducted ones. I wonder about the drag factor also of this CFM design. But obviously new materials make them thinner, lighter and computer controlled, so adjustable every fraction of a second.

I assume (based on TP400) cruising speed will be M .8. Ages ago I did a high capacity, shorter range concept with Heny Lam.

Image


I've got to say Keesje, I've enjoyed your work since I first saw it during the C-Series development. I may be new, but I've been on and off here as a spectator for quite a while.

What is there to keep Airbus to attach a UDF on a resigned A320 based airframe? Design a new wing, possibly elongate the landing gear for slightly more clearance, though I doubt that'd be needed. The SAAB 340 and 2000, as well as the Ilyushin Il-114, work well with a standard wing configuration and a decently low wing to the ground. Though I'm not an engineer. Is there a specific benefit to the shoulder mounting I'm missing?

Not that I mind it per se, but I think it would reinforce for ordinary passengers that the aircraft is "a dinky prop" if it looks like an ATR. A fine aircraft that I personally I love flying on, but from a public perspective that I gather is slightly more... negatively tinted... I think a low set wing would reinforce "same, but different"

Thinking about it... would the UDF impart the same blown surface benefit as an ordinary prop? Or would the airflow be negatively impacted by the peculiarities of the UDF?


I think it would be complicated to place this engine concept on an existing lower wing design like the A320 or A220. Those wings are designed for higher speeds, attitudes and the loads from such engines, structurally as well as aerodynamically would change a lot. An entirely new wing would probably be required. No authority would let you get away with a changed product rule on a change like this.

Image
source: Leehamnews.com / CFM

In case of an emergency, when there is a belly landing or landing gear collapse, there are requirements for propellers hitting the ground and passenger safety. Those requirements seem easier to meet with the blades placed further away from the ground, on a higher place wing. A high speed, energy fan with heavy carbon/Ti blades RISE like engine, hitting the runway during e.g. take-off or thrust reverse, must be a certification challenge in that respect. In the drawing above (with a lot of CFM design disclaimers) you can see the lower wing has a seagull shape like the A380 and E2, to increase ground clearance for the fan.

Image
https://samchui.com/2020/07/07/kenyan-f ... MiMX6gzaUk

I think noise might be a lesser problem than on the older designs. The shock waves from counter rotation props hitting each other (e.g. NK-12) would be absent and also the sharp noise from turbulent airstream hitting the fan (Piaggio's) on pusher propellers won't be there. Those two (unacceptable) noise generators from the GE36 and Pratt & Whitney/Allison 578-DX unducted fans won't be there anymore.

Image
https://www.avgeekery.com/props-for-mcd ... -took-off/
 
avier
Posts: 1308
Joined: Tue Aug 07, 2018 12:38 pm

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 11:50 am

keesje wrote:
Leovinus wrote:
keesje wrote:

Indeed but not the unducted ones. I wonder about the drag factor also of this CFM design. But obviously new materials make them thinner, lighter and computer controlled, so adjustable every fraction of a second.

I assume (based on TP400) cruising speed will be M .8. Ages ago I did a high capacity, shorter range concept with Heny Lam.

Image


I've got to say Keesje, I've enjoyed your work since I first saw it during the C-Series development. I may be new, but I've been on and off here as a spectator for quite a while.

What is there to keep Airbus to attach a UDF on a resigned A320 based airframe? Design a new wing, possibly elongate the landing gear for slightly more clearance, though I doubt that'd be needed. The SAAB 340 and 2000, as well as the Ilyushin Il-114, work well with a standard wing configuration and a decently low wing to the ground. Though I'm not an engineer. Is there a specific benefit to the shoulder mounting I'm missing?

Not that I mind it per se, but I think it would reinforce for ordinary passengers that the aircraft is "a dinky prop" if it looks like an ATR. A fine aircraft that I personally I love flying on, but from a public perspective that I gather is slightly more... negatively tinted... I think a low set wing would reinforce "same, but different"

Thinking about it... would the UDF impart the same blown surface benefit as an ordinary prop? Or would the airflow be negatively impacted by the peculiarities of the UDF?


I think it would be complicated to place this engine concept on an existing lower wing design like the A320 or A220. Those wings are designed for higher speeds, attitudes and the loads from such engines, structurally as well as aerodynamically would change a lot. An entirely new wing would probably be required. No authority would let you get away with a changed product rule on a change like this.

Image
source: Leehamnews.com / CFM

In case of an emergency, when there is a belly landing or landing gear collapse, there are requirements for propellers hitting the ground and passenger safety. Those requirements seem easier to meet with the blades placed further away from the ground, on a higher place wing. A high speed, energy fan with heavy carbon/Ti blades RISE like engine, hitting the runway during e.g. take-off or thrust reverse, must be a certification challenge in that respect. In the drawing above (with a lot of CFM design disclaimers) you can see the lower wing has a seagull shape like the A380 and E2, to increase ground clearance for the fan.

Image
https://samchui.com/2020/07/07/kenyan-f ... MiMX6gzaUk

The first rendering, of engines mounted on a high wing, seem to be the most reasonable one. It's a lot like the ATR design. I realised so many of the future aircraft concepts seem to follow the ATR style design. Also, how ahead of their times they were, i.e the ATR, considering they are an 1980's product.
Regarding the third rendering, with rear mounted engines, how would they balance the CG if these engines turn out to be too big and heavy?
 
airbazar
Posts: 10465
Joined: Wed Sep 10, 2003 11:12 pm

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 12:19 pm

LAX772LR wrote:
planecane wrote:
MIflyer12 wrote:
this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.

That makes no sense at all. Adding a CO2 tax doesn't make anything carbon neutral.

Thank you, because that makes ABSOLUTELY no sense from a technical standpoint...

...but this mentality is pervasive, and politicians love to take advantage of it; so I wouldn't be surprised if it (or something like it) comes to fruition.


By making the current technology expensive to operate it pushes manufacturers to work harder on finding a solution. That's what happened in the automotive industry.
Whether people like it or not CO2 emissions will dictate what new airplanes will look like.
 
planecane
Posts: 1724
Joined: Thu Feb 09, 2017 4:58 pm

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 12:27 pm

airbazar wrote:
LAX772LR wrote:
planecane wrote:
That makes no sense at all. Adding a CO2 tax doesn't make anything carbon neutral.

Thank you, because that makes ABSOLUTELY no sense from a technical standpoint...

...but this mentality is pervasive, and politicians love to take advantage of it; so I wouldn't be surprised if it (or something like it) comes to fruition.


By making the current technology expensive to operate it pushes manufacturers to work harder on finding a solution. That's what happened in the automotive industry.
Whether people like it or not CO2 emissions will dictate what new airplanes will look like.

No, that's not what happened in the automotive industry. In the US, government subsidies of electric vehicles allowed production volume to get battery costs down. If you drive enough per year and charge at home, an electric vehicle can cost less than non-carbon taxed gasoline today.

In some places, internal combustion engines are being outright banned by governments. This forces consumers to purchase electric vehicles and, again, has nothing to do with carbon taxes.

In aviation, there has been a continuous push to get more and more efficiency out of engines and airframes and it will happen without carbon taxes. The taxes do nothing more than pricing out lower income people and adding a "luxury tax" to people who fly. The taxes don't serve the goal of making aviation more efficient as that continues to happen regardless.

The UDF research has been going on for 40 years in search of a leap in engine efficiency.
 
LCDFlight
Posts: 1250
Joined: Wed Jan 01, 2020 9:22 pm

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 12:36 pm

planecane wrote:
MIflyer12 wrote:
So, does this presage the timing for MAX and/or 320neo replacements?

Twenty years for a 20% improvement, and another 15-20 years to replace the prior-gen aircraft: this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.

That makes no sense at all. Adding a CO2 tax doesn't make anything carbon neutral. It may reduce the number of passenger miles flow and reduce overall CO2 emissions, but it doesn't neutralize anything.

Revelation wrote:
It sure does feel disruptive.

It suggests to me that assuming the post-2035 generation of airliners targeted at flights shorter than four hours or so is anything but an OR design with SAF and/or H2 as fuel is risky, as the biggest player is betting that this will be the way things go.

The FG article says these will need new airframes, trying to retrofit them on current airliners is a non-starter.


Targeting use of SAF is why there needs to be a leap in efficiency. SAF is very costly compared to fossil fuels.


Co2 tax changes the decisions made within the brain of the leaders of the airline financial analysis team. A Co2 tax can reduce Co2 emission by 40% easily, and this is without any new technology being invented. It can take effect within 1 year. We are just going slow and inventing technology to make it easier for industry and more profitable. But the reductions are very easy. Actually humanity already achieved huge Co2 reductions thousands of years ago. We have the technology.
 
planecane
Posts: 1724
Joined: Thu Feb 09, 2017 4:58 pm

Re: GE, Safran announce new airliner engine for the mid 2030s

Tue Jun 15, 2021 12:58 pm

LCDFlight wrote:
planecane wrote:
MIflyer12 wrote:
So, does this presage the timing for MAX and/or 320neo replacements?

Twenty years for a 20% improvement, and another 15-20 years to replace the prior-gen aircraft: this is why we're going to need a CO2 surcharge on fuel and/or tickets to get to carbon-neutral by 2050.

That makes no sense at all. Adding a CO2 tax doesn't make anything carbon neutral. It may reduce the number of passenger miles flow and reduce overall CO2 emissions, but it doesn't neutralize anything.

Revelation wrote:
It sure does feel disruptive.

It suggests to me that assuming the post-2035 generation of airliners targeted at flights shorter than four hours or so is anything but an OR design with SAF and/or H2 as fuel is risky, as the biggest player is betting that this will be the way things go.

The FG article says these will need new airframes, trying to retrofit them on current airliners is a non-starter.


Targeting use of SAF is why there needs to be a leap in efficiency. SAF is very costly compared to fossil fuels.


Co2 tax changes the decisions made within the brain of the leaders of the airline financial analysis team. A Co2 tax can reduce Co2 emission by 40% easily, and this is without any new technology being invented. It can take effect within 1 year. We are just going slow and inventing technology to make it easier for industry and more profitable. But the reductions are very easy. Actually humanity already achieved huge Co2 reductions thousands of years ago. We have the technology.

Please enlighten me on what technology currently exists that can reduce aviation industry CO2 emissions by 40% "easily" without reducing passenger miles flown.

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