Rolls will start testing its Ultrafan demonstrator. It features a gearbox "working with two carbon composite fan systems"

I wonder what that means. One with variable fan blade angles? https://youtu.be/zW66-EFvj64?t=60

Article: https://travelandaviation.com/rolls-roy ... t-in-2022/

Very interesting but does it tell us anything new?

I like the idea of ‘Special High intensity technology’ though….

Fred


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keesje wrote:

One with variable fan blade angles? https://youtu.be/zW66-EFvj64?t=60

Article: https://travelandaviation.com/rolls-roy ... t-in-2022/

I've been following the Ultrafan since its inception, and it seems that the variable fan blades were dropped from all renderings, marketing materials, etc. a few years ago (and doesn't show up in the linked article or video).

If someone could correct me on that, that'd be amazing.

rjsampson wrote:

keesje wrote:

One with variable fan blade angles? https://youtu.be/zW66-EFvj64?t=60

Article: https://travelandaviation.com/rolls-roy ... t-in-2022/

I've been following the Ultrafan since its inception, and it seems that the variable fan blades were dropped from all renderings, marketing materials, etc. a few years ago (and doesn't show up in the linked article or video).

If someone could correct me on that, that'd be amazing.

You are correct it is no longer metionef recently. It won't be on the big demonstrator. Recently it popped up (don't remember where) so I starting doubting if it was back. Apparently RR feel the new gearbox, fan, core is enough for now.

Still wondering what "two carbon composite fan systems" means though.

There are some performance and design considerations (slip off the tonque) in this 1 hr RAES Ultrafan video with an chief engineer. https://youtu.be/sRAt8mn3HyY .

Apparently RR is closely working with Airbus on the Ultrafan. This engine could be fit under an A350 efficiently because the smaller sized LP turbine makes installation possible. The A350 wing and longitudinal stability (rudder) can handle the bigger heavier engine, which should be ~ 10% better sfc than the Trend XWB.

rjsampson wrote:

I've been following the Ultrafan since its inception, and it seems that the variable fan blades were dropped from all renderings, marketing materials, etc. a few years ago (and doesn't show up in the linked article or video).

If someone could correct me on that, that'd be amazing.

I receive some material from RR on this, they are still looking at variable pitch fan, variable area nozzle. They also have two different Ultrafans, Ultrafan refers to the the traditional engine start and accessory gearbox, they have another version called the “more electric Ultrafan” which has a somewhat unique power takeoff and engine start.

There is a range of technology they are trying, I would suggest it will be baby steps into a commercial engine, I think the gearbox and new fan with the new core will be the next level of development.

Personally I think they may offer the core alone to existing T1000, T7000, and TXWB and also a NEO option for new builds. This would provide the maximum return for the R&D in my view.

keesje wrote:

Rolls will start testing its Ultrafan demonstrator. It features a gearbox "working with two carbon composite fan systems"

I wonder what that means. One with variable fan blade angles? https://youtu.be/zW66-EFvj64?t=60

Article: https://travelandaviation.com/rolls-roy ... t-in-2022/

Perhaps it means one carbon-titanium blue-colored fan as Rolls has been advertising, and one that's all CFRP?

Or maybe RR is working on a contra-rotating fan system? While the gearbox already decouples fan speed from turbine speed, it alone does nothing to help with larger fan sizes and the resulting issues with ground clearance. Contra-rotating fans would have about a 30% smaller diameter than the equivalent single fan, so or 140-inch single fan could be replaced with a ~100-inch contra-rotating set of fans. Or 140-inch contra-rotating fans would be equivalent to a ~200-inch single fan.

keesje wrote:

rjsampson wrote:

keesje wrote:

One with variable fan blade angles? https://youtu.be/zW66-EFvj64?t=60

Article: https://travelandaviation.com/rolls-roy ... t-in-2022/

I've been following the Ultrafan since its inception, and it seems that the variable fan blades were dropped from all renderings, marketing materials, etc. a few years ago (and doesn't show up in the linked article or video).

If someone could correct me on that, that'd be amazing.

You are correct it is no longer metionef recently. It won't be on the big demonstrator. Recently it popped up (don't remember where) so I starting doubting if it was back. Apparently RR feel the new gearbox, fan, core is enough for now.

Still wondering what "two carbon composite fan systems" means though.

There are some performance and design considerations (slip off the tonque) in this 1 hr RAES Ultrafan video with an chief engineer. https://youtu.be/sRAt8mn3HyY .

Apparently RR is closely working with Airbus on the Ultrafan. This engine could be fit under an A350 efficiently because the smaller sized LP turbine makes installation possible. The A350 wing and longitudinal stability (rudder) can handle the bigger heavier engine, which should be ~ 10% better sfc than the Trend XWB.

What I hear him saying the aim is 10% fuel saving at the aircraft level. As the engine will be heavier and there will be more parasitic drag from the bigger nacelles, the SFC gain would have to be larger than 10% to get to the 10% at the aircraft level unless you take into account you have to fly less fuel to burn fuel. So depends if what is meant is per flight op per unit of time, I suspect the latter:

https://youtu.be/sRAt8mn3HyY?t=3562

Taxi645 wrote:

As the engine will be heavier and there will be more parasitic drag from the bigger nacelles, the SFC gain would have to be larger than 10% to get to the 10% at the aircraft level unless you take into account you have to fly less fuel to burn fuel.

A reduction in fuel burn, means a reduction in the total fuel required, and this then reduces the loads the airframes needs to carry to carry the same payload over a particular range.

zeke wrote:

Taxi645 wrote:

As the engine will be heavier and there will be more parasitic drag from the bigger nacelles, the SFC gain would have to be larger than 10% to get to the 10% at the aircraft level unless you take into account you have to fly less fuel to burn fuel.

A reduction in fuel burn, means a reduction in the total fuel required, and this then reduces the loads the airframes needs to carry to carry the same payload over a particular range.

Yes, but that still leaves the the option that he is talking about per unit of time and then the SFC improvement would have to be bigger than 10%. Makes quite a difference for the economics which of the two he meant.

Contrafan would be awesome. I don't remember ever seeing development of ducted contrafans. Only open rotor.

keesje wrote:

Rolls will start testing its Ultrafan demonstrator. It features a gearbox "working with two carbon composite fan systems"

I wonder what that means. One with variable fan blade angles? https://youtu.be/zW66-EFvj64?t=60

Article: https://travelandaviation.com/rolls-roy ... t-in-2022/

First stage of the compressor perhaps?

I expect the statement "working with two carbon composite fan systems" means two different designs of fan and casing will be tested in the Ultrafan engine test programme. Most likely thus is two different fixed pitches (and maybe casing designs) being tested and no variable pitch technology.

Aerospice wrote:

I expect the statement "working with two carbon composite fan systems" means two different designs of fan and casing will be tested in the Ultrafan engine test programme. Most likely thus is two different fixed pitches (and maybe casing designs) being tested and no variable pitch technology.

One of the constants in competing aircraft is efficiency taking off and getting to altitude, versus efficiency at altitude. So could RR offer two fans for that?

frmrCapCadet wrote:

Aerospice wrote:

I expect the statement "working with two carbon composite fan systems" means two different designs of fan and casing will be tested in the Ultrafan engine test programme. Most likely thus is two different fixed pitches (and maybe casing designs) being tested and no variable pitch technology.

One of the constants in competing aircraft is efficiency taking off and getting to altitude, versus efficiency at altitude. So could RR offer two fans for that?

I don't think they would offer two fans but they are exploring design space to figure out the optimum design over the range of operating conditions.

I don't understand why it's taking so long for the big 3 engine makers to produce a high-volume engine with variable pitch fans. Rolls-Royce and SNECMA were planning for one a half-century ago, and even tested a demonstrator engine in the 1970s.

Here's a 1971 magazine article about the M45S variable-pitch engine: Rolls-Royce design for quieter airliners.

And here's the M45 SD-02 demonstrator on display in what looks like a public library:



So if the VP fan actually ends up on the Ultrafan, does that mean Ultrafan-powered widebodies become viable on short-range routes?

CowAnon wrote:

I don't understand why it's taking so long for the big 3 engine makers to produce a high-volume engine with variable pitch fans. Rolls-Royce and SNECMA were planning for one a half-century ago, and even tested a demonstrator engine in the 1970s.

Here's a 1971 magazine article about the M45S variable-pitch engine: Rolls-Royce design for quieter airliners.

And here's the M45 SD-02 demonstrator on display in what looks like a public library:



So if the VP fan actually ends up on the Ultrafan, does that mean Ultrafan-powered widebodies become viable on short-range routes?

I’m not an industry expert but the reason that I suspect it’s pretty much confirmed by the experts Quora when asked.

This type of fan is very complicated and making it reliable durable affordable all at once it is quite challenging.

It’s too risky at this point they will probably continue to work on it and I’m sure when they are confident they will bring it out to market.

As long as there are more practical less risky avenues to improve their products these will usually get priority.

In other words they still have plenty of low hanging fruit to pick.

And finally you could say that this is a form of vaporware. I mean if you want to take an extremely cynical viewpoint you could say that this is a lot like the ultra fan it is going to go nowhere but Airbus or Rolls-Royce will get a lot of press out of it and a way to keep them selves in the minds of a lot of industry and forum posters here as a company we think of with high technology. Well not actually delivering such a promising product.

snasteve wrote:

This type of fan is very complicated and making it reliable durable affordable all at once it is quite challenging.

It’s too risky at this point they will probably continue to work on it and I’m sure when they are confident they will bring it out to market.

As long as there are more practical less risky avenues to improve their products these will usually get priority.

In other words they still have plenty of low hanging fruit to pick.

And finally you could say that this is a form of vaporware. I mean if you want to take an extremely cynical viewpoint you could say that this is a lot like the ultra fan it is going to go nowhere but Airbus or Rolls-Royce will get a lot of press out of it and a way to keep them selves in the minds of a lot of industry and forum posters here as a company we think of with high technology. Well not actually delivering such a promising product.

It's definitely a form of vaporware. Still, what's confusing is that a single high-reward technology like variable-pitch fans is deprioritized in favor of something like CMCs (which strike me as the opposite of low-hanging fruit) or a collection of low-risk, low-reward improvements within the engine core. Perfecting several improvements, even if each one of them in simpler individually, seems like it can become complicated when you have to do a bunch of them at one time.

Perhaps the "low risk, low reward" stuff has potential application in pipping current in-service engines, thereby generating near term cash

RR been working on composite fan blades since the late 60s hehe.