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(The Drive)   Coming next decade to a passenger jet near you: 'Open Rotor' turbofans, less emissions and more efficient at splattering incoming birds   (thedrive.com) divider line
    More: Weird, Turbofan, Turboprop, new sort of engine, Internal combustion engine, fuel consumption, Jet engine, Open Rotor, Franco-American aerospace company CFM  
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1251 clicks; posted to STEM » on 17 Jun 2021 at 1:41 AM (6 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook



32 Comments     (+0 »)
View Voting Results: Smartest and Funniest
 
2021-06-16 11:11:58 PM  
TFA says quieter but the old unducted fans were horrendously loud. I wanna see the data.
 
2021-06-16 11:17:58 PM  
snarky comment about propellers.
 
2021-06-17 1:52:12 AM  
Propfans aren't exactly something new.
 
2021-06-17 1:58:34 AM  
The GE9X is set to start humming away soon under the wings of Boeing's new 777X. Even if these prop fans are the next big thing, turbofans are going out with a considerable bang.

...

...

I hope not...

I'd like a nice quiet decommission on my jet engines, thanks in advance.
 
2021-06-17 2:14:40 AM  

edmo: TFA says quieter but the old unducted fans were horrendously loud. I wanna see the data.


I remember this from the 1980s. Ducted fans as currently used don't have radial dispersion, and keep most of the noise axial to the turbine. They've probably already shaped the cowling duct to take advantage of the radial air flow.
 
2021-06-17 3:23:31 AM  
Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.
 
2021-06-17 3:37:18 AM  

Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.


j.gifs.comView Full Size
 
2021-06-17 3:41:25 AM  

dyhchong: Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.

[j.gifs.com image 480x270]


Yeah, a turbofan and a propeller aren't the same thing.  Blade loss is a real risk in tubofans and has to be contained.
 
2021-06-17 5:39:32 AM  

dyhchong: The GE9X is set to start humming away soon under the wings of Boeing's new 777X. Even if these prop fans are the next big thing, turbofans are going out with a considerable bang.

...

...

I hope not...

I'd like a nice quiet decommission on my jet engines, thanks in advance.


I for one welcome the opportunity to get my money's worth by watching some impressive piloting skills.

Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.


On an engine like this with minimal noise, there's probably enough blades so that they're not moving that fast, thus reducing both the risk and the damage from a blade loss. Moreover, blade loss is fairly easy to shield passengers from; a kevlar blanket built into the cabin near where the blades could fly off should solve the problem.
 
2021-06-17 5:51:44 AM  
When it comes to this technology, I'm a really big fan.
 
2021-06-17 5:58:00 AM  
With "Open Rotor" I won't be able to throw my coins into the engine for good luck.

Fark user imageView Full Size
 
2021-06-17 6:17:14 AM  

Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.


But the loose blade will be less likely to take others with it.
 
2021-06-17 6:22:15 AM  

khatores: dyhchong: The GE9X is set to start humming away soon under the wings of Boeing's new 777X. Even if these prop fans are the next big thing, turbofans are going out with a considerable bang.

...

...

I hope not...

I'd like a nice quiet decommission on my jet engines, thanks in advance.

I for one welcome the opportunity to get my money's worth by watching some impressive piloting skills.

Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.

On an engine like this with minimal noise, there's probably enough blades so that they're not moving that fast, thus reducing both the risk and the damage from a blade loss. Moreover, blade loss is fairly easy to shield passengers from; a kevlar blanket built into the cabin near where the blades could fly off should solve the problem.


Should...
https://www.usatoday.com/story/travel​/​airline-news/2019/11/19/southwest-airl​ines-fatal-accident-ntsb-recommendatio​ns-boeing-engine-cover-fix/4238550002/​
 
2021-06-17 6:24:34 AM  
An idea shelved in the 70s, they've been playing with since 2017 and It will likely be a decade before all of the kinks are worked out and they start getting tacked onto airliners.

Jesus people. I know R&D needs a minute, but 15 years to make this happen seems excessive. Is this theory problems, prototyping, manufacturing difficulties, or regulatory hurdles? Or is it trying not to cannibalize their current sales of standard jet engines?

I am not very enthused about minor product announcements a decade from production.
 
2021-06-17 6:43:19 AM  

Gleeman: khatores: dyhchong: The GE9X is set to start humming away soon under the wings of Boeing's new 777X. Even if these prop fans are the next big thing, turbofans are going out with a considerable bang.

...

...

I hope not...

I'd like a nice quiet decommission on my jet engines, thanks in advance.

I for one welcome the opportunity to get my money's worth by watching some impressive piloting skills.

Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.

On an engine like this with minimal noise, there's probably enough blades so that they're not moving that fast, thus reducing both the risk and the damage from a blade loss. Moreover, blade loss is fairly easy to shield passengers from; a kevlar blanket built into the cabin near where the blades could fly off should solve the problem.

Should...
https://www.usatoday.com/story/travel/​airline-news/2019/11/19/southwest-airl​ines-fatal-accident-ntsb-recommendatio​ns-boeing-engine-cover-fix/4238550002/​


Well that's on the cover itself. While they should have put shielding on the cabin, they didn't. I'd think that cabin shielding could be more robust than what's on the engine covers since the engine shielding has to fit in a smaller space.

It could still fly through a window although windows in that section could be made from ballistic glass.
 
2021-06-17 8:05:32 AM  

khatores: Gleeman: khatores: dyhchong: The GE9X is set to start humming away soon under the wings of Boeing's new 777X. Even if these prop fans are the next big thing, turbofans are going out with a considerable bang.

...

...

I hope not...

I'd like a nice quiet decommission on my jet engines, thanks in advance.

I for one welcome the opportunity to get my money's worth by watching some impressive piloting skills.

Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.

On an engine like this with minimal noise, there's probably enough blades so that they're not moving that fast, thus reducing both the risk and the damage from a blade loss. Moreover, blade loss is fairly easy to shield passengers from; a kevlar blanket built into the cabin near where the blades could fly off should solve the problem.

Should...
https://www.usatoday.com/story/travel/​airline-news/2019/11/19/southwest-airl​ines-fatal-accident-ntsb-recommendatio​ns-boeing-engine-cover-fix/4238550002/

Well that's on the cover itself. While they should have put shielding on the cabin, they didn't. I'd think that cabin shielding could be more robust than what's on the engine covers since the engine shielding has to fit in a smaller space.

It could still fly through a window although windows in that section could be made from ballistic glass.


All of that adds weight, which is anathema to aircraft designers.

Think about it:  the idea here is more efficient aircraft, right?  If you eat up that advantage by armoring the passenger compartment, what's the point?

Besides which, we've been flying aircraft like this for many decades:  Its not that much different than a turboprop.  Nobody wrings their hands about propeller blade separation on turboprops.
 
2021-06-17 8:31:30 AM  

dyhchong: The GE9X is set to start humming away soon under the wings of Boeing's new 777X. Even if these prop fans are the next big thing, turbofans are going out with a considerable bang.

...

...

I hope not...

I'd like a nice quiet decommission on my jet engines, thanks in advance.


The GEO. is a big 'un

th.bing.comView Full Size
 
2021-06-17 9:09:25 AM  
So, what will contain the rotor blades and prevent them from flying through the fuselage should there be an engine failure?
 
2021-06-17 9:15:40 AM  

dionysusaur: Raoul Eaton: Kind of hard to contain a blade loss engine failure with this design.  I'm not going to hold my breath waiting for these to go into production.

But the loose blade will be less likely to take others with it.


But once you lose a single blade on these engines, they become unbalanced, possibly causing the wing to separate from the plane.
 
2021-06-17 9:22:11 AM  

Saturn5: So, what will contain the rotor blades and prevent them from flying through the fuselage should there be an engine failure?


A layer of gorillas on the plane. And that's the beauty of it, once the plane reaches 50000 feet, the gorillas just freeze to death and fall off.
 
2021-06-17 9:38:57 AM  
I recall that Boeing's 7J7 design from the late 1990s had aft-mounted prop fans and looked very much like the rendering on the RH side of the top article picture.
 
2021-06-17 9:45:14 AM  

Quantumbunny: An idea shelved in the 70s, they've been playing with since 2017 and It will likely be a decade before all of the kinks are worked out and they start getting tacked onto airliners.

Jesus people. I know R&D needs a minute, but 15 years to make this happen seems excessive. Is this theory problems, prototyping, manufacturing difficulties, or regulatory hurdles? Or is it trying not to cannibalize their current sales of standard jet engines?

I am not very enthused about minor product announcements a decade from production.


All of the above, really. It takes a while to turn the idea into a set of product requirements (define what it should do and how, i.e. it should produce at least X thrust, weigh no more than Y kilograms, be no more than Z dimensions, etc), assess those requirements for feasibility, turn those requirements into an actual design (define where all the parts go), do the extensive calculation and modeling to turn the design into a blueprint (define exactly how each part is shaped and what it's made of), machine the prototype parts, build and test the engine, repeat until success.

At the end what you have is a working prototype, but that just means you can build an engine like that - it's not production ready. Now you get to repeat all of the above steps for the production version, which may introduce new requirements that would have been somewhat out of scope for a prototype (such as the control interfaces), then repeat with mounting it on a plane. These parts can be easier since they're familiar processes, but it can still take a while since it's a new engine and you really do want to test it quite exhaustively under a broad range of conditions.
 
2021-06-17 10:22:31 AM  
Not too unlike the retrofitted Scimitar Props that a lot of C-130s have gotten lately:

Fark user imageView Full Size


For comparison, most of them still use the old 4-blade props:

Fark user imageView Full Size
 
2021-06-17 12:29:11 PM  

NikolaiFarkoff: Not too unlike the retrofitted Scimitar Props that a lot of C-130s have gotten lately:

[Fark user image 602x339]

For comparison, most of them still use the old 4-blade props:

[Fark user image 850x491]


It's the J-model that came out with those props, the older models still have the 4-blade props.
 
2021-06-17 12:33:18 PM  

Hospitaller: NikolaiFarkoff: Not too unlike the retrofitted Scimitar Props that a lot of C-130s have gotten lately:

[Fark user image 602x339]

For comparison, most of them still use the old 4-blade props:

[Fark user image 850x491]

It's the J-model that came out with those props, the older models still have the 4-blade props.


Collins says they can retrofit seamlessly, but the wing root needed a complete overhaul on the J when they incorporated the new engine and propeller
 
2021-06-17 12:36:22 PM  
Looks a whole lot like a turbo-prop.
 
2021-06-17 12:53:58 PM  
Turbo anything is so yesterday. What we need is a plane powered by expired pork, and the laughter of small children.
 
2021-06-17 1:31:14 PM  

Saturn5: So, what will contain the rotor blades and prevent them from flying through the fuselage should there be an engine failure?


According to folks around here, you can staple a couple of kevlar blankets to the fuselage.  Okey dokey.

///once had an airline claims adjuster tell me far more than I wanted to know about an incident where a thrown blade entered the cabin and decapitated a passenger
 
2021-06-17 1:32:03 PM  

Hospitaller: Hospitaller: NikolaiFarkoff: Not too unlike the retrofitted Scimitar Props that a lot of C-130s have gotten lately:

[Fark user image 602x339]

For comparison, most of them still use the old 4-blade props:

[Fark user image 850x491]

It's the J-model that came out with those props, the older models still have the 4-blade props.

Collins says they can retrofit seamlessly, but the wing root needed a complete overhaul on the J when they incorporated the new engine and propeller


I didn't realize it was so drastic -- I know a lot of smaller planes (Dash 8 for example) have simpler conversions that net them a few percent additional efficiency, which adds up. Especially for commercial applications.

live.staticflickr.comView Full Size
 
2021-06-17 5:11:05 PM  

khatores: Well that's on the cover itself. While they should have put shielding on the cabin, they didn't. I'd think that cabin shielding could be more robust than what's on the engine covers since the engine shielding has to fit in a smaller space.

It could still fly through a window although windows in that section could be made from ballistic glass.


That all adds weight, and detracts from the profits the airline can make by charging $120 a bag for checked luggage or selling the cargo space to FedEx. It's easier to just put the "Economy Minus" seats in the scatter zone and work an arbitration clause into the ticket contract.
 
2021-06-17 5:16:25 PM  
Interesting, I don't' think I've ever seen stators on an open prop design.
 
2021-06-17 6:04:05 PM  

Raoul Eaton: Saturn5: So, what will contain the rotor blades and prevent them from flying through the fuselage should there be an engine failure?

According to folks around here, you can staple a couple of kevlar blankets to the fuselage.  Okey dokey.

///once had an airline claims adjuster tell me far more than I wanted to know about an incident where a thrown blade entered the cabin and decapitated a passenger


Engine covers, which generally do contain engine explosions with few exceptions, do use kevlar and aramid mats in order to accomplish that.

If you remove the engine cover and go with external blades, why not reposition the same mats in the bulkhead? Should be the same material and same weight.

Are people just being sarcastic or is there really a level of ignorance as to where people don't understand how this fairly simple technology works?
 
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