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Slug71
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Safran inaugurates open rotor test program

Tue Oct 03, 2017 10:29 pm

Looks like ground tests have begun,

Safran is celebrating today the success of the first ground tests of the Open Rotor demonstrator engine in Istres, southern France.


https://www.safran-group.com/media/safr ... e-20171003
 
SCAT15F
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Re: Europe Shelves Open-Rotor Flight-Test Demonstration

Wed Oct 04, 2017 3:00 am

Good! ...Forget the short-sighted "Clean Sky" leadership. Safran knows this is the future. Damn the torpedoes and full speed ahead! (hopefully)
 
parapente
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Re: Europe Shelves Open-Rotor Flight-Test Demonstration

Tue Oct 10, 2017 7:29 am

Thx for the Saran link -very interesting.Was also interesting to note that they were also investigating in parallel a shrouded route for the very reason mantioned earlier i.e. That it could be integrated on existing/conventional plane designs.I think this is a major point.
It seems that Rolls too have put their OR work to sleep for the moment and concentrating on the 'Ultra'.Perhaps for the same reasons.

In a way I was disappointed to note that a new a/c company funded by Boeing capital building 10-20 seater hybrid a/c was also using the shrouded fan (electric) route.I guess it's the noise thing again.

I raised this simply as OR might have had a future for electric/hybrid a/c where every drop of efficiency counts (range).Personally I hope it has,I think that's (hybrid) the right arena for CR OR electric drive engines.
 
Egerton
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Re: Europe Shelves Open-Rotor Flight-Test Demonstration

Tue Oct 10, 2017 7:10 pm

I wonder if the continuing Silvercrest issues have drained both Safran financial and engineering resources to the point that all hands were needed to fix Silvercrest?
 
WIederling
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Re: Europe Shelves Open-Rotor Flight-Test Demonstration

Tue Oct 10, 2017 9:06 pm

Egerton wrote:
I wonder if the continuing Silvercrest issues have drained both Safran financial and engineering resources to the point that all hands were needed to fix Silvercrest?


IMU it is the EU research program that was discontinued not the Safrane test item program.

I find this a bit strange.
Murphy is an optimist
 
r2rho
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Re: Europe Shelves Open-Rotor Flight-Test Demonstration

Wed Oct 11, 2017 2:28 pm

I wonder if the continuing Silvercrest issues have drained both Safran financial and engineering resources to the point that all hands were needed to fix Silvercrest?

My reading of this between the lines is that Airbus didn't want to play along anymore, and thus the EU research program was cancelled due to lack of a platform for flight tests.
The cancellation most certainly did not come from Safran, who is actually proceeding with the program on its own, as we can observe.
 
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KarelXWB
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Re: Safran Inaugurates Open-rotor Test Program

Wed Oct 11, 2017 2:42 pm

Just to be clear, the open rotor demonstrator under the European Clean Sky project has been canceled.

European Clean Sky project shelves open rotor flight-test demonstration

Safran is doing its own research.
What we leave behind is not as important as how we've lived.
 
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KarelXWB
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Re: Safran Inaugurates Open-rotor Test Program

Wed Oct 11, 2017 2:46 pm

As for the Safran demonstrator, note that it is a scaled down version.

Here's a short video of the demonstrator in action:

https://twitter.com/SAFRAN/status/915166463140536321

Image
What we leave behind is not as important as how we've lived.
 
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ro1960
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Re: Safran inaugurates open rotor test program

Fri Oct 13, 2017 9:24 pm

Just curious and maybe naive but wasn't this called UDF or Propfan some 30 years ago? Tested on a 727 and on a MD-80? It never went beyond prototypes. Why? And why would it work now?

 
WIederling
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Re: Safran inaugurates open rotor test program

Fri Oct 13, 2017 9:43 pm

ro1960 wrote:
Just curious and maybe naive but wasn't this called UDF or Propfan some 30 years ago? Tested on a 727 and on a MD-80? It never went beyond prototypes. Why? And why would it work now?
]


It made your ears come off.
the noise was unacceptable even for the timeframe "back then".

If you can reduce the noise you have a potential winner.

No idea how much tech carried over from the abortive UDF design.
Murphy is an optimist
 
kurtverbose
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Re: Safran inaugurates open rotor test program

Sat Oct 14, 2017 5:33 am

I read that when RR looked at open rotors they looked at the Allison experience (they took over Allison who had worked with P&W on the propfan), and weren't very impressed with their attempts at noise attenuation. Specifically, making the rear rotor smaller than the front makes a big difference. I think I read that they can solve the noise problem at current noise laws, but probably not if noise laws become stricter.

The really big issue facing open rotors is airworthyness. I've not read any conclusions about how you get a supersonic fan blade with no containing shrowd through certification.
 
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Starlionblue
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Re: Safran inaugurates open rotor test program

Sat Oct 14, 2017 6:34 am

kurtverbose wrote:
I read that when RR looked at open rotors they looked at the Allison experience (they took over Allison who had worked with P&W on the propfan), and weren't very impressed with their attempts at noise attenuation. Specifically, making the rear rotor smaller than the front makes a big difference. I think I read that they can solve the noise problem at current noise laws, but probably not if noise laws become stricter.

The really big issue facing open rotors is airworthyness. I've not read any conclusions about how you get a supersonic fan blade with no containing shrowd through certification.


I can't see how an uncontained supersonic fan blade would meet with much resistance. ;) :duck:
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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lightsaber
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Re: Safran inaugurates open rotor test program

Sat Oct 14, 2017 3:35 pm

Open rotors are fascinating. Just remember the slower cruise speed than a GTF. They're benefit is they give you a higher bypass ration without the weight of a nacelle. But without a nacelle, blade tip mach number is limited which means cruise speed is limited more than with a nacelle.
Business jets routinely fly at Mach 0.85 +/- 0.07
Commercial jets travel at Mach 0.75 +/- 0.03.
Propfans will be at Mach 0.7 +/- 0.03.
Turboprops are down at Mach 0.65 +/- 0.3

Propfans are the halfway point between turbofans and turboprops for flight speed and efficiency. They're ideal for shorter hop markets such as Europe or the NorthEast US. But they won't be great for 1,500nm+ missions. At some point the slower speed adds up in costs.

And yea, I've read some pretty outlandish claims on propfan cruise speeds matching turbojets. Really? That is someone who doesn't understand shock wave generation off airfoils (the blades pushing the air). If there were such a development in airfoil technology, you would first see a Mach 0.95 business jet.

Please don't get me wrong, I see a spot in the market for propfan's. But as someone who lives in the Western US where a flight is longer, I live in a market that desires speed.
I also know of technology being developed for the next generation GTF. The propfan will not be competing against today's engines, but a RR or Pratt improved GTF. The same airfoil technology that enables the propfan will help make a GTF more efficient.

I do believe the Silvercrest is quite a distraction for the engineering teams. They have had two bad cases in a row (they fixed the SAM146 early enough to keep it out of public discussion). I'm trying to figure out what is up with the recently disclosed compressor issue:
https://www.ainonline.com/aviation-news ... ssor-issue

Safran has to promise Dassault something to keep the 5X alive:
https://uk.reuters.com/article/us-dassa ... KKBN1CG2NH

Lightsaber
You only have the first amendment with the 2nd. If you're not going to offend someone with what you say, you don't have the 1st.
 
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Brixerl
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Re: Safran inaugurates open rotor test program

Tue Oct 17, 2017 6:19 pm

Can somebody explain me the background to this :0)
1988?
https://www.youtube.com/watch?v=1BMNaXc1rL8
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