ERJ135 From Australia, joined Nov 2000, 680 posts, RR: 1
Reply 5, posted (4 years 7 months 3 weeks 6 days 12 hours ago) and read 13681 times:
There are many answers that are possible. We must also remember that the E-Jet also has a similar device, just not in the same position. The E-Jet has been in service for years now so while recent it is certainly not new. It's existence is of course noise related so maybe the engines that will ultimately be fitted to the new Airbus may in fact not need them. Or perhaps it will actually be there but as the Airbus is still a way off we might have to wait and see.
No answer really But honestly having seen the flex of the 787 wing I can hardly wait the see the A350.
EGNR From United Kingdom, joined Feb 2004, 508 posts, RR: 0
Reply 10, posted (4 years 7 months 3 weeks 6 days 6 hours ago) and read 12851 times:
Airbus developed the zero splice inlet during the A380 development. From what I understand, this gives a good reduction in noise, but with no fuel burn penalty (perhaps even an improvement in fuel burn), and will undoubtedly feature on all future Airbus products, including the A350.
"Among the innovations for which Airbus has filed patent applications is the Zero Splice inlet that is integrated into the A380 engines' nacelles. This invention, which consists of a single 360 degree composite piece, instead of several separate panels spliced together, contributes significantly to the A380s very low noise emissions. " Courtesy of Airbus
"Researchers found the gaps in nacelle linings are a significant source of the tremendous noise jet engines generate. Before the zero-splice inlet, nacelle linings consisted of two to three sections that were fitted together, which left gaps between the individual lining sections. The vibration and noise of the engine escape through these tiny gaps and create acoustic scattering, basically deflecting noise in all directions.
To address the problem, Alain Porte of Airbus pioneered a new material for nacelle linings that could cover the entire inside in just one piece. This was achieved through a perforated, heat-resistant fabric that is flexible enough to line the nacelle, but highly sound-absorbent. The innovative material is strong enough to withstand everything from pressure during flight, the weight of people on some portions to the aerodynamic and inertial forces of the entry of air into the motor housing.
Better yet, zero-splice inlet engines are not only much quieter than their conventional counterparts, but also lighter and more fuel efficient. This uniquely high level of acoustic performance has made it possible for the world's largest passenger plane to also be the world's quietest passenger plane, giving it a significant commercial advantage in an environmentally aware marketplace: The Airbus 380, armed with the zero-splice engine housing, generates 50 percent less noise than any other passenger plane in the world." Courtesy of epo: The Story Behind: Quieter Jet Engines
Baroque From Australia, joined Apr 2006, 15380 posts, RR: 59
Reply 11, posted (4 years 7 months 3 weeks 6 days 6 hours ago) and read 12783 times:
Quoting EGNR (Reply 10): Airbus developed the zero splice inlet during the A380 development.
Interesting post. But equally interesting is that you can actually patent the bleeding obvious. Amazing world that of patents. No criticism of your post implied EGNR and thanks for drawing out attention to it. I do rather wonder however if Whittle had not figured that out in about 1940?!? He certainly spent a lot of time on design of casings for this impellers.
Shany From Germany, joined Jul 2008, 113 posts, RR: 0
Reply 13, posted (4 years 7 months 3 weeks 6 days 2 hours ago) and read 10217 times:
Could it just be that the drawings and models are still in an too early stage to have these kind of details? I mean, the pictures I have seen also don't show any antennas nor static dischargers. However, I guess/hope, there will be some.
Etoile From United States of America, joined Jun 2009, 114 posts, RR: 0
Reply 20, posted (4 years 7 months 3 weeks 5 days 16 hours ago) and read 5963 times:
Quoting Burnsie28 (Reply 15): I believe things like that developed by NASA or the US Government are free reign for US Citizen and companies only as we are the ones that essentually pay for them.
It's a little more complex and less nationalistic than that. The government generally will retain title to patents on inventions made by its employees on government time. If the government funds a grantee's invention, typically the grantee will be able to obtain title, but the government will still get a nonexclusive license.
"The team also tested variable-geometry chevrons made with a temperature-reactive alloy. These "smart" chevrons automatically warp into the jet exhaust flow to reduce noise during takeoff and landing and revert to a streamlined position at cruise altitude."
A "moveable" (ie variable geometry) chevron of this type would have the benefit of takeoff thrust noise reduction without a cruise fuel burn penalty. It's possible that the 787 chevrons are variable geometry and would be protected by the patent referenced in Reply 3.
Quoting Kappel (Reply 6): Quoting OldAeroGuy (Reply 3):
This could have something to do with the lack of chevrons on the A350XWB.
No, see the thread mentioned in the reply below:
Quoting Etoile (Reply 2):
See this thread: Why No Chevrons On The TrentXWB Or PW1000G? (by EA772LR Dec 14 2009 in Civil Aviation)?threadid=4638222&searchid=4638533&s=chevrons+lightsaber#ID4638533
I fail to see any reference to the patent linked in Reply 3 to the other thread. Variable geometry chevrons are not discussed in the prior thread.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis