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Topic: Boeing 787 Engines
Username: Legoguy
Posted 2009-01-15 09:06:48 and read 11023 times.

The Boeing 787 will feature engines from both Rolls Royce and General Electric and both as far as I am aware feature the triangular chevrons on the trailing edge of the engine cowling. These chevrons are quite interesting to me. Rolls Royce will also be producing an engine for the A350 XWB (the Trent 1000 XWB?) yet as far as I am aware, the engine will not feature the chevrons. Why is this? Is the Chevron design a Boeing development or engine manufacturer development?

Also, I'm not sure if this is still the case but I believe the engines on the 787 will be one colour as multiple colours would lead to layering of paint layers and the edges would cause extra drag. Again is this a Boeing development to reduce drag or is it an engine manufacturer development again?

Regards,

Dave

Topic: RE: Boeing 787 Engines
Username: TristarSteve
Posted 2009-01-15 09:30:37 and read 11015 times.

I don't know for sure but, the engine cowlings are usually produced by the airframe manufacturer, and not the engine manufacturer. So the chevrons on the B787 are a Boeing design which is why they feature on both engine types.

Topic: RE: Boeing 787 Engines
Username: A10WARTHOG
Posted 2009-01-15 10:42:02 and read 10973 times.



Quoting Legoguy (Thread starter):
Also, I'm not sure if this is still the case but I believe the engines on the 787 will be one colour as multiple colours would lead to layering of paint layers and the edges would cause extra drag.

If the customer wants more than one color or wants a logo on their cowls, I would guess that Boeing will do it.

Topic: RE: Boeing 787 Engines
Username: Kappel
Posted 2009-01-15 12:43:09 and read 10905 times.



Quoting TristarSteve (Reply 1):
So the chevrons on the B787 are a Boeing design which is why they feature on both engine types.

I believe the E-jets also have this feature on the engines. From what I've read, these chevrons decrease noise levels, but also increase drag.

Topic: RE: Boeing 787 Engines
Username: UAL747
Posted 2009-01-15 14:49:04 and read 10856 times.



Quoting Kappel (Reply 3):
believe the E-jets also have this feature on the engines. From what I've read, these chevrons decrease noise levels, but also increase drag.

If this is indeed the case, I can hardly see why it would be beneficial. I doubt these chevrons actually reduce noise enough to make it something that airlines would consider over decreasing drag. If this is indeed the case, then I doubt we will see them on airliners.

UAL

Topic: RE: Boeing 787 Engines
Username: Starlionblue
Posted 2009-01-15 15:15:47 and read 10842 times.



Quoting UAL747 (Reply 4):
If this is indeed the case, I can hardly see why it would be beneficial. I doubt these chevrons actually reduce noise enough to make it something that airlines would consider over decreasing drag. If this is indeed the case, then I doubt we will see them on airliners.

I think airlines are quite willing to increase fuel consumption in some cases. AFAIK SQ needed quieter engines on the 380 to operate at LHR. They took quite a steep fuel burn penalty to get them.

Topic: RE: Boeing 787 Engines
Username: Tdscanuck
Posted 2009-01-15 15:26:21 and read 10839 times.



Quoting Legoguy (Thread starter):
Is the Chevron design a Boeing development or engine manufacturer development?

It's a Boeing thing. They were running around on the Quiet Technology Demonstrator 777 a few years ago.

Quoting Legoguy (Thread starter):
Also, I'm not sure if this is still the case but I believe the engines on the 787 will be one colour as multiple colours would lead to layering of paint layers and the edges would cause extra drag. Again is this a Boeing development to reduce drag or is it an engine manufacturer development again?

This was a change after some of the original livery concepts came out. Apparently, they figured out that if they got the nacelle smooth enough they could preserve laminar flow for a lot longer and make a noticeable drag improvement:
http://www.azom.com/news.asp?newsID=5961

Quoting A10WARTHOG (Reply 2):
If the customer wants more than one color or wants a logo on their cowls, I would guess that Boeing will do it.

I'm not sure that that's the case...they might be able to do it if they agree to accept the fuel burn hit, but that might throw off the performance numbers and force Boeing to do a separate set of documents, which they probably don't want to do.

Quoting UAL747 (Reply 4):
If this is indeed the case, I can hardly see why it would be beneficial. I doubt these chevrons actually reduce noise enough to make it something that airlines would consider over decreasing drag. If this is indeed the case, then I doubt we will see them on airliners.

If you're limited into an airport by noise, it's certainly beneficial. A little more fuel burn makes a lot more money than no flight. OEM's already speed a lot of money and manufacturing time on acoustic treatments for engine nacelles to control noise, this is just more of the same philosophy.

If it were all about fuel burn, they'd ditch the acoustic treatments on existing jets and save the weight.

Tom.

Topic: RE: Boeing 787 Engines
Username: Legoguy
Posted 2009-01-15 19:26:15 and read 10781 times.

Thanks for the replies guys, everything mentioned helps to clear up my questions. As mentioned the Embraer 170/190 series seems to feature the triangular cherons but they look as if they are located on the exhaust rather than the outer cowling.

I didn't realize the engine cowlings were designed and built by the aircraft manufacturers themselves  Smile I did remember seeing an 777-300ER with chevrons as a test bed. I presume there are no plans on introducing the hcevrons to the GE 90 engines at any point in the future.

Topic: RE: Boeing 787 Engines
Username: Tdscanuck
Posted 2009-01-15 22:00:52 and read 10740 times.



Quoting Legoguy (Reply 7):
I didn't realize the engine cowlings were designed and built by the aircraft manufacturers themselves

To qualify that a little bit, they're usually designed by the aircraft manufacturer but often built by somebody else. There are a few companies with major expertise in this area: Middle River, Goodrich, Nordam (part of Goodrich now, I think), and Spirit.

Spirit used to be Boeing Wichita, so Boeing used to do some of their own, but I don't think Boeing has any in-house anymore.

The engine companies often want to stop their responsibility at the engine and let the airframer be responsible for integrating the engine with the airframe. The frequent exception is Rolls Royce, who has the entire engine/nacelle package on several airliners, but they typically subcontract the nacelle out.

Tom.

Topic: RE: Boeing 787 Engines
Username: OPNLguy
Posted 2009-05-27 14:05:41 and read 9212 times.

I appreciate this thread, as I was kind of wondering about them, having recently received this picture:

http://i34.photobucket.com/albums/d143/OPNLguy/ScreenShot110.jpg

Anyone happen to know the significance of some wiring bundles being in red, and others in white?

Topic: RE: Boeing 787 Engines
Username: Brendows
Posted 2009-05-27 14:35:15 and read 9194 times.



Quoting OPNLguy (Reply 9):
Anyone happen to know the significance of some wiring bundles being in red, and others in white?

IIRC the red wiring is part of the flight test equipment.

Topic: RE: Boeing 787 Engines
Username: FTOHIST
Posted 2009-05-27 15:56:35 and read 9158 times.

The wires pictured are orange and are for flight test instrumentation--and there's not a whole lot of them if those bundles are in fact going inboard into the cabin. I'd expect more than that for engine flight tests (I'm assuming the airplane pictured is the RR 747 engine testbed).

Topic: RE: Boeing 787 Engines
Username: JoeCanuck
Posted 2009-05-27 23:13:56 and read 9044 times.

Is there any specific data about the fuel burn penalty of the chevrons?

Topic: RE: Boeing 787 Engines
Username: Dynamicsguy
Posted 2009-05-28 00:19:49 and read 9020 times.



Quoting FTOHIST (Reply 11):
I'd expect more than that for engine flight tests (I'm assuming the airplane pictured is the RR 747 engine testbed).

I believe that is ZA001. The leading edge devices are definitely wrong for a 747.

Topic: RE: Boeing 787 Engines
Username: OPNLguy
Posted 2009-05-28 05:02:38 and read 8937 times.



Quoting FTOHIST (Reply 11):
(I'm assuming the airplane pictured is the RR 747 engine testbed).

Another pix in the group that I received showed it as a RR engine on the 787..

http://i34.photobucket.com/albums/d143/OPNLguy/ScreenShot113-1.jpg

Topic: RE: Boeing 787 Engines
Username: FTOHIST
Posted 2009-05-28 15:21:16 and read 8767 times.



Quoting Dynamicsguy (Reply 13):
I believe that is ZA001. The leading edge devices are definitely wrong for a 747.

OK, thanks. That explains the limited engine instrumentation....

Topic: RE: Boeing 787 Engines
Username: Tdscanuck
Posted 2009-05-28 20:59:14 and read 8707 times.



Quoting OPNLguy (Reply 9):
Anyone happen to know the significance of some wiring bundles being in red, and others in white?

It's orange, actually, the photograph is just a little off in colour. Orange = flight test.

Tom.


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