Liedetectors From United States of America, joined Jul 2005, 360 posts, RR: 0 Posted (4 years 4 months 16 hours ago) and read 5076 times:
I just noticed that Aeroflot's CFM-56-powered A-321, pictured in the link below, has chevrons in the vicinity of the exhaust nozzle. Does anyone know the story behind this? Is this an Airbus upgrade or a long-term test article? The next CFM56-powered 321 (of Air India) off of the line did not have chevrons.
Unfortunately, no. I'd love to hear the inside scoop!
Quoting Mir (Reply 1): What are those two little ports about halfway up the back of the pylon for? They look like drains, but drains for what?
I don't know for sure, but you usually have a drain in that area for the strut. At least one to let fuel/water out so it doesn't pool in the strut and probably another one for hydraulics if they've got a pump or resevoir in the fairing (not sure if the A321 does, but some aircraft do).
I found this article over the CFM56-5B engine, installed on the A321, on the CFM website.
The following is mentioned : "The technology being developed includes: three-dimensional aerodynamic outlet guide vanes; a core chevron nozzle; and improved reverser and inlet linings on the nacelle."
The "noise package" is now standard on the A321 and an option on the other models.
The reason behind this is that the A321 (heavy weight version) doesn't comply with the new stage 4 noise limits in effect for all new aircraft, certified after 1 January 2007.
In fact this is the present noise standard, although legally not valid for the present A320 generation of aircraft, all certified before 1 januari 2007.
All other sub types of the A320 series are at or below the stage 4 noise standard and don't need the chevrons, but can be delivered as an option with this "noise package", to become even more silent.
Also stated in the article is the fact that the FADEC needs some tweaking to produce the same thrust level, so there must be a loss in efficiency somewhere.
Because this is an Airbus brochure, nothing is said about the actual loss in SFC.
Operating a twin over the ocean, you're always one engine failure from a total emergency.