Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Replacing Existing Engines With "ng" Engines  
User currently offlineBoeing nut From , joined Dec 1969, posts, RR:
Posted (11 years 4 months 1 week 3 days 9 hours ago) and read 3629 times:

Greetings all,

Just curious. Is there a specific reason why, for example, a 747-100 could not have a derated, say PW4000, replace the old engines? Thrust is an issue of course, but I included the possibility of a derated engine.

3 replies: All unread, jump to last
User currently offline2H4 From United States of America, joined Oct 2004, 8957 posts, RR: 56
Reply 1, posted (11 years 4 months 1 week 3 days 8 hours ago) and read 3551 times:

I suspect it has more to do with the compatibility of engine accessories then the engine itself. The electrical, pneumatic, hydraulic, etc systems on the original engine all mesh perfectly with their wing or airframe-mounted components.

I'd imagine it would be easy to simply replace the engine itself. Maintaining systems compatibility would be another story. Hopefully someone more knowledgeable can confirm or deny this.


Intentionally Left Blank
User currently offlinePhilsquares From , joined Dec 1969, posts, RR:
Reply 2, posted (11 years 4 months 1 week 3 days 7 hours ago) and read 3528 times:

In the example you used there are several issues. First the engine pylon would have to be redesigned. The wing structure on the 400 wing is different than the pylon attachment on the 100. But, the biggest issue would be the certification process required by the FAA/JAA.

In most re-engine modifications, there is a incredible amount of engineering work to be done for the mods. All of this normally makes the process cost prohibitive.

In the example of the 747-100, there are several very expensive ADs out. Plus the aircraft falls under the aging aircraft program. Both are extremely costly. The -100 also suffers from a very light gross weight making it even less suitable for any engine mods.

User currently offlineTepidhalibut From Iceland, joined Dec 2004, 214 posts, RR: 5
Reply 3, posted (11 years 4 months 1 week 2 days 23 hours ago) and read 3229 times:

On the purely practical side : The NG engines are digital, the 741 cockpit/controls are string and cams. So you need a new cockpit. And then the wiring throughout the aircraft needs to change to suit, and that ain't cheap.

Obviously, you don't want to suffocate the passengers, so cabin air supply is required. The NG engine don't supply that, so you need another new system...

The thrust levels for the NG engine are higher that the example 741 engines, so what do you do? Operate the same engine at lower speed/thrust ? Then you carrying around a heavier engine than you need. Redesign the engine to get the weight out ? You'll then need a new FBO test. Use that extra thrust ? The aircraft just wasn't designed for it.

Really, you'll just spending loads of money to end up with an aircraft that's probably no better than more recent (743?) aircraft, available cheap from the deserts.

To use a technical phraseology "It's no good trying to polish a turd".

Top Of Page
Forum Index

Reply To This Topic Replacing Existing Engines With "ng" Engines
No username? Sign up now!

Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)

Similar topics:More similar topics...
Widebody With Fus Mounted Engines? posted Sun Feb 20 2005 21:56:23 by DAYflyer
747-300 With CF6-80 Engines posted Mon Dec 13 2004 04:47:38 by MrFord
Early Problems With The A340 4 Engines posted Tue Jul 20 2004 16:17:00 by A380900
Can B744s/A345s Take Off With Only Two Engines? posted Sat Mar 6 2004 09:47:38 by StarG
7E7 With Bleed Free Engines? posted Thu Feb 12 2004 01:27:37 by Fly2hmo
Flight Number With An Added "D" In Callsign? posted Sat Aug 16 2003 05:46:48 by Pilottim747
A Taxiway With "3" Hold Short Lines...Why? posted Wed Mar 19 2003 17:54:05 by Mr Spaceman
Choppers With JSF Configured Engines? posted Tue Oct 1 2002 22:04:59 by Planelover
DC-10's With Different GE-engines posted Mon Apr 8 2002 23:25:23 by Ganymed
Aircraft With "turning And Burning"- Engines. posted Sun Oct 30 2005 22:32:08 by AmericanB763ER

Sponsor Message:
Printer friendly format