747ADV engines
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747FOCAL
And "the problem" is? - don't keep us in suspense
I may not have detailed knowledge of how Appraisers arrive at their values (although I doubt detailed knowledge comes into it!) but I know what the market is actually offering today and RR-powered aircraft would sell at a premium to PW powered if not to GE powered.
And "the problem" is? - don't keep us in suspense
I may not have detailed knowledge of how Appraisers arrive at their values (although I doubt detailed knowledge comes into it!) but I know what the market is actually offering today and RR-powered aircraft would sell at a premium to PW powered if not to GE powered.
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aftermarket re-engining
A bit of well-buried history:
1983-84, Delta & All Nippon were gung-ho to re-engine their TriStars. They needed one more operator to make the program viable - TWA - but TWA was in no position to embark on same.
In fact, Harry Stonecipher's MD-80 lease program was the only thing that kept TWA's head above water for a while.
1983-84, Delta & All Nippon were gung-ho to re-engine their TriStars. They needed one more operator to make the program viable - TWA - but TWA was in no position to embark on same.
In fact, Harry Stonecipher's MD-80 lease program was the only thing that kept TWA's head above water for a while.
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Torquelink,
Have you seen an aicraft pricing guide? I have one sitting on my desk, actually from two different sources, and they both show RB211-524 powered 747-400s and 767s as +20% less value than a comparable GE or Pratt.
If you would read back, I said search around PPRUNE and you will find what I am talking about. I am not going to do it all for you. Try and learn something while your at it.
Have you seen an aicraft pricing guide? I have one sitting on my desk, actually from two different sources, and they both show RB211-524 powered 747-400s and 767s as +20% less value than a comparable GE or Pratt.
If you would read back, I said search around PPRUNE and you will find what I am talking about. I am not going to do it all for you. Try and learn something while your at it.
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744 RR engines are always are having problems with :
1. attrition liner damage/replacement
2. ogv infill panel seperation/ogv cracking
3. titanium acoustic panel delamination
4. ice breaker panel delamination
5. thrust rev motor failure
6. flex drive cable breaking/seizure
6. thrust rev sense line failure/leaking
7. bleed valve sense line failure/leaking
8. selector seq valve malfunction
9. sense line clamp failure
10. interservices structure cracking
11. N1 fan vibrations
744 GE engines nothing goes wrong except the odd thrust rev does not deploy and a bit of anti ice fluid poured into the cdu can fix this.
GE engines a little bit harder to work on with but a better fuel burn than RR.
1. attrition liner damage/replacement
2. ogv infill panel seperation/ogv cracking
3. titanium acoustic panel delamination
4. ice breaker panel delamination
5. thrust rev motor failure
6. flex drive cable breaking/seizure
6. thrust rev sense line failure/leaking
7. bleed valve sense line failure/leaking
8. selector seq valve malfunction
9. sense line clamp failure
10. interservices structure cracking
11. N1 fan vibrations
744 GE engines nothing goes wrong except the odd thrust rev does not deploy and a bit of anti ice fluid poured into the cdu can fix this.
GE engines a little bit harder to work on with but a better fuel burn than RR.
Usual disclaimers apply!
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Acoustic panel:
Aft of the fan attrition liner, are honeycombe panels which on pre sb engines there were 9 of them that were bonded onto the fan case with additional bolts for security, over time they would suffer from disbond due to their being too rigid and start to break up losing the top skin and damaging the the underlying honeycombe. The fix was for 'bluefill'. (which compromised the acoustic properties... thats the bit FOCAL has been hinting at
) The later post mod panels are 1/3rd the size and bonded in with BMS5-95 which is flexible. I've only seen a couple of the post mod panels replaced and that was due to impact damage (bird strike).
Not seen a cracked OGV for years.
The T/R can be a pain (designed by Nordam I think) AFAIK we have incorporated the mods and SB's for the sense pipes etc at overhaul so sense line failure thankfully is thing of the past. But! they tried to be clever and it's all prox. switches, what's wrong with a good old fashioned mechanical micro switch? that would have cured 99% of T/R problems.
Other than that they stay on wing for a long time and suffer little in the way of performance degradation over the life of the engine.
And the best thing from a maintenance point of view they are sooooo simple to work on!
Aft of the fan attrition liner, are honeycombe panels which on pre sb engines there were 9 of them that were bonded onto the fan case with additional bolts for security, over time they would suffer from disbond due to their being too rigid and start to break up losing the top skin and damaging the the underlying honeycombe. The fix was for 'bluefill'. (which compromised the acoustic properties... thats the bit FOCAL has been hinting at
) The later post mod panels are 1/3rd the size and bonded in with BMS5-95 which is flexible. I've only seen a couple of the post mod panels replaced and that was due to impact damage (bird strike).Not seen a cracked OGV for years.
The T/R can be a pain (designed by Nordam I think) AFAIK we have incorporated the mods and SB's for the sense pipes etc at overhaul so sense line failure thankfully is thing of the past. But! they tried to be clever and it's all prox. switches, what's wrong with a good old fashioned mechanical micro switch? that would have cured 99% of T/R problems.
Other than that they stay on wing for a long time and suffer little in the way of performance degradation over the life of the engine.
And the best thing from a maintenance point of view they are sooooo simple to work on!
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gas path,
You gave them a piece, but not exactly what I am hinting at. Breakdown in acoustics is not the RR problem I am getting at. It's the darn ******* and no amount of acoustic panels can be put in the engine as it is today to change that. Now if you add 5 foot of tailpipe completly lined with the right acoustic panels then you might have something.........
You gave them a piece, but not exactly what I am hinting at. Breakdown in acoustics is not the RR problem I am getting at. It's the darn ******* and no amount of acoustic panels can be put in the engine as it is today to change that. Now if you add 5 foot of tailpipe completly lined with the right acoustic panels then you might have something.........
Last edited by 747FOCAL; 18th May 2005 at 05:37.
