Boeing are FINALLY about to deliver a 787!
Discussion
AlexS said:
coanda said:
I tend to think that extensions will be given wherever possible. I should think that a re-engine campaign will occur at least once during the life of these airframes. I'm interested to see if geared fan technology can be scaled up from single-aisle sized applications to ETOPS aircraft.
The question is, whether there is any need. The GE engine on the 320-Neo is just as efficient as the P&W GTF and doesn't need to use any unusual technologies.As to the GE vs GTF on the Neo, there is demonstrable little benefit in the new technology and a whole big question mark over gearbox reliability and maintenance costs at this time. However as an in-service development programme for Open Rotor technology (the gearbox is where the work will be) and more importantly a way back into the market (profit less important!), P&W are right to take the risk.
As to the long term viability of these aircraft once OR is available, questionable at best and certainly not the 25yrs commonly assumed. The OR fuel burn improvement is so large that it should be the way forward......
....as long as fuel prices stay high!
Number31.
AlexS said:
coanda said:
I tend to think that extensions will be given wherever possible. I should think that a re-engine campaign will occur at least once during the life of these airframes. I'm interested to see if geared fan technology can be scaled up from single-aisle sized applications to ETOPS aircraft.
The question is, whether there is any need. The GE engine on the 320-Neo is just as efficient as the P&W GTF and doesn't need to use any unusual technologies.GE have aimed to increase thermal efficiency by getting high TET's using advanced materials and better combustion with their TAPS technology.
P&W have gone down the route of trying to increase propulsive efficiency by decoupling the fan from the LPT and slow it down.
Ultimately, both thermal and propulsive efficiency need to be increased with their respective technologies - slower fans and higher temperatures.
navier_stokes said:
AlexS said:
coanda said:
I tend to think that extensions will be given wherever possible. I should think that a re-engine campaign will occur at least once during the life of these airframes. I'm interested to see if geared fan technology can be scaled up from single-aisle sized applications to ETOPS aircraft.
The question is, whether there is any need. The GE engine on the 320-Neo is just as efficient as the P&W GTF and doesn't need to use any unusual technologies.GE have aimed to increase thermal efficiency by getting high TET's using advanced materials and better combustion with their TAPS technology.
P&W have gone down the route of trying to increase propulsive efficiency by decoupling the fan from the LPT and slow it down.
Ultimately, both thermal and propulsive efficiency need to be increased with their respective technologies - slower fans and higher temperatures.
I definitely see OR being used on next gen single aisle, which is why we are having to wait. OR makes the next leap in efficiency possible, but for single aisle to begin with. I'm really excited about next gen single aisle because we may finally see a move away from the current configurations. I think that should be cause for celebration on it's own, let alone the other new technologies on the way.
toppstuff said:
I sometimes worry if, lets say in about 10 years time when the first 787's are being run by outfits such as Tunisian Airways or Air Burkina Faso, we might find out what happens when they do...?
Theres video out there of the wings being tested on rigs and it is phenomenal the amount of flex they can take before they break. 
RR OR Concept Speculation Here
GE Here
NASA Paper Here
Thermal efficiency is the bread and butter of the big three, $100Ms a year are spend on R&D. This has provided the bulk of the 1% per annum improvement in SFC that have been the normal over the last couple of decades. However the laws of physics will dictate an end to this at some point in the not to distant future so the search for greater efficiency naturally moves elsewhere - OR being one of those areas. PW has chosen to focus on GTF while GE and RR are off looking at OR again!
GE want this game to last as long as possible as it has most to loose in the 150 seat market, the longer it can delay the OR the better as currently GE is incumbent on the 737 and takes 50% of A320 business. The move to new airframes would likely see either an engine choice on both marks or sole source on both (from different engine makers).
If fuel prices remain high, the most efficient choice is to optimise the power plant and airframe together which would give another 1-3% improvement over and above what new power-plant and airframe currently generate. This would drive the sole source engine choice.
can we have real looking planes too?
shouldbworking said:
Open rotor will never happen unless a resolution to the noise issue is found.
The noise issues appear to be solvable....."Rolls-Royce began wind tunnel tests for the open rotor system in 2008 and 2009 in the Netherlands and the UK. The tests showed that, as well as being more efficient, the engines were quieter than existing types and would meet future noise legislation."
Quote from RR website.
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