Preliminary investigations within Rolls-Royce indicate likelyhood of un-dampened resonance degrading oil lines in the intermediate turbine area.
Pratt and Whitney and General Electric use a two turbine system.
The Trent engine is a three turbine system allowing shaft speed/compressor optimization at three levels thereby enabling a shorter, lighter engine …not unlike a modern multivalve car engine. (One can optimize throughput at 2 levels with 4 valves/cylinder thus giving two peaks on the RPM curve …with 6 valves/cylinder, one can engineer 3 peaks across the RPM range)
The bottom line is power to weight ratios improve.
Pratt and Whitney and General Electric use a two turbine system.
The Trent engine is a three turbine system allowing shaft speed/compressor optimization at three levels thereby enabling a shorter, lighter engine …not unlike a modern multivalve car engine. (One can optimize throughput at 2 levels with 4 valves/cylinder thus giving two peaks on the RPM curve …with 6 valves/cylinder, one can engineer 3 peaks across the RPM range)
The bottom line is power to weight ratios improve.
Unwanted resonance is by no means a new design issue inherent to the addition of a third turbine. Nor would be the fix.
The analysis was from telemetry data only. (the various bits of interest were all virtually unsalvageable, deep in the Atlantic)
Yet so confident in the fix were these pioneers, the next use of the Saturn V was a manned flight to lunar orbit (Apollo 8).
The fix was centred around using material variety to dampen against each other sufficiently to block strong resonances.
With the Trent, little doubt this aspect of the problem would be fixed promptly.
However, mentioned by Stephen Purvinas, Secretary Australian Aircraft Engineers Association, no-one's talking about the containment failure of the engine casing.
It’s shaping to be design-time pressure that’s driven this top-end engine to market early.
In a sense Rolls-Royce may be let off the hook on this one, more by good luck than any design rigor. Particularly if they’ve the guts to advise disuse until all known major problems are resolved.
However, mentioned by Stephen Purvinas, Secretary Australian Aircraft Engineers Association, no-one's talking about the containment failure of the engine casing.
It’s shaping to be design-time pressure that’s driven this top-end engine to market early.
In a sense Rolls-Royce may be let off the hook on this one, more by good luck than any design rigor. Particularly if they’ve the guts to advise disuse until all known major problems are resolved.
Interestingly, Qantas chose the 72,000 lb version of this engine, RB211 Trent 972-84.
Singapore Airlines and Lufthansa possibly went for a touch of pragmatic modesty with the 70,000 lb option.
Potential oil problems appear to be in the slightly higher rated Qantas version.
If one suspects heraldry in insisting on flagship thrust and excess pride over their excellent safety record, it’s certainly fleshed out by their latest stance on locking out A380 service log data from members of the Association.
Unlike NASA of the Saturn V Apollo era, Qantas, seemingly in their quest to paint a picture of lawful ‘perfection’ for sick publicity reasons, are surely inviting disaster by locking out a proportion of their engineers from key data around this incident.
http://timezombie.blogspot.com.au/2010/11/criminal-minimization-of-qf32-drama.html
http://timezombie.blogspot.com.au/2011/07/bob-quiggin-rupert-murdoch-bows-to.html
http://timezombie.blogspot.com.au/2010/12/lisdoondvarna-matchmaking-festival.html
http://timezombie.blogspot.com.au/2010/11/criminal-minimization-of-qf32-drama.html
http://timezombie.blogspot.com.au/2011/07/bob-quiggin-rupert-murdoch-bows-to.html
http://timezombie.blogspot.com.au/2010/12/lisdoondvarna-matchmaking-festival.html
