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Old 24th May 2020, 22:46
  #461 (permalink)  
tdracer
 
Join Date: Jul 2013
Location: Everett, WA
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Originally Posted by krismiler
With engine bypass ratios becoming higher and ground clearance being reduced, has adequate consideration gone into the location of vital components such as pumps, gearbox’s and supply lines ? Whilst space is obviously constrained, having vital systems in a vulnerable position should be avoided.
There are numerous design considerations that going into the design and location of the gearbox and other accessories (cross-engine debris, cooling, fire protection being just a few) - and as DR noted I don't think doing a go-around after a wheels up landing is one of them.
Many larger engines (larger than a CFM - e.g. PW4000, GE90, GEnx) have the gearbox located on the core instead of the fan case - but that's done for aerodynamic drag reasons (smaller diameter nacelle), not any consideration of wheels-up damage. On CFM sized (and smaller) engines there simply isn't enough room to make a core mounted gearbox practical. Similarly the 3 spool RB211 and Trent engines have a relatively fat core that also makes a core mounted gearbox impractical. The 737 engines have 'split' accessories on the fan case - instead of at ~six o'clock, they're moved to ~4 and 8 o'clock - but that's done for ground clearance - not for any consideration of a wheels up landing - furthermore there is a great deal of plumbing and wiring crossing the six o'clock so I doubt it would fare any better in a similar scenario.
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