So, 737 and A320 replacements - UDF or GTF? Presumably a UDF will need some sort of a gearbox anyway not to mention variable pitch blades/rotors. I suspect that installation complexities, weight and noise will favour GTF or, at least, will not favour UDF. Watch out for GE/Snecma launching gearbox demonstrator programme and RR conceding that PW can put a geared fan on V2500 replacement?