Ah… tilt-rotors. Hmmm. Ask the US armed forces about those. Many, many moving parts involving twiddly blades for helicopter-style hover, change to coventional blade for forward flight; then chains, sprockets, gears and diffs to tilt four whole engine-rotor assemblies up and down. All, presumably, being made by lowest bidder. No thanks. Now, if we hadn’t dumped the (much simpler) Harrier…