Hi Shy, my engineering degree friend, some questions for you:
1 'Mandraulics' (great term) sure, agree - no good for autopilots.
As for Tail Rotors: IF Hyd TR is not necessary AND HydTR can kill you, THEN do you chose HydTR? (AW139 drivers?)
2 "One engine = one power source for electrical equipment." Sounds like a thoroughly lousy reason to carry a spare engine.
Spare electricity can be provided in so many more ways. Maybe like HYD, a GENi on the XMsn(?), if you were really worried about that then 30kg of extra batteries would do it ... OR 500kg of spare engine complication ((that can kill you)).
Which source of spare electricity would you chose?
3 'Stats against Twins look bad, because the singles aren't flying there'. You said it. YES THEY DO LOOK BAD... they are bad. The singles ARE THERE (eg only restricted in LONDON by R160) and the rest of history and the rest of the world leaves a data set that blows that argument away, and that argument flips the other way too: look at the MAJOR twin accidents that have not killed people on the ground because they were over barren sea/land, and NOT over urban areas !! Had they been over urban areas we'd have a total disaster for helicopters in general. (maybe over the NS but over London? A risk worth taking??)
4 Engineering wise: isn't simplicity the goal? Leonardo DaVinci, Simplicity is the ultimate sophistication. Occam, Newton, Einstein, KISS (Kelly Johnson). Not a fan of simplicity ?
1) The A139 accident appears to have been caused by a tail rotor control failure, not by a hydraulic failure. As you obviously don't hold an engineering degree, perhaps you haven't grasped the reality that control feedback forces increase markedly with an increase in aircraft size. Perhaps you drive a car with servo assisted brakes or power steering? If so, have you complained to the manufacturer that both systems add unnecessary weight, complication and expense? I doubt it. Perhaps you would prefer to fly in an airliner without powered controls? I doubt it.
2) The main thrust (!) of your campaign is to make the main rotor gearbox simpler by only having one engine. Yet now you advocate making them more complicated to generate electrical power.... I fail to see any contiguous logic in that.
3) I take it that you operate singles in other congested areas. I hope that you make a point of obtaining the necessary CAA Permissions. I always do, for twin engined helicopters.
4) Engineering always requires compromises and there is seldom a simple answer. There could never be an autopilot or stability systems, a point I already stated and with which you agreed. Pilot fatigue would become a more important factor. If you wanted to build a large helicopter with no hydraulics, there would be considerable design compromises. These would include heavier control runs, which in turn would require structural reinforcement, adding weight and reducing payload. A much larger, single engine, rather than two smaller ones, would require a far stronger and heavier gearbox that you might at first imagine. Again, it would require a far heavier structure to support it. A doubling of size doesn't necessarily result in a doubling of material strength. - it might require a "square" increase. Again, see my answer 2).
A further point. I noticed that you posted your last two replies at 01:07 and 03:54. As flattered as I am that you consider me a friend and that a prompt reply to my post obviously so important for you to stay up so late, I suggest you get more sleep, it helps engender rational thought. Obviously, as an instructor, you already will know that. I'm not flying today, but still got a good night's sleep. I hope you aren't in the air until well rested.
