I don't know if 2-bladed TR systems take less control input force than three bladed, I'm just expecting some correlation between weight of helicopter and the tail rotor thrust, or control input force. AW169 gross (increased with a kit) is 10582 lbs. Bell mediums with a single hydraulic to the tail-rotor were the 430 - 9300, 205 - 11,200, 212 - 11,200, 412 - 11,900. All these are flyable and landable with no hydraulics to the tail-rotor servos. I had to do it in training for those types and I trained others to do it later.
I'm hesitating on the AW169 because I'm unsure of the mechanics of the Teleflex system and whether the leverage and control strength is there. Agusta/Leonardo, like Bell, can build some pretty stout pedals though, judging from the abuse they can take on the AW139 just setting the parking brake. It would be a major surprise to me if the 169 tail rotor wasn't controllable without hydraulics Gotta eat crow and agree with crab on this one, given no drama's patient explanation, but it has two systems and the main rotor isn't controllable without at least one, so a somewhat moot point that only serves to pad the thread while we wait for answers.
Not thread drift, but just to correct any misunderstandings, the 212 main rotor is controlled through a stab bar and can be flown with both hydraulics shut off, of course, otherwise Bell could not have certified it with that switch logic. Flight Check Procedures require shutting both off in flight at 70 knots - look it up. In my early days in the industry we expected pilots to be able to land it with both systems off, and we all did, and when we became instructors we taught it. Even spaghetti-armed Brit pilots that found it impossible at BHL, magically found the strength on this side of the Atlantic where failure meant no job.
Last edited by malabo; 11th Dec 2018 at 15:41.