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Old 29th Apr 2019, 13:51
  #1437 (permalink)  
Triple Nickel 8 Ball
 
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Cool

Originally Posted by WillyPete
I enjoy flying the Cabri.
Yes, the Fenestron and right pedal action takes a bit of getting used to when transitioning from types like the R22 and 44, but it is not difficult. Like learning how to drive a manual car with a "late" clutch pedal effect, rather than a large soft zone of effect.

Things that were driven home early on were "More right pedal!" when coming to the hover, and to always perform your turns in the hover to the right.
There's too much danger in letting the aircraft get away from you if you turn to the left.
Bringing the nose back from too much right pedal is not simply a matter of pushing on the left, it's easier to describe it as releasing the right pedal pressure.
Even in the R22 it's sensible to turn against the torque.

I've chosen to practise airfield manoeuvres in the hover during 20+ knot winds, to get to know the aircraft and my own skills better. It handles absolutely fine in strong winds, but the pilot needs to be aware of the influence of that massive tail and shroud when the wind gusts or you have to make a turn into a tailwind.
We practised 360 turns around a point and yes, having a tail pointing directly into the wind takes all of your concentration. It's massive compared to the R22 tail.
As you pass the point where the wind switches sides of the tail, it can and will grab suddenly and you have to be on top of it - ready to stomp the right pedal. Dicking about with the collective at that point will definitely add or remove some yaw to the equation.

I never felt at any point that there was a loss of authority for such an "underpowered" helicopter as some have called it. Absolutely no evidence of any of the fabled "fenestron stall".
A few times I had to use almost full deflection of the right pedal to hold it there, but we never lost it even in such a relatively high wind for a trainer.
I've been at schools that ground you in the R22 at lesser wind speeds.
It's all up to the pilot to practise and be aware of their own limitations as well as those of the aircraft. From my limited time in it, and experience flying, it's hard to imagine it's a flawed design when it behaves properly within recommended handling guidelines.

"I have to fly it differently than my other types" is not a design flaw.

The article does list several accidents due to uncontrolled yaw, but when you look at them and the circumstances leading up to it you have to ask - would a conventional tail rotor deliver a different, safer result? If the answer is yes, then the design is not flawed but instead has "vulnerabilities" that should be avoided.

I could not agree more with all of this. I've come from a fixed wing background (and "do fixed wing" for a living...) and have recently qualified in the Cabri. I learned a valuable lesson with a superb instructor re the correct pedal input. I've told the story somewhere here before, but in brief, I approached a confined area into wind. A fairly steady 12-15 knots was present and, as we had to turn DOWNWIND for the actual landing (the IP did enjoy making me work on the pedals during downwind hovering), so we could land upslope, for some reason, known only to my sub conscience, I elected to turn LEFT and not RIGHT. All was fine, feeling it around slowly, when the wind took the tail and WHOOSH....we were off at a decent rate of "spin". The IP grabbed it straight away with the standard "I have control (and in his head...."YOU IDIOT!")!" and he sorted it out with a SHED load (nearly all of it?) of right pedal and got us straightened out and immediately gave it back to me to land.

When it first happened, I genuinely thought that the tail rotor had failed or something. I was like a rabbit in headlights.......however, NOW....I think I would recognise the signs of it....and will ALWAYS turn RIGHT in the hover. Actually, if I had turned LEFT very gingerly, and NOT with the same kind of input/pedal speed as I would when turning right, it would probably have been okay.

Overall, the Cabri is an amazing little helicopter (and don't forget....it's a "TRAINER", that was really designed for its UAV capability/military applications).

Roll on the Turby 5 seater!
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