It depends what is your flight condition or flight profile. For Cat A operations optimum NR is 102% as pubblished
With respect the aircraft does not know whether you are flying Cat A or Cat B so the type of profile selected cannot affect the rotor efficiency. It is either more efficient at 102% or not. If it is more efficient then why not use it for Cat B ops and for OEI landings? I suspect, but I don't know (and I wish I did) that the helicopter is designed to fly at 100% because that is the most efficient Nr.
In order to meet the RFM Cat A performance you have to stick to RFM procedures that are quite clear. FADEC will take care of the power once you take care of the pubblished procedures
The FADEC (actually it's not a FADEC but I know what you mean) will only deliver if you put the collective in the right place. As the RFM invites you to adjust collective during the response to engine failure it may not be in the right place to get max power from the remaining engine. 'FADEC' wont help you then.
Not true, collective has to be kept at the same position of a standard AEO maneuvre unless a droop is necessary to achieve transational lift to accelerate to Vtoss
Well the only practical way I know that you can be sure the remaining engine is at max power is to pull until the NR droops. Exactly how much droop would depend on the circumstances.
The starting point for Cat A can only be 102%. The droop is allowed up to 90% and is not meant to achieve a better efficiency but to convert the huge M/R inertia into transational lift, once you have achieved Vtoss you have to recover your 102% NR setting.
Agree
100% Nr is only for Cat B because there is no need for extra power to ensure best Cat B performance in the entire envelope.
Surely any wise pilot who believes that 102% Nr endows the machine, in some way, with better performance, would select 102 for every take off - A or B.
I am not sitting here thinking I know all the answers that's why I'm enlisting Ppruners help and advice but if it's not published by AW then I have to be sceptical. If AW say 102 is good for Cat A but not for Cat B then I have to look deeper for an answer. It cannot be performance, it must be technique. Somebody show me otherwise and I'll be a happy man.
G
