Dagger
16th Feb 2008, 00:05
Hi all.
The operation I work for uses constant angle of attack cruise, with reducing mach no. for any given en route step climb altitude. I assumed this was the optimum way to fly the A/C as part of a normal step climb profile, but have been told by someone who claims to be in the know that Boeing recommends a constant mach no. for any given altitude, with angle of attack reducing with decreasing weight.
I thought that constant AOA would provide the most optimum wing/body angle for the best efficiency. The only thing I can think of is that given we are 1000ft off our optimum altitude at the start of any level step, then the AOA would be slightly above the optimum and thus if maintained would always be less than ideal. Whereas a decreasing AOA would account for this.
Would appreciate if any of you smart people out there could help enlighten me about this one.
Thanks.
The operation I work for uses constant angle of attack cruise, with reducing mach no. for any given en route step climb altitude. I assumed this was the optimum way to fly the A/C as part of a normal step climb profile, but have been told by someone who claims to be in the know that Boeing recommends a constant mach no. for any given altitude, with angle of attack reducing with decreasing weight.
I thought that constant AOA would provide the most optimum wing/body angle for the best efficiency. The only thing I can think of is that given we are 1000ft off our optimum altitude at the start of any level step, then the AOA would be slightly above the optimum and thus if maintained would always be less than ideal. Whereas a decreasing AOA would account for this.
Would appreciate if any of you smart people out there could help enlighten me about this one.
Thanks.