Extrapolation of VMCa to minimum weight
Thread Starter
Joined: Dec 2011
Posts: 8
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From: France
Extrapolation of VMCa to minimum weight
Hello,
I would like to know if some of you have ever participated to VMCa testings.
I have found in the FTG from CS-23 or FAR-23 guidance for extrapolating a value obtained at a given density altitude to SL - ISA conditions (it's quite easy since it's just a kind of thrust correction).
However, this method doesn't propose any correction to account for the aircraft (since VMCa is determined at a 5° bank angle, but cannot always be tested at the certification minimum weight).
If any of you has developped a method to account for the weight in VMCa determination from flight tests, a few tips would be appreciated.
thanks!
I would like to know if some of you have ever participated to VMCa testings.
I have found in the FTG from CS-23 or FAR-23 guidance for extrapolating a value obtained at a given density altitude to SL - ISA conditions (it's quite easy since it's just a kind of thrust correction).
However, this method doesn't propose any correction to account for the aircraft (since VMCa is determined at a 5° bank angle, but cannot always be tested at the certification minimum weight).
If any of you has developped a method to account for the weight in VMCa determination from flight tests, a few tips would be appreciated.
thanks!
Joined: Sep 2002
Posts: 2,188
Likes: 6
From: La Belle Province
AC25-7B contains two appendicies which provide some general guidance on correcting VMCA test results. If the required additional aerodynamic data are known, correction for weight is possible using the Appendix 3 or Appendix 7 methods. if a properly validated simulation model of the aircraft is available (note: that means better than the match-where-it-touches Level D sim) that could be used as well.
Thread Starter
Joined: Dec 2011
Posts: 8
Likes: 0
From: France
Perfect, thank you. I did not think of looking at 25 FTG ...
(A little bit of rewriting the equations and I could have approached the solution by myself, but at least I'm sure to follow an approved method which won't call any discussions).
Again, thanks for your quick answer.
Chti
(A little bit of rewriting the equations and I could have approached the solution by myself, but at least I'm sure to follow an approved method which won't call any discussions).
Again, thanks for your quick answer.
Chti
