To: Kyrilian
"Ask the following: Since the Robinson helicopters are restricted from sideslip and out-of-trim flight can the R22 and R44 meet the requirements of the Certification Requirements for Normal Category Rotorcraft which require demonstration of both to include 90-degree sideslip and 10-degree out of trim."
Consider also that helicopters (as well as other aicraft) are restricted from flying faster than Vne, yet there are several regulations that require flight testing (and thus demonstrating that such is doable) beyond this limiting speed (i.e. 27.143(e)(2) for power-off controllability). Just because one is not allowed to operate regularly in a given condition doesn't mean that such flight it not demonstrable.
It is not that the Robinson helicopters are not capable of sideslip angles of 90-degrees and out of trim flight at 10-degrees it is that they are restricted from doing it because of inducing high flapping loads leading to mast bumping. You can operate any piece of machinery to the point that you exceed operational limits but you are inviting disaster.
My point was that if the Robinson helicopters have this restriction, and let’s say that Frank Robinson,placed them up for certification at this date and, he told the FAA that his helicopters could not meet the certification requirements of operating at sideslip angles of 90-degrees + - or, fly out of trim by a ten degree angle + -, the FAA would most likely not grant approval.
In light of the above, the question begs asking and that is if it was discovered in 1995 that sideslip and out of trim flight would result in extremely high flapping loads why wasn’t this discovered when the helicopter was demonstrating these maneuvers to gain certification?
Regarding your comment above, I do not believe that the certification documents specify a Vne for any type of aircraft. This is established by testing and possible computer analysis to determine the operational limits of the aircraft. Once established, it becomes a part of the operational manual.
[ 31 October 2001: Message edited by: Lu Zuckerman ]