Tail Boom 'Crinkling'
I am interested to know if seeing ‘crinkling’ on the tail is usual on helo’s in the hover.
For instance, recently I saw an aircraft (one of Mr Sikorsky’s finest, think Blackhawk / Seahawk) in the hover, and the starboard side was ‘crinkly’, around the transition section and forward half of the tail boom. The crinkles on the transition section were larger in width, and not as noticeable as those on the forward half of the tail boom, which were smaller in width, but more numerous. These are not visible when on the ground (ie no load).
All crinkles ran aft as they went from top to bottom (ie top right to bottom left as you look at the starboard side). The aircraft has had some additions in this area, presumably the engineers did appropriate strengthening etc.
Is this crinkle a normal thing? I understand why it is on this side, as this is the side under compression due to tail rotor force.
I’m especially interested if this is normal on Blackhawk / Seahawks. It’s not something I have ever seen before, as I’m normally inside looking out.
Thanks,
SUA