CFI
Anyone out there know the full story?
A quick seach on the NTSB web site found this
NTSB Letter to the FAA.
OK maybe the word "shudder" was a little unspecific, but that is the way I describe the movement of the airframe and the sound it makes when you shut a little aeroplane down.
Shudder is a good word, I like it

I just got back from putzing around in the aerobatics box with a Great Lakes. I could not get the airframe to make any strange noises/vibrations when shutting down power to idle, entering a spin or recovering. I turned around to watch the tail during the procedure - easy as it's an open cockpit biplane and you just stick your head out the side

- and didn't see any nasty movements. Note to oneself: Hold expensive sunglasses on tight when back of head is pointing into wind, and make sure stomach is settled before spinning looking to rear
Having said all that I prefer my students to do their spinning in a C152 Aerobat so they can see some other upside downy type things at the same time, and hopefully enjoy the experience a bit more!
Indeed! It is so difficult to resist the temptation to go straight into an Immelmann or hammerhead when pulling out from a Spin. Cannot do that in a tomahawk, - or maybe some of you can