Was thinking it may have been an auto competition against the Wessex and Lynx, how quick to the ground from ten grand. :p

30 seconds :) No parachute.

The US Army also required Parachutes for certain Test Flights....and had a requirement for helicopter units to possess such.

They bright sparks writing the TO&E (Table of Organization and Equipment) for helicopter units sagely demanded each unit have exactly one Parachute.

That the minimum crew on a Chinook never crossed their Pea Brains and there we were equipped with the one and only....and no Parachute Loft, Parachute Rigger, and no way to maintain that single chute.

Desperately needed to talk to someone one day so climbed the faithful Jetbox up to 16,500 +- 15,500 Agl.
Passed the message and wanted to initiate re-entry, lowering the pole and the RPM wanted to exit the powered flight regime even with min beep.
Auto- rotated down…no problem....missed my spot by miles but over the Eastern Canadian Tundra that would not have been a problem. The whole darn place is a “Suitable Forced Landing Area” …except for the wet spots of course.

In flight school I got a 47G-2 up to 11,000 ( 10,000 AGL ) once. The view was great but you felt you were balanced on the end of a pin.
Instructor: “Where did you go?”
Me: “I got her up to 11,000+ before she ran out of steam. Toronto Centre thought it was hilarious.”
Instructor: “Jesus H. Christ! …..You did WHAT!” Yell to the CFI “Hey Wayne you ain’t to believe what our twisted maniac has done this time!”

Did that too 20 year ago, in the flight school H269, solo with very little pilot experience, used the steady marine brise and a perfectly located sloping mountain to help me get there.
All the throttle I could get (manual governor) for a good 20min. Coming back 3 days later, the H269 is out of comission!, a airline crack was running along the engine block for a good 12inch. good thing there was no GPS flight tracking back then

Felt sorry for the flight shool ever since.

No reason to feel guilty….as you climbed you would have been pulling less and less power. As long as temps, pressures and RPM were in limits during your long climb and descent it should not have caused any engine problems. Probably much, much less wear and tear on the engine, drive train and airframe than doing practice confines for the same amount of time for example.