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To: Paal Gulli

Harmonic resonance is the bane of mechanical engineers, and especially aircraft engines.


3 posted on 02/28/2023 8:45:12 AM PST by Lonesome in Massachussets (Forsan et haec olim meminisse iuvabit.)
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To: Lonesome in Massachussets

Spent 36 years in aviation maintenance and I’m familiar with Harmonic resonance but I’ve never heard of it in regards to an ejection event......I guess it’s possible.


5 posted on 02/28/2023 8:49:36 AM PST by V_TWIN (America...so great even the people that hate it refuse to leave!)
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To: Lonesome in Massachussets

Couple of wheel weights on the end of a a few turbine blades should do it.


6 posted on 02/28/2023 8:49:44 AM PST by Cold Heart
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To: Lonesome in Massachussets

“Harmonic resonance is the bane of mechanical engineers, and especially aircraft engines.”

I’d add bridge/ structural engineers and provide an example of that bridge in the Pacific NW that shook itself to pieces back in the 1940s.


9 posted on 02/28/2023 9:00:11 AM PST by T-Bird45 (It feels like the seventies, and it shouldn't. )
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To: Lonesome in Massachussets

Picked up an Engineering class a few years ago where the instructor showed a clip of a CH-46 (chained down) and it just beat itself to pieces during ground runs.


27 posted on 02/28/2023 9:25:41 AM PST by Psalm 73 ("You'll never hear surf music again" - J. Hendrix)
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To: Lonesome in Massachussets

IIRC, harmonic resonance was tearing the wings off of early Lockheed Electras.


29 posted on 02/28/2023 9:31:54 AM PST by SIDENET (Whatever they're threatening, the vaxx is worse. Don't give in to coercion. )
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To: Lonesome in Massachussets
"Harmonic resonance is the bane of mechanical engineers, and especially aircraft engines."

Ever hear of a phenomenon in helicopters called "ground resonance"?

https://en.wikipedia.org/wiki/Ground_resonance

It only happens to 'copters with articulated rotors and some sort of impact damping system on the landing gear (pneumatic wheels, oleo struts, or even thick rubber bushings on the saddle tubes of skids). The a/c enters a positive feedback loop and when it's pronounced enough to be noticeable, it's probably irreversible and the aircraft is going to shake itself to death.

https://www.youtube.com/results?search_query=ground+resonance

Frightening to watch, especially if you've ever been inside on of them thangs.

40 posted on 02/28/2023 11:40:59 AM PST by Paal Gulli
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