Airframe affect on powerplant vibration characteristics?

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fadec

Well-Known Member
Joined
Aug 18, 2011
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105
Location
New Zealand
For this exercise lets assume that to design an aircraft powerplant properly the engine/psru/prop needs to be analysed/tested/optimised as a whole system rather than as seperate components. The problem is that the powerplant doesn't fly around on its own, it needs to be bolted onto something.

I know that engine vibration can certainly cause airframe failure but what of the reverse? Does the airframe have any significant affect on the vibration characteristics of the powerplant system? Is it possible for the airframe to affect the vibration characteristics in such a way as to cause premature failure in the engine/psru/prop?
 

Dana

Super Moderator
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Apr 3, 2007
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10,225
Location
CT, USA
If the airframe is insufficiently rigid so the engine can move around, or if there's a resonant frequency within the engine's rpm range, then yes, it could conceivably cause problems.

More common is an engine on too-soft vibration mounts, so the engine dances around enough to wreak havoc with external engine components (cracked exhaust, most likely).

-Dana

The speed of light is greater than the speed of sound. That's why some people seem very bright until you hear them speak.
 
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