Bouncing needles

[bongodriver]

so I definately give more about them than about random internet "flight instructors".

I wonder who that is refering to......unnecessary personal attack

I happen to be a physicist (for real, it's not just a random claim )

why didn't I think of that......I forgot to say cross my heart

and the thing is that the engine has its resonance frequency just like anything else. So, if you have tuned your engine badly, it will be go into resonance, causing it to shake and vibrate. And, because the engine represents a large mass, it will shake up the entire airplane with it. This, in turn, includes cockpit instruments and, since the the instrument needles are allowed to move relative freely, inertia causes them to bounce as well.

I really don't agree, based purely on my 'claim' to be an actual pilot, not an effect I have heard of (until an eminent internet physicist said so), resonance on an airframe is a high frequency vibration, it doesn't cause needles to bounce as if you are driving a car off road.