Prop balancing and assorted observations - long

On Sat, 26 Jun 2004 14:54:49 -0500, "Fly" wrote:

I've been dynamic prop balancing for 15 years.

0.3 plus a little is not a severe vibration but could be improved.
Many skeptics would call it smooth to begin with.
What was the IPS amplitude of the engine aft,.... or did the operator just
use a single sensor? A sensor on the rear will give you an idea of
crankshaft and rod balance. Lycomings usually are 0.15 to 0.18 the rear.
If it was a custom balanced engine, the rear should run just as fine as the
front.

I looked at the mooneymite site. Interesting. The same principle as a
reed tach. Its just a pendulum adjusted to resonance. Insturment face
vibration frequency will be at crankspeed, 1/2 crankspeed or some other
multiple half order.
The author is painting the tips, which will change the spanwise balance but
not chordwise balance.///
Take Care
Kent Felkins
Tulsa

Browsing the sci.engr groups I noticed a suggestion
for a cheap n cheerful vibration sensor:
take a piezo buzzer, and add a weight to load the cell.

This gives a (high-impedance) signal at the output. You can see it on
a scope by shaking the sensor, as described.

Brian W