Originally Posted by
dubbleyew eight
second correction. there really is no allowable imbalance for a propeller.
the propeller must be in perfect balance for vibration free flying.
if you do fly with an out of balance prop every part of the aircraft will be subject to relentless vibration.
Um... that's ridiculous. If after a flight, you notice a dead gnat stuck to the hub of your prop, are you going to ground the airplane and send it for prop balancing? Not likely. OTOH if you notice a dead raccoon impaled on one of the blade tips, you probably ought to get it checked out.
From the webpage of a company that balances props
(http://www.expaircraft.com/PropBalance.htm):
"
We typically see beginning vibration levels from 0.25 - 0.60 IPS (Inches Per Second) or more, anything above 0.20 IPS is considered out of limits and requires balancing. The industry standard after balance limit is 0.15 IPS, this where your average balance shop will say it's "good enough". We guarantee a level of 0.07 IPS or less after balancing, less than half the industry accepted after balance limit!"
Note that they do *not* state the limit, even their "stricter than standard" limit, is zero.