Here's the ticket for a stock Legacy prop, it's 70 inches as shown by the serial number (73 minus 3). Rickard's LIV prop appears to be 76 inches, from the serial number.
I too have a vibration in my Legacy IO-550 and have had dynamic balance check out perfect. It's around 20Hz, I'd guess, and the visible amplitude at the wingtips is about 1/4 inch. Most passengers don't notice it; I normally cruise at 2300 rpm; it seems a little smoother at higher rpm. I have a hard time believing that all Hartzell 3-blade props on all Lancair 550s, regardless of diameter and horsepower, have the same problem; but now I wonder.
Just before Placerville I let the USAF's chief F-16 test pilot fly my Legacy and he commented immediately on the vibration. I figured that's because he flies jets and gliders, neither of which ever vibrate... but my friend's 2-blade RV-6 / O-320 doesn't have this vibration either...
Has anyone definitely flown a vibration-free IO-550 Lancair (or TSIO-550) with *any* propeller? And by vibration-free, I mean it is free of low-frequency 10-20Hz stuff, not the normal noise of flying. What I'm wondering is... is it the 550, making such vibration with *any* propeller?
Charley Brown Legacy RG 280hr
On Jul 23, 2013, at 6:37 AM, Steve Colwell wrote: We have been chasing a vibration from the first few hours on our Legacy IO-550 with stock compression and a Hartzell 3 blade. I don’t have easy access to the prop model but it is the standard Hartzell supplied by Lancair for the IO-550. Our vibration varies in magnitude with power setting and air speed. It is most noticeable with control stick shake but also could be felt on the dust cover. I went thru an exhaustive series of finding engine/cowl contact points, questioning gear doors, rechecking control surfaces, two prop balances and an engine rebuild (cracked case). I thought it was almost fixed several times since it was not easily replicated. Then it would come back, sometimes very slightly, other times worse. Actually, this is a relief to know what the likely problem is after 5 years and 400 hours of chasing a fix. We just booked a Southwest round trip to OSH. I really don’t want to be the next statistic. Thanks Bob and Ed. Steve
|