Rotor blades - Airworthiness Directive - Celier - Trendak - Argo

C. Beaty

Gold Supporter
Joined
Apr 16, 2004
Messages
9,724
Location
Florida
Doug, you’re the expert but wouldn’t those manufacturing inconsistencies result in 1/rev vibrations, much like out of balance, out of pattern or out of track?
 

Doug Riley

Platinum Member
Joined
Jan 11, 2004
Messages
6,339
You'd think so, Chuck. It's so long ago I don't recall the mix of vibes, only that there was more overall vibration with this second set than with my original set. I did chase the adjustments available to minimize 1/rev: tracking and chordwise movement of the whole rotor via the threaded teeter barrel. The fact that the blades had a "handmade" look does make me wonder about what other aspects may have varied from set to set -- stiffness, mass and even actual teeter height. Some of those items could create a 2/rev, though not one derived from in-plane flexing, just from incorrect teeter height.

The person I bought them from, a good honest gyro guy, said he could never get them really smooth. He therefore gave me a nice price. I had fair warning, and no reason to be dissatisfied.
 

C. Beaty

Gold Supporter
Joined
Apr 16, 2004
Messages
9,724
Location
Florida
Thanks, Doug; like you, it’s been so long ago that my limited exposure to Skywheels is a fading memory.

I finally learned, mainly from watching “Birth of the Bell Helicopter” on the Discovery Channel that 2/rev rotor vibration was a Bensen legacy; a result of necking the rotor down to 2.5 inches at the hub and the use of a square mast tube.
 
Top