R44 - it just started vibrating...
Anyone familiar with R44's might be able to help.
I was flying with front 2 doors off, took off and about 10 minutes into flight noticed vibrations - more of a noise than a feel - sounded like someone blowing over a bottle. descended and slowed up, then noticed that it seemed to go away below 60-70kts. Landed and looked around but couldn't find anything out of the ordinary to explain the noise.
I fly every day - it just didn't sound right to me.
I've heard all kinds of stories about blade delamination etc, so thought i'd ask on here for ideas.