Strange Noise

[Andy]

Gang,

I've got a strange noise I need help troubleshooting.  This started after a troublesome conditional the inspection, 5 year rubber replacement, and replacement of the head due to a stripped spark plug.  After two months of getting oil leaks associated with the head straight, now I've got this noise.  While I think it's airframe related (and the wings were pulled off and the fuel tubes replaced), I'm not sure.  It is airspeed related and not related to any engine power setting (confirmed by a static ground run).

There are two videos you can view.  Both the audio and video are captured by a cockpit mounted Go Pro allowed to pick up the cockpit environment vice internal audio (i.e., radio chatter).

Noise Clip 1 runs for 5:40 total.  The first 30 seconds is from an earlier "normal" flight so you can hear the normal cockpit background (baseline).  The flight today starts at 31 seconds and the anomalous noice starts at 40 seconds elapsed.  The rest of the clip can be used to see the relationship of the sound to airspeed and power setting, if you want to go there. 

Noise Clips 2 runs 3:01.  The first thirteen seconds is normal background with the anomalous sound from there to the end.

 

Thanks!

 

Andy

 

[Tom Baker]

I couldn't get the video to play, but the 2 most common airframe noise culprits are wing tape and stabilator tape. Both are normally speed related. 

[Andy]

Those were just replaced.  I'll take a closer look at them and see if one of them could be it.  if it is, it's probably wing tape up on the left wing.  It sounds like it's coming from the left side. (I updated the links and embedded the video,) 

[Roger Lee]

Yep that is noise coming from the wing root tape. It either has a crack in it or it doesn't go back underneath all the way to the flap bracket.

[Andy]

I didn't see any cracks.  I thought it went back to the flap bracket on both sides.  Sounds like the easiest thing to do is to overlap what's been done and see if that does it.  I'll go out in the morning and give it a try.  Thanks.

[CT4ME]

Definite tape noise.  The last time I had that noise (had it twice) it was on the underside of the wing, above the door.  I searched over and over and couldn't find the "crack" or "split" that I expected.  No, this time it turned out to be a section about 6 inches long, where it wasn't sticking.  I looked like it was sticking, but it wasn't.  In the right conditions, it was acting as a reed.

[FlyingMonkey]

That root tape noise really gets your attention, it's shockingly loud.  Scared the crap out of me when I had it happen.

I use a double thickness of tape at the curve around the leading edge to prevent tears, it seems to help.

[Andy]

You guys are the CAT'S MEOW!!!  I put two overlays over the original tape so that they overlaid the original and each other as well as the edges and made sure they both went to the flap bracket.  Worked great!  THANKS SO MUCH!