ASG-29 Coke Bottle Whistle

I've noticed only a quiet ~50Hz oscillation in flap position 3 at the higher end of the WK3 speed range.
Jim

On Sunday, June 12, 2016 at 12:43:14 PM UTC-6, RickH wrote:
I hope some of you ASG-29 drivers have either experienced or heard of
this issue I'm having with my 2012 ASG-29. The ship has about 200 hours
on it. At about 100-110 knots I have a very loud and annoying sound
that comes from the rear of the ship. It sounds just like someone
blowing over a coke bottle to create a tone. I can get rid of the sound
by applying a little rudder although the yaw string is running true
while the sound is being generated. Rex Williams said he thought it was
the tail dump opening. I've put duct tape over the tail dump valve and
still have this annoying tone accelerating through 100-110 knots. John
Murray thought that it was the gap seal tape on the rudder. I would
have thought that would have produced more of a buzz sound but this is
probably my next step. Hopefully someone can enlighten me as to a
possible cause!




--
RickH

When my 29 was new in 2006, I had maybe the same noise around 95-100 kts. When I got home from the Nationals, I removed the rudder and really bent the mylar over. Used a small wood block and even creased it at almost a 90 degree angle. Reinstalled the rudder and the noise went away.
Then several years ago, installed new mylar. Didn't crease it over. Flew it and the noise came back. Came home, removed the rudder and bent it over using again a small block of wood to crease it and the nose went away. Several other folks with the same noise simply trimmed the mylar down from the top by an inch or so. The bottom they trimmed up. Their noise went away.

Best. Tom #711.

I had this last season and fixed by adding V seals to the fin each side of
the
rudder.


At 14:37 12 June 2016, RickH wrote:

I hope some of you ASG-29 drivers have either experienced or heard o
this issue I'm having with my 2012 ASG-29. The ship has about 200 hour
on it. At about 100-110 knots I have a very loud and annoying soun
that comes from the rear of the ship. It sounds just like someon
blowing over a coke bottle to create a tone. I can get rid of the soun
by applying a little rudder although the yaw string is running tru
while the sound is being generated. Rex Williams said he thought it wa
the tail dump opening. I've put duct tape over the tail dump valve an
still have this annoying tone accelerating through 100-110 knots. Joh
Murray thought that it was the gap seal tape on the rudder. I woul
have thought that would have produced more of a buzz sound but this i
probably my next step. Hopefully someone can enlighten me as to
possible cause




--
RickH

Originally Posted by Tom Kelley #711

On Sunday, June 12, 2016 at 12:43:14 PM UTC-6, RickH wrote:
I hope some of you ASG-29 drivers have either experienced or heard of
this issue I'm having with my 2012 ASG-29. The ship has about 200 hours
on it. At about 100-110 knots I have a very loud and annoying sound
that comes from the rear of the ship. It sounds just like someone
blowing over a coke bottle to create a tone. I can get rid of the sound
by applying a little rudder although the yaw string is running true
while the sound is being generated. Rex Williams said he thought it was
the tail dump opening. I've put duct tape over the tail dump valve and
still have this annoying tone accelerating through 100-110 knots. John
Murray thought that it was the gap seal tape on the rudder. I would
have thought that would have produced more of a buzz sound but this is
probably my next step. Hopefully someone can enlighten me as to a
possible cause!




--
RickH

When my 29 was new in 2006, I had maybe the same noise around 95-100 kts. When I got home from the Nationals, I removed the rudder and really bent the mylar over. Used a small wood block and even creased it at almost a 90 degree angle. Reinstalled the rudder and the noise went away.
Then several years ago, installed new mylar. Didn't crease it over. Flew it and the noise came back. Came home, removed the rudder and bent it over using again a small block of wood to crease it and the nose went away. Several other folks with the same noise simply trimmed the mylar down from the top by an inch or so. The bottom they trimmed up. Their noise went away.

Best. Tom #711.

Thanks Tom, that sounds promising as well as some of the other tips regarding sealing around the rudder cable faring. I do have the MN exhaust and I glassed up the edges of the cockpit exhaust collector so it seals tightly. Wing gap seal tape is good all around as well, so directing my attention to the tail is probably the best bet. I had a 27B before my 29 and it had the MN cockpit exhaust as well. It was quiet all the way up to as fast as I dared take it! Thanks again for the comments, at least I don't feel that I have a one-off now-

Rick
NR

When my 27 was refinished Aerospool fitted seals below the bottom hinge
which were not there before. Now my glider 'farts' if I do not have the
rudder bang on straight.

I quite like the feedback!

Jim

Love the feedback on this subject. Probably not your problem but on my Ventus B, I was getting a buzz/ rattling noise from the tail area. Turned out to be the cheap read junk replacement tail wheel I put on it last winter. The junk roller blade wheel was falling apart at the hub where the bearings go in and was very loose on the bearings causing it to rattle and shake while flying. Should have new wheel today. I temp fixed it with fibrous tape around the bearings but the wheel has/is getting worse. Your results may vary..

Yuh know, if its only happening at 100-110 knots,
watcha doing flying so wimpy slowly???
Jest sayin...

There is an access hole in the bottom of the rudder about the size of the mouth of a coke bottle. Seems obvious to try taping it, but I don't see it mentioned.

I had this last season and fixed by adding V seals to the fin each side of
the
rudder.


At 14:37 12 June 2016, RickH wrote:

I hope some of you ASG-29 drivers have either experienced or heard o
this issue I'm having with my 2012 ASG-29. The ship has about 200 hour
on it. At about 100-110 knots I have a very loud and annoying soun
that comes from the rear of the ship. It sounds just like someon
blowing over a coke bottle to create a tone. I can get rid of the soun
by applying a little rudder although the yaw string is running tru
while the sound is being generated. Rex Williams said he thought it wa
the tail dump opening. I've put duct tape over the tail dump valve an
still have this annoying tone accelerating through 100-110 knots. Joh
Murray thought that it was the gap seal tape on the rudder. I woul
have thought that would have produced more of a buzz sound but this i
probably my next step. Hopefully someone can enlighten me as to
possible cause




--
RickH

On Sun, 12 Jun 2016 15:37:46 +0100, RickH
wrote:


I hope some of you ASG-29 drivers have either experienced or heard of
this issue I'm having with my 2012 ASG-29. The ship has about 200 hours
on it. At about 100-110 knots I have a very loud and annoying sound
that comes from the rear of the ship. It sounds just like someone
blowing over a coke bottle to create a tone. I can get rid of the sound
by applying a little rudder although the yaw string is running true
while the sound is being generated. Rex Williams said he thought it was
the tail dump opening. I've put duct tape over the tail dump valve and
still have this annoying tone accelerating through 100-110 knots. John
Murray thought that it was the gap seal tape on the rudder. I would
have thought that would have produced more of a buzz sound but this is
probably my next step. Hopefully someone can enlighten me as to a
possible cause!


I just had this case with the 29 of a friend.
It turned out that the gap seal of the gear doors was loose. Replacing
it fixed the problem immediately.

Cheers
Andreas