ASG 29 organ pipe like noise above 83 knots

[Tony Gaechter]

I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.

[JS]

On Tuesday, July 18, 2017 at 6:32:14 PM UTC-7, Tony Gaechter wrote:
> I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.

Tony, join the ASW27 newsgroup and search for the thread about Noisy Cockpit.
Jim

https://groups.yahoo.com/neo/groups/ASW27owners/info

[Tom Kelley #711]

On Tuesday, July 18, 2017 at 7:32:14 PM UTC-6, Tony Gaechter wrote:
> I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.

Well, we need to know where the noise is coming from. BUT most will have the mylar on the rudder causing this noise as air exhausting will cause the mylar to hummmmm. Mine did, as other's did. My fix was to remover the rudder, crease the mylar (don't worry about over creasing as more is better) with a small wooden block inward and reinstall the rudder. With the right tools, simple job. Watch the rudder cables as they will have to be removed and are spring loaded. I used wire to help pull them back out on the reinstall.
Getting the small lock nut back on is easy. Putting the bolt back thru the lower hole, well, sometimes it takes time.

Other's have trimmed the mylar on the top and bottom, but I found it's best to crease it over.

Best. #711.

[[email protected]]

My '27 had rudder noise while thermalling, so I replaced the mylar, which was very loose. Now it makes the howl at 90+ knots, and I've confirmed it's the rudder by moving it and having the sound change depending on deflection and direction.

I'll give 711's suggestion a shot before my next flight. There are also a few more suggestions on the ASW-27 group that I'll also consider.

5Z

On Tuesday, July 18, 2017 at 6:32:14 PM UTC-7, Tony Gaechter wrote:
> I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.

[Andrzej Kobus]

On Tuesday, July 18, 2017 at 9:32:14 PM UTC-4, Tony Gaechter wrote:
> I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.

You are probably flying on the wrong flap setting. Try different flap position for the weight.

[jfitch]

On Wednesday, July 19, 2017 at 8:42:18 AM UTC-7, Andrzej Kobus wrote:
> On Tuesday, July 18, 2017 at 9:32:14 PM UTC-4, Tony Gaechter wrote:
> > I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.
>
> You are probably flying on the wrong flap setting. Try different flap position for the weight.

This is quite a common complaint with the 27/29 so there must be a lot of people flying it wrong.

[Charlie M. (UH & 002 owner/pilot)]

Or do a Murray/Nixon turtledeck vent so the pressurized cabin air goes out in a low pressure spot on the fuselage. Keeps it from going down the tailboom through the rudder seals, also moves more air through the cockpit.

[Dave Leonard]

Check that turbulator strips are installed in front of the NACA scoops on the bottom of the flaps and ailerons per the maintenance manual. My old 27 was very loud until stacking two layers of zig-zag tape there.

[[email protected]]

On Wednesday, July 19, 2017 at 11:42:18 AM UTC-4, Andrzej Kobus wrote:
> On Tuesday, July 18, 2017 at 9:32:14 PM UTC-4, Tony Gaechter wrote:
> > I recently bought a used ASG 29 and get a loud noise like an organ pipe above 83 knots. Can anyone suggest a cause and cure. The noise is very loud and distracting.
>
> You are probably flying on the wrong flap setting. Try different flap position for the weight.

If the noise starts at a particular speed, and is not just changing pitch and volume with speed,Andy is correct. The sound is the separation due to a laminar separation bubble. Change flap settings as suggested.
That sound is how Waibel and the Delft people knew the airfoil and blow turbulation worked.
UH