Howling sound when flying

My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

On Saturday, 12 October 2019 18:42:44 UTC+3, Armand Charbonneau wrote:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

Ventus-2c (and D2b) has an extremely loud cockpit. You cannot do much for it.

Might also try rudder left and right, elevator, etc.

On Saturday, October 12, 2019 at 9:57:58 AM UTC-6, krasw wrote:
On Saturday, 12 October 2019 18:42:44 UTC+3, Armand Charbonneau wrote:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit.. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

Ventus-2c (and D2b) has an extremely loud cockpit. You cannot do much for it.

It is not just in the cockpit. I am told it is loud on the ground when flown overhead.

On Saturday, October 12, 2019 at 9:45:01 AM UTC-7, Armand Charbonneau wrote:
On Saturday, October 12, 2019 at 9:57:58 AM UTC-6, krasw wrote:
On Saturday, 12 October 2019 18:42:44 UTC+3, Armand Charbonneau wrote:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

Ventus-2c (and D2b) has an extremely loud cockpit. You cannot do much for it.

It is not just in the cockpit. I am told it is loud on the ground when flown overhead.

Well that sucks, literally. Start sealing. I have owned two SH gliders (N4, V2C) and they both benefited from gear well sealing, canopy, rudder, and control surfaces needed S-tape under mylar.

On Saturday, October 12, 2019 at 11:42:44 AM UTC-4, Armand Charbonneau wrote:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

It is surprising that this has not been aired before.
When I first flew my PIK 20 E there was a similar loud howl
at zero and neg flap settings. I speculated that this was resonant
vortex shedding from the top surface; the flap had an internal fabric seal
but this will not stop oscillatory flow.
The Aerodynamics prof at my alma mater replied that I was probably right;
resonant vortex shedding on the BAE 146 stol transport was close to
ending sales due to passenger complaints; when CU dept eng. found a solution.

Armand Charbonneau wrote on 10/12/2019 8:42 AM:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

Did the howl start recently? Are the zig zag tapes in the correct position? Does
the back edge of the Mylar fairing strip (top and bottom) press against the
flap/ailerons in the Flap 0 position?


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Saturday, October 12, 2019 at 4:57:48 PM UTC-6, Eric Greenwell wrote:
Armand Charbonneau wrote on 10/12/2019 8:42 AM:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit.. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

Did the howl start recently? Are the zig zag tapes in the correct position? Does
the back edge of the Mylar fairing strip (top and bottom) press against the
flap/ailerons in the Flap 0 position?


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Howling has been there since I started flying about 105 hours ago. zig zag tapes look okay.

I will check the mylar strips (top and bottom) carefully with the wings assembled looking at flap 0.

Armand Charbonneau wrote on 10/12/2019 5:52 PM:
Howling has been there since I started flying about 105 hours ago. zig zag tapes look okay.

I will check the mylar strips (top and bottom) carefully with the wings assembled looking at flap 0.

Did the howling exist before the refinish? Perhaps the zig-zag was not placed in
the correct location, or it's the wrong zig-zag (too thin, perhaps).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Saturday, October 12, 2019 at 8:42:44 AM UTC-7, Armand Charbonneau wrote:
My Ventus 2c makes a howling sound when flying at 0 flap setting. It is significantly less noticeable immediately after changing the flap setting either positive or negative. Pilots tell me they can hear it when flying overhead or landing. I can hear it seemingly behind me, inside the cockpit. Gear up or down does not seem to make a difference.

The glider was refinished with poly in 2012, so I suspect the wing seals are seven years old. Otherwise the ship in very good condition and soars nicely.

Does anyone know what could be causing this sound? I can replace all the seals this winter, but they appear to be in good condition, except maybe on the tail plane.

I own and fly V2C s/n 51 and have never experienced that problem. I also find the cockpit reasonably quiet if everything is well sealed; even more so since having a Hank Nixon turtleback vent installed.

But what initially struck me about your question though, is your use of the 0 flap setting. My SH flight manual doesn't even acknowledge 0-flaps as a cruise setting. By virtue of that (and advice from other V2C pilots) I never routinely use it. It's just a transit point between positive and negative settings. Sorry, if I steer the conversation off-topic.