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byronmfox(at)gmail.com
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 Posted: Mon Jul 16, 2018 12:38 pm Post subject: Nanchang Hissy Fit Flap |
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When last reported, I left my hangar baffled. Having replaced my old flap valve with the three-month old one, the result was unchanged. The flap would go down, but not come up.
The following morning when I arrived at the hangar, I knew air pressure in the plane's plumbing would be zero. So I decided to see what would happen, if first, I raised the flap handle, and then turned on the main air. Instantly, up came the flap!
It was clear, therefore, that there was no blockage in the upside air lines. The same was true of the downside air lines. What then was impeding the flap from rising when there was air pressure in the system?
So, I started playing with the flap handle. Raising the handle straight through the neutral position, as I normally would, I'd hear a quick "Psst" out of the flap valve as I went through neutral, but the flap would not come up.
Then raising the flap handle more slowly and pausing in the neutral position, the downside pressure in the actuator vented and the flap came up when the handle was moved to the up position. So, it's a work-around, but it's not right.
It was Saturday, so my neighbor two hangars away had his Nanchang on the ramp. With his permission, I turned his air on and lowered the flap handle in the front cockpit with the handle in back in the neutral position. Down, of course, went the flap. I then lifted the front flap handle, and the instant I went through the neutral position the downside pressure started to vent and continued to vent and then pressurize as I smoothly went to the up position. And, of course, up came the flap.
So it would appear that my new flap valve is not venting properly. But wait! The same thing happened before I swapped my old flap valve for the new one. The flap would go down, but not up. By capping-off all three air lines to the backseat flap valve had an effect I don't understand?
What do you think?
--
... Blitz
[img]https://docs.google.com/uc?export=download&id=0B_Mqbj1Pr-xVTXVKN0t1SlVGT2M&revid=0B_Mqbj1Pr-xVcW0vU2crV2hMeVBQdVBmYWlaT0w2cVF3K2xBPQ[/img]
Byron M. Fox
80 Milland Drive
Mill Valley, CA 94941
415-307-2405
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jonboede(at)hotmail.com
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| Posted: Mon Jul 16, 2018 1:07 pm Post subject: Nanchang Hissy Fit Flap |
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By “flap valve” do you mean the actuator handle or the shuttle valve that lets the back seat override the front? Are you sure your system isn’t convinced that the instructor’s handle isn’t somehow not in the middle position?
Jon
On Jul 16, 2018, at 3:57 PM, Byron Fox <byronmfox(at)gmail.com (byronmfox(at)gmail.com)> wrote:
| Quote: | When last reported, I left my hangar baffled. Having replaced my old flap valve with the three-month old one, the result was unchanged. The flap would go down, but not come up.
The following morning when I arrived at the hangar, I knew air pressure in the plane's plumbing would be zero. So I decided to see what would happen, if first, I raised the flap handle, and then turned on the main air. Instantly, up came the flap!
It was clear, therefore, that there was no blockage in the upside air lines. The same was true of the downside air lines. What then was impeding the flap from rising when there was air pressure in the system?
So, I started playing with the flap handle. Raising the handle straight through the neutral position, as I normally would, I'd hear a quick "Psst" out of the flap valve as I went through neutral, but the flap would not come up.
Then raising the flap handle more slowly and pausing in the neutral position, the downside pressure in the actuator vented and the flap came up when the handle was moved to the up position. So, it's a work-around, but it's not right.
It was Saturday, so my neighbor two hangars away had his Nanchang on the ramp. With his permission, I turned his air on and lowered the flap handle in the front cockpit with the handle in back in the neutral position. Down, of course, went the flap. I then lifted the front flap handle, and the instant I went through the neutral position the downside pressure started to vent and continued to vent and then pressurize as I smoothly went to the up position. And, of course, up came the flap.
So it would appear that my new flap valve is not venting properly. But wait! The same thing happened before I swapped my old flap valve for the new one. The flap would go down, but not up. By capping-off all three air lines to the backseat flap valve had an effect I don't understand?
What do you think?
--
... Blitz
[img]https://docs.google.com/uc?export=download&id=0B_Mqbj1Pr-xVTXVKN0t1SlVGT2M&revid=0B_Mqbj1Pr-xVcW0vU2crV2hMeVBQdVBmYWlaT0w2cVF3K2xBPQ[/img]
Byron M. Fox
80 Milland Drive
Mill Valley, CA 94941
415-307-2405
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
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byronmfox(at)gmail.com
Guest
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| Posted: Mon Jul 16, 2018 1:23 pm Post subject: Nanchang Hissy Fit Flap |
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Sorry if I’ve failed to be to clear, Jon.
By “flap valve” I mean the valve to which the flap handle is attached.
My understanding heretofore, was that the sole function of the shuttle, or diverter valves, in the backseat was to permit emergency air into the flap system if required. That would be how I’ve interpreted the pneumatic system diagram and Craig Payne’s air system guide.
On Jul 16, 2018, at 2:07 PM, Jon Boede <jonboede(at)hotmail.com (jonboede(at)hotmail.com)> wrote:
| Quote: | By “flap valve” do you mean the actuator handle or the shuttle valve that lets the back seat override the front? Are you sure your system isn’t convinced that the instructor’s handle isn’t somehow not in the middle position?
Jon
On Jul 16, 2018, at 3:57 PM, Byron Fox <byronmfox(at)gmail.com (byronmfox(at)gmail.com)> wrote:
| Quote: | When last reported, I left my hangar baffled. Having replaced my old flap valve with the three-month old one, the result was unchanged. The flap would go down, but not come up.
The following morning when I arrived at the hangar, I knew air pressure in the plane's plumbing would be zero. So I decided to see what would happen, if first, I raised the flap handle, and then turned on the main air. Instantly, up came the flap!
It was clear, therefore, that there was no blockage in the upside air lines. The same was true of the downside air lines. What then was impeding the flap from rising when there was air pressure in the system?
So, I started playing with the flap handle. Raising the handle straight through the neutral position, as I normally would, I'd hear a quick "Psst" out of the flap valve as I went through neutral, but the flap would not come up.
Then raising the flap handle more slowly and pausing in the neutral position, the downside pressure in the actuator vented and the flap came up when the handle was moved to the up position. So, it's a work-around, but it's not right.
It was Saturday, so my neighbor two hangars away had his Nanchang on the ramp. With his permission, I turned his air on and lowered the flap handle in the front cockpit with the handle in back in the neutral position. Down, of course, went the flap. I then lifted the front flap handle, and the instant I went through the neutral position the downside pressure started to vent and continued to vent and then pressurize as I smoothly went to the up position. And, of course, up came the flap.
So it would appear that my new flap valve is not venting properly. But wait! The same thing happened before I swapped my old flap valve for the new one. The flap would go down, but not up. By capping-off all three air lines to the backseat flap valve had an effect I don't understand?
What do you think?
--
... Blitz
[img]https://docs.google.com/uc?export=download&id=0B_Mqbj1Pr-xVTXVKN0t1SlVGT2M&revid=0B_Mqbj1Pr-xVcW0vU2crV2hMeVBQdVBmYWlaT0w2cVF3K2xBPQ[/img]
Byron M. Fox
80 Milland Drive
Mill Valley, CA 94941
415-307-2405
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http://www.matronics.com/Navigator?Yak-List |
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jonboede(at)hotmail.com
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| Posted: Mon Jul 16, 2018 1:48 pm Post subject: Nanchang Hissy Fit Flap |
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The aft cockpit gear handle has five connections while the aft flap handle has three. The diverter valves give the aft flap handle the ability to have priority in the same manner as the gear handle. Why they use two different methods to achieve the same ends is a mystery to me, but they do.
I’m guessing one of your flap diverter valves has a stuck shuttle. They’re pretty easy to change. The Russian ones for the Yak work exactly the same as the Chinese ones.
Jon
On Jul 16, 2018, at 4:37 PM, Byron Fox <byronmfox(at)gmail.com (byronmfox(at)gmail.com)> wrote:
| Quote: | Sorry if I’ve failed to be to clear, Jon.
By “flap valve” I mean the valve to which the flap handle is attached.
My understanding heretofore, was that the sole function of the shuttle, or diverter valves, in the backseat was to permit emergency air into the flap system if required. That would be how I’ve interpreted the pneumatic system diagram and Craig Payne’s air system guide.
On Jul 16, 2018, at 2:07 PM, Jon Boede <jonboede(at)hotmail.com (jonboede(at)hotmail.com)> wrote:
| Quote: | By “flap valve” do you mean the actuator handle or the shuttle valve that lets the back seat override the front? Are you sure your system isn’t convinced that the instructor’s handle isn’t somehow not in the middle position?
Jon
On Jul 16, 2018, at 3:57 PM, Byron Fox <byronmfox(at)gmail.com (byronmfox(at)gmail.com)> wrote:
| Quote: | When last reported, I left my hangar baffled. Having replaced my old flap valve with the three-month old one, the result was unchanged. The flap would go down, but not come up.
The following morning when I arrived at the hangar, I knew air pressure in the plane's plumbing would be zero. So I decided to see what would happen, if first, I raised the flap handle, and then turned on the main air. Instantly, up came the flap!
It was clear, therefore, that there was no blockage in the upside air lines. The same was true of the downside air lines. What then was impeding the flap from rising when there was air pressure in the system?
So, I started playing with the flap handle. Raising the handle straight through the neutral position, as I normally would, I'd hear a quick "Psst" out of the flap valve as I went through neutral, but the flap would not come up.
Then raising the flap handle more slowly and pausing in the neutral position, the downside pressure in the actuator vented and the flap came up when the handle was moved to the up position. So, it's a work-around, but it's not right.
It was Saturday, so my neighbor two hangars away had his Nanchang on the ramp. With his permission, I turned his air on and lowered the flap handle in the front cockpit with the handle in back in the neutral position. Down, of course, went the flap. I then lifted the front flap handle, and the instant I went through the neutral position the downside pressure started to vent and continued to vent and then pressurize as I smoothly went to the up position. And, of course, up came the flap.
So it would appear that my new flap valve is not venting properly. But wait! The same thing happened before I swapped my old flap valve for the new one. The flap would go down, but not up. By capping-off all three air lines to the backseat flap valve had an effect I don't understand?
What do you think?
--
... Blitz
[img]https://docs.google.com/uc?export=download&id=0B_Mqbj1Pr-xVTXVKN0t1SlVGT2M&revid=0B_Mqbj1Pr-xVcW0vU2crV2hMeVBQdVBmYWlaT0w2cVF3K2xBPQ[/img]
Byron M. Fox
80 Milland Drive
Mill Valley, CA 94941
415-307-2405
|
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|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
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byronmfox(at)gmail.com
Guest
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| Posted: Mon Jul 16, 2018 2:49 pm Post subject: Nanchang Hissy Fit Flap |
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I just looked at Craig Payne's air system guide again and I was quite
wrong, Jon. Craig says and the diagram is clear that:
"Emergency Air is routed from a check valve on the firewall and is NOT
supplied directly by Diverter Valves on the Actuators like the Landing Gear
Circuit. "
Staring at the diagrams, however, I'm puzzled as how the diverter valves
play a role venting down pressure when the forward flap handle is moved to
the up position.
I'm also assuming that when the backseat flap handle is in the neutral
position no air is entering the aft flap valve. When the aft flap handle is
put in the up, or down, position air from the aft valve flows through the
diverter valves to the flap.
On Mon, Jul 16, 2018 at 2:48 PM, Jon Boede <jonboede(at)hotmail.com> wrote:
[quote] The aft cockpit gear handle has five connections while the aft flap handle
has three. The diverter valves give the aft flap handle the ability to have
priority in the same manner as the gear handle. Why they use two different
methods to achieve the same ends is a mystery to me, but they do.
I’m guessing one of your flap diverter valves has a stuck shuttle
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
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