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dan(at)syz.com
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 Posted: Thu Dec 31, 2015 3:47 pm Post subject: FAB drain usefulness |
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Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
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Kellym
Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ
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| Posted: Thu Dec 31, 2015 4:15 pm Post subject: FAB drain usefulness |
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Interesting you pose this question. I have that little task to do, but I
question more the need and design of the alt air door. With a circular
filter, no amount of freezing rain or snow will ever impact the back
half of filter. Seems like bigger risk is blockage of the inlet to the
FAB by ice or a bird. I think installing the flapper valve for carb heat
should provide adequate alternate air.
On 12/31/2015 4:44 PM, Dan Charrois wrote:
| Quote: |
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
| | - The Matronics RV10-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:
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Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
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flying-nut(at)cfl.rr.com
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| Posted: Thu Dec 31, 2015 6:22 pm Post subject: FAB drain usefulness |
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I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
[img]cid:part1.06070100.03010500(at)cfl.rr.com[/img]
[img]cid:part2.06010308.00030902(at)cfl.rr.com[/img]
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
|
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gengrumpy
Joined: 07 May 2013
Posts: 131
Location: Tullahoma, TN
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| Posted: Thu Dec 31, 2015 6:30 pm Post subject: FAB drain usefulness |
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If you’ve ever flooded the engine on start, you know why there is a drain hole in there……
grumpy
do not archive
| Quote: | On Dec 31, 2015, at 8:18 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air. So, here's what I did ..... [img]cid:part1.06070100.03010500(at)cfl.rr.com[/img] [img]cid:part2.06010308.00030902(at)cfl.rr.com[/img] On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
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| | - The Matronics RV10-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:
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philperry9
Joined: 23 Nov 2011
Posts: 381
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| Posted: Thu Dec 31, 2015 7:19 pm Post subject: FAB drain usefulness |
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My concern about relying on the Alt Air door as a drain revolves around its relative position to the exhaust. Dripping fuel would turn to mist in the lower cowl air flow and potentially ignite.
The advantage to the drain (on the back of the box) is that it can be plumbed to an area where the exhaust pipes aren't a factor. The ram air would push the fuel to the back of the box, then it goes out the drain and down the plumbing.
Also, FWIW, my alt air door opens and closes and was built per plans. I haven't operated it on a running engine yet so it's possible that could change with negative pressure in the box; but I can open and close the door using the control cable without any issues.
Phil
Sent from my iPhone
On Dec 31, 2015, at 8:18 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
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| | - The Matronics RV10-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:
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jump2(at)sbcglobal.net
Guest
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| Posted: Thu Dec 31, 2015 8:09 pm Post subject: FAB drain usefulness |
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Think about unfiltered air going around your plate that does not make a complete seal.
Not so much in flight, but on ground.
Patrick Thyssen
Sent from my iPad
On Dec 31, 2015, at 8:18 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
|
|
| | - The Matronics RV10-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?RV10-List |
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Kellym
Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ
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| Posted: Thu Dec 31, 2015 8:18 pm Post subject: FAB drain usefulness |
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If I understand his pictures properly, I believe the butterfly valve is
to keep unfiltered air out unless alt air is needed. One could have the
valve open for startup and shutdown to allow draining when there is
potential for raw fuel.
On 12/31/2015 9:06 PM, Patrick Thyssen wrote:
| Quote: | Think about unfiltered air going around your plate that does not make a
complete seal.
Not so much in flight, but on ground.
Patrick Thyssen
Sent from my iPad
On Dec 31, 2015, at 8:18 PM, Linn Walters <flying-nut(at)cfl.rr.com
<mailto:flying-nut(at)cfl.rr.com>> wrote:
> I would guess if you never over-primed you'd not need the drain.
> However I've seen pictures on this list of misshaped filters that I
> believe are caused by the rubber sitting in avgas for an extended
> period. I thought about the alt air valve and just didn't like it a
> whole lot. I just don't like an engine control that I can't return to
> normal until I land and shut down. I don't think snow, heavy rain or
> anything of the sort would cause the filter to seal up, but a
> well-placed bird could block the inlet so I didn't want to just do
> away with the alt air.
> So, here's what I did .....
> <alt air mod 01.JPG>
>
> <alt air mod 02.JPG>
> On 12/31/2015 6:44 PM, Dan Charrois wrote:
>>
>>
>> Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
>>
>> Thoughts?
>>
>> Dan
>> ---
>> Dan Charrois
>> President, Syzygy Research & Technology
>> Phone: 780-961-2213
>>
>>
>>
>>
>>
>>
>>
>>
>
|
| | - The Matronics RV10-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:
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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD |
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jesse(at)saintaviation.co
Guest
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| Posted: Thu Dec 31, 2015 8:26 pm Post subject: FAB drain usefulness |
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The ram air fills the cavity outside the filter then turns inward and goes through the filter from all sides. Fuel inside the filter would stay there and evaporate and be ingested into the engine intake. The drain is so fuel from over boosting can drain out when the engine is not running. Am I missing something here? Fuel can't even get into the airbox when the engine is running, can it?
Jesse SaintSaint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
C: 352-427-0285
F: 815-377-3694
Sent from my iPhone
On Dec 31, 2015, at 10:15 PM, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> wrote:
| Quote: | My concern about relying on the Alt Air door as a drain revolves around its relative position to the exhaust. Dripping fuel would turn to mist in the lower cowl air flow and potentially ignite.
The advantage to the drain (on the back of the box) is that it can be plumbed to an area where the exhaust pipes aren't a factor. The ram air would push the fuel to the back of the box, then it goes out the drain and down the plumbing.
Also, FWIW, my alt air door opens and closes and was built per plans. I haven't operated it on a running engine yet so it's possible that could change with negative pressure in the box; but I can open and close the door using the control cable without any issues.
Phil
Sent from my iPhone
On Dec 31, 2015, at 8:18 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
|
|
|
| | - The Matronics RV10-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?RV10-List |
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flying-nut(at)cfl.rr.com
Guest
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| Posted: Thu Dec 31, 2015 8:31 pm Post subject: FAB drain usefulness |
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Not a bad observation. However, on the ground, with the engine running ..... I think there's enough air flowing down and out to keep any dust from being sucked in. There are really small gaps where the bushings are, but the plate is an ellipse and seals really well since it's at an angle in the tube. The hole in the original FAB (per plans) has screen over it to keep out FOD in event the screws (or lizards, mud daubers ....) holding the plate to the shaft come loose.
You'd be amazed at what some certified aircraft have for alternate air ......
Linn
On 12/31/2015 11:06 PM, Patrick Thyssen wrote:
| Quote: | Think about unfiltered air going around your plate that does not make a complete seal.
Not so much in flight, but on ground.
Patrick Thyssen
Sent from my iPad
On Dec 31, 2015, at 8:18 PM, Linn Walters <[url=mailto:flying-nut(at)cfl.rr.com]flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)[/url]> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
|
|
|
| | - The Matronics RV10-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:
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flying-nut(at)cfl.rr.com
Guest
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| Posted: Thu Dec 31, 2015 8:47 pm Post subject: FAB drain usefulness |
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Nope .... no fuel can enter the FAB when the engine is running. I suspect that the mis-shaped filters I saw were due to avgas entering the FAB due to overpriming .... and once in the belly of the FAB it won't get sucked up into the engine when it starts, so it's there until it evaporates. Repeated doses of avgas causes the rubber on the filter to expand.  I may be wrong ..... 
Linn ... painting
On 12/31/2015 11:23 PM, Jesse Saint wrote:
| Quote: | The ram air fills the cavity outside the filter then turns inward and goes through the filter from all sides. Fuel inside the filter would stay there and evaporate and be ingested into the engine intake. The drain is so fuel from over boosting can drain out when the engine is not running. Am I missing something here? Fuel can't even get into the airbox when the engine is running, can it?
Jesse Saint Saint Aviation, Inc.Â
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
C: 352-427-0285
F: 815-377-3694
Sent from my iPhone
On Dec 31, 2015, at 10:15 PM, Phillip Perry <[url=mailto:philperry9(at)gmail.com]philperry9(at)gmail.com (philperry9(at)gmail.com)[/url]> wrote:
| Quote: | My concern about relying on the Alt Air door as a drain revolves around its relative position to the exhaust. Â Â Dripping fuel would turn to mist in the lower cowl air flow and potentially ignite.Â
The advantage to the drain (on the back of the box) is that it can be plumbed to an area where the exhaust pipes aren't a factor. Â The ram air would push the fuel to the back of the box, then it goes out the drain and down the plumbing. Â
Also, Â FWIW, my alt air door opens and closes and was built per plans. Â I haven't operated it on a running engine yet so it's possible that could change with negative pressure in the box; but I can open and close the door using the control cable without any issues. Â
Phil
Sent from my iPhone
On Dec 31, 2015, at 8:18 PM, Linn Walters <[url=mailto:flying-nut(at)cfl.rr.com]flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)[/url]> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
|
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|
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| | - The Matronics RV10-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:
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jump2(at)sbcglobal.net
Guest
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| Posted: Thu Dec 31, 2015 10:33 pm Post subject: FAB drain usefulness |
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The air. filter do not expand they shrink. I'm talking about dust and cr--p that will be sucked in since its on the lowest side of sucking pressure, not required to go through air filter. You don't have a positive seal with your plate. Only you will know when you start getting oil analysis and see what shows up.
Sent from my iPad
On Dec 31, 2015, at 10:28 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | Not a bad observation. However, on the ground, with the engine running ..... I think there's enough air flowing down and out to keep any dust from being sucked in. There are really small gaps where the bushings are, but the plate is an ellipse and seals really well since it's at an angle in the tube. The hole in the original FAB (per plans) has screen over it to keep out FOD in event the screws (or lizards, mud daubers ....) holding the plate to the shaft come loose.
You'd be amazed at what some certified aircraft have for alternate air ......
Linn
On 12/31/2015 11:06 PM, Patrick Thyssen wrote:
| Quote: | Think about unfiltered air going around your plate that does not make a complete seal.
Not so much in flight, but on ground.
Patrick Thyssen
Sent from my iPad
On Dec 31, 2015, at 8:18 PM, Linn Walters < (flying-nut(at)cfl.rr.com)flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
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Kelly McMullen
Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ
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| Posted: Fri Jan 01, 2016 5:15 am Post subject: FAB drain usefulness |
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The question is what air flows past the outside of the airbox, what direction it is flowing, and how dirty it may or may not be.
Likely to be air that has passed through front inlets and cylinders. Less likely to come up from nosegear. Both may be dirty on a dirt strip, not so much on paved airport. One of many choices/mistakes we have the opportunity of selecting.
-sent from the microchip implanted in my forearm
On Thu, Dec 31, 2015 at 11:29 PM, Patrick Thyssen <jump2(at)sbcglobal.net (jump2(at)sbcglobal.net)> wrote:
| Quote: | The air. filter do not expand they shrink. I'm talking about dust and cr--p that will be sucked in since its on the lowest side of sucking pressure, not required to go through air filter. You don't have a positive seal with your plate. Only you will know when you start getting oil analysis and see what shows up.
Sent from my iPad
On Dec 31, 2015, at 10:28 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | Not a bad observation. However, on the ground, with the engine running ..... I think there's enough air flowing down and out to keep any dust from being sucked in. There are really small gaps where the bushings are, but the plate is an ellipse and seals really well since it's at an angle in the tube. The hole in the original FAB (per plans) has screen over it to keep out FOD in event the screws (or lizards, mud daubers ....) holding the plate to the shaft come loose.
You'd be amazed at what some certified aircraft have for alternate air ......
Linn
On 12/31/2015 11:06 PM, Patrick Thyssen wrote:
| Quote: | Think about unfiltered air going around your plate that does not make a complete seal.
Not so much in flight, but on ground.
Patrick Thyssen
Sent from my iPad
On Dec 31, 2015, at 8:18 PM, Linn Walters < (flying-nut(at)cfl.rr.com)flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: [url=tel:780-961-2213]780-961-2213[/url]
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|
| | - The Matronics RV10-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:
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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD |
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flying-nut(at)cfl.rr.com
Guest
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| Posted: Fri Jan 01, 2016 8:33 am Post subject: FAB drain usefulness |
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On 1/1/2016 8:11 AM, Kelly McMullen wrote:
| Quote: | The question is what air flows past the outside of the airbox, what direction it is flowing, and how dirty it may or may not be.
Likely to be air that has passed through front inlets and cylinders. Less likely to come up from nosegear. Both may be dirty on a dirt strip, not so much on paved airport. One of many choices/mistakes we have the opportunity of selecting.
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Having thought about the comments about dirt ingestion through my modified FAB ..... I'll get a motorcycle filter to fit over the tube ..... thanks for the 'heads up'.
| Quote: | -sent from the microchip implanted in my forearm
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I love it!!! Thanks for the chuckle .... and Happy New Year!
Linn ..... almost noon and it's already 80* outside!!!!
| Quote: |
On Thu, Dec 31, 2015 at 11:29 PM, Patrick Thyssen <jump2(at)sbcglobal.net (jump2(at)sbcglobal.net)> wrote:
| Quote: | The air. filter do not expand they shrink. I'm talking about dust and cr--p that will be sucked in since its on the lowest side of sucking pressure, not required to go through air filter. You don't have a positive seal with your plate. Only you will know when you start getting oil analysis and see what shows up.
Sent from my iPad
On Dec 31, 2015, at 10:28 PM, Linn Walters <[url=mailto:flying-nut(at)cfl.rr.com]flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)[/url]> wrote:
| Quote: | Not a bad observation. However, on the ground, with the engine running ..... I think there's enough air flowing down and out to keep any dust from being sucked in. There are really small gaps where the bushings are, but the plate is an ellipse and seals really well since it's at an angle in the tube. The hole in the original FAB (per plans) has screen over it to keep out FOD in event the screws (or lizards, mud daubers ....) holding the plate to the shaft come loose.
You'd be amazed at what some certified aircraft have for alternate air ......
Linn
On 12/31/2015 11:06 PM, Patrick Thyssen wrote:
| Quote: | Think about unfiltered air going around your plate that does not make a complete seal.
Not so much in flight, but on ground.
Patrick Thyssen
Sent from my iPad
On Dec 31, 2015, at 8:18 PM, Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)> wrote:
| Quote: | I would guess if you never over-primed you'd not need the drain. However I've seen pictures on this list of misshaped filters that I believe are caused by the rubber sitting in avgas for an extended period. I thought about the alt air valve and just didn't like it a whole lot. I just don't like an engine control that I can't return to normal until I land and shut down. I don't think snow, heavy rain or anything of the sort would cause the filter to seal up, but a well-placed bird could block the inlet so I didn't want to just do away with the alt air.
So, here's what I did .....
<alt air mod 01.JPG>
<alt air mod 02.JPG>
On 12/31/2015 6:44 PM, Dan Charrois wrote:
| Quote: | | Quote: | --> RV10-List message posted by: Dan Charrois <dan(at)syz.com> (dan(at)syz.com)
Though I've already completed it some time ago and it's done anyway, I'm wondering what other people's thoughts are on the usefulness of the filtered air box drain. It would seem to me that the fact that there isn't any kind of seal on the alternate air door would cause it to act as the exit point for fluids before they ever make it to the "proper" drain. I can't see how any water/fuel/whatever that ends up at the bottom of the filtered air box wouldn't just escape around the alternate air door and dump itself inside the cowl, instead of take the preferred route through the drain hose outside. Unless I'm misunderstanding something, were I to do it again, I'd just skip the whole process of fibreglassing in the drain if I was including the alternate air door... or come up with an alternate air door design that's a bit more air and watertight.
Thoughts?
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: [url=tel:780-961-2213]780-961-2213[/url]
|
|
|
|
|
|
|
| | - The Matronics RV10-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?RV10-List |
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