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06-02-2017, 12:49 PM
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Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,530
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home-brew overhead console: air vents
Those of you who rolled your own - what did you use for vents? I think I'm going to control overall airflow with the AeroSport butterfly valve, and save some shekels on the air vents by not getting the machined aluminum aircraft grade vents.
Miata dash vents seem popular on eBay, and there is a ragtag assortment of very used aircraft eyeball vents for sale there as well. Curious what others have gone with.
__________________
Bill Boyd
Hop-Along Aerodrome (12VA)
RV-6A - N30YD - Built '98 / sold '20
RV-10 - N130YD reserved - under construction
donating monthly to the VAF - thanks, Doug
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06-02-2017, 01:12 PM
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Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 4,196
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Quote:
Originally Posted by Bill Boyd
Those of you who rolled your own - what did you use for vents? I think I'm going to control overall airflow with the AeroSport butterfly valve, and save some shekels on the air vents by not getting the machined aluminum aircraft grade vents.
Miata dash vents seem popular on eBay, and there is a ragtag assortment of very used aircraft eyeball vents for sale there as well. Curious what others have gone with.
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I would still go with either the Aerosport Products or the SteinAir vents. I've seen too many qualities issues to trust just any aluminum valve. At least with these two vendors, you know you're getting a quality product.
Even with the Aerosport Products NACA valve, you still want to ensure that the vents close, especially in the winter.
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06-02-2017, 06:42 PM
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Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,530
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Bob - do you see this as a belt-and-suspenders thing where both turn out to be necessary?
I was hoping the butterfly valve would mitigate both leaky eyeball vents of the cheap/automotive surplus variety, and the inevitable leaks in the switches, lights and panels in the overhead that everyone says are quite noticeable in the winter.
I dislike the thought of having to pay a premium for both the NACA butterfly controller and top-tier eyeball vents to be comfortable in cold air, but I want to be realistic about what's needed for a satisfactory solution to cold air ingress.
There is a $498 difference between 4 vents from SteinAir and 4 used Miata eyeball vents from Ebay.
__________________
Bill Boyd
Hop-Along Aerodrome (12VA)
RV-6A - N30YD - Built '98 / sold '20
RV-10 - N130YD reserved - under construction
donating monthly to the VAF - thanks, Doug
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06-02-2017, 06:54 PM
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Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 4,196
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The only way I can answer your question is that I purchased the Stein vents for the overhead and the two front vents. I would probably buy the Aerosport Product vents if I were to purchase today, but I have a little bias towards Aerosport Products. I felt it was worth the expense to me.
Only you can make that determination for you. It's all about risk management. If you install the less expensive vents and they work, you managed the risk well. If they don't, you'll have to replace them with the more expensive vents costing the sum of both. There's no right answer.
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06-02-2017, 07:04 PM
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Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 1,039
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I was in Japan for a couple of weeks last December, and in several vehicles there I saw these neat air vents that are like an eyeball, with a dial in the center that opens and closes a set of radial vanes to control air flow. I wasn't sure where to find them until I rented a Chevy Sonic during a trip last month. Very similar to what I saw in Japan. I think the vehicles in Japan where I saw them were a Mazda and a BMW. Anyway, I think I have found them here: https://www.ebay.com/p/?iid=25198877...pItem=1&chn=ps
Now, they are rather large in diameter, and possibly too deep for an overhead console, but I am still considering them for the foward and rear fresh air vents. Bonus: They're pretty inexpensive, and probably available at an auto wrecking yard. I may pick one up just to see where I could make it fit.
Edited: Now that I look at these pictures, I see these are different than the ones I saw in Japan in that they have a folding butterfly behind the vanes to regulate airflow rather than the radial "petals" that rotate on their individual axes like I saw over there. I will now have to find those. I bet the "petal" ones aren't as deep, since the split butterfly has to have at least a depth equal to one radius of the opening...
Edited: Here's an Audi air vent that looks like the ones I am thinking of: https://services.edmunds-media.com/i..._31815_717.jpg
Edited: Are these the Mazda air vents the OP was referring to? 
Last edited by 1001001 : 06-02-2017 at 07:34 PM.
Reason: wrong picture at first
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06-03-2017, 10:58 AM
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Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,530
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Thanks, Bob
The message I'm getting is that the AeroSport valve does not shut off the airflow enough to obviate the need for good butterfly eyeball vents (and presumably extra attention to sealing switches and panels and lights) to control cold drafts from the overhead.
This is disappointing info from the field, but it's what I need in order to over-think this
Maybe someone who sealed things well and used the expensive vents but not the AeroSport valve will share their impressions of how well their set-up mitigates the cold draft issue and any other drawbacks.
__________________
Bill Boyd
Hop-Along Aerodrome (12VA)
RV-6A - N30YD - Built '98 / sold '20
RV-10 - N130YD reserved - under construction
donating monthly to the VAF - thanks, Doug
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06-03-2017, 11:03 AM
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Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,530
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1001001 said:
"Now, they are rather large in diameter, and possibly too deep for an overhead console, but I am still considering them for the foward and rear fresh air vents. Bonus: They're pretty inexpensive, and probably available at an auto wrecking yard. I may pick one up just to see where I could make it fit."
I agree they look big and deep on the Ebay photos - one more reason I was asking what's been tried successfully.
If you get one, please let me know what you think of it!
__________________
Bill Boyd
Hop-Along Aerodrome (12VA)
RV-6A - N30YD - Built '98 / sold '20
RV-10 - N130YD reserved - under construction
donating monthly to the VAF - thanks, Doug
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06-03-2017, 11:42 AM
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Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 1,039
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Quote:
Originally Posted by Bill Boyd
The message I'm getting is that the AeroSport valve does not shut off the airflow enough to obviate the need for good butterfly eyeball vents (and presumably extra attention to sealing switches and panels and lights) to control cold drafts from the overhead.
This is disappointing info from the field, but it's what I need in order to over-think this
Maybe someone who sealed things well and used the expensive vents but not the AeroSport valve will share their impressions of how well their set-up mitigates the cold draft issue and any other drawbacks.
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I have looked at pictures of the Aerosport valve (I have not seen one up close) and think it could be made to seal better if a half-ring of felt were bonded to the inside of the valve body, on opposite sides of the butterfly such that when closed, the butterfly would rest against the felt edge.
This is a common way to seal large butterfly valves and could be adapted to these valves, I believe. If the felt were cut to a cross section of about 3/8" x 1/4" (with the 3/8" being the bonding surface to the valve body), I think it would hold up. The small dimension might even be as small as 1/8". It just needs to create a seal between the butterfly and valve body tube.
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06-03-2017, 04:25 PM
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Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,530
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another idea
The overhead and its fitments leak because of high-pressure/low volume air making its way through the butterfly even when closed. I wonder if a small, always-open overboard scoop (cabin top facing aft, perhaps) could be designed to bleed-off this "leakage current" air in the "high-impedance"/low-flow scenario of a closed valve, yet have negligible % loss in the low-impedance, valve-open, high-flow scenario where you want as much vent air as possible blowing on you.
Trade-offs abound, like in everything engineering.
With any luck our guru DanH will pop in here with some graphs from the 1930's showing that this question was answered long ago  I'm sure it was; just not willing to dig out the answer for myself.
__________________
Bill Boyd
Hop-Along Aerodrome (12VA)
RV-6A - N30YD - Built '98 / sold '20
RV-10 - N130YD reserved - under construction
donating monthly to the VAF - thanks, Doug
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06-03-2017, 04:45 PM
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Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 4,196
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Quote:
Originally Posted by Bill Boyd
The message I'm getting is that the AeroSport valve does not shut off the airflow enough to obviate the need for good butterfly eyeball vents (and presumably extra attention to sealing switches and panels and lights) to control cold drafts from the overhead.
This is disappointing info from the field, but it's what I need in order to over-think this
Maybe someone who sealed things well and used the expensive vents but not the AeroSport valve will share their impressions of how well their set-up mitigates the cold draft issue and any other drawbacks.
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I don't think Geoff has indicated that the valve was 100% effective. Just like the similar valves used in hvac, it cuts off most of the airflow. It's really a necessity if you pressurize the overhead plenum. You would be surprised how much air will leak through switches and some types of lighting.
I fly when it's below zero, so I want to ensure the entire solution can prevent any cold air blowing into the cabin.
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