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Cabin air vent caps

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ve0kog

Well Known Member
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My cabin vents leak some air even in fully closed position. This isn’t a problem except during a few cold winter months.

I’ve seen different/better than the OEM vent types and even 3d printed outside air intake covers held with a screw through the fuselage but Im curious if something dirt cheap and simple like a rubber cap that fits snuggly over the vent could be a solution.

has anyone found something that works?
 
ve0kog said:
My cabin vents leak some air even in fully closed position. This isn’t a problem except during a few cold winter months.

I’ve seen different/better than the OEM vent types and even 3d printed outside air intake covers held with a screw through the fuselage but Im curious if something dirt cheap and simple like a rubber cap that fits snuggly over the vent could be a solution.

has anyone found something that works?
Click to expand...

This is going to sound crazy but it was always meant to be temporary. However it works great. Several years ago just after Christmas we headed down south for the winter. Never got the chance to figure out how to close off vents. Grabbed the white pom-poms off the Santa hats that were sitting on the kitchen table. They filled the hole perfectly. They are light, soft, and very easy to store year round in the plane. Just got them out for the first time this fall.


santahats-2048px-8442.jpg.webp
 
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ve0kog said:
My cabin vents leak some air even in fully closed position. This isn’t a problem except during a few cold winter months.

I’ve seen different/better than the OEM vent types and even 3d printed outside air intake covers held with a screw through the fuselage but Im curious if something dirt cheap and simple like a rubber cap that fits snuggly over the vent could be a solution.

has anyone found something that works?
Click to expand...
Do you have the black plastic vents that Van sold? Back in the day some of us would go down to the local Ace aviation department and pick up a couple of pvc pipe caps. I don't remember the size off hand but if you measure the O.D. of the vent I think you'll find some that fit snug. I used those for a few years before I finally bought and installed the better vents. Some people suggested placing a bead of silicone inside the plastic vent to act as a valve seat. I personally didn't have much luck with that.

Joe
 
Jetmart said:
santahats-2048px-8442.jpg.webp
Click to expand...

I had an instructor who used soap suction pads to cover the instrument dials for the partial panel work. I bet he'd be really excited to hear about the pom-poms aviation air blockers!

1764780551314.webp
 
As a data point, I installed the aluminium vents sold, I believe back then by Stein ??.
They seal very nicely when closed. Glad I chose to get them.
Last Monday, I flew with OAT of minus (-8°C), no sun.
Worked hard to eliminate cold drafts and I still have some. At that temperature it's only lukewarm in the cabin, it's no surprise, this is not like a properly sealed car and I dress accordingly.
I did tape shut the rear NACA vent once as a test, but drafts in the back were not from the vent.
Sealed up the wing spar to fuselage, the aileron push-rods and the SCAT hose to fuselage for the rear vent (RV-8).
Lot better now, though not perfect.

As others suggested, you could find a cap to cover/seal the vents.
I would not recommend to tape shut the outside NACA vent, you never know if or when you could need some fresh, despite cold, air.
Good luck
 
A standard business card cut down the middle. Slip each piece into the vent and close the vent.
Can't get any cheaper than that.
 
As my (amazing) flight instructor would say: Don't overthink this! Wouldn't a foam rubber plug or something similar cut to size plug that hole? My fresh air vents close off at the source, and I also have metal eyeball vents on the panel that close completely. Nice. Happy that was an area I didn't scrimp. AND they look pretty cool!
 
Yes. I took a piece of 1" thick black foam that was packing for some sort of delicate aviation gizmo. Cut a square just a bit oversize, and then trimmed the corners at a 45. Stays put all winter, and I know where I can get another one if it goes missing in the summer.
 
gasman said:
A standard business card cut down the middle. Slip each piece into the vent and close the vent.
Can't get any cheaper than that.
Click to expand...
flew with the business cards today while waiting for pom-poms or a package with the foam. I have never been so comfy on a December flight! This is a genius tweak, thank you! The others sound good too!

1765159465727.png
 
ve0kog said:
My cabin vents leak some air even in fully closed position. This isn’t a problem except during a few cold winter months.

I’ve seen different/better than the OEM vent types and even 3d printed outside air intake covers held with a screw through the fuselage but Im curious if something dirt cheap and simple like a rubber cap that fits snuggly over the vent could be a solution.

has anyone found something that works?
Click to expand...
Assuming you are referring to the van black vents. You can go to the plumbing isle. The make a rubber pipe cap that fits perfectly and even comes with the ss clamp. Iirc it is a 2” cap. Meaning for 2” pipe, which isn’t really 2”
 
riseric said:
I would not recommend to tape shut the outside NACA vent, you never know if or when you could need some fresh, despite cold, air.
Good luck
Click to expand...
Very good point
I used to put a sock in from the outside to the NACA scope but after doing it for a few years I thought better of it. You want to be able to have the ability to get fresh air in the cabin, even when cold out. Two examples are smoke in cabin and the CO detector making noise.
 
Just as an aside, and I don’t want to take away from the OPs question. Does anyone put mesh over the air inlet to keep out bugs? And if so, how fine?
 
lr172 said:
Assuming you are referring to the van black vents. You can go to the plumbing isle. The make a rubber pipe cap that fits perfectly and even comes with the ss clamp. Iirc it is a 2” cap. Meaning for 2” pipe, which isn’t really 2”
Click to expand...
I use rubber pipe caps minus the clamp. The clamp is a good idea. I have to warm mine up before they’ll slide on easily. 🤣
 
Jonnyb said:
Just as an aside, and I don’t want to take away from the OPs question. Does anyone put mesh over the air inlet to keep out bugs? And if so, how fine?
Click to expand...
Yes.
Whatever plastic mesh you can find in black.
Wrapped around back of vent, secured with SCAT hose and clamp.
 
Jonnyb said:
Just as an aside, and I don’t want to take away from the OPs question. Does anyone put mesh over the air inlet to keep out bugs? And if so, how fine?
Click to expand...
Yes. Typical metal screen door screen cut to fit at the air intake. Did not seem to slow the flow of air down. Keeps bugs coming in the cabin at 152kts! :oops:
 
Proseal fillet in/out against the respective halves of the vent door. Packing tape on the door to keep it from sticking, peel off after cure.
IMG_20251209_105352147.jpg
 
Roadjunkie1 said:
Yes. Typical metal screen door screen cut to fit at the air intake. Did not seem to slow the flow of air down. Keeps bugs coming in the cabin at 152kts! :oops:
Click to expand...
Or when the plane is just parked, perhaps outside on a ramp. Bees, wasps, hornets, or just annoying flying insects...don't want any of 'em sneaking into my cockpit when I'm not looking :).
 
If you want total blockage that looks purpose built - take the outside diameter measurement and have someone 3D print a cap in TPU (rubber like - undersize it a bit so it's a snug fit to put it on).
 
We had a small plug that fit inside the air vent, but it was a bugger to get out without pliers. Since it was the 2nd iteration of the same concept and was still not as functional as I wanted, I started over and came up with a 3-D printed variant that has handle with a "finger hole". I left the outer wall thickness of the plug pretty thin so that it expands just a fraction as it is put over the vent. Rounded corners of the inside "plug" keeps the sharp corner from binding on the vent as the cap is installed.

I had PLA in the printer, so that's what I used.

It's easy to get on and off - even in flight.

Regards,
Rob
N706DR
RV-7A

Vent Plugs.jpg
 
rmd said:
We had a small plug that fit inside the air vent, but it was a bugger to get out without pliers. Since it was the 2nd iteration of the same concept and was still not as functional as I wanted, I started over and came up with a 3-D printed variant that has handle with a "finger hole". I left the outer wall thickness of the plug pretty thin so that it expands just a fraction as it is put over the vent. Rounded corners of the inside "plug" keeps the sharp corner from binding on the vent as the cap is installed.

I had PLA in the printer, so that's what I used.

It's easy to get on and off - even in flight.

Regards,
Rob
N706DR
RV-7A

View attachment 104363
Click to expand...
Rob. Do you have an STL available? Save me reinventing the wheel?
 
Jetmart said:
This is going to sound crazy but it was always meant to be temporary. However it works great. Several years ago just after Christmas we headed down south for the winter. Never got the chance to figure out how to close off vents. Grabbed the white pom-poms off the Santa hats that were sitting on the kitchen table. They filled the hole perfectly. They are light, soft, and very easy to store year round in the plane. Just got them out for the first time this fall.


View attachment 103774
Click to expand...
Jetsmart,
Brilliant.
Daddyman58
 
I took apart my Van's air vents and cut a piece of felt a little bigger than the flapper. I riveted the felt to the flapper with a couple of half-moon shaped pieces of aluminum as backing material. Works great. Doesn't leak.
Bruce
 

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Bruce9A said:
I took apart my Van's air vents and cut a piece of felt a little bigger than the flapper. I riveted the felt to the flapper with a couple of half-moon shaped pieces of aluminum as backing material. Works great. Doesn't leak.
Bruce
Click to expand...
.......the Mother of Invention! 😊
 
rb14 said:
Rob. Do you have an STL available? Save me reinventing the wheel?
Click to expand...
Attached is a file that contains three slightly different designs of my vent plug as Solidworks native format, STL and Step files. Also included is a PDF that depicts each style of part.

Some folks have the "geared web" of the plug facing towards the seats and use it as a thumbweel to adjust the flapper and needed a slot or a smaller, inner portion of the plug. I have that piece facing into the duct and use it as a friction device to keep the flapper where I put it. I have know idea which way is best, but the plug I initially designed didn't need a slot to accommodate that feature.

I found the "finger hole handle" really useful the other day when I needed to remove the plug in the middle of a flight. The plug removed easily from the vent.

Regards,
Rob
 

Attachments

rmd said:
Attached is a file that contains three slightly different designs of my vent plug as Solidworks native format, STL and Step files. Also included is a PDF that depicts each style of part.

Some folks have the "geared web" of the plug facing towards the seats and use it as a thumbweel to adjust the flapper and needed a slot or a smaller, inner portion of the plug. I have that piece facing into the duct and use it as a friction device to keep the flapper where I put it. I have know idea which way is best, but the plug I initially designed didn't need a slot to accommodate that feature.

I found the "finger hole handle" really useful the other day when I needed to remove the plug in the middle of a flight. The plug removed easily from the vent.

Regards,
Rob
Click to expand...
Thanks Rob. Printing now. I'll keep you posted.
 
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