Cabin Vents

[Ed.Meyer]

I notice that many Bearhawks have the Cessna style wing root cabin vents as Bob recommends. I am having trouble finding the parts for them. Are there parts available that I am not finding or are they being made from scratch? Seeking ideas/methods...

[tf104]

I got mine from an aircraft dismantler , Faith air in sacramento ca

[Mark Goldberg]

There are some plastic kits for use on experimentals that are the same shape and design as the better ones pulled off Cessnas. Mark

[Ed.Meyer]

Where can we find the plastic kits? Google is turning up plastic tubes for the inside part but not the whole kit that includes the part to attach inside the wing leading edge.

[Wayne Massey]

http://www.aircraftspruce.com/catalog/appages/ventube.php

http://www.aircraftspruce.com/catalog/appages/venttubeadaptercessna.php

[N942VT]

You can make that part with some aluminum and central vac pvc tubing and elbow

[jaredyates]

I've been really happy with the plastic Vans NACA vents at $5 each mounted to the boot cowl, plus some eyeball vents on the panel. The eyeball vents are a little expensive, but work well and seal tight. The two are connected with 2" SCAT duct.

[Chris In Milwaukee]

I've always wondered about those. Any problems with water intrusion when flying in weather? Or do they effectively only allow the air in and keep the water out?

[jaredyates]

I wouldn't know, I don't fly in that kind of weather There is a pretty good mass-separation element to it, being that the water would pass by the side of the plane and the air would turn the corner.

[dedgemon]

I fly the RV in rain periodically to wash it. No problem with water in the vents. Now I do not fly through super heavy rain. I would expect that there is a point at which you start picking up the water.

[Ed.Meyer]

Thanks for the responses...

[Battson]

I made these adapters myself from fiberglass.

http://www.aircraftspruce.com/catalog/appages/venttubeadaptercessna.php

I made the mould for them from a toilet-paper tube taped onto cardboard, shaped to match the wing form (held in place with another bit of card). It was a 60 minute job. Much better than $150 for the OEM ones.

[Mark Moyle]

Other options are the window vents. I went with these on a certified Piper I've restored....fuselage is done...waiting on wing parts. Javron Cub sells non-certified that are identical to PMA'd from Univair.
Can get a close up picture if interested.



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[Battson]

The window vents don't always work so well. My BH's sister ship here in has them, and they are unusable. Perhaps in a slower aircraft, or one with smaller windows?? I can't say why. I have been assured they were a bad idea in his case, and he wished he didn't install them. Certainly when we flew together, it was a hot ride. He said he wished he went with the vent tubes in the wing root.

I am talking about this kind:
http://www.gt40s.com/forum/attachmen...9&d=1199218692

IIRC, the air pressure broke them when full open at cruise speed, or pressed them shut. I don't know which.

[JimParker256]

On the circular window vents - I read somewhere that they are limited to opening only below 120 mph... Unlike SuperCubs, this could definitely be a problem in any of the Bearhawk models!

[James]

Yeah, they use these window louvre things like the picture above on the old Seahawk helicopters, but they eventually develop small cracks, and then get ripped out in the cruise ~140kts. Makes a really startling noise the first time you hear it, and you wonder if something important just fell off your frame.

[Bradrock]

Jono - what arrangement have you got in the cabin for your air vents?

[Battson]

I have the wing vents which the guys discuss above. The hyperlinked venttube ones - they are very effective. http://www.aircraftspruce.com/catalo...es/ventube.php

[Nev]

There is a pretty good mass-separation element to it, being that the water would pass by the side of the plane and the air would turn the corner.

Anyone know if this works for bugs, bees etc ? I would have thought that they’d have a hard time changing direction to enter a NACA vent, but there’s a thread on the Vans forum where guys are installing mesh in the NACA vents to keep the bugs out. Am I missing some there ?? I wasn’t planning on using mesh.

[jaredyates]

I would worry more about bugs getting in while parked. But I'm not running mesh and so far it's been ok.

[AKKen07]

I am not planning on mesh. I am planning on a windshield cover that wraps around the vents on the cowl as well for parked bug/precip protection.

[spinningwrench]

Just finished installing the NACA vents from VAN's in my boot cowl. I think boot cowl vents provide better overall cooling than the Cessna style which blast you in the face.

NACA Inlet.jpg

[Nev]

Just finished installing the NACA vents from VAN's in my boot cowl.

I’m at almost the same point as you, I made the cut outs this morning and am using Vans NACA vents as well.
I see you’ve drilled and countersunk holes. Are these for screws or rivets ? I’m wondering how well rivets will hold in plastic. My initial plan was to use #6 screws into nutplates, bonded to the plastic. But the screws also require quite a large countersunk hole for .025 aluminium.

Thoughts ?

[jaredyates]

I riveted the inlets but made a .020 backing ring so that the plastic is sandwiched between two layers of aluminum.