Wing root air vents

[Zzz]

Thinking ahead, because my wings have yet to be touched, still hanging on the hangar wall.

Any ideas for off-the-shelf wing root vents? I've always somewhat deplored the Cessna ones, and I can't stand the plastic ring on them. The cheap ones you can get some spruce with the bell-end (ha) seem...cheap. After seeing a few of the ball-joint adjustable style, it seems like the way to go, but what's out there that can be had for less?

The Precise-Flow look nice, but at $450, it's a little steep. At first I thought they might be targeting the fat wallets of newer Cessna owners (or something) but when shopping on Spruce I see other eyeball vents like this, at $264/ea.

Spruce also carries these Aveoair vents, which seem like they might work, and a little more reasonably priced. They have different scat-couplers so if you had 4 of them, you might use 2 for the wing root air vents, and 2 for the heater vents (if you wanted such a fancy feature for the heater.) They also carry Steinair vents, which are a little higher priced by look quite nice.

Finally, what is used for the leading edge inlet? Are there pre-fabbed intakes you can rivet into place after cutting the hole in the wing leading edge?

Curious what others have done.

[Mark Moyle]

Javron sells window vents that are identical to the PMA'd vents from Univar. http://www.javronaviation.com/Piper-Window-Vent/


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[Bcone1381]

Thats a nice vent! Seems like Javron does things right.

[whee]

I've never been a fan of the Cessna vent so I've been planning all along for naca ducts in the boot cowl and eyeball vents in the panel. I'm not sure I'm going to go through with it now though.

[Battson]

I used the VentTube ones in the wing root, which perhaps are not for everyone.
To me they are light-weight, simple, and cost effective at $90 for a pair. They are not cheaply made, it's good strong UV resistant plastic. Most importantly they provide a tonne of air straight onto my face / body / hands as desired. I have enjoyed them each summer.
Happy to share details if you decide to go that route.

It seems like you are thinking ball vents on the wing root? Do you think they will shoot enough air down to your hands / lower body?

Be careful where you place the inlet holes on the L/E of the wing, if you go that way. Mine whistle when I am close to the stall, which is good and bad. They also let rain in while my ride is parked outdoors, which is just bad. Fortunately the VentTube forms a watertight seal, but if I open them after rain while the engine is running, I get a little shower! To position the inlets, I followed instructions which I should have thought to question at the time. In fact you want them under the L/E by a margin.

You can purchase plastic ducts which you rivet onto the inside of the wing skin, but they can be pricey and may not fit the BH dimensions. I just decided to make my own from fibreglass, it was easy.

[Pat Fagan]

I put the cessna style vents in the wing roots and have NACA ducted eye ball vents in the boot cowl and under the wing. The boot cowl feeds pilot and copilot while the under wing ducts are for the rear seat, but without passengers we point them at the back of our necks when it gets really hot. Can't have too much air in the desert. The air from the pilot side boot call duct is measured 10 degrees hotter than the air from the copilot side.

[Zac Weidner]

I put the cessna style vents in the wing roots and have NACA ducted eye ball vents in the boot cowl and under the wing. The boot cowl feeds pilot and copilot while the under wing ducts are for the rear seat, but without passengers we point them at the back of our necks when it gets really hot. Can't have too much air in the desert. The air from the pilot side boot call duct is measured 10 degrees hotter than the air from the copilot side.

Have you pinpointed why the pilot side is hotter than the copilot side? That's intriguing.


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[Pat Fagan]

I assume it has to do with the air flow caused by the propellor. It seems to be the same phenomena that causes more damage from rocks on the underside of the tail on the pilot's side compared with the other side.

[Battson]

I assume it has to do with the air flow caused by the propellor. It seems to be the same phenomena that causes more damage from rocks on the underside of the tail on the pilot's side compared with the other side.

That certainly is very interesting.

Do you think it's hot air from the engine cooling, or hot combustion gas / exhaust fumes?

[JimParker256]

That certainly is very interesting.

Do you think it's hot air from the engine cooling, or hot combustion gas / exhaust fumes?

A Carbon Monoxid detector would answer that question pretty easily. (Not the stupid "spot" things, a REAL CO detector like this.)

[Pat Fagan]

Must be cooling air. I have louvers in the cowl which could provide a source. I also have a battery operated CO detector and it has never gone off.

[Zzz]

I
It seems like you are thinking ball vents on the wing root? Do you think they will shoot enough air down to your hands / lower body?

I don't know. Do you think they'll be flow-challenged?

Interesting point on the rain entry to the wings through the vent openings. How do Cessna and Maule address this?

[Erbman]

My vent system is very similar to Pat's, which is not surprising since I basically copied his. I also have louvers in the cowl and a CO detector. The temperature variation is also very similar to his. It comes from the cooling air, because I didn't have that variation before I put in the louvers. Unfortunately, it makes the boot cowl inlets rather useless, since the air out of them is not very cool.

[Battson]

I don't know. Do you think they'll be flow-challenged?

Interesting point on the rain entry to the wings through the vent openings. How do Cessna and Maule address this?

Not flow challenged. I was wondering whether those vents can angle down far enough, to blow air on your hands. Sometimes those ball vents only move through a small angle, not the 70-80 degree angle necessary. I need that hand-cooling in summer, it gets hot in a sunny cockpit, and it's especially hard to grip the flap handle and uncomfortable on the stick. I often struggle with the flap a lot, and need to slow down well below the V speeds to get the last two notches on. I often strain my back if I am doing dozens of landings in an hour. Thread hijack - but - do seriously consider lengthening your flap handle by 4-5 inches, I am planning to do this mod this spring (your autumn).

I think if the vent inlet is just under the wing, while the plane sits in the three point attitude, then rain will not easily collect in the vent. The shape of the inlet also matters I think, to keep water out, the upside down triangle. Of course, once you cut that wing skin, you are committed. Its not a big problem, I don't worry about it very often. The final idea I had, was to put in a drain from the lowest point, so the water can run out into the wing root and escape past the fairing (which is not watertight). Of course you would also lose air pressure through the drain too.