Insulation in wing root to stop airleak

[Kyle Wolfe]

I've always had a bit of an air leak around the upper corners of my windshield - up by the flat template just in front of the airvents. I put foam in my airvents for winter flying, but was thinking of what I could do to stop the other air from coming in.

I stopped at a local airport today and they were doing an annual on a 185. They had the wing inspection panels dropped - the ones just outside the door that wrap around the leading edge of the wing. And there in front of me was my answer. This owner had placed insulation around the joint where the wing root and windshield meet. He had placed duct tape there as well. The nice thing is that it's all hidden under the inspection panel. (I'm just too picky to go plastering duct tape on the outside of the airplane.)

I've searched all the other posts regarding winter flying and haven't read anywhere about this trick. Anyone else done this? Any issue anyone can think of?

[N2865C]

Well, living in sunny California I didn't put any insulation in there, but when I installed a new windshield I used duct tape as described. It was recommended by my IA.

[cessna170bdriver]

Kyle,

If you do decide to put insulation in there, try to find something that won't absorb water and have a potential for causing corrosion. I don't have any sources, but there is insulation that is fiberglass completely enclosed in plastic. There may also be some foam insulation out there that is sealed or backed so it won't absorb water. Loose fiberglass batting WILL hold water.

Miles

[GAHorn]

Virtually any insulation will pose a risk of added corrosion, regardless of whether it's encapsulated with plastic. The best solution is a pretty simple one,...exclude all air and water. You can do it by dropping the wing-root to cabin fairing, and bridging across the gap with either duct tape or vinyl leading edge tape. It's common practice on later Cessnas to do this, as their entire fairing can be removed all the way around the wing root,...not just the lower surface such as on our 170's.
In that later design, water will migrate via capillary action and gravity to the upper cabin area an contribute to corrosion, and will allow the interior, headliner, sidewalls, etc to become soaked after a night outside in the rain. (This was a problem on my 206 until I taped it.)
By bridging the gap completely with tape, the water would not enter the upper cabin area at all. Neither would air in flight.
Use either duct tape or vinyl tape. Do not use aluminum-foil tape. It isn't durable enough and you'll soon end up replacing it. Be careful as you place the tape so that it'll be hidden by the fairing when it's reinstalled.

[HA]

sometimes it gets cold here even in sunny ND, so every Cessna I've seen up here has insulation in between the wing and cabin, and up in front by the windshield. makes me sneeze and cough when I pull it out for inspections from the dust, otherwise no ill effects.

I went a little further and put camper tape (thin foam weatherstrip, 1.5" wide) on the bottom of my top wingroot fairing so that it seals to the wing and windshield. no drafts.

not sure how yours is, but my windshield shakes some on startup and so you'll want fairly flexible tape if you decide to tape the gap, or leave some slack in the tape.

[Joe Moilanen]

One of the former owners of my plane sealed insulation in seal-a-meal type bags and stuffed them up in the wing root void (about 6 bags per side). I've had the plane since '89 and haven't had any corrosion. I give them a thorough inspection every year at annual time.

Joe
4518C