Rear window loose Carbon Cub FX-3

[Neal]

I have never flown with a window open to date as I fear a rear window separation. It’s sad CubCrafters has made no effort to afford us the cub experience we all desire which is door and windows open.

I sometimes runup with both windows open and have been hearing a rattling sound. I thought it was just my window rattling on the latch. Today after flying I did a post flight runup after replacing my right ignition spark plug wires due to coil pack failures and notice the left aft window forward edge not secure and the cause of the rattle.

What are suggested options to secure with confidence? I see the only thing holding it is a thin strip of black double side adhesive tape.

I’m considering a bead of Sikaflex 221 black. I’m open to suggestions.

 

[Neal]

 

[Cactus Charlie]

I'm surprised it has not departed the aircraft.

If you search around you may find references to fitting a U channel section over the front edge of the window and the frame tube. I think this is standard fit on the XCub but I couldn't find any references. Perhaps an XCub owner could check and provide photos.

I usually close my FX-3 door and both windows for run-up but I quite often fly with one window open for photography. That's always low power and well below limit airspeed.

 

[Cactus Charlie]

This thread mentions a change in window adhesive but it could have changed since then -

Flying with windows open. - CubCrafters Forums

General discussion of all CubCrafters aircraft models

forum.cubcrafters.com

 

[Neal]

I can tell you that a 1/8" strip of double-sided tape is NOT acceptable and it's an embarrassment to any engineering involved in this window mount. I posted on the Facebook "Official" product support page which I rarely touch and the comments were:

• Use a channel bar if you're capable of making one to cover the window and column
• Use clear tape to adhere from the outside of the window to wrap around the inner black tubing
• Use silicone sealant

I suggested to Pete that maybe a service instruction would be worthwhile with a part that CubCrafters can produce for owners to keep any chance of this window from delaminating/separating. We all want to fly with windows and doors open in a cub (well, some) but I've never done it as I've seen videos of windows flying off. I also don't want it to hit my tail and mess up the cover on that.

I have 3M clear protective "clear bra" tape that I use on the leading edge of some areas, it's a durable clear tape product. I plan to first use Sikaflex 221 black (a stronger type of silicone that I use on my RV (wheeled type)) that works well. I'll use that to both adhere and provide a front bead to seal the gap. After dry I'll then use the 3M clear tape to ensure a wind barrier that can't force a separation. I'll review the entire rear window mounting structure and sikaflex as needed.

Will follow up with pictures after done. I have to gain trust that these windows are with me forever.