L21 wieght difference

[Farmer Ted]

I’m considering switching to l21 window vs D window during the rebuild. What are the disadvantages? How much weight would this add? They say it’s a lot warmer in the summer, what’s the experience with those that have this? Thanks

[BC12D-4-85]

Gets warm. Solar tinting film applied to the inside can help reduce that, plus light colored upholstery.

Gary

[SchulerJL]

I have an L21, no problem at all, if it gets warm I open the door. The visibility for the back seat passenger is great - definitely not claustrophobic. I think it's actually lighter - just guessing.

[Farmer Hank]

I started to install the L21 kit but decided it was way too much glass. I’ll try to post a photo of my alternative tomorrow.

[sjohnson]

I used smoked plexiglass - heat has not been a problem.

[KevinJ]

I have an L21, no problem at all, if it gets warm I open the door. The visibility for the back seat passenger is great - definitely not claustrophobic. I think it's actually lighter - just guessing.

L glass, from guys in the know, is anywhere from 11-13lbs heavier. Vis is second to none especially when other planes are around. I like the way they look but if weight is your ultimate concern……

[Farmer Hank]

I started to install the L21 kit but decided it was way too much glass. I’ll try to post a photo of my alternative tomorrow.

. Here is what I came up with. The rake of the rear glass support matches the A pillar. All the supports are .020 steel, joggled to fair the fabric with the glass, and wide enough to give a good surface to glue the fabric.

[Bugs66]

No problem with mine. I used smoke Lexan for the top. Pax love it the most. Can be handy to look behind when taxi. If you want it, do it. Can save some weight somewhere else.

[DENNY]

Weight difference depends on a few things. Are you replacing a metal headliner? How thick is the glass? How much ginger bread you use for support (thinner glass more gingerbread/standoffs) I put .060 glass in my stock cub. Light but pretty easy to get a crack. One advantage is more headroom without the headliner. It might get a bit warm sitting in the TX sun all day, tinted would be the way to go. DENNY

[KJC]

Here is what I came up with……

Hank if that’s a experimental Cub, then have at it. If it’s certified, then I have to ask why you are going off script on this.

There are two options for glass in a certified Cub. D windows or L21 glass. If you want to put L21 style glass in an aircraft that didn’t originally have it, Atlee sells an STC or I think it can be done as a major repair using the Piper drawings as a reference. Either requires a 337. Your going to have a one off hybrid and I’m not sure I’d be willing to sign off on that.

Maybe your mechanic will sign it as a minor but I think it’s a stretch with an STC available.

Reinventing the wheel is sometimes not a good call. If yor experimental, do what makes you happy.

[Taledrger]

I'm on my 2nd L21 and I love the extra visibility!! I do have the smoked roof but have never thought it was too HOT.. The pluses, I think, far out way any possible negatives..

[Farmer Hank]

I built my Cub clone in 1986. Flew it 260 hours and went on to other projects. Now it is getting a complete rebuild with many of the proven Cub mods, and yes, I’m a little off script here and there. Many thanks to this group for all your knowledge - most of which I have not publicly acknowledged in any way.