I think I may have asked this long ago here, but I can't find it if I did. I just can't seem to visualize a confident way of doing this. I've got an Electra kit that I need to get at sometime but the canopy (glass) install has me nervous. For those not familiar with the Electra, it has essentially the same cockpit/canopy design as a Smoothie, a clear one piece windscreen with windows that wrap around to the sides with a solid painted "roof".

 The "glass" is simply a plastic one piece wraparound of the necessary shape to land correctly into position. The goal of course is to end up with the cockpit side glass on the same level as the fuselage sides when finished. It seems tough for me to describe exactly, but what I mean is that when finished you could essentially lay a straightedge along the side glass rearward to the fuselage and it would have an uninterrupted smooth transition with the glass being at the same height as the fuselage. I see this on finished models all the time, but can't figure out how it's done so that later on there is no cracking of seams or blended areas. I can easily install, fill and blend the "glass" into the fuse, but I can't get over thinking the transition area ends up so thin that it will be very likely to crack or split. So anyway, how is this done so you don't have any problems with cracking?

 Thanks Tim, I forgot to mention that detail, but I did already plan on recessing for the glass and doing it that way.

 Yep, I also realize those details and have that more or less figured that out too. FWIW, I have installed bubble canopies, but with those you simply glue it into a "trough" like you say and then put a fillet around it afterward. Relatively easy and simple.

 This is what I mean by my main question being kind of difficult to explain, at least for me apparently.

 I'll try again. I would normally assume and plan on recessing the perimiter just enough for the plastic to sit flush with the wood at and around the transition point. I would also do the "trough" and fillet around the base of the front windshield area. My main concern and question here with this type of installation is that once you have everything filled and sanded, say ready to finish, that the filler or glue at the blended transition point will end up being extremely thin, making it very prone to cracking.

 Bill,

 By "scab" do you mean pre-coating, and allowing the chosen adhesive to cure, the recessed area where the plastic will be set in and attached first?


 (I can't help but feel like I'm really overcomplicating this installation)

Bill,

 By "scab" do you mean pre-coating, and allowing the chosen adhesive to cure, the recessed area where the plastic will be set in and attached first?


 (I can't help but feel like I'm really overcomplicating this installation)

Hi Wayne,

I wish there was a drawing function in the posting tools! LOL!!

I make a piece that fits inside the fuselage (turtledeck) sides.  Then the wood stays full size, and doesn't have to be thinned for the "glass".  A "ledge" so to speak, so no "recessing" is needed, only the trough on the nose block, but that is never a problem....  you might have to shim out the "ledge" so that the glass is flush.

A picture would have already been worth a couple thousand words! LOL!!
Am I making sense?  Maybe you already know that? 

Big Bear

Bill

Don't you realize there is a little difference between the surface of the planes skin and the glass peices that go on/in.  I always over lap the canopy/windshield with some form of glue.  Maybe the unlimited Reno racing planes are nice and smooth around the canopies/windshields.   

... However, it still doesn't address my primary question/concern of the thin-ness of the blended exterior of the joint being prone to cracking. I'm thinking that to end up with the glass level with the finished fuselage exterior, I'll need to sand and blend whatever glue, epoxy, or filler is used down to that same level. This will leave no "buildup" over the "seam" or "joint" between the wood and the plastic. To my imagination, it ends up being essentially a butt joint with no material over the top. I envision a crack just waiting to happen at that "seam" or "joint" in short order after first flights, and that would suck.

Taper the canopy material over the width of the ledge that it sits in, so it's full width where it exits, but transitions down to nothing at the end -- that'll give you a canopy-thick glue edge that tapers down.

I've built two Electras over the years. I did not experience the problem you are worried about. I created a 1/64" plywood backing flush with the inside of the cockpit sheeting. This created a very narrow shelf. I used epoxy to glue the windshield into place. After that had hardened, I masked off the wind shield with fine tape around the edges, and regular tape covering the rest. I held the fine tape out a little, so later coats of epoxy, and paint covered the shelf from view. While sanding the area, I tried to leave a sleight edge, or coming, as I believed a full sized plane might have in those areas.

Thanks, John, the "shelf" is what I have been trying to describe.......

  Hi Wayne,
  I'm a bit behind here,,, can you bring me up to date as to how far along the olane is?
  John

 Heh-Heh, it's still in the box John.  I'm still doing research for the future Electra project. I've still got some other projects in front of it. I'm very close to finishing up a very modified Brodak Zero right now, (it's almost ready for the final clearcoats) and then next will be a new "Super Combat Streak" kit by Walter Umland.