Building and finishing my 2+2/PA 14

[skywagon8a]

Marty, Once you get the boot cowl in metal, I would fit the windshield next. Do those tubes which match the wing leading edge shape line up with the wings correctly? If not there will be some shapes there with which you will not be happy. Once the windshield is fitted all around satisfactorily, then make the two trim pieces to fit. The only screws which penetrate the windshield are on the vertical door posts. Cut the plexi here last as you will find the edge moving around as you progress. All the rest is just sandwiched in the frames and allowed to float. The further forward the you can place the lower edge of the windshield the better. More slope will provide less drag. (= more speed :smile: ). Every little bit helps. Let the top edge float on top until you get the lower edge done.

You can cut the plexi with a fine toothed blade on a band saw. Use some of your cardboard between the plexi and the saw table to prevent scratches. File all the edges along the edge making sure that you have no nicks or scratches. If you apply any bending pressure and there happens to be a nick or scratch you could break the plexi. Drill holes with a unibit.

 

[Marty57]

Marty, Once you get the boot cowl in metal, I would fit the windshield next. Do those tubes which match the wing leading edge shape line up with the wings correctly? If not there will be some shapes there with which you will not be happy. Once the windshield is fitted all around satisfactorily, then make the two trim pieces to fit. The only screws which penetrate the windshield are on the vertical door posts. Cut the plexi here last as you will find the edge moving around as you progress. All the rest is just sandwiched in the frames and allowed to float. The further forward the you can place the lower edge of the windshield the better. More slope will provide less drag. (= more speed :smile: ). Every little bit helps. Let the top edge float on top until you get the lower edge done.
.

The tubes at the top of the fuselage do line up nicely with the wing root so that should fit ok. This shot was with the wing mounted before I painted the fuselage.



The door post is another case. On the Super Cub, the windshield seems to fit on top of the steel welded to the post. On my fuselage, the windshield seems to go below the trim piece. There will be a trim piece inside the fuselage; maybe that trim piece could have the nut plates for the fuselage.



Like much of this project, lots more to figure out. Thanks for the info.

Marty

 

[skywagon8a]

I'm not familiar with the PA-14 in the door post area. If it calls for two trim pieces as you mention, you should not need any fasteners through the plexi at all. The outside lower trim strip will be screwed to the boot cowl. That would be the only screwed on part. The whole windshield will be allowed to float in place just like Cessnas.

 

[Marty57]

I'm not familiar with the PA-14 in the door post area. If it calls for two trim pieces as you mention, you should not need any fasteners through the plexi at all. The outside lower trim strip will be screwed to the boot cowl. That would be the only screwed on part. The whole windshield will be allowed to float in place just like Cessnas.

You may be on to something here ..... i think the windshield could float. Time to make a few more patterns and get some aluminum for the boot cowl.

Thanks,
Marty

 

[Hardtailjohn]

Use an abrasive wheel on a die grinder to cut and trim the windshield. It's the only safe way. I've had too many break with a saw.
John

 

[skywagon8a]

Marty, before you cover the fuselage you should review this AD note for guidance. It was derived when planes were still being covered with cotton and linen, however the extra reinforcement strip of fabric would still be a good idea.
AD74-17-04 http://rgl.faa.gov/Regulatory_and_G...3CEE8EBCA9FEB8D786256E120049906B?OpenDocument The original AD 61-06-06 had a drawing of the method of wrapping the fabric in the slot of the windshield retainer and around the tube under that. Perhaps someone can post that drawing.

 

[Marty57]

Marty, before you cover the fuselage you should review this AD note for guidance. It was derived when planes were still being covered with cotton and linen, however the extra reinforcement strip of fabric would still be a good idea.
AD74-17-04 http://rgl.faa.gov/Regulatory_and_G...3CEE8EBCA9FEB8D786256E120049906B?OpenDocument The original AD 61-06-06 had a drawing of the method of wrapping the fabric in the slot of the windshield retainer and around the tube under that. Perhaps someone can post that drawing.

I've read about the AD and the fabric issues up top by the windshield. I'll be installing a skylight up top so no fabric above the windshield. With fabric in that area, a second tape of fabric inside the channel that holds the top of the windshield would be a good idea. I am curious what the drawing for that tape looks like. I got a call from an IA last week asking if Stewarts Systems glue would work to bond fabric to the skylight on a T Craft. Apparently, from his explanation, the fabric is glued directly to the skylight with out any metal strips? I'm not familiar with that set up but would be a bit concerned with glue only to plexiglass to secure in a skylight. He indicated that the skylight was only secured with fabric and glue. He was repairing a T Craft that had the skylight depart in flight due to fabric failure. Not really sure how that would work .....

Marty

 

[skywagon8a]

Here is Piper Service letter 362B: http://www.univair.com/content/PIP_SL0362B.pdf My recollection was wrong as this drawing does not show the fabric actually going into the windshield retaining channel. Perhaps the drawing was changed in this revision?

Here are some pictures of the T-craft skylight. The plexi is held in with screws all around and down the middle. https://www.stevesaircraft.com/skylightstc.php I would never trust a skylight to remain in place with only glue holding it down.

There is a tremendous amount of lifting force on the top of a fuselage. When I was still a newby with my T-craft, being anxious to get it flying I took it for a high speed taxi run on the runway before I had fastened the screws into the top edge of the windshield. Well! There was a loud bang when the top 4" of the windshield snapped off. This with only a high speed tail high taxi.

 

[Marty57]

That drawing makes more sense. My 2+2 drawings don't show any trim piece across the top of the fuselage where the windshield slides in place, only for the skylight. On my fuselage, the channel is welded to the windshield flange, not sure if I can get a nut plate in there or not. I not, I can rivet a bracket with a nut plate to the face of the channel and attach a trim piece that fits inside like shown on the drawing and comes over the top of the front edge of the skylight. I can also have nut plates in the three channels that run aft, making up the upper bird cage. That extra trim piece should hold the windshield in at the top still allowing it to float without any screws through the plexiglass. Thanks for service bulletin.

Marty



Marty

 

[skywagon8a]

That channel which you now have is more than adequate to hold the top of the windshield as is.

I can rivet a bracket with a nut plate to the face of the channel and attach a trim piece that fits inside like shown on the drawing and comes over the top of the front edge of the skylight.

This should work to hold the leading edge of the skylight as well as keeping the rain out.

 

[mike mcs repair]

On the sides at least on a Scout the fabric is just glued to the skylight. Don’t remember the rear method


Sent from my iPhone using SuperCub.Org

 

[Hardtailjohn]

Here are some pictures of the T-craft skylight. The plexi is held in with screws all around and down the middle. https://www.stevesaircraft.com/skylightstc.php I would never trust a skylight to remain in place with only glue holding it down.

There is a tremendous amount of lifting force on the top of a fuselage. When I was still a newby with my T-craft, being anxious to get it flying I took it for a high speed taxi run on the runway before I had fastened the screws into the top edge of the windshield. Well! There was a loud bang when the top 4" of the windshield snapped off. This with only a high speed tail high taxi.

Ummmm.... that's not a Tcraft skylight. That's Steve's for a Piper. Greg Clayton holds the STC for Tcrafts. I'd have to look to be positive, Marty, but I sure don't remember that when I've installed that STC before. I'll try to remember tomorrow when I go to the shop. I've got the STC sitting there for mine.
John

 

[skywagon8a]

Hmmm? You're right. Google lied when I asked for Taylorcraft skylight. Looking further there are lots of pictures but I couldn't find any with close detail shots.

 

[Hardtailjohn]

 

[Hardtailjohn]

Marty, here's one from the inside, looking out. Fabric should wrap around structure in the rear, and around wood formers on the side. There's 4 hold down screws in the center and a bunch front and rear.
John

 

[Marty57]

John,
Great pictures, thanks. I should be able to cover just about the same way. The channels up top will be easy to wrap the fabric around to give me a 1" or more overlap of the fabric. Should be pretty easy. I need to decide how big to make the skylight. I can go 30" or 40" inches. The cross tube on the top of the fuselage in the picture is at 30", 40" would put it right above the back seat. I'll use a tinted plexiglass and will need some type of sun screen up there so it doesn't get too hot inside. I hope to have the fuselage covered and painted by Sun N Fun ...... but ....... I've said that before!

Marty