Aluminum Strip

[cpirrmann]

How aerodynamically vital is the aluminum strip that covers the seam where the windscreen curves over the top of the cabin? I.E. Can I still fly while I figure out how to get it back on without recovering the fuselage?

[Guest]

Re: Aluminum Strip

I suspect aerodynamic imortance is zero.

Water shedding importance is fair.

Load distrbution over the top the plexi is high. The window is captured between that al strip and the one on the boot cowl.

That's my opinion, of course I think very highly of it!

[VictorBravo]

Re: Aluminum Strip

Why are you having trouble putting it back on? I believe the screws go through the aluminum, then the plexiglass, then through the wood former and finally into some blind nuts stuck in the bottom of the former. If you got the screws out without breaking anything they should go back in.

In short, IMHO if you can get the screws back in to hold the windshield then you should be ale to put the strip back on too.

If you cannot put the screws in to hold the windshield then you should not fly, with or without the strip.

All that being said, it was a BITCH getting those blind nuts out and changed when I had to do it.

You might be able to loosen the screws holding the wood former onto the tube, move the former out of the way enough to swap the blind nuts, without cutting the fabric. It will be a bitch, sorry to inform you.

For an emergency ferry flight or two, you can wrap safety wire around the wood former, put both ends of the wire up through the windshield screw holes, run the wire through a brass eyelet or something that will not allow the wire to put stress on the windshield hole edges, then twist the wire around a piece of Birch dowel above the windshield, making sure there is padding under the dowel. Four or six of these impromptu fasteners will get the airplane home safely, but you'd better not fly anywhere near a Flight Service Station. Oh... never mind, they're all gone

[Hank Jarrett]

Re: Aluminum Strip

Strange, the fasteners holding the metal strip on the top aft edge of my 41 and 45 wind screens DO NOT go through holes in the transparency. The metal strip just holds the "glass" down. Also, the 41 has wood screws, not machine screws and "T" nuts. The 45 used the "T" nuts but I just asssumed the old wood screws had sripped out somewhere along the line and the "T" nuts were put in to fix it. The "T" nuts are MUCH more secure and there were all Stainless parts on the 45. My 45 IS a bit of an "odd dog" since it was one of the first post war "Deluxe" models built and had some interesting features that didn't make it to the production builds. The big ones are VERY light tube doors and two triangle shapped skylight panels on top.
Hank

[cpirrmann]

Re: Aluminum Strip

My situation is thus: I noticed that the screws had backed out somewhat and had tried to tighten them but they were frozen. I couldn't even back them out. finaly through much trial and error. I started getting them out and one of the blind nuts came with it. I saw from that and the residue, that the wood underneath was rotten. It looked like a bitch to replace and would take a loooong time to do, so I basicaly wanted to know if it was a groundable issue or mostly cosmetic to keep the rain out (which it obviously didn't). I thought about just using regular nuts and bolts but then I saw the wood sits right on that cross tube. It looks to me like I need to take the headliner out,
remove the fabric, replace the wood, blind nuts, et al, reattach the fabric (can that even be done? My only experience is with removal and putting on new fabric.), reattach the strip, reinstall the headliner. This all sounds like amajor BITCH in one of the most confined work areas imaginable. Now, I'm seeking sage advice. On the good side, initial inspection looks like my strut attach fitting are in good shape. I can see mine wuite well just by removing the kick panels on the inside.

[1938BF50]

Re: Aluminum Strip

I can't imagine why you could not remove the windshield and then cut the fabric back at 45deg angles from each corner to allow removal of the old former. Yes, it will be a pain to work it out from the corners and from under the stringers but should be do-able. You can then make a new former (with blind nuts) and pre-wrap it with (same process) fabric to then get the required(+) overlap back across the top of the existing fabric cut to match the top/front of the former. Pic's show sky-lite installation, but concept is similar.


Mine were wood screws as well and totally rotted. Friction and side load were the only things keeping them in.

[cpirrmann]

Re: Aluminum Strip

Thanks for the photos and suggestions! They are a great help!

[Acroeric]

Re: Aluminum Strip

Be really careful if you decide to fly it before replacing it. . . . .there is alot of airflow in that area- if the air got under the fabric it could be really bad!

[cpirrmann]

Re: Aluminum Strip

Be really careful if you decide to fly it before replacing it. . . . .there is alot of airflow in that area- if the air got under the fabric it could be really bad!

In the Navy, we had 500 mph tape and 800 mph tape. Where does duct tape fall in at

[d.grimm]

Re: Aluminum Strip

Not that a T-craft is a Tri-Pacer, however, they have an AD for this spot as some people lost the fuselage fabric and their lives when the fabric ripped back in flight.

[Forrest Barber]

Re: Aluminum Strip

U]Fix it , don't fly it!! [/U]The screws do not go thru the windshield, The strip holds it down into place, at the side, same way , there are slots that go back beyond the screws. The windshield as on most aircraft "floats" in place.... bolt them in and the first taxi will usually crack the windshield.
IF the windshield pops way up the ship will hardly fly. We had a J-4 do that in the pattern and they could not hold altitude, BIG spoiler out there... plus you could lose fabric and the Tri-Pacer is the prime example....

[cpirrmann]

Re: Aluminum Strip

Roger, wilco. I'll let you all know what I find and do. Thanks. Anymore advice on the replacement work would be most appreciated. Now, where's my spruce?

[VictorBravo]

Re: Aluminum Strip

If the wood is rotted only near the screw holes, then you can drill out the screw holes in the wood with a 1" diameter drill (CAREFULLY so you don't ding the main crosstube), and inlay a one inch round spruce dowel that has the blind nut already put in. If this is possible then cut the dowel slugs, put in the blind nuts, and epoxy the dowels in with approved glue.

If the wood is rotted all the way thru then it is a bigger bitch but there MIGHT be a way. Rotted wood can be removed (with great prejudice and mal-intent) using pliers, chisels, pry bars, and a hammer-screwdriver combination.

If you CAREFULLY peel off the existing fabric from the wood remnants, you might be able to glue the new wood former to the existing peeled fabric, matching up the creases and folds to be sure it is located in the right place.

When the fabric glue is completely cured, you can possibly leverage and maneuver (and curse and threaten) the wood back into position where you can mount it against the mounting tabs. This would require some supports and clamps to hold the wood forward, against the tension on the fabric. It is probably a two person job. But there is the POTENTIAL for being able to do it without cutting fabric, or cutting the bare minimum slice in the fabric and not having to remove any fabric.

Forrest is correct there SHOULD be rounded slots in the top of the windshield instead of holes, but I've seen both. If you have a good windshield I would suggest modifying it so that the holes become slots that go to the aft edge, and make the forward part of the slots (the old hole) perfectly smooth, round, and about 3/8" diameter using a Dremel tool and fine sandpaper. If you prefer actual holes then I'd drill them out to a larger diameter and install rubber grommets in the holes. The top of the windshield is clamped in position, the screws should never touch the inside edges of the holes. You should use screws with a short section of shank that has no threads under the head too.

[VictorBravo]

Re: Aluminum Strip

Forgot to mention... the headliner will more than likely have to come out. Also, the top of the windshield being secured IS a flight safety thing, it is far more than just a rainwater thing. You should not fly with the top windshield not secure. As per my previous post, there is more than one way to secure it mechanically for an emergency ferry flight, so that it will not come out, but most of these "other" methods are not very attractive to any FAA folks that happen to be walking by.

If you fly it with the headliner out, you will notice you have more effective headroom and a much less cramped claustrophobic feeling in the airplane.

If you look at the photos of skylights (mine and Mike's), I think you'll agree it is a huge improvement on top of everything else. This might be a good excuse to think about a skylight installation.

Mine was finally approved, albeit for my own airplane only... HOWEVER, you might receive a very favorable and inexpensive reception if you approached the same DER I used and asked him to approve this skylight design for your aircraft serial number.

I would be glad to write a letter to this DER if appropriate, explaining the difference between the pre-war and post-war airplanes in the area of the front wood former, showing that it will not affect the security of your installation and explaining why.

Bill

[cpirrmann]

Re: Aluminum Strip

Thank you very much for the info Bill. My windshield has holes just slightly larger than the bolt. I will enlarge them. I could lift up the back edge surpisingly easily and I can see how that would come up in flight. To use your dowel approach (a very good one I might add), I'd have to remove the windshield. I saw today that the head liner is not as daunting as I'd thought. And I got a nice dust/crap facial in the bargain! My main concern was whether I could glue the fabric back in place as an acceptable practice and from what you say it seems to be. I also found a loose bracket near the trim tab that once I get to it, I'll ask questions about it too.