Saturday, July 27, 2013

Come fly with me...

I was covering the stabs the other day when I heard a familiar call. By the time I was able to stop what I was doing, grab my camera and get outside it was almost out of sight.



For comparison.



I'm hurrying.... I'm hurrying....




Tuesday, July 23, 2013

Is it still a mistake if you learn something from it?

Just a quiet, reflective shot as the full moon rises over another late night.




OspRey was one of the first LSX kits, and there was still some testing to go when I got her. One thing that was discovered was that the stabs and fin needed a little reinforcement, and a couple years ago I was sent a set of reinforcing sleeves to rivet onto the existing structure. Presumably, newer kits have different reinforcements. (I also have a clause in my contract that says I will get any changes free of charge, but that's another story. Stay tuned.)

At first I thought of trying to mask the reinforcements, but it wasn't possible, and I've since grown to like them. Gives OspRey a little touch of Steampunk.  





The stabs were the first thing Einar and I built so many years ago, and Yeah, being a sentimentalist I took a few minutes to reflect on the journey, thing things I've learned (both good and bad), and the people I've met and learned from. 



The stab are covered using the same methods as the flaps and ailerons, but I deviated from the manual and used a single piece of fabric. I'm not going to repeat the process except for a couple highlights. Here I'm shaping the curve over the tip.




Attach, glue, wrap, flip, and iron the other side to make the curve. It was a challenge to do it without cutting the fabric, the kind of challenge I like. Craftsmanship and all that.



With the stab covered I couldn't resist fitting it and taking a look. She's getting closer to looking like an airplane and not a collection of parts.



Moving on to the right hand stab, I took a moment to make a CS check to prevent DS mistakes. (A Common Sense check to prevent Dumb Shit mistakes.)

Despite this, when I went to attach the fabric to the structure something slipped, the fabric got misaligned and I ended up with a fold in the covering. I tried to salvage it but couldn't, and made the decision to start again.

I had been cutting my fabric with an extra (some may say wasteful) margin, and after trimming it off and looking at the remainder, I decided that IF I did it correctly I could still salvage the piece, and it would be a challenge to be precise in my work.



I was extra careful, did a good job and was able to reuse the piece. Fun!



Scott stopped by while the PolyTak was drying, and I spent some time showing him how it all worked. Like a lot of us, Scott is a former model airplane builder, and the PolyFiber also reminded him of working with Monokote. The PolyTak wasn't quite set up enough for full shrinking, but he was able to get a feel for the basics of shrinking the fabric.



A few hours later though, it was time. I will confess that ironing has gotten old.



I was only home for a couple days, long nights trying to squeeze in every minute of summer while I can. 




But pinking tape is still another challenge to do right, and make look good. The next day a bit of heat sealed the edge of the fabric,



and a little reducer and/or MEK cleaned up the tips of the tubes.




Remember what I said about a CS check to prevent DS mistakes? Everybody sing: "One of these things is not like the other thing..." I... uh... forgot to remove a couple bolts from one stab.



The bolts are for the hinges, and it would have been necessary to melt a hole in the fabric for them anyway. A soldering iron carefully cut the fabric away from the bolts, allowing them to be removed. Pinking tape then covered the holes, and got cut away again.




The manual calls for the tip bolt to be removed, and the angle brace should hold it in place. It's not that I don't trust the manual, but I decided to leave the bolt in place while I covered. I'll remove them before I do the pinking tapes.






Getting the elevators ready, I bent the edges of the trailing edge sheeting down, like you do on the wings.



My little pink OspReyMingo will have to wait until mid-August for more work.






Saturday, July 13, 2013

Read, Pray, Cover.

Continuing with the learning, we'd like to do everything right the first time, but sometimes we learn more from fixing our mistakes. Here I've put the reinforcing gusset over the aileron horn reinforcing panel crooked. Yeah, it's only about 5 degrees off, and it will be on the bottom of the wing so it won't be easily seen, but...

A quick call to PolyFiber, and Greg told me to use reducer on the gusset to remove it, clean off all the old PolyBrush, and redo.





Now I know how to fix mistakes. 



 After that it was time to continue with the pinking tapes for the wing.


 
Snap a chalk line for the leading edge pinking tape, and attach.




The PolyFiber video emphasizes that "If you can feel it, you'll see it." and that paint will only magnify mistakes, not hide them.  Just like painting a house is all about the preparation, now I know why Jim was on my case to be neat when I was laying down the Poly. I'm going to be spending some time with reducer and an iron working out any imperfections, good workout for my OCD.



Until now I've been following in Jim's tracks, but it's time for me to go it on my own with the flaps and ailerons.  I started with the ailerons since they're small pieces, easier to work with, and less fabric wasted if I mess up.



A good cleaning with MEK first. 



Really nasty stuff, that MEK. I go through a couple dozen gloves a day, easy. 



The ailerons are taped together, and the endcaps riveted on. 



Little bit of a fit problem was taken care of with a belt sander. 




At first I used the anti-chafe tape on every rib, and over every rivet



but I decided the tape might interfere with the covering, so except where it went over the rivet on the leading edge and over the trailing edge junction I cut it off. (Later I found out it was a good decision.) The wrapped and shrunk fabric is the only thing holding the aileron and flaps together, there is no mechanical attachment.



Measure out the fabric,



 review the dvd



and take a trip down the road to the museum to check out the covering on a Stearman. Nice to understand what I'm looking at, and be able to start to see subtle things in their job. 



A layer of PolyTak, let it dry, then attach the fabric with a thinned layer of PolyTak.



Wrap the fabric over



trim,



apply a layer of full strength PolyTak, and let dry.



Then a diluted coat of PolyTak thru the fabric.



The tips are next, and proved to be a real PITA.



These were shot later during the edge pinking taping, but it's representative of my first try at the tips. I folded the top down,



trimmed, Tak'd, and put in place,



then repeated for the other side. 



While it was acceptable in terms of strength, it left a lot to be desired in terms of looks. We'll get back to the solution later.




Let dry, and shrink in two stages.
 


After the covering was shrunk it got the fine tooth treatment with an x-acto knife, trimming loose threads.



In some areas the covering had stuck too far into the aileron



a little MEK and a hit with the iron fixed that.





A first coat of thinned Brush to seal the fabric.



What does the X-15 and OspRey have in common? The first coat of covering is pink.



Of course, the X-15A-2 was pink because it was an experimental ablative coating to insulate it against the heat of a Mach 6 speed run. Don't think Osp will have that problem. I hope.



With some scrap wood and tubing, I made some jigs to hold the ailerons while I was working on them.




Later I modified it, making the space between the uprights narrower and allowing both flaps and ailerons to be put in place at the same time.



However, one thing to watch out for is where the fabric rests against the uprights.




Quick hit of the iron and it was good as new.




Next came the pinking tapes. Chalk lines on the long runs, sharpie on the short runs to mark the lines for the first coat of Brush. Neatness counts, I've learned.




Start at the back and work forward so everything overlaps,



and the pinking tapes for the tips.






This was my first try at the tips, and while it was strong enough, it didn't look good.



I decided to remove the pinking tape from the tips and redo them.



Applying the reducer resulted in the fabric separating from the tip,  and it just got to be a mess,



so I took a knife to the covering and started over again. 



This time things went faster, easier, and better. 




I made sure there was more than enough overlap this time, even tucking a bit of the bottom layer of covering into inside of the tip, and let it dry overnight before ironing.


 



Einar showed up, and together we made short work of the flaps.