Monday, November 25, 2013

Mind the gap.

When we moved into Einar's shop, he asked me when I would be ready to paint. About a week, I replied.

Boy, was I wrong.


Ailerons, flaps, rudder, elevators and stabs all have gap seals, and I decided to fit the gap seals to everything before painting so that I wouldn't have to worry about scratching the paint while mounting them. While the latest round of assembly manual updates (posted on the builder run support site in March 2013) had information about the gap seals for the tail feathers, there was nothing for the ailerons or flaps except for a single sketchy page from the Classic manual for the flaps. I emailed PA asking for any updates, but there's been no response, so I was on my own. ("think of those who went through it before you, and say to yourself, 'What they could do, I can do.'")


I could have done the gaps seals back at my hangar when I had everything set up after completing the covering, but I wanted to get everything tucked away at Einar's before the bad weather hit, and later you'll see how good a call that was.



First, scrap wood clamped the aileron to the wingtip to line them up. 



Luckily, mi amigos came through and told me to set up the aileron gap seals so there was 1/8" space between the wing trailing edge and the seal. I set them up so the cutout in the outer gap seal was centered on the hinge, then drilled the tangent of the aileron leading edge tube and the gap seal on each end of the top.



Then I crawled under and did the same for the bottom. 



Unmounting the seal, I used the 2.5" rivet spacing from the elevators and rudder gap seal mounting instructions for the aileron gap seal, and drilled 1/8" holes for the AN4-2 rivets I'll use later.



Remounting the seal to the aileron, I drilled the top and bottom of the leading edge, then repeated the process for the inner gap seal.




Poor thing looked like a pincushion by the time I was done. 



For some reason the flap gap seals are shorter than the aileron gap seals, and there's no way to get the same 1/8" spacing as on the other control surfaces. However, on the flaps in addition to the rounded gap seal there's a flat piece over the top of that, so getting the 1/8" spacing is not as critical. Since I was unable to set the 1/8" spacing I just mounted the trailing edge of the gap seal to the leading edge of the flap, allowing room for proper rivet spacing.



Since I wasn't worried about setting a spacing for the wing-gap seal, I was able to do all this on the workbench. 


 


Just to be sure, though, I drilled the initial bottom holes with the flap mounted on the wing. Yes, I'm wearing a headlamp, they do come in handy after all.



It took almost all of Einar's clecos to do the gap seals.




After I finished the left wing Einar helped me swap wings onto/off the stands, and I started on the right wing. I was able to reference the left wing flap, and it went quickly.



The inner edge of the flap gap seal is supposed to be supported by a Flap Gap Seal Support, but looking at photos of other SeaReys I could see this part was buried under the engine mount, and the gap seal served no aerodynamic function inboard of the flap root. In fact, I noted that many builders had trimmed their gap seals to end at the root of the flap. Made sense to me, so I did the same.



This meant a quick run to my hangar, since my bandsaw is set up with a metal cutting blade. It also reminded me why I wanted to get the wings to Einar's and out of my unheated hangar. 



The stack of scrap wood is all that remains of the dolly the hull used to rest on. 



Nailed the cut on the first try on both sides.



The real proof of my work, taking the clecos off and seeing how I did lining up on the aileron/flap leading edge tube. Not bad at all. Later I'll go back over all the holes with the soldering iron to seal the fabric.



Next will be the left aileron, then the tail feathers. THEN we might be ready to paint. 

An extra access panel.... Yeah, that's what I'll call it.

I hate to make this post, but if it saves someone else......

When I was ready to lift my wings off the jigs I made a simple end stand, and put it on small wheels. I rested the wingtips on milk cartons and they worked fine.

 
 


Until the night we moved the wings to Einar's shop. While Einar was holding the left wing I took the stand off and leaned it against the wall, then headed over to lift the wingtip. I heard Einar call out STEVE!!!!, then came the sick, wet sound of tearing fabric. The stand had fallen off the wall, impacting the bottom of the wing and making a 3/4" puncture and a 3" long scrape that didn't quite go through the fabric. I stayed calm on the outside, but was furious and disgusted with myself on the inside.



If it had to happen, it happened in a good spot (not on a rib or in a high visibility location), and IAW the PolyFiber manual a simple patch covered it up. I did make an elongated patch instead of the rectangular one they recommend, though, since I hate having corners that can easily peel up. And it looks better, too.




But it motivated me to build some new stands the way they should have been done in the first place. (Thanks to Ralph for going out of his way and bringing the 2 4x6x16 beams all the way out to Einar's.) 



A piece of threaded rod is inserted into a hinge point, and locked into the outer frame with wingnuts. That's some beautiful scrap cedar I found in the miscut bin at Home Depot for $1.



Now the wing can be easily moved around the shop, without worrying about it falling over. Could have made the end bracket wider, but it's ok.



If the patch is visible after painting I'll make up a decal that says "Wing Monkey Access Compartment. No Step."

Sunday, November 24, 2013

Bits and pieces....

A lot of small jobs to get done before painting, like finishing up the wiring. I had a clamp left over, and I knew it had to go somewhere but I was danged if I could figure it out. Finally found where it was supposed to go, and it gave me an excuse to do a bit more stitching.



While at Hardware Sales one day I grabbed some of these on impulse, now I wonder how I lived without them. They worked great for wrapping up wiring until I got to them with the lacing, much easier to use than the small velcro ties.


Much better......



Next was the hull side angles. First came some trimming around the bulkhead attachment bolts, 




Then some trimming around the instrument panel. 




They're attached with10-32x3/4" machine screws, they stuck out a bit far for my taste so I've ordered some 10-32x5/8" ones. 1/2" is too small, 3/4" is too big, it's a small thing, but.....



PolySpray and PolyBrush are expensive, over $80/gallon and you don't want to waste it. But the PolyFiber manual also points out that of you start spraying a wing with no practice and mess up, the cost is even higher. They recommend using an old door to practice on before you start spraying, but since I had some leftover fabric I decided to mock up some control surfaces out of PVC pipe and use those.



We weren't sure what the chemicals were going to do to the PVC pipe, but the fabric held fine. I wouldn't want to fly under them, though 



PolyFiber is very similar to the Monokote I've used on my models for decades, but PolyFiber does not let you use a heat gun on their fabric due to uneven application of heat. Since these surfaces weren't going to fly I indulged myself, and let it rip with my gun. I didn't melt any holes, but I didn't try too hard to see if I could, either.



 In the other shop Einar has been working on his OX-5 rebuild



which motivated me to go back and work on the Jenny model I've been working on...  oh... forever. Should be ready to cover pretty soon.