Friday, March 29, 2013

Ospreys (done by frickin' laser beams)

While picking up the labels at Bay Engraving, another idea struck me. Talking it over with Kurt, we decide to try and burn an image of an Osprey into the panel.


The first problem was that because of the wing getting in the way of the suspension arm and the size of the panel, the laser could only reach so far. This limited the placement of the image to the right center, which was ok because it took away any temptation ot make it big and obscure the beautiful grain on the right hand side.

Using one of the old pulls, we experimented with the technique and limitations, and like so many who have become involved building Osp, Kurt is a perfectionist took his time making sure it would come out right.



I picked a couple images, converted them to outline and played with the placement...





Kurt burned a few test images to see which one would come out the best, and played with the resolution/shadowing of the images...



while I obsessed with exactly where it should go and at what angle. 



It was a multi-stop process to make it happen. Kurt appreciated all the hard work we've put in, and while there was an element of risk doing this, he wasn't going to be the one to mess it up.

Finally, the panel was put into place. A scrap piece of veneer was placed over the real panel and burned to verify that everything would work. (Note the QB logo from another job.)



Then he placed and burned a piece of plexiglass over the final location for one last check.




After that there was nothing to do but take a deep breath, start it up and try not to bump the machine while hovering over it.




It came out beautiful, and as usual I was so excited I did not get a better picture. 



A quick run to the airport confirmed how good it looked.



Back to Gordon, first to fix a small section of veneer that had splintered during all the handling. Can you spot the repair?



Thought you might like to see some of Gordon's non-airplane work.



The next to last step, a light coat of natural stain




Before



After. I love how the stain made the grain just pop. The pic does not do it justice. 




A couple days for the stain to outgas, 3 coats of spar varnish, and it should be at Jim's before Sun n Fun.


Wednesday, March 27, 2013

False starts, fine tuning, and redos

With the labels attached, for some reason I decided I wanted a glovebox in the dash. I spent some time with an old pull trying to make one up, but it just wasn't going to happen.




When fitting the panel we found the light bezels did not go all the way through the dash, some gray of the foam showed, so I carefully used a sharpie to darken the inside of the steam gauge instrument rings. I didn't want to hit the veneer because the capillary action of the wood grain would draw the ink out, ruining the area.



I also realized that I had forgotten the label for the gear circuit breaker, so that gave me a chance to try out the doublestick tape method of attaching one.




"Homebuilt" aircraft require a warning to passengers that the aircraft they're about to fly in was not professionally built. This warning is usually in the shape of a big, ugly generic placard, and while the phraseology is specified, unlike N-numbers the font and size are not specified in the FARs. I decided OspRey's should have some elegance and style.



Friday, March 22, 2013

More power!!!!


When I started planing my build I intended to use the external Rotax alternator, since the internal PMG only produces up to 18 amps. (Hello, electrically heated seats!!) However, as I got to know the SeaRey I realized that it had a weight problem, and decided to reduce the “goodies” to try to keep the electrical load within the 18 amp limits of the PMG. Good practice says you should limit your electrical load to 80% of the generator output, and the 914 manual recommends that if your aircraft requires loads above 12-15 amps you should use the external alternator. (Goodbye, electrically heated seats...)

While cutting the panel Jim showed me the external alternator he was installing on another aircraft. It was smaller than I thought, and only 8#. Of course, in addition to those 8# there is the wiring, etc it adds to the airplane.



As we continued cutting the panel we talked more about the pros and cons of adding the external alternator vs the weight penalty. The generator on the Rotax 914 is a “permanent magnet generator”, which means the magnets are fixed to the outside of the engine, the engine flywheel acts as the armature, and the rotation of the engine directly produces the electrical current for the plane.



Since both fuel pumps are electrically powered, as the manual states “In all cases the electrical system design should assure that no single failure mode (IE: alternator, battery, voltage regulator) causes both fuel pumps to stop. Careful design consideration must be given towards this issue!

While it would take a lot to cause a PMG to fail, Jim led me down the primrose path by asking me what I intended to do when I started flying Osp. “A lot of landings!!” I replied. We then discussed the power output of a generator, that it only developed power when at a higher rpm, and the lower the rpm, the lower the electrical output. As we all know, when in the pattern full power is used for takeoff but once at altitude power is reduced for level flight on the downwind, and further reduced for descent and landing, resulting in lower generator electrical output, and fewer amps for the system.

So while in the pattern, what's going on? Radio calls are being made and received, nav/strobe/landing lights are on, power is being used by the Skyview, but most importantly-the electric landing gear is being cycled, putting a high load on the electrical system.


The SeaRey is the only retractable gear aircraft I have ever flown that does not have a backup gear extension system, and it's kept me up many times at night. It's an elegant, yet simple system using dual electric motors for main gear extension/retraction and a garage door spring for tailwheel retraction (slaved to the left gear actuator for extension). But since it uses separate gear actuators, a bad day could see you with the gear stuck up or down, and a real bad day (like a failed connection ) could leave you with one gear up and the other one down, and few good alternatives.

More realistically, when doing pattern work the combination of low electrical power output and high electrical demand might end up inadvertently draining the battery, leaving you without enough power to extend the gear. While you could go fly around and charge up the battery, the SR has a narrow weather window, and if the winds or weather were kicking up, that might not be a good option.

End result, I'm reversing my decision not to go with the external 40 amp (Hello, electrically heated seats!!) alternator, and will be adding it to Osp.

Thursday, March 14, 2013

Travels with Puff

In case you haven't heard, Richard's book about his adventure with Puff is now available from Amazon, or even better, from your local independent bookstore


"Lasers" (but no sharks)

So what do you do with leftover veneer????


I needed some green and blue plastic labels for the Water and Ground gear warning lights, and while at Bay Engraving looking at the trophies I thought "Hmmmmm...." Talked with Kurt and a week later



I had him laser etch the labels in both light and dark sections of the scrap, which meant G & I got to play Scrabble with them and debate what looked best where.



Plus it looked different in the light of day the next morning, and after having some stain applied to the extras to test. I decided the dark background with dark lettering was just too dark to see, so we went with light overall.
 


Finally I taped them to the panel, sprawled out in the living room in SeaRey flying position and did some more Hmmmm'ing.
 

 


One of the hardest things was to decide the placement, above or below the switches. In some cases I didn't have a choice, in other cases after it was all done I realized small changes that would have made it look better. Oh well, nothing got put in the wrong place or upside down, so it's all good. 




Lots of clamps hold small pieces of cheap Harbor Freight straightedges I cut up and fixed in place.



Upon seeing a new airplane, most people immediately head to the cockpit and check out the panel ("Hey kid, want to look in the cockpit?"). I know Osp is going to gather attention because there aren't too many SeaReys up here (yet!), and for my own pride of building I wanted her panel to look beautiful, so I was pretty hesitant about this part.



We thought about some very thin doublestick tape, but decided against it in favor of a firmer glue attachment. This is a little CA (superglue) gel that was given to me as a sample to try a while back but never got around to using. Experimenting, I found the first small amount would soak into the paper backing, then stabilize and a tich more could be applied for the bond. It took a little practice to find the perfect amount that gave a bond but did not seep out, and a couple spots needed a little work with a knife point and/or sandpaper when it was all done, but overall it worked fantastic. If I was going to do it again, I'd probably use 30 min epoxy, though.



The other good thing about the IC-Gel was that it did not set up right away, but gave about 20-30 seconds before bonding. This was perfect because I could still make small adjustments, not so perfect because a couple parts moved slightly after placement. I had drawn some small pencil marks, but they would be covered when I put the piece down, and I thought the glue would adhere instantly. Since it turned out it took 20-30 seconds for the CA to set up, I wish I had used the pencil marks and 30 min epoxy, I could have made small changes to fine tune the layup after putting the piece down. Then again, in those 30 minutes the piece might have moved completely out of position and left a glue smear, sooo.....




The usual stack of gloves...



Followed by my old friend, the vacuum bag. I didn't pull a heavy vacuum, just enough (~20") to give a gentle but firm press for a couple hours.



The upper left Water is one that got away from me, about 1/32" off nominal above the alignment with the warning light, and the bottom light labels are off ~1/64" from left-right. I know, small things and probably won't be noticed, but one strives for perfection. And again, by blind luck I only trimmed 3/4" off the bottom, which was the perfect amount.



The rest came out just beautiful. Can't wait to see Gordon work his stain and varnish magic on it.



The Aux Power and Headset on the right wing are examples of seeing what I should have done after it was too late. Instead of aligning the bottom of the labels, I should have aligned the tops and stepped the Aux Power label down above the power socket. And Yes, as I was typing this I had to get up and fiddle with it a little to see if I could lift the Aux Power label up and reposition it. Not a chance, I'll have to live with it.




I thought about trying to remove them and going for a redo, but I remembered a story (and G told me a similar one) that one should always put a small flaw in your work that only you know about, to remind yourself that you are not perfect and to stay humble. I'm nowhere near good enough to have to intentionally put flaws into my work to stay humble, I find enough flaws as it is.


Now, about those glovebox hinges....

Wednesday, March 6, 2013

Brace for impacts

Back home, and it was time for final trimming and shaping.

The hull not only tapers from top to bottom, but allowances must be made at the hull/panel junction for any flexing as a result of hard landings or water impacts. The edges were brought in about 1/8”, and a D cell battery made a fine radius for the corner.

 

 



We had left the panel oversized, and Jim had drawn a max amount that could be trimmed off the bottom while allowing for an aluminum brace to be ran along the edge. Sitting in the cockpit I scrunched and wiggled and bent my legs around, looking to see how much room I needed vertically and laterally. Aesthetically, I wish I had made the wing panels deeper for more of an LSX style corner panel triangle, but that was the limit of my mold. “On my next SeaRey......”



While Jim said I could cut up to 1 1/4” from the bottom, I looked at the margin underneath the MFD and decided that it would bring the reinforcement brace too close to the base of the Skyview for my taste, and that trimming off another 3/4” would be enough. When we made the instrument cutouts the tape had served well to keep the veneer from splintering, so I ran another line of blue tape before measuring, marking, checking twice and cutting. I'm also glad I did not do the center console, it's nice to have the room to wiggle my feets.




First I cut the broad swatch of the base, then sketched the step from the wing to the center panel. I was worried that each side would be different, so after sketching them I used a small protractor to check the angle. Surprisingly, both were within a few degrees of each other, near 45 degrees. There's some meaning to that, I’m sure, but I’ll leave the magic of a 45 to others to explain. 



 
As usual, my Dremel stylus tool sanded the curve, with a little fine tuning once inside. The grain of the veneer at the base of the panel is at an angle, and it's sometimes difficult to overcome the optical illusion that I’m cutting my lines off-line, when I know they're correct.





Tape removed, time to sit back, relax and enjoy the work. One surprise was the solid, woody, almost sensual *thunk* the switches make I've not heard in other SeaReys, I'd like to think the panel has something to do with it.

Later a friend stopped by and pretended to wipe the spittle from the panel, telling me to not make such a mess when I was sitting making  “Pbbbbttttttt, pbbbbttttttt." airplane noises. Ummm... guilty, except for the spittle. 



A lousy photo, I was trying to sneak it in, but Merrill Wien stopped by to check on my progress, and share a tale of flying C-119 Boxcars in a classified program to retrieve Corona spy satellite capsules in midair. Merrill is writing his biography, and I can't wait to hear the stories he's putting down about his family's life and his flying career. I’m lucky I’ve gotten to know him.



In the meantime Mike dropped off his nosedeck, he's going to have Jim install his “Megahatch” and hitched a ride with mine. Jim will integrate my panel and nosedeck into one unit while  he installs the avionics/electrical.






Trimmed to final size and shape, the panel is very flimsy along the bottom edge, and by the time all the avionics are added in it's carrying a considerable load. A piece of 3/4” 6061-T6 takes care of the flexing and reinforces the bottom, it got trimmed for switches and the backup fuel pump circuit breaker.
 
 

I did a test with some scrap to see if resin alone would hold the angle to the panel, and the test held fine but I decided to add a half dozen #6 stainless steel screws too. Note the two center screws are vertically aligned with the radio mounts, the back of the radio stack will mount into these screws.
 
 


The screws also served to hold the strip in place while the West Systems 205 set up. Note how close to the MFD the reinforcing strip is, I’m glad I only trimmed 3/4” off the bottom of the panel.




I left the screws in place for about 3 hours, then gently removed them so they would not become permanently attached and replaced them with clamps for the final setup overnight. I did get a couple small bits of epoxy leakage around two of the screws, nothing that a swipe with the sandpaper didn't easily fix.






Before I left for a trip this morning I took the clamps off, the epoxy will have a few good days to finish setting up while I'm gone. Hopefully the labels will be done when I get back, and I'll try to figure out the glovebox hinging.