I got two false ribs glued up last night and pulled them from the forms today. The new razor saw arrived yesterday afternoon, so that was nice to have. I’m leaving all of the ends of the top and bottom capstrips a little long. I am planning to just build a sled for the table saw out of MDF, with dowel pins or wood blocks to locate the ribs for the four cuts I’ll need, referenced to the main spar and rear spar. That’s one cut for the nose, one for the trailing edge, and two for the tail ends of the false ribs. That can wait until all of the ribs are finished, maybe later depending on how cold & crowded it is in the garage. They really don’t NEED to be trimmed until I’m ready to assemble the wings, so that may be a while yet.
I figure I’ll get two, maybe three false ribs out of a pair of capstrips that would make one regular rib, so I’ll have plenty of opportunity to use whatever method I do finally end up using to pre-bend the wood. Over the past couple of nights I’ve tried a couple of methods of bending capstrip. The other night I ran a bucket of the hottest water I could get from the tap. It was probably 140 F or so, coming from a bar sink just a few feet from the water heater. I put half a dozen capstrip pieces in there, let them soak a couple of hours, and put them on the bending forms. That seemed to work well, with no broken pieces.
Last night I added a gallon or so of hot water to the bucket, just to top it off some more. The water would have been lukewarm at best. I soaked another half dozen strips for 12 hours or so. Of the six, one snapped as I was bending it in the form. That’s about what happened the last time I tried soaking in cold water, so obviously that’s a waste of time and good spruce. Won’t make that mistake again.
I was filling the 60cc syringes I use for dispensing T-88 epoxy in an exact 1:1 ratio. Typically I overfill them a little, then stand them on end tips up to let the bubbles rise to the top, then squeeze a little back into the bottles to get the amounts in each syringe evened out. Yeah, it’s a little picky, but it lets me easily keep the ratios exactly the same. Anyway, I got a little distracted, and accidentally squirted about 4cc of hardener right into the half-full bottle of resin. Oops. All I could do without making things worse was let it sit. I thought about trying to scoop it out with a long handled spoon, but decided all I’d really do was mix it in. I figured either I’d end up with a hardened mass on top that I could scoop out later, or it would ruin the entire remaining half bottle of resin. That would be about $22 worth of epoxy… not the end of the world, but it would kinda suck. I was hoping the hardener would not slowly sink to the bottom, ruining resin as it went.
Well, I got lucky (or science worked in my favor). Today there was a gooey layer of semi-cured epoxy sitting on top of the resin. I was able to scoop it out using a chunk of scrap spruce. Assuming things don’t go south in the next few weeks until I need to refill the syringes again, it looks like things will be OK.
Well, the work bench is cleared off — well, at least enough to get both jigs on it. I’ve got a couple dozen sticks of geodetic brace stock shaved down. The epoxy syringes are filled. All I need now is a razor saw and a steam setup.
Yes, I have a razor saw. Somewhere. I pulled it out during the kitchen remodel, and I remember seeing it in a box of tools we were using, but now I can’t find it. It’s a Zona, good quality but inexpensive. A new one is on the way. Two, in fact; one medium and one fine tooth. I also have a steam box that I built for the capstrips, but I’m unsure whether I’ll use it in the basement. It takes bench space (which I now don’t have down there), and drips water out the end by design. I’m thinking about ways I can use it vertically. I had looked at rigging up a piece of pipe or something with a heating element for hot water, but it looked like an awful lot of extra work considering I’m over halfway through the ribs. I’ll probably need it for the tail and wingtip bows as well, but I’m not entirely sure yet how I’m going to steam 6 to 9 foot long strips of wood. Tonight I tried soaking half a dozen capstrips in a bucket of hot water for an hour — we’ll see how well tat worked.
Well, I thought it had been a lot longer since I did any construction, but I see it was only back in February. I really wouldn’t have been surprised to find that I’d gone an entire year without building anything. But, I’m getting ready for winter and more building. To be honest, I’d had second thoughts recently about even continuing with this project. Sometimes it seems like such a massive undertaking, especially when I see pictures of guys attaching the wings and getting flying wires made and rigging done… only to tear it all apart again and then start covering. Covering!! How the hell an I ever going to cover this beast? But then I decide that maybe I’ll keep at it after all. Hey, it’s relatively cheap… so far… as hobbies go. It keeps me occupied for as long as I care to work on it, and nothing bad happens if I let it sit idle for a while. Even a long while.
Over the past few days I’ve been working on getting my absolute pit of a basement workshop cleaned up at least enough to be able to move around and use the workbench. A new water softener installation, a kitchen remodel and a few other household projects meant there was a lot of mess left over, and a whole lot lot of crap got just piled everywhere. Most of it’s cleaned up. Not enough, really, but at least enough for me to be able to take stock of where I am. In hindsight, I suppose I could have, you know, looked at my blogposts, but where’s the fun in that?
I need 26 normal wing ribs, and they are all done. I need 16 aileron ribs — the same as the normal ribs, but just missing a couple of cross pieces. Of those, I have built ten, so there are six left to build. Then there are 34 false ribs — just stubs from teh leading edge back to just behind the main spar. I’ve built one of them, so 33 left to build. Those should be quicker to build, since there are only about a quarter of the geodetic braces to cut and glue. Unfortunately, each will still occupy a full rib jig — so two at a time is still the limit. Unless… maybe after the aileron ribs are done, I can tear down one of the rib jigs and rebuild it to do several false ribs at a time. I think keeping one rib jig intact would be good, just in case I should ever need to build more ribs for a repair or whatever.
I’ve got a bunch of geodetic brace stock sanded down to the correct thickness. Enough for sure to do the rest of the aileron ribs and get a good start on the false ribs. I’ll probably do half a dozen more, then put the oscillating sander away and maybe knock out a few ribs. I’m starting to get a little fired up again.
I haven’t been doing much on the biplane recently, but I did manage to score an altimeter for it. I’ve been watching the for sale ads on line for decent deals. Someone offered an altimeter that worked, but failed an IFR certification due to out of tolerance leakage at 15,000′. Well… if I ever do finish the bipe and fly it, it certainly won’t be at anything over 10K, let alone 15K. So for fifty bucks it was a no-brainer. It’s a pretty nice altimeter, not one of the super cheap imported junkers that’s being sold now. It’s really more altimeter than I need…
So… I have an altimeter, and a quad oil temp / oil pressure / CHT / EGT gauge for monitoring the engine. I will still need an airspeed indicator. Most that I see for sale have speed ranges not appropriate for the Celebrity — I really don’t need or want a 200 knot ASI. Then I’ll need a compass, of course; a slip/skid ball; a tachometer. Whether I need a fuel gauge or not depends on what I decide to do for fuel tanks. I’m thinking no electrical fuel gauges, all float or sight type.
I could just ditch all of it and go with a single instrument from Dynon or Garmin, but I just think such a thing would look out of place in a classic biplane. I’m not sure what I’ll do for the front cockpit, though. It would be nice to at least have airspeed and altitude there for passengers, but I’m not sure I’ll be able to score a deal like this again. There’s always UMA…
I’ve knocked out a few more aileron ribs, two at a time. I’m about halfway through them and trying to speed things up a little, so I don’t die of old age with a half finished airplane.
Yesterday I decided to use up a piece of obviously bad capstrip Aircraft Spruce saw fit to ship me. This piece has a large chunk missing out of one edge, part of a knothole or pitch pocket or something. Part of it is in no way suitable for aircraft use or much else for that matter. But – there’s enough good wood there to use it for false ribs, so I made one of those. That went OK, but it’s apparent that I will need to soak the top capstrip in HOT water for the false ribs.
I’m looking forward to starting work on the tail surfaces. I’m planning to get out to the garage and clear off the workbench this week, lay out the plans and see exactly what I will need to get started. The wood called out is white pine, so I’ll start checking the local places for suitable pieces of white pine or Douglas fir… a little heavier, but I know Menard’s sells some good boards from which I can cut suitable pieces for the laminations.
Five down, eleven to go. Cutting the geodetic braces individually is really not as much of a chore as I thought it would be. I am finding that I’m going through the 6′ lengths of stock quickly, though — I figure I have enough shaved down for the next 3 ribs, maybe 4, then I’ll have to fire up the drum sander again and make some more. Not that it’s stupidly tedious work or anything, mind you.
In hindsight, it would have been a whole lot less work and actually less expensive to have bought 3/8″ thick spruce spar stock and just ripped it down to 3/32 strips, losing half the board to saw kerf. I am at a loss to explain why that little bit of math didn’t make itself obvious. Of course, I thought at the time that shaving 1/32″ off those strips would be quick and easy. Not so much. So… if you’re building a Celebrity from plans, you’d be better off doing that.
It’s a little early for this debate, but given the long lead times for ordering wood… not too early. I could possibly be done building the wing ribs in a month or two, if I get on it with a purpose. If I’m going to need a bunch of spruce, I probably need to get the order in now. So the question becomes — what next?
I could build the wings. It looks like the wood for the spars will cost me around $8-900, plus substantial shipping. I’d also need to extend my workbench by at least 4 feet, so that’s another project in itself. But I’d have wings, man, which would look bitchin’ cool hanging in the garage or hangar.
I could start on the fuselage. It’s a big piece that would be a huge leap forward. I haven’t calculated the wood cost yet, but it’s a significant amount of birch ply and spruce. Again, I’d have to build another workbench to extend what I have by 8 feet or so (and rearrange the garage).
I could start on the tail feathers. I could do all the work on my existing workbench. After looking at the parts list, most of the wood specified is pine; I’d need some aircraft ply as well. The elevator & stab. spars are specified as spruce, but I could source suitable quality Douglas fir locally and substitute that. I’ve seen boards at Menard’s with growth rings and grain slope that meet specs, with enough defect-free wood to be usable. That means all I would need to ship from Aircraft Spruce or Wick’s would be a couple sheets of plywood. Plus, building the tail would give me some valuable experience with large/long glue-ups that I’ll need to do for the wing spars, and if I screw it up it’s relatively cheap pine instead of very expensive spruce.
So… tail feathers it is. Now I just need to consult the plans and see what size sheets of plywood I will need to order.
Yesterday I glued up the last full rib (#26) and the first aileron rib. I’m going to call this a milestone. 🙂 I now have 15 more aileron ribs to go, then 34 false ribs. I suppose I should pull out the plans sheet for the spars and see exactly what I need to order for them. I have the BOM, but it doesn’t really tell me what I need to know without looking at the plans too.
I had to look at the plans a few times. It looked like the plan sheet was calling out just one geodetic brace to omit for the aileron ribs, but the locations to mark for eventual cutting didn’t make sense. I finally realized that the text read, “Omit this X-brace for aileron ribs”… as in, BOTH braces, not just the one. Great! That’s two less pieces to cut and glue.
I finally went out and got the second rib jig from the garage and brought it down to the basement. Ribs 24 & 25 are now curing, they will be ready to pull tomorrow evening. My new routine:
Put the first jig on the bench. Cut all the pieces fro one rib and set the geodetic pieces above and below the rib caps, ready to glue.
Stack the second jig on top of the first, cut all the pieces for it.
Mix up enough glue for both ribs (14cc seems about right)
Glue up the rib in the top jig and set it aside.
Glue up the rib in the bottom jig.
Double the completion rate. I’m out of pre-cut geodetic pieces, so now I”m marking and cutting them individually with a razor saw. It doesn’t take much longer, really, and each one is cut exactly to fit.
I’m almost out of pre-curved top capstrips. The comments on the plans say you can bend the spruce dry and glue the ribs. I don’t like the idea of having that much tension on the wood. The nice thing about working indoors, though, is that I can keep hot water hot longer. When I run out of pre-bent pieces, I’ll try the hot water bend method again. In the garage the water cooled off far too quickly. In the basement, I can get REALLY hot water in a capped length of PVC, and keep it hot long enough to soften the capstrip. System 3 says T-88 works fine on damp wood… I’ll try that and see how it goes.