Spar Party

[Chris In Milwaukee]

So the first wing milestone has been achieved: time to start the spars! As I mentioned earlier, the Expedition spars are essentially Patrol spars, but about 10% taller. I fashioned the end plates more like the 4-place to make sure I had enough rivetage to withstand the compression forces I expect to see.

Since I'm building three wings, I opted to build routing jigs for these plates, just like with the wing ribs. That way they're all the same. Tonight I created the master patterns from which future jigs will be made.





















I'll keep all spar activity in this thread so it's all together.

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[DRLPatrol]

Looks good. Thanks for including us in your project.

Doug

[Chris In Milwaukee]

Slow last couple of weeks, but managed to get the routing jigs for spar plates wrapped up tonight with Don's help.








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[Chris In Milwaukee]

I started cutting cap strips yesterday. I have no room in the basement for handling sheet this large, so I built a bench in the garage that I can easily disassemble and store for later.



After hauling up the sheet of 4' x 12' x .125" from the basement, I covered the one uncovered side with some plastic sticky sheet from Menards that one would buy to stick on carpet and other floors. You might find these on stairs or high-traffic areas when you're visiting a home for sale or similar. It was a good way to protect the sheet from the saw as I was cutting. (Note to self: when buying metal, be sure to ask the supplier to cover *both* sides). Don is getting the air bubbles out.





I put the edge guide on my saw and set it to the width I needed the strips to be, and set the blade depth so it cut through the aluminum and just barely into the table top, as suggested by another builder.



I put the aluminum sheet even with the edge of the bench top, clamped it down, and ran the saw guide up against the edge of the bench.





The first strip came out okay, but there was too much width variation to my liking using the edge guide like that, and with the blade so high. So I won't be using this approach any more. Instead I'll get a long piece of steel angle and bolt it to the side of the bench, and run the edge of the saw up against it. Comparable to a track saw, but in reverse. This should be much straighter and reliable. I also plan to replace the saw blade with something that has more teeth per inch for a finer cut. Since the strips need to be 1.5", and the distance from the edge of the saw's base and the blade is exactly 1.5", I expect that technique to work better. I'll post photos for that step once I get it set up.

As a fall-back position, I've contacted my friend who is a manufacturing and fabrication ME to scout the local fab shops to see if there is a machine option for this close by, like a water jet or hydraulic shear, that can handle the task. If it comes to this, though, it'll be cheaper to buy bar stock and be done with it!

The sheet approach, strictly from a materials cost standpoint, was nearly half the cost of the bar stock at the time I purchased the aluminum. I'm hoping that this event doesn't turn the tides.


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[DRLPatrol]

Chris,
A blade for your saw that is for aluminum will leave a lot better finish. Has to do with the angles the teeth are ground. I believe this is the one I got off ebay.
http://www.ebay.com/itm/7-1-4-60T-Ca...MAAOSwjXRXaNPf

Doug

[Chris In Milwaukee]

I hadn't seen such a blade before. I'll be sure to grab one of those. Thanks for the tip!

[Chewie]

+1 on what Doug said. Works great, also on the miter saw for the spacers.

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[Chris In Milwaukee]

I set up the bench last night, with a fair amount of Muttley speech, and got everything perfectly aligned. Because I'm impatient, I wandered over to Menards and was able to score a very nice CMT blade for non-ferrous material. As described by Doug, Chewie, and John, it cut like butter. And perfectly straight with no width variation. Now I only have to do it again 40-something times.








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[Chris In Milwaukee]

Now that I have a system for ripping the spar caps, things moved along quite nicely. I finished 15 of the 30 spar caps I need to make (3 wings). I wondered how I was going to clamp down the sheet to keep it tight up against the fence. My friend suggested that since there's going to be some waste for the spar attach plates, just drill a hole close to the edge/ corner and screw it directly to the table top. So simple, yet so functional!












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[Bcone1381]

It look great Chris. You do awesome work.

Brooks

[Chris In Milwaukee]

Thank you, sir :-)

[Chris In Milwaukee]

I ripped a couple more spar caps out of the remaining sheet tonight, and left enough behind for the attach and splice plates. So I traced everything out, and cut it down to reasonable-sized chunks that I could run through the bandsaw.











Brought them down to the basement shop, and Riley helped me with the rough cuts.





Afterward, I drilled the jig holes in the rough parts, and then bolted together the routing jigs with the aluminum sandwiched between. Don and I took turns on the bandsaw cutting away excess material to get ready for routing.







We got about half of them rough cut tonight.






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[Chris In Milwaukee]

Finished rough-cutting the spar attach and splice plates tonight. Routing is the next step.



Fairly expensive looking pile of scrap, huh?



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[Chris In Milwaukee]

I've been there :-). Thanks for the reminder. I've had the nut come off the bearing before, it certainly made a mess.

[Chewie]

Keep all of it! Perfect for shimming under the spar on your table.

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[Chris In Milwaukee]

Got about half of the plate stock routed tonight. As luck would have it, crises at work kept me from finishing them all. To keep the router bit safe, I only did two pieces at a time. They'll be matched pairs that way, too.

















With luck, I can find some time to finish them before the weekend is over. The pieces are covered with clear plastic sheet, so they're not scratched as they appear.


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[Chris In Milwaukee]

Finished up all the spar plates tonight. The last bit of work before the Big Show. After Airventure, the main spar is going together!
















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[Chris In Milwaukee]

Now that Oshkosh is over, back in the shop to assemble spars. It's the first time all the pieces have touched each other since I started working on them. A family gathering of sorts.

I did a rough fitment to make sure I got the pieces the correct size. So far, so good! Time to get them all deburred now.















That's one big spar (16' 7")! I'll name it "Sparticus".

[Chris In Milwaukee]

Miss Alexandra told me that she wants to help me build the plane, so she's cutting her teeth on deburring attach and splice plates.

Of course, she couldn't dive right into good stuff without doing some of the mundane stuff first. So she got her first taste of removing a lot of plastic from a lot of parts.



Then we moved on to deburring holes. She quickly learned that there's a feel for how much to take off.



Then we talked drill press safety and how important it was to keep her hair tied back and keeping that and loose clothing and jewelry out of the way of spinning death machines. After that lesson, I showed her how to deburr with the ScotchBrite wheel. She quickly became an expert.





I think we got the last of the life of the ScotchBrite wheel knocked out of it tonight. Time to order another. This one had a lot of miles on it. But a fine looking batch.



Now, imagine how much fun it was trying to explain galvanic corrosion to a 12yo girl who lives Minecraft and My Little Pony.

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