A Table Full of Parts!

Here's a short video showing most of the parts I've completed to date. There are around 250 or so parts shown (around 550 total in the airplane), and, ironically, they represent close to 250 hours worth of work in about 7-8 months. Pretty cool sight! And finally looking like some real progress.

Workspace Concerns

Hey friends, in this video segment, I talk about the amount of space you really need to plans-build an airplane. The standard Zenith kit can be built in a single stall garage (roughly 12' x 24') until it's time to mount the wings. With plans-building,  you need a lot more room than that because you have so much fabrication to do. So in addition to the recommended 4' X 12' assembly table, you also need a cutting table/platform, various workbenches and space for fabrication tools (belt sanders, drill press, bench vise, saws, presses, etc.). This video specifically addresses the problem you run into when trying to use your assembly table as a cutting/storage area for aluminum.

A Couple of Discouraging Days

Well friends, the last couple of milestones have brought more stress than satisfaction. Last week I spent a good bit of time fabricating my 2nd fuel tank, and getting all the holes for fittings drilled, de-burred and polished. A local welding shop had agreed to weld them for me back in August. At that time, they were shown the blueprints, we discussed what was required, and I was told "no problem." Their welder was very experienced in aluminum/TIG welding, even with thin material. Fast-forward to Thursday, Jan 21. I took the tanks in to drop them off for welding, and they turned me away with very little explanation. I have a friend who works there, and he believes that the new TIG welder doesn't have enough experience in thin stock to be able to weld the tanks. The former welder is now a supervisor, and is not allowed to weld anymore. Really took the wind out of my sails. I have a few other options to explore, but what a bummer.

Yesterday, I spent most of the day at a friend's machine shop. He has a 10' bending brake and heavy duty finger brake needed to bend some thicker stock. I'd cut my parts blanks out based on the developed length calculations for the bending characteristics of my DIY brake. I successfully turned out some longer angles, but when I bent the horizontal stabilizer front spar, it was off by several millimeters in a critical area. I had made a few test pieces, but depending on the orientation of the part in the brake, you can mess up the geometry of the part. My spar was completely unusable. Had to scrap it, thought I can use the bent flanges for standard "L" angle elsewhere. Took several more hours to cut and bend test pieces until we were confident the elevator spar and horizontal stabilizer spar would turn out, which they did. But, I didn't have a way to cut a new front spar blank, so I'm stalled on the tail assembly until I can get back down to his shop (an hour away). It was truly amazing how different the bending characteristics of my friend's brake compared to my DIY brake. Although we can both turn out identical parts, the way they get measured and the way the bending lines get laid out are completely different. Frustrating learning curve! I'll be spending plenty of time down there...lots of fabrication that will just be easier with his heavy duty finger brake, but that's 2 big disappointments in one week. At least I have all the parts I need to get started on the wings. My new rivet gun comes in this week!

Calculating Developed Length

In this video, I talk about calculating developed length for your parts blanks, using variables that are specific to my bending brake. I've learned the hard way, that every bending brake, whether it is a professional, industrial grade brake or a DIY brake, has its own bending characteristics. You absolutely have to experiment with those characteristics and learn exactly how a part needs to be measured and where the bend lines must be placed in order to bend the part to the correct size. In my next post, I'll talk about how I had to scrap an expensive part because I didn't take the time to verify developed length properly when using a different brake.

Fuel Tank progress, and other parts

Well, I put in some serious hours after work this week and last weekend. Spent the bulk of the time finishing up parts I needed to make in .025" sheet. To my chagrin, I discovered that I needed another full sheet of .025" to finish all the parts! I was using another person's reference material to determine how many sheets of it I'd need to build the whole plane. His reference said that 2.5-3 sheets would be enough to build the whole plane. While I had some scrap from several test pieces I am certain that the Edition 3 version of my plane requires 4 sheets. I still have to make about 55 pieces of "L" angle (4 feet long, 19mm on each side), the top "dash board" skin and a few other good-sized pieces for the plane...no way only 3 sheets could supply all that material, even if I'd never made a bad part.

 Fuel Webs and Fuel Channels (these support the fuel tanks inside the wings):

Fuel Tank Ribs (a total of 4, but only 2 in the picture):

 

One Fuel Tank fabricated & clamped together! The ribs were easy enough to form, but getting the skin measurements correct so that every seam lined up perfectly took a while. I used a 20mm-wide test strip and bent it up in stages until I had the exact bend line measurements. I also left it long, and cut the excess off after I'd bent it up, just to be sure. Worked like a charm, though...didn't have to scrap the skin! I still need to fabricate the 2nd tank skin, cut holes for drain, fuel line, return line and filler fittings, and then have the whole assembly welded. I'm hoping to drop them off at the welder sometime next week!

Baggage Angle and Longeron Gussets (just a couple basic, boring parts):

 Seat Supports. I'm still debating about whether to put in lever-adjustable seats in the plane. The original plans call for a series of bolt holes and nut plates added to the seat pan, so you can manually set the seat location. However, the seats are not not in-flight adjustable and it's not a quick operation to unbolt the seats, move them and try to figure out what position you'd like them. Further, I've heard from other 750 owners that the lever-adjustable seats (much like manually adjustable seats in a car) make accessing the baggage area easier, and egress/exit easier for folks who are less flexible. So, if I go the lever-adjustable seat route, these seat supports aren't even used, and are replaced with a total of 4 different web channel cross braces. I may have made these parts for nothing! But they sure turned out nicely. Just wish I hadn't spent a couple hours on them.

Stay tuned for more to come. I have lots of video to edit and more pictures on the way!

Fully Forming the Rear Wing Ribs

Although I posted a while ago about forming all my wing ribs, I finally got around to editing my video of the process. Below, check out the 2-part video detailing how I built everything.

Rear Rib Forming, Part 1:

Wing Rib Forming, Part 2:

More Ribs Formed, a parts order arrives, and miscellaneous angles.

Last night I finished almost the all the remaining ribs needed for the aircraft. Below you can see the horizontal stabilizer right and left tip ribs, and the main wing root nose and rear ribs:

 Last week, I got my shipment from Wag-Aero for the fuel caps, fittings and quick drains for the fuel tanks, which will be welded up from .025" 6061-T6. I just need the finger screens for the tanks from Zenith, and I can start fabricating these. The tanks take special "ribs" that form the ends, and are roughly the shape of the main wing rings. Once the "ribs" are wrapped in an aluminum skin and welded, they fit right between 2 wing ribs at the roots.

 The other night, I also finished a couple fittings in 1/8" angle. The longer strips are the main wing strut fittings that attach to the spars. The smaller fittings are just other odds and ends I needed to make.

 

Firewall

A few months back I worked on the main firewall. Below you can see the formed firewall itself, which is made from .018" galvanized steel. It gets reinforced by lots of stiffeners and other support structures I have yet to make. But with all the parts coming together, it's starting to resemble an aircraft. More on this specific part later.

Methods for Cutting Aluminum

If you're wondering how all this aluminum gets cut, check out my video below for the basic methods. In addition to the methods in the video, I've also use my band saw, router, belt/disc sander and spindle sander to shape everything from thin metal sheet to heavy metal plate up to 1/2" thick. Enjoy!

Another tip on using the Olfa knife: