Winter before Thanksgiving?

Mother Nature just can't figure things out this year. We had a very nice snow flurry day over the weekend that was quite pretty and pretty promptly melted. It did make for a neat Friday morning though. Saturday was just cold. This whole week has been in the lower 20's overnight, making the apartment quite chilly.

While it was snowing, I was working on math, nice quiet, relaxing progress time. Not quaternions this time, linear least squares on a nonlinear model with constraints and weighting. Lovely fun when it works, but so time consumingly frustrutating until then...

On Saturday, for a change I was in all day and was able to put several hours in on Goat progress (after working more math until noon).

I now have it to the point that I can sit on a fake seat made of couch cushions! With the monster padding, it's SUPER plush and comfortable. I can sit on the couch for hours and therefore can imagine sitting on these cushions in the Goat for hours!

I haven't figured out a plan for the seat yet, but I think I may try to find an old comfy couch on the side of the road and yoink the pillows for their foam. Maybe it will take getting some new foam from a re-upholstery store.

Taking off my removable seat, you can see what progress I've made. The seat was resting on some very temporary wooden cross pieces. The seat back was resting on the rear seat supports that are mostly in place.

I am short five inches of u-channel to make the rest of the brackets to finish off the nose section (hence stealing a couple from under the seat area; you can see a couple truss members dangling). This u-channel will get ordered whenever I decide to do another order. I also am short several bolts because the grip lengths specified in the drawings aren't always exactly right. Several times I have dipped into the AN-14A stash because 16's were just too long, or vice versa. If I'm not mistaken, you're supposed to have 1.5 threads showing outside the nut for a proper joint.

Here is a closeup of the rear truss connection. There is a piece of aluminum hiding inside the crimped tube that also serves as a flex joint to get the right pitch angle to match the rear tail tube attachment point. The aluminum piece is thru bolted and also riveted in place.

I think most aero loading on this truss section will be small. Probably the landing and handling loads back here will be put more stress on this joint. I'm going to especially keep an eye on this one though because the aluminum could fatigue here if there are indeed significant loads over time.

There is one more area worthy of a closeup. This rear assembly is where the tailboom will eventually attach. I haven't done the side brackets that actually will transfer the loads from the boom into this section, but I think you can get the idea where these brackets will go.

For now, I had to tie the seat top tube and hold pressure on it because I'm shy a couple u-bracket pieces. That's why the string is showing.

I also will be going back over the next whenever and filing all the bracket and tube ends round, where appropriate. I definitely just skipped the finishing part in order to make a little more assembly progress.

To think, I started the rear section with this:

Axles, axles, everywhere!

It's late, but not because I was up working on Goat. I was honestly working on work-work, trying to figure out how to software-in-the-loop simulate multiple Piccolo aircraft at the same time! Whoa that was a mess! I'm not really sure when I'm going to use that, but at least now I have a better idea how to get it to run.

Anyhow, I thought I'd show a before-and-after shot of some truss work on the rear of the fuselage. This area is where the wheel mounts. The shiny solid aluminum rod stock is actually the axle! Several folks saw me around campus today wielding this little beating stick and commented "that's the axle? Is it big enough?"

So here I have just started to get it installed in the truss system. It needs two holes in the ends for the thru-bolts to go through. You can see a bugger bracket is missing from the far-side as well. I haven't put the holes in the u-bracket closest to the camera either. Lots of little things to do.

And the after shot now shows all of this assembly put together in a happy marriage of aluminum tubes and steel bolts! Several of the pieces have not been rounded off yet, like the u-bracket closest to the camera or the bottom plates that capture the axle. That filing will come when I have more disposable time.

I did spend a fair amount of time while the Simpsons was on aligning the trusses such that the axle was parallel with the main section tubes and the lower triangle was the right distance away from the main triangle. I suppose I could try to describe this better, but it's late and there is no good way without you actually holding a bubble level up to the part yourself. I used several clamps and some old winch string to jig everything in place for match-drilling. I have learned that match-drilling is my bestest friend ever. This project would likely be impossible without it.

I have also learned that assembly is a lot different than making individual parts. I really need to go into the assembly with a plan of which part needs to be drilled first, which parts will support the assembly while I match-drill others, etc. Especially for the axle alignment, it was a headache to decide which to drill first and hold the alignment.

On another note, you can actually sit on the frame now and it somewhat balances on the triangle wheel well created! Yay for making airplane noises!

Nose trusses and a heel tube

I was able to spare a couple hours tonight to work on the nose a bit more. In particular, I added two cross trusses (truss 3 if you count from the front) that definitely stiffened things up a lot. You can sit on the assembly now and it doesn't flex near as much. You can definitely see I have not done any end finishing on them and the tips are still sharp. I didn't get a lot of working time in tonight...

Oh and the mega obvious, I beat into "oval" (near rectangle) the footrest tube. This bugger is for placing your heels when you operate the rudder pedals that hinge on the tube just forward of the rectangle tube. Yes, I beat this tube forever with a hammer to get it this shape. I stuck a wooden piece of tail rib into the center and that's what allowed me to get a near flat top and bottom. I'm not entirely sure if this was Sandlin's idea, but this is non-structural anyhow, so I'm not going to sweat it.

One thing I will sweat later is the lower tube's poor bend. I haven't worked with aluminum before this project, so the kinkds in the tube were the only way I was able to get the big 1" tube to bend. Lesson learned, a large trashcan or something sturdy and round would have been much better to use. I will be ordering a replacement tube when I get more long tubes and I'll just rebend this and match-drill to fit my other truss members. Like I said, no sweat!

Next I have the other end of that truss attachment, where it fits into the mass of several other trusses coming in too. Like I said last post, the washers are for spacing out for another crimped tube to fit in here, but now I added that forward truss without the spacing washers. This is the truss that really made things more rigid. The end angles are mighty complex, but the aluminum is soft enough to play happy with the weird bending.






I have one more view of this same junction area in this picture. The overlap is clearly visible and you can see where I have actually dressed the ends of these crimped tubes a bit. Not too much rounding yet until I figure out what is appropriate.

My crimping is getting better though. The hammer does seem to make a bit of a difference.





Last picture of the day is the aft section where I started the tubes that will support the wheel axle. I have to make more of the bugger u-brackets to put on the ends of these before I can start assembling, so it's going to take another couple evenings of work. That's the fun of it though, yeah?

Nose section coming together

I swear I haven't quit! I've just been super busy taking care of other things like school.

Last night I had several hours to work on the nose section some more. I finally put in the forward seat truss, the seat cross-truss, and one of the three forward trusses near the rudder pedal support.

At this point, I can pretty well add some temporary wooden pieces and sit on my seat and play the imagination game!

Major items to do still:
- squish rudder foot support tube and mount
- control stick cross tube
- six more brackets from G4N2 (I have material for four)
- add the doubler to the lower nose tube
- finish all those trusses in the nose...

I'm sure there will be another half month at least completing what you see here and I definitely have started coming up with a few parts I came up short on, so there will be one more small order to finish off the nose. But, by then I should be able to get close to having a seat-back ready to go and can start thinking about what's next.

Thought I'd show a picture of the rear section flipped over. There are two more good trusses that comes to this point and help distribute loads from the pilot sitting there.

The frame isn't quite as rigid yet as I thought it would be, but there are more trusses yet to go in that I'm hoping will really make a difference in stiffness.

Does anyone know where to get plastic end-caps that fit inside a 3/4" OD tube?



Somewhat of an overview of the nose section. You can see that I haven't finished filing the 2nd truss ends yet, but they're mounted and just need that cleanup.

The rudder tube is the cross-piece attached to the main triangle.

The nose section is pretty cool, though I forgot a 1/4-20 nut, so I'm having to temporarily hold that section together with a 10-32 and live with the play during assembly. The bent tube is relatively flexible, so it usually doesn't mind being yoinked on.

This is a closeup of the rear main structure. The big tube is the wing carrythough, so this one is mega important. The rear seat tube is just right of it a couple inches and you can see the method of tube attachment with the bolt going through. I did slightly overtighten this bolt to get two threads out of the nut.

You can start to see how those little u-brackets are used. The cross-brace attaches to the main structural members through two of the bugger brackets. The open one goes to the main wheel supports, not quite yet worked on. I did come on a snafu here thinking all the trusses were spec'd to proper length. Turns out you have to pick one or two to set the location of the attach points, then trim the remaining trusses to fit. This 22" truss had a bit over 3/4" removed to fit nicely.

Moving a step forward, we get to the lower joint. This thing is busy. Two more trusses come in here, one pair from the left and one pair from the right. The washers set the approximate spacing for the tube coming in from the right.

I will say, this was a hard place to pick as a learning curve. Since this area is so busy, I really have spent a bunch of time staring and measuring to see how to fit things here and get the tube end angles right.

Oh I should mention I'm using a hammer to crimp the tube ends together as you see them. Using a pair of heavy pliers was leaving tool-marks, but the hammer flattens smoothly. I'm not sure how I would have done this with a vice.

Moving forward a bit we get to the forward seat tube. It also doubles as a width spacer for the lower frame truss system.

More of those bugger brackets are used to get the correct angle for the lower truss system. This was the first tube I cut to fit in them and I think I trimmed it a 1/4" short. You can see it's a bit squished to get in there. But since this was the first and sets the spacing for everything else, I suppose this is okay because everything else would have been trimmed to match anyway.

Part of the learning process...

Another step forward gets us to the rudder cross tube and the 2nd truss. I set this truss 2nd after the one above so that I could really get the parallel nature of the main triangle and the lower tube correct.

I'm not sure how best to dress the ends of squished tubes. I filed sort of round corners as you can see here, but it still isn't pretty and I'm worried much more corner rounding will result in cracking along the crimp.




Now all the way at the nose, we're at another important and busy junction point. Remember I forgot to get the 1/4-20 nut, so there is an overly-long 10-32 bolt holding the u-brackets onto the nose plates right now. The 10-32 bolt is also a tad long, so I grabbed some other bracket pieces as spacers.

This nose section is otherwise pretty stout. The main triangle pieces are definitely held rigidly by the rectangular plates and the lower tube is farily rigid from the trussing aft below the seat area.

More to come after school project work. Ahh quaternions!

A nose job!

I was able to get a bit of a start on the nose this weekend. This is a small collection of inserts and other tubes likely to go inside bigger tubes. The angle pieces were mostly for the tail, but will certainly come back in the wing. The channel and flat stock mostly is for the nose section. You can see the tip of the rudder to the right.

I will say I'm pretty much out of electrical tape from taping up all the inserts. In .035" tube, it takes three full wraps and typically happens in three places for a short sleeve.



I thought to take a picture of a part in progress. This is a bracket for G4N2 made from 1"x1"x1"x1/8" channel stock. With the new hacksaw blade, this is a fairly quick process, but these parts are still taking about 20 minutes each to cut out and file the ends round. I center punched this particular one already because the last cut is a straight easy one. I started alternating directions with the pieces after number two to cut down on the number of total cuts. Every little bit helps.

I should mention I found an error in Sandlin's drawings. The part shown on G4N2 is actually used 15 places, not 6. I don't quite have enough channel material for making all these, so reluctantly I'll have to make another order before I can sit in the seat of my Goat. Maybe Thanksgiving time frame...


After a bit more time watching Simpsons and filing, my collection of brackets and parts is growing. Three of the 15 channel brackets, the nose plate, and a bunch more still to come.

I have been match drilling all the mating parts as best as possible. For example, the nose mount plates I took to the drill press and clamped them together to drill exactly the same pattern. Perhaps I'm opening the first hole a little when drilling down through it, but the bolts still fit through pretty doggone tight in some cases. The u-brackets are not match drilled except that I run the 3/16" bit all the way through where a bolt eventually goes to ensure the holes are properly aligned.

I did a little tube works for the nose as well. This shows the main structural member in the nose assembly. In particular, this tube (the right one with a bolt protruding) will carry the tension loads of the guy wires from the wing. As you can see if you zoom in closely, this member has two sleeve inserts, not to mention the outer tube is .058" wall thickness already.

I took special care when drilling the bolt holes in this one to ensure they were carefully aligned and were not wallowed out. I stepped up bits in 1/16" increments from the first 1/16" pilot hole. It doggone took forever, but I am quite happy with the alignment and the precision of the cut. I will be keeping the long AN bolt installed to ensure the sleeves do not fall out. They're a pretty tight fit already, but insurance is nice to have.


I tried to finish off the elevator since I'm waiting for more tube to continue work on the nose section. You see the "swiss cheese" part in process of being installed on the elevator leading edge. These two brackets will help transmit a torquing moment to the elevator, hence all the fastners.

Speaking of fasteners, I am liking my clickos. I could see getting really sick of them if I had a ton of rivets to do, but Sandlin did a good job using bolts in shear and using rivets for mostly non-structural joints (as he put it).


The control arm brackets have now been riveted into place and I stuck a piece of scrap tube to show you where the elevator control arm will eventually mount. The hinge assembly now works too and it's a lot of fun to grab this temporary tube and move the elevator! I guess I'm just excited to be making progress. This is technically my first working mechanism and probably one of the most important ones in the whole airplane. I need to consult a manual to ensure I use the castle nut and cotter pin correctly.





Well that's it for now. My next shipment comes in Monday according to UPS. My roommate and I are fixing his car tomorrow and flying RC gliders over the next couple days anyhow.

A new order for the nose!

Yay, I got an order in today for nose parts! It's a collection of a lot of AN3 aircraft hardware, a handful of rivets, a 1/4" drill bit, and a couple AN42B eyebolts. Aluminum wise, there are a two pieces of u-channel, a few 5-foot pieces, and a piece of 2"x1/8"x24" flat stock. It's pretty neat to have a small army of bolts waiting for homes to go. The progress thus far has used bolts fairly sparingly for the amount of hours I have spent, so I think it's a bit of shock seeing the bag of 22 AN3-12 bolts. This order (when you include the 60' of tubing showing up from California on the 10th) really should keep my evenings fun through Christmas Break.

I really think it would be fun to figure out how many pieces are actually in the nose section as I build it. When you include the sleeves that go inside some tubes, all the washers, the castle nuts and their cotter pins... I'm sure it adds up quickly!



I couldn't resist last night not starting a few parts from the new material. I changed out my hacksaw blade to a new one that I bought on the first order and it cut SO much faster! These three parts I knocked out in about 20min each. I haven't taken two of them to the drill press on campus yet.

The two u-channel pieces are for the nose tube and the lower pod keel. The rectangular piece is the most forward piece on the plane, being sandwiched by the two u-channel pieces and itself sandwiching the two forward tubes in the nose pod triangle. This rectangular piece will also be the part that transmits the loads from the aero-tow attachment to the rest of the airplane ... a bit of an important part!

I also drilled 8 holes and riveted the horizontal stab rounded tips into the horizontal stab trailing edge as piece View C on G4T3.

On another note, a friend of mine who knows who he is has been thinking about building an ultralight too. You should definitely start! So far, it hasn't been all that hard and it is definitely rewarding!

I finally have a picture for the holes I put in the parts on Thursday evening. I also spent an hour last night watching Simpsons (heh, I think there is a pattern) and cutting out the parts on the right for the nose. I have a couple more parts for the nose I can cut out before I have to have new material. That'll come later tonight perhaps.

The lower triangle pieces look like swiss cheese with all those holes in them!

This is a lot of fun building something out of aluminum. I admit it's really slow without power tools, but that's part of the fun I suppose. If I had my magic way, I think I'd have a metal bandsaw and a belt sander. A drill press would be nice too, but I think the band saw probably wins. I have a drill press I can borrow as needed already :-)

I haven't counted how many parts are needed for the nose, but it's on the order of two dozen. Guess I have some more nights filing aluminium in my future.

Wheel & Nose

I still have the parts list for the nose materials saved, just kinda waiting around for time to pass. I did find the wheel spec'd on the drawings. It's cool and round.

I had some leftover material from building the tail, so I started making a few parts for the nose. I forgot to take pictures though, so this is just a text update.

Happy November Day!