Building adventures of an Ultralight Glider

Order up

2012-02-04T18:35:00.001-05:00

A box of tubes, 12ft long, 7in x 7in square: this is my wing...

Thanks UPS Freight!

Back Order

2012-01-22T08:57:00.001-05:00

Two of the spar tubes were on back-order at Aircraft Spruce, so I'm still patiently waiting for them to come in before A.S. ships the rest of the order. I've been told by the end of the month.

Update 1/26/12: Spruce called today and should be shipping the tubing order out tomorrow.

Some work in AVL

2012-01-02T16:46:00.000-05:00

MIT published as freeware the panel method CFD code called Athena Vortex Lattice for analyzing the geometry of aircraft. I input the Goat4 geometry into the program to do a little investigating. I used a 300lb takeoff weight, a 29% root chord CG location (the wheel location), an 11.7% ClarkY smoothed airfoil (from UIUC's database), and tried hard to match the wing/tail angles to Sandlin's drawings.

I also plotted this in AVL Editor, a tool by Cloud Cap Technologies. Their tool shows control surfaces a bit better.

The incorrect tip taper isn't a huge issue considering the tips aren't loaded heavily and quite frankly there is enough other guesswork right now the tips are of the least concern. I haven't added cabanes or the nose or a pilot either.

As a start, I'm using 30 mph (44 ft/s) as a cruise condition and assuming sea level atmospheric properties. AVL gives the neutral point at 40.6% root chord for an 11.7% static margin and predicts a 0.2 deg (down) elevator to trim. Speeding up to 45 mph (66 ft/s) requires 4.1 deg (down) to trim and slowing down to 25 mph (36.7 ft/s) requires -1.1 deg (up) to trim. Based on watching the in-flight Goat videos, I'm seeing more up trim for typical cruise, so this CG location may be a bit far aft. Sandlin recommended balancing nose-heavier than this 29% location anyway,

Moving the CG position up two inches to 15.4 in aft of the LE (25.7% root chord) and re-running the 30 mph case yields -2.1 deg (up) elevator, 45 mph case yields 3.1 deg (down) elevator, and 25 mph case yields -4.4 deg (up). That's just for trim. There is some +-25 deg or more of total elevator travel for maneuvering.

I don't have anything good right now to compare these numbers to, but this is a starting point. More number crunching later...

Wing order is in!

2012-01-01T14:25:00.001-05:00

I finally hit submit on the wing material order! Should be here in a week or two. Holy muffins, it's going to be a big pile of tubes...

I am going with similar mods described by the Yando Goat builder: G3 wing struts & attachments, G4 fuselage/tail/cabanes, up one size on the spar and flying strut tubes (0.049 spars, 0.058 struts), and fingers crossed I can keep it all under 155lb :-)

I'm still not 100% sold on the simple flat-bottomed airfoil compared to something spiffy like the G3's attempt at an FX63-120. But you know what, I have the power to run the numbers and I just haven't done it yet. Regardless, I'm keeping the wing area of G4.

I do feel better about the structure after seeing someone else doing load testing. I don't have more details right now ... reprinted from here:

Posts may become more regular as I actually have material (and more financial incentive) to continue on.

New Aerotow video of Yando's Goat

2011-10-04T20:06:00.000-04:00

Not mine, but fun to watch! I'm getting mighty close to placing an order for wing materials finally :-) Quote in hand, just need to hit the order button.

Yando Goat

2011-08-27T08:18:00.000-04:00

I've been slack getting wing materials... but the Yando Goat is up and flying!

More training time

2011-05-25T09:45:00.006-04:00

Over the last few weeks, I've done more flying than in a long while. I'm calling it all flight training to keep the wife happy ;-)

A friend and I are working on a new thermal-finding instrument for full-scale applications, so he took me up on a familiarization flight in the North Carolina Soaring Association's Grob Twin-II.

Since I'm pretty sure Brett wanted to see if I got sick, we did a bunch of acro and wore parachutes as a precaution. Conditions were already way over-developed and it was flat out raining on us before the tow. Then Brett's breath was fogging up the canopy (he sat in front). On ground roll and tow, he was wiping the inside while the accumulated drops on the canopy came streaking past like Star Trek. Did I mention the canopy seals aren't great and it was practically raining on us inside too?

Anyway, it was neat being in an airplane in the rain, basically the same sensations and sounds to driving fast in a car through a downpour. We still did three wing-overs, some zero-G pushovers and a very interesting feeling negative G pushover. I got to fly us back to the airport in the rain a bit. It was surprising how sensitive the rudder felt compared to the little Cessna. I need to work on coordination, but the task of keeping the plane in the sky was relatively easy.

Just yesterday, I finally took hang-gliding lessons through Kitty Hawk Kites flying at Jockey's Ridge State Park ... the back-story is that I had a 10-year old "wind check" from trying to do this once before and getting blown out due to high winds. Kitty Hawk Kites honored their well-worn receipt!

Okay, so the Eaglet wing is certainly no high-performer, but my five flights were sufficient to get the feeling of how different (and entertaining!) hang-gliding is. I think the most interesting parallel to Goat flying is the feeling of being out in the open air. No instruments, just the feeling of air on my face and the sounds of the wind in the wings. Five flights of probably 15 seconds is by no means conclusive or constitutes a training regimen. However, I'm happy to personally have the exposure to the origins of the Goat and get the best parallel I can think of to the flying sensations.

Back to the Grob in a month and a half for more flight testing. Maybe I can finish off the tool chest and get back to hobby work for a bit?

How about a hang-gliding video??

Side Project -- continuing to set up the shop

2011-05-14T21:53:00.003-04:00

In the do-it-yourself spirit, I have been working to build up my shop capabilities and storage space. The first real project was (is) a shop tool chest to finally combine all my smaller storage into one central location. Or if you're reading between the lines, it was an excuse to try my hand at furniture fabrication ;-)

I have had the tool chest case done for a few weeks and finally today cut out all but one of the drawers. The upper three are installed, the lower two ready for drawer slides, and the sixth is waiting for a measurement of what space is left over before I knock it out on the new (used) table saw. I love the stacked dado set ... I had always watched Norm Abrams on New Yankee Workshop and wanted to try that myself. It takes a bit of time making sure the settings are right, but then it's really easy to knock out a half dozen parts in mere minutes.

Next up is the false fronts that absorb any visual misalignment that the drawers have. That's a project for another weekend I'm afraid.

Another picture of moving Goat

2011-03-31T18:04:00.003-04:00

Haven't figured out how to trailer Goat quite yet ... I cheated and used the open structure as fair game for lashing ;-)

Actually doing some work

2011-03-29T15:54:00.001-04:00

It may not be a glamerous part, but its a flight piece.

A new home for Goat

2011-03-28T19:30:00.001-04:00

Still without internet access, I'm posting via my phone to keep up a monthly post. Goat has moved to a nice large basement area with access to more than one tool at a time. I even bought a whole bunch of nice oak ply sheets to make a sturdy and true table for constructing the wings. There is of course some setup to go still before being back on real Goat construction, but the next project (other than fixing the occasional water heater and lousy hvac system) is the airchair. I have renewed confidence in both the design and my skills after watching the ground loop in last post's video. This just might work :-)

New Goat video online ... and a move

2011-03-15T19:41:00.003-04:00

I recently came across a new Bug (son of Goat) video, showing some auto-towing at Soggy Dry Lake: http://www.vimeo.com/21046038. Thanks to the San Bernardino fliers!

In other news, I'm moving over the next couple of weeks to a place with a dedicated hanger (okay, basement and garage) for my Goat project. Expect to see some renewed progress over the summer!

Progress is slow, but coming.

Flight training time

2010-12-18T16:48:00.005-05:00

My lovely wife got me a first training lesson at a local flying club. It's quite impressive timing that our day was so calm for having been blowing +20mph for the past two weeks... We stayed at 2500ft and flew locally in the SFZ north of Washington DC. Having flown general aviation so infrequently and only at uncontrolled airports, it was interesting to actually have to file a flight plan. But it wasn't that bad actually.

Once getting to know me a bit, my instructor-for-the-day Oren walked me through the pre-flight checklist and we taxied to the runway. I was interested as I got a good walk-through of the engine run-up, hearing how to use carb heat and what to look for with the instruments. We taxied out and the takeoff was a piece of cake. It's funny how temperatures in the 30's helped the performance. We were at 2500ft in no time. Oren said "alright, plane is yours" and I avoided the rookie mistake of trying to do anything. Heh, new RC pilots have the same tendency of immediately jamming a stick to the side when given the controller for the first time. So I basically let the plane fly itself. It's stable, why do anything?

It has been a while since I flew, but it was easy to pick back up. Oren asked me to do some turns and fly to headings. Not bad. It's a lot to remember, watching airspeed, keeping track of altitude, remembering to glance for my heading... not hard to keep the plane in the air though. That was apparently easy enough, Oren suggested doing some slow flying. He put in some flaps, had me pull the throttle back (whoa cool, I moved the throttle!) and I worked to figure out the new pitch attitude to maintain airspeed. A couple gentle turns got me some feel of the difference of flaps being down. Well, time to pull them back up and go back to the airport. I got to put us in the pattern, but then it was back to the pro for base and final.

Not bad for a random snowy day!

From the perspective of Goat, I have no fears that I can pick up the skills. I'm thinking of doing the same in a glider and making sure to request some good stalls and spin recovery to get familiar with the entries in particular. Welcome back motivation!

Fixing a canoe

2010-12-06T20:47:00.003-05:00

Canoe believe (heh, love the water humor) that I took a break from the plane to work on a boat? Okay, it really only took a half-day. First was to flake off any loose fiberglass from the last repair, meaning most of it. Next was to clean up any poky sharp bits. I used the edge of a chisel to put some deep scratches in the area where the repair cloth was going to go. The rear damage actually had a full hole into the boat. For this, I mixed up a small cup of resin thick with cabosil and then tried some chopped strands. The resulting blob was a tarball that would slowly ooze off the stirring stick. I stuffed this into the hole, taped over the hole with masking tape, and flipped the boat over to let the epoxy settle into the el-cheapo masking tape mold. Worked like a charm! I had a little run-out where the masking tape wasn't perfect, but knocking off the sharp edges with a chisel did the trick. While the epoxy was still green, we started putting on layers, bringing resin up through the cloth by putting raw epoxy down first and using squeegies to mash the cloth into the resin and ensure it was fully wetted. I forget already, but we put some 8-10 layers of 6oz tooling cloth in the damaged areas and feathered out from there. The last layer was a large piece to tie everything together and give a nice finish. It didn't need to be smooth since the rest of the bottom of the boat is scuffed up from years of use, so I left raw 6oz print.

I haven't tried one of these slide shows before, so please ping me if it fails...

Goat is slowing down until I have more space to build a wing... I'm hopeful for early summer to have a basement or at least a dedicated room. Fingers crossed ;-)

Just a cool link

2010-10-22T20:55:00.001-04:00

This is pretty cool, a solo launch method: http://www.vimeo.com/15297650

Ovalizing the nose fairing tube

2010-09-26T20:27:00.004-04:00

I finally pulled Goat back out for some work. I ovalized the nose fairing tube using my vice and some perseverance. It looks pretty good mounted on the fuselage section, but I didn't take any pictures of that yet...

Hang Gliders!

2010-09-25T09:39:00.012-04:00

I happened to be in Utah for business and ended up with a free day. A new friend, Greg, took me to the local hang-glider site in Salt Lake City. I believe this was called the South Side and is a small cousin to the North Side of the famous Point of the Mountain at the Wings over Wasatach field. Despite being the smaller of the two locations, I was rather impressed at the 200 ft cliff at roughly 45 deg steep and in the perfect bowl shape for flying. Greg got off two flights and a few other dudes were flying as well. I took wayyyyyy too many photos, but wanted to share a few highlights here.

Setting up Greg's "old rag-wing."

Putting in the lower battens.

Strapped in and ready to fly!

Taking a giant step...

Setting his feet looks rather awkward, but it's not a problem.

And just like that, Greg quite literally flies with the birds!

A few comment replies

2010-09-16T22:53:00.001-04:00

I wanted to reply to a couple recent comments from folks...

Hi George,

I'm glad you're enjoying the close-up photos. I too was struggling with Mike's zoomed-out pics and really wanted to fill in some missing gaps. I'll work on posting some more close-ups, especially if you have any requests!

I'll see what I can do with the key-words for finding this page easier. Great suggestion.

I don't have a parts list, per-se. I have kept every order form, so I definitely have an order list if I go through the pile. Some of Mike's bolt call-outs didn't work for me, so I'd really just prefer to measure each assembly to make an as-built list.

I haven't done any welding, especially aluminum. The reliance of Sandlin's design on thru bolts was attractive for a novice metal worker, so I'm following by-the-plans. Most every rivet I've found is either non-structural or backed up by several other rivets (as on tube end inserts).

I'd love to see you start up a build-log as you get your project up and rolling! The support is worth it alone :-)

Hi Craig,

I'm just busy :-) Spending two weeks in Utah for work currently and I've been working on an RC Long EZ project for the past few weeks after working on an RC discus launch glider project with some old school buddies.

And now for everyone,

In other news, I'm about ready to go get the wing tubing! It's a couple hour drive up to Pennsylvania to pick up tubing at Dillsburg Aero-Works ... and I have to figure out how to stuff 12ft tubing into my little Civic.

I'm also ready to try my hand at covering. I have enough material to do the rudder. A local guy gave me some tips how to use the Stits Poly-Fiber method, given my weight constraint. I need some Poly-Tack and Poly-Span and MEK. I think I'll go get that wing tubing first ;-)

Birthday tool

2010-08-12T15:13:00.003-04:00

Thanks for a wonderful birthday present, a 10" drill press for working on Goat and anything that needs drilling. I'm so tired of hand-drilling all the brackets and tubes and getting them misaligned, so it's going to be wonderful to simply clamp it up and drill.

Meanwhile making the drill stand, I also finished cutting, deburring, and drilling all 8 of the wing compression strut fittings. Yay, progress (yeah, I know it seems slow right now)!

Wing parts

2010-07-29T20:54:00.002-04:00

Cutting, cutting away ... I finally finished making all 16 of the G4W2 strut fixtures. One at a time, they're a pain, so I did six a shot out of a piece of 2.5" sheet stock. They look better in person than with the camera flash, and they'll get a final clean-up with the fine file. I also knocked out half of the compression strut channels from G4W6. Four more to go...

Stuck in the elevator?

2010-07-19T19:00:00.003-04:00

No longer stuck! And now there are two aluminum supports instead of just one. I'm feeling rather happy with this arrangement, given how stiff the right elevator half now feels compared to the actuated left side. It's a small change, but makes me feel better. Watching the video of Floyd flying at Torey, I realize that the elevator really is going to hit its end stops and need all the help it can get.

I also settled in to the idea of bolting the seat belt to the frame, so I finally drilled the holes and slipped in the massive 5/16" thru bolt. A quick whip with the deburring tool and both belts are mounted! I also put in some seat time and figure the 2A style buckle should be enough for the first few hops. I shall revisit this as necessary.

Red Goat video at Torey Pines

2010-07-13T17:39:00.006-04:00

This video of Floyd Fronius is too cool not to re-post from Sandlin's update page. Four minutes of un-narrated and multiple-view aerial video from Red Goat:

Thanks for posting Mike!

Seat Belt fun

2010-07-11T10:57:00.007-04:00

Thanks Mike and Alan for comments about the seat belt. This is very valuable experience for you guys to share. In light of your feedback, I'm going to make sure to change or at least seriously evaluate how easily the belt opens before any flying. I can find a replacement lap belt with the push button type buckle with the same steel end plates, so I figure installing this belt won't be a backward step.

The original location Sandlin used was to loop the webbing material aft of the rear seat tube, just forward of the structural wing cable/strut attach point. Since I'm using the steel plate style with a 5/16" bolt, this location doesn't work exactly. The belt would rub on the end of the lower seat tube. My option is to move the belt to frame attach point forward.

Trying to figure out where to mount the lap belt, I have turned to aircraft standards, which are less descriptive for this mounting location than I hoped. From my student club days, I know the Formula SAE car competitions have stringent requirements on the students' creations, so I consulted the 2009 rules: http://www.sae.org/students/mbrules.pdf. Section 33.3 covers lap belt and in particular Figure 9 (shown here).

The Formula SAE regulations give a minimum of 45deg to a maximum of 65deg for the lap belt centerline to body angle. I clamped my belt in my proposed location and took a side-on self-portrait to compare the angle. I'm relatively happy with this angle, maybe even fine sliding the bolt forward a bit, and figure my updated seat will put my behind in a similar location for the belt angle. I'll probably sit on this (pun intended!) for a few days and pull out my 5/16" drill bit.

Some stainless hardware

2010-07-08T17:36:00.002-04:00

No, not knives ... stainless steel clips, buckles, and coolness!

Berkley Point has the cutest little micro spring-clips that will do great keeping the horizontal tail secured. The extra spring-gate clip is actually going to be for the seat belt. The thimbles I purchased simply to have some on hand. And the "web threading plates" are for the shoulder harness of the seat belt, for 1" webbing.

The Aircraft Spruce order arrives tomorrow afternoon. What perfect timing for the weekend :-)

4th of July order

2010-07-04T11:41:00.002-04:00

Okay, I bit the bullet and ordered all the remaining hardware for the wing & miscellaneous areas. It's a hodge-podge of bolts, some tubes that Dillburg didn't carry, and a seat-belt in there for good measure. On the seat belt, I'm going with a Style 2A and think I'll use the steel end-plates and 5/16" bolts through the frame instead of simply using rope. I'm pretty sure all the other tubes would be bent before the tied version of the seat belt broke, but I feel more secure with a massive bolt.

Steady progress

2010-07-03T11:27:00.006-04:00

I did a bunch of work last weekend and figured I'd share. The control line came in sometime I think two weeks ago. In the same order from West Marine, I picked up two RF1853 Wide-D shackles. I was worried because they are 1/16" too narrow, but other folks seem to have them listed in their parts lists. After drilling out the threaded end to a 1/4" thru-hole, I had the anticipated problem fitting the shackle over the cabane end. These little parts are rather stiff too, being hard to force open a bit to slip over the ends; I tried to permanently deform the part, which might have helped a little. Anyway, they're on now and I'm sure a bit of tweaking will help the fit over time.

The major win last weekend was some time spent with a home-brew bending jig made from scrap 2" tubing and piece of MDF. I finally bent the elevator 3/8" x 0.035" trailing edge tubing and the other matching half. I'm pretty sure I've had this tubing since the very first order, so it's almost funny how long it has taken for me to get to this point. Now that I have the trailing edge on though, it makes the tail so much cooler ... when I move the elevator stick, something actually moves back there!

I am debating with the right inner trailing edge to hinge tube connection whether to use the fiberglass attachment method or borrow an idea I saw on another Goat construction site to make a more typical gusset plate type attachment. Right now I'm leaning toward the more rigid, but heavier, method. I've flown enough RC planes with similar torque rod arrangements for the opposite elevator half to know that a symmetric elevator is really nice to have.

As part of the elevator work, I was on a roll and also pulled out some foam and a new X-Acto blade to cut the ribs. Because these have a taper to them, they have to be cut individually instead of the all-at-once method I was able to use on the horizontal tail ribs.

Just last night during a really bad movie on TV, I made the slit to install the carbon rod spar caps. Unfortunately, I have now finished my carbon rod stock and was two ribs short. Fortunately, I recently came across a cheap site for more carbon rods (http://www.goodwinds.com). I need to get some 0.020" rod for hand-launch glider pushrods anyway, so it's convenient timing.

I also re-made the two right angle brackets that hold on the tail struts to the vertical tail. One of the previous ones I accidentally ovalized when drilling the 3/16" hole. This time I also took more time to make sure the strut can rotate around freely without binding. Yay.

In forward thinking news, I struck a deal for the timing of purchasing tubing for the wings. Aircraft Spruce was really expensive and would destroy me for shipping 12' tubes, so I'm going with a less-advertised company that is only 2hrs of driving time away: Dillsburg Aero Works in Pennsylvania. Their price was much better and I can go pick up the tubes in person to save on shipping. Look for a huge aluminum order around mid-August :-)

First time assembly :-)

2010-06-13T20:50:00.004-04:00

Thanks to Matt for coming over and helping move Goat outside for the first time ... nice to get some grass underneath the wheel!

It was a neat test on the assembly procedure too. It's a pretty quick assembly, maybe 5 minutes for what you see put together. I imagine adding the wings and associated cables would double the time, but even that isn't too bad. It'll take more time driving than it will to get through the fun assembly time.

It's a little bit rickety right now without the cable bracing. The rudder makes the tail rack a bit, even with the stretchy line. I'm looking forward to having the real low-stretch control line. The wings and cables will be nice too of course, heh.

Oh yeah, the neighbor kids of course found us. They were a bit rough on the rudder. Sonya sure is cute not reaching the pedals though!

The only casualty is two $0.18 bolts that fell in the grass, DOH.

Wheee!

2010-06-13T13:44:00.003-04:00

Cooking with gas again!

I was never really satisfied with 25deg rudder for only 1" rudder pedal deflection, so I started the morning by making a longer rudder control arm. I lengthened the part by 1" each side and now the pedals feel much better.

I also ordered 1/8" AmSteel-Blue 12-strand rope (very-low stretch) for the rigging. At only $0.43/ft, it wasn't too hard of a choice to use the "free shipping" that West-Marine has going on this weekend. I did a LOT of research yesterday to move away from the Lightning Rope. The AmSteel-Blue looks to be the updated version of Lightning Rope. It has a similar low-stretch: less than 1% elongation at 30% of breaking strength (2500 lb). Sandlin spec'd 7/64", so since I'm deviating I thought it was prudent to go the next size up to 1/8", which costs only two-tenths of a pound per 100ft of rope and gives almost 1000lb extra breaking strength. I'll consider this well-purchased insurance and eat the nose weight.

Speaking of control rigging, I finally used some of that Berkley Point hardware to connect the lines in a similar fashion to how it's supposed to work. Previously I had been simply tying new knots every time I assembled the plane. Now, I can get used to connecting the quick links to the snap hooks and start making a mental procedure to keep from connecting them incorrectly. I haven't set these up for the right lengths yet, so don't stress. I did install four new line guides on the bottom of the main fuselage carry-through tube. Coolbeans.

Last, I installed the tail strut end brackets on ~Thursday evening. They sure make quick assembly of the horizontal stabilizer onto the vertical tail. It's super nice to have the horizontal structurally held in place rather than with the stupid string I was using.

Feels like it's all coming together. 'bout time to get material for and start on the wings and feel under-whelmed again, heh ;-)

A whole evening for two parts

2010-06-09T21:19:00.003-04:00

Does anyone have a better way to cut square holes?

I made the upper two ends for the horizontal tail support struts tonight. They are supposed to fit over an AN-42B eye bolt on either side. Sandlin has the builder to cut a row of holes and file down in-between to make a slot. I have a set of pin files that I've practically worn smooth now... whew, a few hours ticked away, but I'm done with the two strut ends.

After camping Goat work

2010-05-31T19:45:00.004-04:00

The first annual Memorial Day camping trip is over and the 10 miles we hiked on Sunday is still hurting my calf muscles ... wow.

Goat is for some reason back on the front burner. I decided today to work on the tail struts. After cutting and filing the four pieces, I fitted one end of each and have yet to cut the struts to length until I do the final alignment against the vertical tail. I also should note that Aircraft Spruce did not have 3/8 x 0.035" in stock, so I used 0.058". This puts more weight in the tail, which is never a good thing, but the extra security feels nice.

I also assembled the whole aircraft (minus wings) in the apartment again. This included finally drilling holes in the upper vertical tail attach point to accept the upper pin; this tube end was replaced when I mis-drilled the original, so I took my time. Now I can fold up the vertical tail and use the real forward pin to attach it to the lower, rotating vertical tail part from G4T14. Two birds with one stone.

The control lines are currently simply a tied up messy bundle and rather stretchy. I really should use the quick links and at least make my temporary lines the right length. I just noticed in the picture that the right rudder line is running beneath the wrong tube. Remember this setup is temporary. Also temporary is the lower attach pin is shown here as a 3/16" bolt before getting stepped up to the correct 1/4" diameter.

Oh I also took a shot on Friday of the horizontal tail ribs still with peel-ply. I'm really dissatisfied with the finish of the blue foam compared to the pink foam. I think the bond is roughly equivalent, but the finished rib in blue foam sure looks comparatively awful. It's all hidden by covering in the end of course...

More ribs

2010-05-28T21:41:00.003-04:00

What can I say? I've not been working much on Goat recently. Sadly, the Sandlin main site is down too :-( Instead, I've been making composite discus-launch glider pods and just starting to make molded horizontal tail mounts. The techniques have certainly been perfected by others, but I'm finding it rather rewarding to improve my own skills. Each fuselage is taking about an hour of prep, an hour of layup, and a half hour of cleanup. The tail mounts are still slow, with only one flyable part out of the mold thus far. Thought I'd share a picture of the current inventory, which doesn't include the two I've given away to friends.

I did do a little work on Goat today and over the last week between test flights at work. I finished putting the other graphite rod in the long rib blank and sometime over the week cut and installed the four remaining ribs. Yesterday, I wrapped the ribs with fiberglass tape, using 3M Super 77 to make the process easier. And this afternoon, I cut eight strips of peel-ply and epoxied all the ribs. A little cleanup a few hours ago and the horizontal tail is looking rather complete!

I know I shouldn't, but I looked into covering a bit. A coworker recommended the full Stitts Polyfiber treatment as the best investment ... but it's sooo expensive, on the order of the price of materials in the whole airframe. I'm wondering if I'm reading too much into the process, but I haven't found a great tutorial online to review and see if I'm just being overly conservative. Suggestions are welcomed. I have a long way to go before covering.

To do:
* finally remake the last two cabane truss members I've been meaning to do
* make a jig and try bending a new keel tube, make a replacement fuselage carry-through assembly and match drill several existing bolt locations
* drill the top tail attachment in the re-built upper tail tube (*mega alignment needed*)
* finish gluing the foam crush supports in the vertical tail
* final drill the vertical tail lower control rod guide and rivet it on
* make the horizontal tail struts

That's plenty for now...

Mmmmm, Ribs

2010-05-05T17:36:00.004-04:00

I stole some time from my take-home final and worked on Goat over the last week (?). I can't really remember when I did this work, but I have a few pictures.

To the left is how I'm making ribs now. I cut a several foot long piece of 1"x1" pink foam, made a slit for the carbon cap, and glued each long cap in at once. The picture to the left shows the first of two caps getting bonded in the slot, this time with West Systems resin. The board and PC power supply are simply to keep the part straight as it cures. To the right is one of the completed ribs, installed near the tip of the horizontal stabilizer. I bonded the unfinished rib to the leading and trailing edges and added a wrap (with 3M Super 77) of fiberglass cloth. I have yet to put resin on this cloth (like I showed for the rudder ribs) instead waiting to have all eight horizontal stab ribs ready for that stage at once. Now I simply need to make six more foam ribs...

I had some leftover curing epoxy from another project, so I started gluing in the tail anti-crush foam blocks. These go between the 1/4" x 0.035" truss tubes on the vertical tail. This is the aft-most lower corner block bonded in place.

These foam pieces see virtually no loading that I can think of. Maybe they see some shearing from torsional twisting of the whole vertical tail ... but the fabric will probably take most of that load. I think they're mostly to keep the covering from dimpling the thin truss pieces in. So, I didn't work too hard on getting a super-uber-bond.

I did remember to take a finished shot of the lower horizontal stabilizer control rod guide bushing support structure. I mentioned I believe last post I added an additional wrap from what I had a picture of.

You can see the PVC bushing (white) held firmly between the two 1/4" x 0.035" truss members and with two layers of 1" fiberglass tape wrapped around the trailing edge tube, all of this supported by a foam stand-off. I'm quite a happy camper with this arrangement.

Tail work

2010-04-02T19:12:00.006-04:00

I'm back ... slowly.

I did some work on the rear tip of the vertical tail, namely on the elevator control linkage area. I added the PVC guides between the rear 1/4 x 0.035" tubes. Instead of just making a slurry of epoxy, I manufacturer a couple foam stand-offs to tie the guide tubes to the structural member. I 3M'd some 1" wide fiberglass tape around the foam, PVC, and aluminum tube, then I added some thickened epoxy to fillet the sharp intersection of the 1/4" tubes, then I 3M'd another glass wrap around the whole thing, on the outside of the fillet. I mashed epoxy into the fibers and thoroughly wet out enough to practically see through the fiberglass tape. A simple layer of peel-ply and clamps to ensure the fabric fit down in the fillets nicely, let cure overnight, and admire the handiwork. I'd say these aren't going ANYWHERE without some severe hammering. I remembered to add some shims/spacers inside the guide tubes while I was doing this bonding, so both guides are parallel and in good alignment. It's super smooth motion. Yes I couldn't resist putting the horizontal stab back on and seeing how the elevator stick felt ... 'bout the same as before.

While I had epoxy on the brain, I finished off the rudder ribs. I did two at once, pushing epoxy through the fibers of the 3M'd fiberglass tape, then using a wrap of peel-ply to get a nice finish. In the morning, I pulled off the peel-ply and knocked down the edges with an 80 grit sanding block. Two evenings' work, and the rudder is as good as done!

Oh I just checked the pictures of the elevator guides above. I guess I took the photo between layers. You can see the flox fillets around the 1/4" tube before putting the final wrap over them. Take my word for it, the next wrap actually went on rather well (3M is great stuff).

William-T-Pique through the Panama Canal!

2010-03-21T17:11:00.002-04:00

Slightly off topic, but I very much enjoyed reading Alan's boat-building blog for both his previous projects. Currently, he is sailing around the world and just made the trek through the Panama Canal! The crew is keeping a wonderful news site of their progress with an educational spin: Eye of the World/

I took screenshot videos of the boat passing under the Centennial Bridge and moving through the first Miraflores lock.

Awesome job Alan!

2010-02-27T11:38:00.003-05:00

I'd really like to hear from anyone reading this ... I opened up the comments to anyone with or without signing in to whatever account thing this site has. Just a few words of "hello" or "having fun reading" or even "I have a hanger and towplane and a trailer you're welcome to use." I'm just curious who all is reading.

So I caught up on some other pressing stuff around the house & office, so I decided to do a little assembly work this morning. Notably, I installed the elevator control line pulleys sometime earlier this week while it was raining.

Now, I also made the control linkage part to connect the sliding tube to the elevator itself. Well, um, there is no elevator per-se. I haven't yet bent the 3/8" tubes to make up the trailing edge for the elevator. Despite this, the elevator leading edge is done and hinged. So it's a little anti-climactic. But now I have another moving part!

The bottom of the control linkage shows off more of the temporary work back here. The marine pulleys from Harken are rather smooth and very nice actually. They'll do much better with larger line. The control tube guides will also do much better when they're bonded to the structure with epoxy and cabosil. The foam anti-twist supports will be nicer too without the wrap of electrical tape, so look out for that to happen when I mix up some big batch for doing ribs in the next month.

Speaking of ribs, I did a little work during the last snow storm to attach the horizontal stabilizer to the vertical tail, necessitating some filing of aluminum and using the die set from Harbor Freight.

That's all for now!

Harbor Freight is my friend

2010-02-13T11:44:00.004-05:00

I have heard the name Harbor Freight before, but hadn't ever really looked into them. With the snow finally plowed enough to get out, venturing to Harbor Freight was on the list! Their prices on tools I have bought before were generally half what I paid ... meaning a half-hour drive to the store is worth the savings. I bought several random things, including a tap & die set to make the quick-pins for Goat. I already modified the horizontal stabilizer AN3-30A bolt to accept two lock-nuts (low profile ones) and trimmed it to 1-1/8" long. Now my previously jury-rigged bolt actually stays in by itself! I was thinking hard about getting a drill press for making all those sheet metal parts a bit easier, eventually deciding against it since I'm almost done making those kinds of parts, heh.

In other news, I started a jig to re-bend the keel tube. I have to find some fine-grained sand to stuff the tube before I try to bend it this time. I have been told that will dramatically help reduce the kinking, along with a good jig of course.

No pictures this time.

I did give a go at sleeping inside that igloo by the way. Unfortunately, I didn't put in a secondary vent hole, relying simply on the main entrance for ventilation. After about two hours outside, I woke up extremely light-headed and abandoned it... I was quite warm, I think my CO2 was just not escaping enough without that vent. DOH.

An igloo?

2010-02-06T17:29:00.005-05:00

Goat is waiting in line behind some RC projects right now ... and then it snowed ~20" today, so we made an igloo in the front yard. Oh yeah :-)

It's big enough inside that I can crouch on my feet and we can get two adults inside. I'm seriously debating sleeping inside just to be EXTREME! Actually, if I kept dry, I'm sure it would be fairly comfortable inside. While digging it out, you could see steam leaving the entrance from body heat melting the snow. Despite being soaking wet from working several hours on it, the temperature change (or at least getting rid of wind chill) is noticeable. Ah, the insulating power of water!

If I had to do it again, I would buy a snow shovel first.

A little snowy work

2010-01-31T18:00:00.003-05:00

Finally I beat a stomach bug ... four inches of snow meant staying inside and getting a little work done on Goat.

These are the aft control line guides from G4T14. I have yet to put in the 1/4" spacers, instead simply using a washer to give just enough space for the temporary control line. I think they look pretty slick :-)

I also worked a tad on the rudder, evening up the control throw stops so now the rudder pedals feel more balanced. I'm a bit taken back at the short stroke of the pedal for full ~30deg of rudder deflection. An easy fix will be to lengthen the control arm on the rudder to suit. What should a "normal" stroke for the pedal be (let's say measured at my toes)?

So what's next?
* 8' of 1/4" x 0.035" tubing for the vertical tail internal struts
* peel ply for horizontal stabilizer rib LE and TE wraps for securing the ribs
* redo the bolt hole in the upper vertical tail tube (one hole is out of line with the other, hmmm)
* elevator linkage for inside the vertical tail
* finally do the two cabane replacement tubes
* measure the nose keel bend, make a jig, and bend a new keel without kinks
* 1-1/8" x 0.058" x 20" and 1" x 0.035" x 20" to redo the main structural member from G4N1
(ouch) ... the holes for the cabane pins are not orthogonal as one expects from View D G4N2.

Marine hardware: check

2010-01-20T18:19:00.001-05:00

I placed an order with Berkley Point for some hardware ... in fact for pretty much all the marine hardware. A good price break on 25 quick-links made that an easy choice and saved hundreds compared to West Marine. The steel rings are pretty cool and the snap hooks are quite pretty. I dropped in six quick links in the nose section alone. Next for some more cleanup of the nose section, including a new keel and a new structural carry-through since the last one actually wasn't drilled orthogonal as the G4N1 drawing suggests.

Rudder pedals with some control lines

2010-01-10T18:31:00.002-05:00

I found some time and worked on the rudder pedals a bit this weekend. First, a suggestion from a friend was to get some 6063 bar stock from a local place for easier bending for the rudder pedals. This worked and was a lot less cutting than the 2" wide piece of bar stock I have been making all my parts from. About an hour after cutting the two pieces to length, I had them both bent (using a spare drill bit to make the bend radius) and then spent some time getting the pieces mounted to the pedals and symmetric left and right. Then I made the little support pieces from 1/4" x 0.035" tube to triangulate the structure.

Here is an overview picture of the control rigging. The piece of white going from the pedals to the nose bolt is just string and will get replaced by some 3/16" shock cord, per plans. For now, it's just providing some resistance so the pedals don't fall over!

The elevator rigging is about how it'll be. I still need to get some larger washers to hold in the turn-around pulleys mounted in the center of the photo. I only had some small AN washers on hand.

Anyhow, yeah the control rigging is coming along nicely. Here is a closeup of the line guides on the control rod tube and the front seat tube. In earlier photos, I had the elevator line guides on the bottom of the tube, before I realized they went on top. I just flipped around that tube :-)

I also put in a little plastic end cap in the aileron torque tube, you can see on the right middle of the picture. I liked how the plastic caps dressed up the front and other tubes, so I sampled one that would fit in this location. Much prettier!

One more thing. My homebuilder buddy has made custom seats for other folks using foam bases. I'm hoping we can get together to fit the space better and be a bit more secure than the parachute cord version.

One other thing. I put in an order for 25 quick-links, several 2" marine snap hooks, and a few stainless steel rings. They should get here middle of next week. Cool, hardware!

Two rudder pedals installed

2010-01-05T20:39:00.004-05:00

I had a pair of pair of pieces (4 total) to attach the first rudder pedal. Tonight I whipped up 4 more to attach the second rudder pedal. Now both of my pedals are riveted to their hinge pieces and are mounted on the eye bolts. Cool. Now I need to make the long 9" u-shaped piece that makes a place to capture my shoes and attach the control lines too. All in good time...

Here is an image of putting the hinge supports on. The holes are match drilled by using a cleako and a clamp after the first one and then replacing the clamp with another cleako. This way I'm assured that the holes are all aligned when I install rivets.

Rudder Pedals

2009-12-30T19:17:00.004-05:00

I did some work on the rudder pedals. I did a test wrap of the 1" wide cloth a while back with quite unsatisfactory results. After cutting all the wrap off and sanding things flush again, I decided to go with some 6oz S-glass I had laying around. I put a similarly sized piece to seal the top and bottom of the pedals and then did a bias cut wrap around the pedal in one piece, using 3M Super 77 to make it all awesome. This is tremendously nicer than doing it with strips and the 3M really helped too. I show here one pedal wrapped except for the little exposed piece at the bottom and the other pedal with just the top end seal done. The other ends of the tube were sealed out with a hunk of foam wedged in the end of the tube. The bottoms will just stay open.

I actually epoxied them tonight too. I used an acid brush to push the epoxy down through the layer(s) of glass. It's not the most structural way to do it, but this is just a rudder pedal, so I have no doubt even this method is overkill. I wrapped the pedals in peel-ply to make a prettier finish and stuck them in a trash bag and used my vacuum to give a few inches of vacuum. It actually pulls down pretty well and I'm sure is more pressure than my tool chest's weight over the area of the pedals stacked on top of each other. This'll keep 'em flat though. Tomorrow I open my Christmas present and see how I did this go around.

I also put in two more sleeves into the cabanes that I missed the first time around. Now I simply have to replace the upper aft triangle tube that was a little short and the cabanes will be happy.

Progress is fun. It'll be nice to work through getting the tail group completely installed and take this puppy outside for a real assembly! (without the wings yet of course)

By the way, to the gifter of the drill, it works quite well, thank you :-)

Short update

2009-12-29T10:24:00.004-05:00

I have a few pictures for this update. I am sort of in detail-mode right now. I'm out of all the big tube material from last order, so it's time to start tweaking those little details that I glossed over to make forward progress. For instance, I used my West Marine quick-link and some sampled (free!) Alliance Plastics plugs on the nose area to make the tow release. The end caps sure clean up the look of the nose too. I sampled some more end caps hopefully to close out all the 1" tubing in the seat area and give that some more professionalism.

I worked on the aileron linkage underneath the seat too. I added the torque tube doubler (missed that before), so I feel much better about man-handling the controls (though as I understand it, the control forces are actually fairly light). I also split the PVC pipe and filed away material to make a "C" shaped until it fit with just about 1/16" of gap when the C was closed up to a circle. When I glue the bushing into the frame, the epoxy will help keep this gap from opening. Additionally, I added the 1/4" retainer piece to assist holding that bushing in place. I thought about leaving this with cleacos, but they interfere with the aileron crank, so I went ahead and riveted the support piece in.

As you might tell from the photo, I'm also concentrating on replacing any short bolts with ones that clearly use the shank as the load bearing intersection, instead of the threads. This also means I have at least 1.5 threads showing outside the locknut. I think this is proper use of these bolts, but I'll still have an A&P look over the structure before I do any covering. No sense in pushing when I have wiser folks around to critique.

Last, I added a couple of the line guides for the elevator control system. They are made from 1/4" x 0.035" tube ovalized to 3/16". The tiny supports are cut from the same ovalized stock and I used a Dremel sanding drum to put a curved surface on the ends of the support. This lets the supports have better surface contact and really takes no extra time.

I shall head off comments about the test control line saying it's some parachute cord that I had laying around and is just for mockup purposes. I'll get real spectra/dyneema when the time comes for rigging the lines.

Question: Do the ailerons need some stop-blocks somewhere? My aileron crank touches the wheel at full stick deflection and makes the wheel harder to roll. Maybe Sandlin used a rounder wheel?

We have a tail!

2009-12-21T20:22:00.005-05:00

I made a bending jig from a few spare drill bits and a bench vice. This kept from marring the surface of the soft aluminum parts. It took a few tries bending to get the right angle. I bent the pair at the same time so they have the same angle. Eventually I cut the two parts free, cleaned everything up, then started tweaking them individually... I really should mount my vice to the bench.
After a while, I mounted them to my jig and got things moving. Spaced properly and with a perfectly fitting bolt between the two tabs, I was able to match drill each of the connecting holes one at a time to have a perfect joint. Yay, one more hard step to go!

Then I finally actually mounted the tailbooms! The lower one was considerably easier with the nice alignment from the jig and all the close-up attention. The top one wasn't quite as easy. But it's done, so that's that. I used a 3/16" bolt so I can enlarge to 1/4" like I'm supposed to and take care of any misalignment.

I'm happy to sit in the seat with the tail sticking out behind me, self-supported. I just have to be careful not to lean it over and twist the two joints all to pieces.

The tail is almost on

2009-12-21T10:11:00.001-05:00

I'm making great strides on the vertical tail, almost to the point of getting it put on the fuselage! To start, this is where I am with the vertical tail. I'm out of 1/4" tubing for the truss structure, but what I have done gives me a good idea that adding the other trusses will be pretty trivial. I did 3M the glass tape on the two rudder ribs that had not been finished. I will indeed be taking out that one finished rib and redoing it.

Here is a closeup on the lower rudder connection area. You can see the vertical tail ribs made of 1/4" tubing and the different composite rib on the rudder. The lower rudder hinge area is that crazy bolt area in the middle of the photo. I put the rudder stop blocks in yesterday too, though one is a touch longer than the other. I think I'm shooting for about 20-30deg of rudder deflection until I can find the recommended throws. I also pinched the tail skid with the intention of rounding it off somehow later.

I also have the top rudder connection pretty well completed. The hinge was a piece of cake part with a slight bend in it and the tapered rib on the vertical tail is the same as on the lower side. You can also see the horizontal tail connection part, yet to have a modification to further thread the bolt for a captured part. The rudder rib in the lower left hand of the photo is the one I'll remove and redo. It might look decent from this zoom level, but I'm just not happy with it in person. In other news, I have not put the elevator control rigging slot in the upper boom yet (that would be between the rudder post and the h-stab mount). I'll probably wait that one out until I start all the rigging.

To mount the vertical stabilizer to the fuselage, I made a little tooling jig to hold the mounting flanges the proper 1.75" distance apart. This way, I would be assured that the tail boom would fit perfectly and the fuselage holes would be match drilled to suit. Unfortunately, where I put the bend in the mounting parts meant the bolts would physically conflict with other bolts in the area, so I have to redo those parts. This next time, I'm going to leave the fuselage end undrilled until I can hold them both up to the fuselage and ensure proper clearance. I am pretty happy with the jig though! It looks ungainly, but it worked great for the test fitting.

Finally, I leave you with a shot showing the temporarily clamped beast all put together. I don't have a wonderful place to take photos, so it's a busy background, but I think the idea still gets across .... the tail is almost on! It's remarkable to put it all together like this and realize this is actually going to be an airplane :-) I'm excited to finish off the little material I have remaining and do some cleanup on the tail section. I think within the week I should be able to get the v-tail actually mounted to the fuselage and start mounting the horizontal stab too. Perhaps I'll work on the tail ribs some more as well and feel like I'm actually finishing something off. Right now I sort of feel like I've started all the major sections (less wings of course) and completely finished none of them. Perhaps the rudder should be first to finish. Who cares though, I'm having fun :-)

"Storm of the Century" aftermath

2009-12-19T21:35:00.003-05:00

I wasn't kidding about the snow ... I took this picture just before dusk and the snow was still coming down at +1" per hour! It just quit (9pm) after starting up last night just after 9pm. 24 hours and roughly knee-height snow and definitely over my knee in drifts. I won't be going anywhere anytime soon...

I should have ordered another 8' section of 1/4" x .035" while I was already paying for shipping last order. I have a few of vertical tail ribs to go, but the aft four are all done (pictures tomorrow). It's nice to start cleaning up and seeing the vertical tail start to really stiffen up.

"Storm of the Century"

2009-12-18T22:33:00.006-05:00

Why is it that snow inspires me to work on Goat? DC is in for "a historic snowfall" tonight according to the meteorologists on the news. I took the quiet day to work on the tail section now that I'm back with all my parts and tools!

First, I sampled a rubber/plastic handle for the control stick. It isn't much, but it's very pretty looking. I think it is a little detail that adds a personal touch to the otherwise very metallic and impersonal beast. I haven't glued it on, so I can twist it around and somehow slide it off now, but I've heard of some tricks with hairspray for bicycle handles that might work. If nothing else, I have some 3M Super 77 that will make the two parts neigh impossible to separate...

I also installed the 1/8" quick link from West Marine in the upper elevator arm (hard to see). I have the pulleys too, but figure I'll hold those off for a day when I only have enough stamina for a 10 minute job (or when I decide to get the 40 some odd quick links).

Then, for whatever reason the mood struck me and I made channels in the horizontal stab ribs for the carbon caps. They're not glued in yet, but I'm about ready to do it (and probably will tomorrow night). I realized I forgot my magic trick for the fiberglass wrap on the rudder ribs: 3M Super 77 to make putting down the cloth a breeze. The rudder ribs were torture trying to hold the glass in place while squishing it with a peel-ply wrapped layer being pulled taut. Now I just can pre-bond in the carbon spar then gracefully wrap the 3M'd glass around before saturating it with epoxy. Duh to me, that'll work super well.

Now I started on the fun stuff, making the vertical tail. I quickly made two gusset parts and bolted them carefully to the upper tube and allowing to align the middle tube with the proper twist. The middle tube with all the rivets in it was already done from my last post.

Then I made slowly the four sheet parts to attach the rudder post to the upper and middle vertical tail tubes. Making the rudder post assembly let me match drill the upper and middle tube holes perfectly. A little while later I made and attached the upper rudder hinge.

The lower rudder hinge is a simple trio of AN42b eye bolts. I'm not really sure why Sandlin used the eye bolt pair and axle concept here and not elsewhere, but I like how friction free it is compared to the elevator. I'm going to debate for a while if I should do the same on the elevator. It's the idea of adding another pair of holes so close and in a critical part, we'll see...

And then to cap off the day's work, I made the horizontal stab bracket to mount on the vertical stab. I did the front one too, but put a circular hole in it and forgot it was an eyebolt that needed to go into a slot ... so I'll remake that part later sometime. I have not yet modified the AN3-30 bolt with more threads and no head to match Sandlin's drawings. I need to borrow/buy a die set to make that one happen.

This is a bad picture, but I really wanted to get the point across that this plane is really coming together! Sure there is a long way to go, but it's fun to start making an assembly :-)

A trip to West Marine

2009-12-13T14:45:00.002-05:00

I decided to go get some more parts for Goat. Unfortunately, West Marine didn't have any more quick links than just this one, nor did they have the Ronstan shackle RF1853. Bummer. That's okay I suppose though. I'll try again later at another store...

I also need a cheaper source for 1/8" steel quick-links than West Marine. I counted over 20 at first glance at the plans and at $7 apiece, this begins to hurt a little. Surely there is another source without as much markup.

The pulleys are super sweet though!

It's riveting work .......

2009-11-23T19:40:00.004-05:00

The Simpsons was back on tonight! I broke into that Christmas order a bit early ... I split a tube to make sleeves for the upper and lower vertical stabilizer tubes. Since the long tubes have inserts with rivets, I thought that would be a fun way to spend the evening. I have to get to DC to do the rest of the alignment before making holes in the others ends ... something about alignment, heh. I also have another half-dozen brackets to make before I do that alignment step. Good thing the Thanksgiving holiday is upcoming :-)

Car-Tow

2009-11-11T07:49:00.003-05:00

I'm starting to feel better about this whole car-launching thing. Here is a picture of an Australian powered Goat on an engine-off flight. From what I can tell, it is essentially tying a rope to the car bumper and attaching that to the tow-bridle of Goat. I read that for a short field, it is proper to have a ground pulley that turns the car to face the glider. This way, the driver can better see the aircraft on launch too. Of course, the driver does not drive directly at the aircraft. Also, I find a slight issue that the glider needs to have a very good sense of where the turn-around is located so the glider doesn't get pulled down. In the desert areas, the pulley isn't used and the vehicle simply drives along a road as far as the glider pilot wants, getting better altitude than if a pulley was used. Still, it sounds pretty cool since I don't know anyone in the DC area yet with a tow plane; suggestions are welcome!

Christmas order

2009-11-09T08:58:00.003-05:00

If anyone is still reading, I just put in an order for the aft fuselage (tailboom?) section as an impulse. I had the order prepped sometime over the summer, just didn't have the guts to hit the "order" button. Despite having two other active RC airplane projects going on and the school semester wrapping up, I figure having the raw material makes getting back working on Goat more accessible when I finally get the time again. Yay!

In particular, I'll be receiving material for the vertical tail triangle and lower boom support such that I can join the tail feathers to the fuselage. I'll have material for the anti-twist bracing, as well as picking up several spare parts to finish off specific areas of the nose section. A bucket of rivets will let me finalize the cabanes too. I suppose I probably could have done work on the tail ribs, but aluminum work is more satisfying to me right now.

'least I got this out of the way before Christmas hits and I feel that pinch!

PS: I just found a plastic part company that has free samples ... so we'll see if I can get the end caps on sample!

Cabane happiness

2009-07-28T21:09:00.003-04:00

It's growing slowly but surely.

The nose section now has cabanes with all the pieces attached! I added the compression struts to the back of the cabanes using some long rivets and two 1/16" washers. It took a bit of filing to fishmouth the tubes to match both angles and fit to the correct depth. Sort of glad that I'm bolting rather than welding.

A bike trainer stand does a great job of keeping the nose section standing upright while I'm working on it.

The central cabane intersection in progress. The main plate has the proper bolts and associated hardware. The forward cabane strut has the insert and is happily riveted. The aft strut is what needs work next. By the plans, it is about 1/4" shorter than I'd like to see. I have an extra piece of 3/4" x .035" tube that I'll cut long for this replacement piece. I also need to do the insert for it and then all the riveting. I'm out of rivets again.

Yeah I'm out of washers too... 200 washers last time wasn't enough!
I worked a tad on the kingpost too, despite that I can't assemble it on the aircraft inside! I haven't cut the large holes in it to pass through the cable connections.

I have not yet bought the tubes that go over these inner structural piece. I still need to get a vice so I can ovalize the outer housings. I think it will look better with the ovalized tubes dressing up the structural pieces.

So next I'm going to work on the tail ribs back down in North Carolina before coming back to the nose section. I'll then order the rivets, washers, and materials to make the vertical fin (aft fuselage, tail section, whatever you want to call it) so that the nose and tail are connected! That'll be four or five months from now though :-)

Summer cabane

2009-07-11T13:18:00.005-04:00

Time has come for another post. Life is changing ... a semester away from moving, a year away from graduating (yet again), a full 20 days until getting married. But Goat still progresses at its own pace.

Just this week, I received an order for a red Nelson Booster seat. It is a tad smaller than I anticipated, so the fit isn't quite exactly right, but the idea is there. I can always make a custom one that fits later when I care, heh. I laced the seat bottom and back with 3mm utility cord from REI. It's in the climbing isles and boasts 400lb strength, so I figure it should hold my butt up just fine. I painstakingly cut and tied each side with one tube removed such that when I pushed it back into place and dropped the bolt in, all the lines are tight. That sucked. The seat back was easier because I could slide the completed web down until it was snug, but getting the spacing right took several tries. I still have yet to cement the loops in place using some ShoeGoo. The seat itself will eventually be laced onto the cord instead of using a temporary loop around the seat back. I must say, it's pretty comfortable. It's no Tempurpedic, but works for me :-)

Also I have been working on getting the cabanes installed. This meant making the temporary center section pieces include ribs connecting the leading and trailing edges. Quite simply, I could not have purchased enough washers. There is a lot of spacing distance to cover to center the ribs, but whatever, washers are cheap. Next time I'll get 2000 instead of just 200. That should cover me :-)

Anyhow, I put the new long $7 ea. AN-42B eye bolts through the spar LE and TE to make the attachment point to the cabanes. A temporary short bolt and then a few pieces of 4-40 steel rod snaked through the test holes and now the cabanes are up by themselves! The nose tube goes up and supports the front of the cabanes just as nicely as can be. I even spent this morning on the forward pieces of the cabanes, so my head actually fits up inside closed structure (okay, I'm short so not actually inside, but it's nearby). This now is the configuration that it will be for flight. Everything else goes behind me (tail, aft fuse, wings). The wings have cables that tie into the tip of the nose, so I suppose those are ahead of me, but that's splitting hairs. The seating arrangement now is fairly close to the flight configuration.

I also bought a new nose section keel piece. This will replace the one with several kinks in the upper radius. I talked with an A&P guy who suggested filling the tube with sand and using a forming jig (which I can make from plywood). I'm hoping this new part will dress up the nose to look a little more professional. I also purchased a length of 3/4" OD tubing to replace a yet-undecided pair of truss members. Nobody likes the crimped 6061-T6, but if I can figure out which crimp everyone hates and make that look reasonable, perhaps they'll stop complaining.

I also need to figure out where to buy plastic tube end inserts like you might find in lawn furniture. You know what I'm talking about, a little plastic black cap that slides into a tube and dresses up the end to prevent snags on the thin wall and make it look solid. Where can I buy 3/4" and 1" ones of those?

Oh I guess I should also mention that I bought a handful of AN-14A bolts that fit better in the cabanes to get rid of the super long ones. Between making these updates and switching out the low-profile nuts for regular ones, the cabanes are looking rather dressed up.

What's next?

I still have some finishing-out work for the cabanes and replacements on the nose, so that's the immediate plan. After that, I'll be back on campus close to the tail sections again. I'll likely work on the ribs for the rudder and the horizontal stab. Figuring out and finishing those out will be a good accomplishment and set me up for the ailerons/flaps later down the road. I'll also take the sheet stock and start cutting out parts for the wing. I don't have all that many little parts to do, so I fear this will go fast enough I'll want to buy tubes again. My next tubing order I want to be the wing spars and tail tubes. This is all that's left for an easy next-step. I take that back, I guess the vertical tail (aka aft fuselage) is only an 8-ft tube, so UPS won't destroy me too badly. That settles it, I'll finish up the tail feathers then order the aft fuselage tubes. That will keep me busy for a while. I can even go so far as doing the elevator and rudder control rigging after attaching to the fuselage. That will be awesome. Yay for something to look forward to!

Semi-Update

2009-04-28T13:44:00.003-04:00

Nothing really has happened since the last post except for a move and two trips to move everything to DC. I suppose I have cut out a few more parts, such as the four trailing edge joining pieces and some other miscellaneous pieces. I joined the trailing edge root pieces too and started on the right cabane. I guess I have done a bit. No pictures this post because it's mostly just busy-work to prep for more fun assembly later.

I think the plan of attack is to tackle the last order that includes some hardware to finish off the cabane attachment (AN42B-26A in particular), a few more pieces of 3/4 x 0.035" tubing to serve as ribs and finish off the cabanes, and perhaps even a seat :-)

I don't know what I'll work on after this order is finished being installed because the more I look, the more it looks like the wings or tail section is next, which means about a $500 order and a trip to pick up the material so I don't get eaten for shipping. I figure I'll get all the remaining aluminum at the same time so I don't have to pay for any more shipping, which means I'll be getting the tubes for the tail section as well as a few pieces for things like ribs and wing tips. I wouldn't be surprised to double the price of the order. So much for buying into this piecemeal.

On the other hand, I still have not finished making the rudder or horizontal tail ribs, which I already have all the material for. The composite fabrication I haven't figured out as well as the metalworking (which is not arguably 100% what it should be). As an alternate, I could work on fleshing out the nose section with some part replacement and fleshing out things like pullies. This probably makes more sense to do all at once though. Hm.

Well, maybe I'll have another post this summer with an answer and some actual pictures of some more progress.

Cabanes and a wing section?

2009-03-05T09:43:00.003-05:00

I know this is a bad picture, but here are the pieces for the cabanes laid out on the floor. They are a lot bigger than I thought they would be! I don't think I realized the scale of this project, heh!

I should note that in putting these together with the mass of brackets that I have found two more parts that are mis-dimensioned. The top triangle 3/4" OD tube should be 20-7/8" instead of 20-3/4" and the front one I have not measured yet because my remaining tube is too short to fit. Dang. Also, the cabane channel on G4W10 is too narrow; it should be 1-1/4" channel to fit around the 1" OD rear cabane tube.

I also worked on the wing! Well, I'm making a fake center section that will allow me to put the cabanes on the nose section. This shows just 6" little pieces of the spar tubes that represent the whole wing. I likely can also add a rib down just a few inches to make these sections more stable and get the feel of how they go together.

You can see the mass of brackets that are going into these pieces. So far, running on 10 pieces of bracket and still have another 6 flat ones to go. I am out of 3/4" OD tube to make the root rib, so it'll be a while before this really goes on the nose/cabanes. But, it's cool to hold these in my hand and realize how sturdy they are and get a feel of the mass of the root joint. Whew!

Order up!

2009-02-26T09:46:00.005-05:00

It's almost sad how little material you get for an order ... I guess I did get several pounds of bolts this go-around, different from before.

This material is enough to finish off the cabanes, make the control stick assembly, and to make a test center-section so I can mount the cabanes and down-tube. After this, I'll be able to sit in my cockpit, wiggle the stick & pedals, and be fully enclosed like the final product will be!

I guess I didn't really pick up more material to clean up the nose section yet. I guess I'll get to that next order, sometime over the summer.

I started out by finishing up some pieces needed for the control stick assembly. This is where the belt sander really turned out to be useful. Such a long cut from sheet left a rough edge that would have taken an hour to file out by hand. Three minutes on the belt sander and the rough edge was super flat and no nicks were to be seen!

I haven't drilled these yet because I'm going to match-drill a bunch of these holes. The end pieces (triangular ones) will get bolted into the first hole and then I'll drill through the other hole to ensure I get a good fit. This also makes sure the holes are parallel between the two sides.

The plans show the final arrangement of the control stick assembly.

I should note, I had to redo two parts from the next page of the plans due to mis-dimensioning. They should be made from 1-1/8" x 1-1/8" angle, not 1-1/8" x 1".

The control stick as it sits in my living room. I still need to put on the aileron connection pieces and bend the (not shown) front mounting piece into a U. That comes when I have time. Oh, you can see here to the lower left the two brackets I had to redo. Bugger parts...

Out!

Yet more brackets, foam, carbon, and aluminum composites

2009-02-23T23:33:00.003-05:00

I spent some time this weekend working on Goat. I split about 50/50 working on foam versus cutting more brackets.

I have quite a large pile growing and it's getting time for some more fun assembly! Several, if you notice, are multiples up to 4 of any individual part. For the cabanes in particular, I need one bracket each side and then a duplicate pair for the other cabane. Several of these parts also need to be match drilled to align with each other, so some of these are not yet drilled. Fortunately, only a pair of each need to be match drilled, so it's not like I have to drill through four and have them all agree!

Next I moved to the rudder to do some foam and carbon work. I typically dislike this more than the metal work which I like less than wood work. However, I took my time and vacuumed several times and it was much more enjoyable than normal.

First, let me say I am not pleased with my first rib installation job. I have determined I will pull this one off and replace it in the future. I thought it more important this go around to get a rib right before I destroyed my old one. One step forward before one step backward.

I already had the fiberglass collars wrapped around the leading and trailing edges from months ago when I did the original rib. These I sanded a bit to get rid of sharp edges (ouch, pointy!) and to create a better surface for bonding the second layer of glass. One rib was already cut, so I simply tack-glued that on with some quicker setting epoxy. This helped keep it from moving around on me. I used a straight-edge and a razor saw to put a slice down the middle of the rib. Then I took a scrap piece of carbon and ensured the hole was large enough for the rib carbon to fully seat in the foam. After trimming a new piece of carbon to length, I glued it in the slot and double checked to keep the top surface flush. Before I add the wrap, I will install the other two ribs.

I did a little metal work on the horizontal tail too. I finally had a piece of scrap 3/4" x 0.035" tubing long enough for the elevator. I squared it up and drilled holes for the bolt and rivets.

I think doing rivets is fun, so it was exciting to have six to do all at once! Maybe my next plane should include more rivets. Okay, I admit that pop rivets aren't the most structural, so maybe I would say differently if I had to use real rivets.

I also watched an EAA Homebuilders video on the proper technique for installing cotter pins in castle nuts. The elevator hinge line eventually gets this locking feature, so I thought it would be nice to brush up on (who am I kidding, learn) the proper techniques.

While I had the foam out and my scrap 3/4" tubing handy, I started the rudder pedals. They are quite simple, just two tubes and foam in the middle. They will receive a wrap of 6oz fiberglass cloth to seal the foam and give it more rigidity. Whereas they look rather unfinished now, once the fiberglass goes on, they should look and feel much more rigid.

You might be able to see that I roughed up the aluminum in order to bond the foam on. This simple step is really important for getting a good bond. Imagine that the sandpaper is making several miniature scratches in the surface that the glue can creep down into and get a grip. You can bond things to glass this way even! Don't try it though, it's a good way to ruin a window...

Brackets and that's about it

2009-02-19T14:22:00.002-05:00

Progress is slow now that weather is better and I have school/work to do. I still have about 8 linear feet of sheet stock to cut, so expect more of this kind of update.

Just cutting parts ... mostly doing ones for the cabane area because I hope to do the cabanes next as a set. I still have a lot to touch up on the fuselage, don't get me wrong. But if I'm going to order material, I might as well be prepped for two duties at once and only have to pay once for shipping.

For the fuselage, I'm thinking of re-doing the lower tube with more effort on getting a bend with no kinks. Also on the list is to redo a few of the truss members that the holes are wallowed out or slightly off center. Most of the structure beneath the pilot looks to be non-structural in the sense that they do not carry flight loads. There are a few obvious exceptions, and that's why those pieces receive more attention. At any rate, will be fun to clean up some of the messier areas and take stuff back apart.

Snowy day again, this time for real!

2009-01-20T08:21:00.004-05:00

Apparently I like snow :-)

We got a solid 3" with areas of +4" this morning and it's still coming down. I really like working on snowy days because it is so quiet outside and peaceful to just watch the snow coming down when arms or eyes need a break.

Actually, I haven't done a whole lot of work on Goat in a bit. Occasionally, I'll sit down and knock out a part or two. I have all this sheet stock for making brackets, so there won't be much visual progress except for a growing pile of brackets. As it stands, I have a small mountain already and still over 9 linear feet to cut!

Here is the growing collection. Most of these belong to the cabanes, but the larger ones are for the wing root area and I have a couple more roughed that didn't make it into the photo.

One last hoorah for snow!

Wheel wouldn't ya know?

2008-12-28T18:42:00.004-05:00

For Christmas my brother and sister got me an Azusalite 6" wheel ... which I promptly mistook for a hat }{;-)

It took some massive persuasion to get the first hub half to fit into the tire. Finally with some Vaseline to let the hub slide on the rubber and using a dowel to help get it moving, we were able to get it set in place. Insert the tube and the other hub half, bolt the hubs together, add more Vaseline, then pump up the tube to get the other hub half set. It will take some more air to get the pressure up to full recommended, but no hurry. I'll set the final pressure based on how it feels rolling around on the ground in a year...

I also got a very nice belt sander /disc sander combo from my parents. This will really help make the bracket manufacturing go faster. I'll still need to file the last bit by hand, but this will help knock corners off and square up edges much faster. I have yet to turn this one on to see the dust collection in use, but you can see I already put the tool near the A/C intake vent for my apartment. Thinking ahead!

Oh you can also see the filled tire in the picture to the left if you look closely through the nose section structure.

Thanks for a nice Christmas from family and I'm sure that you'll see more posts within the month documenting some spiffy progress.

Parts order

2008-12-23T17:53:00.002-05:00

Shhhh, don't tell but I ordered some more aluminum today. It was all sheet stock, namely 9ft of 2" wide 1/8" thick stuff and 3ft of 1-1/2" angle. This many linear feet of brackets should keep me totally mired down in hacksawing for weeks and maybe months! But since I have the raw material in-hand, I'll be more likely to make large pieces of aluminum into smaller pieces of aluminum.

More cabane parts and a bit of drilling

2008-12-14T08:40:00.002-05:00

Not a ton of work today, but I did manage to crank out a few more cabane parts yesterday. The rectangular pieces have match-drilled 3/16" holes now. The triangular pieces also are for the cabane, but so far are only center punched. You can't really see from the photo, but there are four of these as well. The two little angled parts to the right are actually for the tail boom section, but I was looking for parts to make that I had material for.

Merry Cabane!

2008-12-12T22:01:00.003-05:00

After a slight hiatus, I am back slowly making progress. This time it's four cabane plate pieces. I haven't taken the time to drill holes yet because I want to match drill all of them so I'm going to wait until tomorrow when I'm not so tired.

It's almost time for another metal order. Methinks I can get just a bunch of hardware and bar/angle stock to make brackets for this order and get a massive tube order sometime early in the spring so I am careful with the time input. Slow and steady wins the race. I think I blitzed through the nose a bit too quickly. I need to step back and do some careful maintenance on the parts to remove any nicks or rough edges. Also need to replace a couple u-brackets that likely are under some stress. I also can add spacers inside tubes that would otherwise be getting crushed (that seat tube comes to mind).

Bed time...

Winter before Thanksgiving?

2008-11-23T12:44:00.005-05:00

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!

2008-11-20T01:01:00.004-05:00

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

2008-11-18T22:52:00.003-05:00

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

2008-11-17T09:54:00.005-05:00

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!

2008-11-07T23:50:00.003-05:00

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!

2008-11-06T07:53:00.003-05:00

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-channe l, 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!

2008-11-03T09:15:00.002-05:00

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

2008-11-01T11:46:00.001-04:00

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!

Nothing major, but starting work on the elevator

2008-10-29T09:03:00.000-04:00

Not much major went on last night. I made two parts for G4T5 that hold the elevator leading edge onto the trailing edge piece and shores up the link between the control arm and the elevator torque tube (i.e. the leading edge).

Making these kind of parts isn't bad, but my right arm sure does need a break after cutting about two inches of aluminum plate. Maybe this is a good exercise for me!

I did apparently mis-order trailing edge tubing and missed one of the 70" tubes for the elevator trailing edge. I'll just have to wait until next order to finish the elevator. The next order will also pick up about 5 bolts I missed for miscellaneous locations, too. I definitely am learning how NOT to miss parts for the next order; it's mega sad to go through my box of parts and go "oh man, where's AN3-6A? Doh!"

In related news, I spec'd out the parts needed for the nose section (G4N1 through G4N6). I think I have planned this to be my Thanksgiving project. Maybe I'll take the lot home when I head to the family's house? Hm. At any rate, sticking to my plane budget, I can't spend any more for three weeks anyhow. But, at least I have the parts list done! It's actually not as bad as I thought it would be. I kept the pieces to 60" (a bit cheaper to ship) and checked them off the plans as I went. There is a TON of 3/4" x 0.035" tube, something like 60ft!

Definitely a fun project to keep me company in the evenings after work is done.

Horizontal stabilizer

2008-10-27T21:34:00.000-04:00

Well I think I ignored my homework a bit too much today, but here's another update on the tail.

I figured out a way to get a straight line across an 8-foot tube. I made little idential end plates and strung a string between the plates. By pulling the string really taut, the line that the string created was a non-rotated reference along the span of the tube. All that remained was to mark off the string with Sharpie and pull the tube out of the jig.

My kitchen area hopefully has a flat floor. The linoleum was definitely flatter than my carpet, so that's why I did the work there.

Here is a closeup of one end of my jig. Yes it's cardboard! It's actually a few layers glued together with 3M spray adhesive. I know my cardboard stuff apparently. I made a cool little circular cutting bit out of a spare piece of 1" tube. I used my spiffy new round file to sharpen the ID so the OD of the tube would cut through the cardboard. A bit of pressure and viola, matching end plates! The string shown fits into a little notch that was match-cut into the cardboard, so I know as long as the floor is flat, there isn't twist in the reference line.

The next step was to start working on the trailing edge tube of the horizontal. It had several inserts that had to be made that slide into the main tube. A few rounds of electrical tape space the 7/8" OD inner tube to fit the 1" diameter by 0.035" wall thickness. The center doubler is 10" because it has to capture the rear fuselage mount and the center hinge, which also is the closest to the torque rod that transfers the stick force to the elevator.

You can see two wooden pieces that I cut from scrap to space out the tubes to be 18" chord. It's nice to have a spacing reference while I wait for the carbon rod to show up to make ribs.

Here is another shot of the horizontal stab with the wooden rib spacers and the tube inserts in their appropriate spanwise locations. The leading edge tube has already been riveted into place with the tip tubes previously bent to shape.

I don't think I realize this 8 foot long thing is really as big as it is. My roommate even said the same. My theory is, we've built RC planes with larger wingspan and area than the horizontal stab, so I think we're in denial of the eventual size of the wing!

Here is a real close-up of the innermost doubler tube. The black rounds of tape make a snug fit when sliding the sleeve into the main tube. You may be able to make out my marks for the sleeve alignment. I generally use a marked spare tube of some smaller diameter to push the sleeve down the main tube until it's at the mark. Then I try not to move the main tube much and I drill the first 1/16" hole. After that, the little aluminum chips smear a layer of the tape's adhesive in the hole enough the tube really doesn't want to slide around.

After dinner and some Simpsons, the trailing edge tube is all done up in proper fashion! I installed the three hinge eye-bolts up at 30deg from level. One eye bolt for the horizontal stab tail strut I must have misordered, so I have only one of those installed right now.

I was doing some research while dinner was cooking, using eyebolts for hinges like this does mean that they can potentially rotate and prevent the hinge from operating. I have been brainstorming ways around this. Mostly I have come up with ways to double-up on the eye-bolts or to use a single hinge axis with a long piece of steel rod threaded through all the eye bolts. For now, I'm going to keep moving and keep thinking about it.

I should mention that working with aluminum over carpet is probably not the smartest work environment. I'm keeping things pretty well vacuumed, but geez one day I'm going to step on some shard and walk funny for a while.

This is a close up of the tip joint between the stab and the elevator. The round tip tube spec'd at 30" was about an inch and a half too long, so I used my pipe cutter to trim it a bit. Now the tube fits cleanly into its slot and preserves the 18" chord. The pipe-cutter was only $12 and is a really super quick and precise way to trim the tubing.

I haven't started work on the elevator leading edge (the smaller diameter tube). I guess that's next once I get through some school work tomorrow.

One last shot of the horizontal tail tip showing my collection of tools laying around. This part is too large to fit on my RC building table, so the floor is getting some good use; then I clean up and vacuum.

Rudders away!

2008-10-27T09:08:00.000-04:00

I decided a few weeks back to start building an ultralight closely modeled after the Goat 4 by Mike Sandlin. His Basic Ultralight Glider series are meant to be home-built using hand-tools such as a drill and hacksaw. He also publishes well-drawn plans online, which is a major part of the draw to this project. Also, Sandlin actually has flown several permutations of this series, leading me to put more faith in the design.

I started the rudder and the horizontal stab recently. The first couple pieces are these offset angles that hold the rudder control horn onto the rudder leading edge tube. The first one took about an hour (eek!), but the next two only took about half an hour apiece. This is definitely going to take a while.

I haven't worked with aluminum much before, so these parts are my experiment. I cut them out of 6061-T6 aluminum (per plans) with a hacksaw and then filed the rounds. I also center-punched the hole locations and later took these to a drill press to make nice straight holes.

Next came the frame of the rudder. It is essentially two tubes, a leading edge and a curved trailing edge. The leading edge actually has two inner stiffener tubes inside that reinforce the bolted areas. The trailing edge tube gets riveted into slots in the leading edge tube.

I must admit that the trailing edge tube I bent over my knee and had no intention to make it precise. It does look roughly like it should, hehe.

Just yesterday I finished the rudder control horn assembly by adding the control horn and another hole through the leading edge tube. This assembly does seem very rigid and I can see putting some torque on the rudder.

I still don't have a good idea how to drill several holes in line or in perpendicular on a tube. Any references here would be most appreciated. It seems straight forward to drill straight through with a drill press and a v-block, but how do you get a hole perpendicular to the first one?

That's all for now. Next come the ribs of the rudder made of foam, carbon rod, and a wrap of fiberglass. I have already cut the blue foam rib blanks, but not yet fit them into the rudder itself. I still need to order $60 of carbon rod.