Apr 11, 2024     Aileron setup (cont'd) - (11.5 hours)       Category: Controls

Continuing to fiddle around getting the ailerons to move to the plans limits of 25 degrees up and 20 degrees down.

Between the control arm at the base of the control stick to the aileron control tabs on each wing there are three linkages, an idler and a bellcrank as well as six rod end bearings (for a total of twelve). This doesn't include the fourth set of linkages to the upper ailerons also utilizing a pair of rod-end bearings each.

Given all the aforementioned bespoke components, each of which are connected by a pair of adjustable rod ends, some differences can be expected between the left and right systems due to "building tolerances". So setting both sides to match one another's movements has been an iterative process.
They're pretty close now, and probably good enough. To reach the full 25/20 degree throws shown on the plans, requires a full 30 degree throw of the control stick to each side to achieve same.

I don't think that much control stick throw is going to be available once everything is connected up. The aft end of the control torque tube at the base of the stick connects to the elevator pushrod assembly via a rod-end bearing. There is a total of two such bearings until reaching the elevator idler. Each of those rod ends would need to allow 15 degrees of rotational travel to reach the above limits. I'm thinking these rod ends will bind up at less travel than that and so will have to check that out with further assembly. Wherever the travel limits are, I'll need to set the aileron stops in the cockpit accordingly so things don't get bent.

Edit 4/19/24: Turns out the Aurora bearing co. publishes a 13.0 degree divergence angle for their bearings. In a perfect world that would give me a 26 degree control stick swing each direction prior to reaching a binding point on the elevator pushrods.

  Mar 05, 2024     Aileron setup - (12.5 hours)       Category: Controls

I've been busy completing the connections for the ailerons setup. The project to this point has been mostly a part-task, bit at a time affair. Now, the disparate components are coming together for the first time looking a little more like the finished product. This leads to the next challenges. While the wings are on and generally rigged in position, time to finish the aileron connections and get them working properly.

Interference problems tend to pop up unexpectedly. So far, just a bit of sanding and filing which will require some touch-up paint and varnish once disassembled again. Each one takes time to resolve and make sure I'm not creating more problems. The most concerning interference problems haven't developed - yet anyway.

I was concerned the aileron pushrods crossing the lower longerons may bump at the neutral (centered) stick position. Was prepared to splice in smaller diameter tube to the pushrods, but unnecessary. I think the 2.5 dihedral on the lower wings caused the miss.
The same pushrods cross under the #1 inboard compression tube under the wingwalks as well. At a full 30 degree control stick roll input, the math looked as if they would collide as well. So far, it's a clean miss. Still making measurements, but I think I'm reaching other travel limits before getting to 30 degrees of stick input.
Have been monkeying around trying to adjust aileron travel and differential. There's no information on this in the plans, so it's been a bit of trial and error to see what the next thing does.

  Sep 23, 2023     Completing the upper ailerons - (26.5 hours)       Category: Controls

So the upper ailerons are completely fabricated, all done, fini, in-the-can and Bob's yur uncle.

The "parallel" construction process I used to sort of Ping-Pong between one and the other sort of worked out, reducing the time required to complete them. The first two ailerons I completed individually took about 50 hours apiece to finish, and I stumbled a bit trying to recall how I had done portions of the first in completing the second. Hopping back and forth between each of the second pair of upper ailerons helped reduce tooling setup time and confusion about what to do next and how. Some caution had to be taken to avoid repeating my mistakes exactly, so slow and deliberate also helped produce consistent, flat panels.
These second pair took, by my estimates about 66 hours to complete. So some economy of time improved with this technique.

These time estimates represent only the "direct" aileron fabrication times... that is, once all the components are in hand. Much more time was involved in fabricating each of the individual components required in the aileron assembly. These included things such as developing Form blocks to form the proper shape and size ribs, cutting sheet metal for those same ribs then forming them. Also cutting out the spars and trailing edge pieces both straight and curved and finally, locating and using a shear and brake large enough to accommodate their size. The tapered hardwood inserts called for in the plans also required time in the wood shop. All of this time to fabricate these components from raw stock is not included in the above estimates and yet represents a significant portion of the overall time invested in the finished product.

I have to say again, I purchased the corrugated skins I used, further reducing the time required significantly. There are several builders I know of and likely many others that have produced their own corrugated skins to plans from raw sheet metal stock. They are to be commended. Each I am aware of required building multiple iterations of presses or components thereof, all of which are bespoke, individual adaptations to achieve these skins. Even then, lots of sheet metal wound up in the scrap pile as each iteration needed fine tuning. I would have been a frustrated mess, even more than usual, trying to do the same. Heck, even after I had the produced corrugated stock in hand, I couldn't figure out how to cut it or how the stuff squirms around accordion-like when you're trying to work it into shape. It took ---days--- waiting for inspiration to strike, before I blundered upon even getting a straight edge on this stuff. Oh, it already had a straight edge. D'oh!

That being said, there's still some work to be done, I only have T-nuts inserted in one wing so far and have yet to resolve any potential interference issues installing these panels to the wings. I'm thinking a short work session will see the left one mounted to the wing and T-nuts installed in the right wing.

As an aside, I think I'm better able to estimate the time required to complete a given task after this aileron experience: Make an initial estimate, then multiply that times two and add another ten percent. Failing that, chalk it up to gaining experience and education, knowing the next attempt might save some small percentage of time, effort or frustration.

  Sep 17, 2023     Upper Ailerons work continues - (6.5 hours)       Category: Controls

Yeah, so figured out how to get the beads to match along the trailing edge. The spacing was just barely narrower on the lower skin than top one. So, although they matched at one end of the surface, they gradually diverged so they were way off at the other end of the aileron. Pretty sure Mr. Brown who stamped these skins out used the same jigging or process to produce all these skins, so how could they come out different? Well, they got shipped rolled in a box and some were wrapped just slightly tighter than others so they would nest together. This bottom skin was pretty springy, needing to be bagged down to work on it. I just un-wrapped it rolling it opposite the pre-existing curl. The more I did the un-wrapping the closer the bead spacing got to one another until they matched the full length of the aileron. Problem solved. Too bad I got smarter about this stuff on the last aileron.

Got both ailerons completely drilled and both are ready to fit and install the steel tabs for the jury struts, disassemble, deburr and crimp the bead ends. That should do it prior to riveting.
Following riveting, fitting the hinge halves to the wing aileron spars and installing T-nuts into same should complete the installs.

  Sep 15, 2023     More upper aileron work - (16.0 hours) Category: Controls

Continued to fabricate both upper ailerons in parallel with one another. Upper left is completely drilled, but haven't fitted the jury strut attach tab. That and crimping the bead ends and the usual deburring is all that remains prior to riveting that one together.

Work on the upper right one is to the point of match-drilling the bottom skin along the straight portion of the trailing edge. To begin attaching the oversized bottom skin, it's clamped between two lengths of square steel tube to keep the surface flat prior to match-drilling.
The beads don't quite line up... I'm thinking of ways to "stretch" the bottom skin so the beads will better line up with the top. Dunno if clamping and pulling on it will help stretch it into position, or maybe pressing on the beads where they begin to diverge to help lengthen the skin enough to better line up the bead intervals. TBD.

  Sep 10, 2023     Upper Aileron work - (10.5 hours)       Category: Controls

Continued to construct both upper ailerons in parallel with one another. Fabricate and drill one, then repeat the steps on the other aileron. This minimizes tool setup and take down time. As a plus, It's easier for my geezer-brain to recall the process I used for the previous one since I just did it. Duh!

  Sep 07, 2023     Upper Ailerons - (6.5 hours) Category: Controls

Began fabrication of both upper ailerons. Started in on the left one with the spar and ribs then decided to approach both uppers together, in a parallel process minimizing the amount of setup time required to go through all the steps in the fabrication process twice. We'll see how it goes, so far I have both a left and a right spar with associated ribs and not two left ones. Had a potential misstep laying out the topskins, but caught myself before cutting any sheet metal. The whole left/right, inside/outside, build it inverted on the jig thing kind of catches up with my cognitive limits once in a while. So far, so good... as far as I know.

Of note: I think I mentioned having graphed out the aileron jury strut actions. Since it is attached to the top of one aileron and the bottom of the other, those attach tabs on the ailerons swing in different arcs because of their relationship to the hinge point. Consequently, for both ailerons to displace similarly, the upper aileron attach tabs need to be located about 3/4' to 1" farther aft from the spar than the lower ones.

  Sep 04, 2023     Finished the lower left, began upper left aileron - (6.0 hours)       Category: Controls

Fitted, fabbed and welded the aileron link to the aileron bellcrank for the lower left aileron. Tapered the spar for the upper left aileron and fabbed the flange insert piece for same.

  Sep 03, 2023     Attaching the lower left aileron - (2.5 hours)       Category: Controls

Drilled and installed the T-nuts to hold the aileron to the lower left wing. Bonded them in with JB Weld. Cleaned up same.

  Sep 02, 2023     Finished the bottom left aileron - (6.0 hours) Category: Controls

Finished up the riveting on the bottom left aileron today and moved on to drilling and installing the hinge half on the wing aileron spar. Not quite ready to install the T-nuts yet, but will be bonded in with JB Weld just like the first one. Should complete that step first thing tomorrow.
This aileron came out flat too, but I noticed a small shift on the trailing edge after I had finished drilling it. The rolled beads gradually started to offset from one another beyond the taper point along the curved trailing edge. Realized it only after it was too late to do much of anything about it. It's not a lot, about 1/3 of a bead width at the worst point, and the ends being tapered kind of masks the problem. Don't think it's significant enough to do anything about, but I do think I can do it better on the following ones, just have to watch them more carefully when I flex the skin over the taper and around the curve.
So far, it's taken about 50 hours each to complete an aileron. That's excluding the time spent socializing when the door is open (constructus interruptis). That's about 50 hours in just under two weeks, but I wasn't out there everyday. Spent a few days at the in-laws and the days I was out there some socializing and a coupla welding projects also came up. Not sure what that means if anything, but planning ahead I don't think my working pace is going to get any faster anytime soon.
I'll post some photos of this finished aileron tomorrow and the bead offset if I can.

  Sep 01, 2023     Closing in on the bottom left aileron - (7.0 hours) Category: Controls

Okay, so I'm a little over 40 hours in on this bottom left aileron. More than I would have expected at this point, but hopefully I can wrap it up tomorrow.
Closed all the skin bead ends per the previous aileron, riveted together the steel tabs, ribs and spar and riveted the bottom skin in place.
Minor setback: Discovered five rivets on the bottom skin need drilling out and replacing (managed to cut a smile into each using the C-frame riveter). That task should begin tomorrow's adventures.
For this aileron assembly I have kept a running log of steps to accomplish in sequence so as to produce a flat aileron. So far it's two and a half pages of handwritten line-item steps. I did this because: 1.) I couldn't find a comprehensive explanation on anybody else's online build (and now I know why) 2.) I just went about building the first aileron based on the pictures and guidance I had come across from other builders and the Makelan photo CD. I took pictures, but no notes and by the time I started the second one, I had already forgotton how I had accomplished some parts of the process and sort of had to "reinvent the wheel" This should help me economize the process in completing the last two. And lastly, 3.) If anyone else decides to attempt this and stumbles across these notes, maybe it could help.

Once I get this second one complete, I'll try to summarize the process instead of writing the whole mess in agonizing detail here.

  Aug 31, 2023     Getting ready to rivet the bottomleft aileron - (6.0 hours) Category: Controls

More prep work today closing in on the final stages of the bottom left aileron. Drilling is complete, cleaning up some corners, deburring, trimming, etc, etc. I also slotted both skins for their respective steel actuator tabs to poke thru.
Managed to snip the bead ends of both skins in preparation of crimping them down. This is one of the last steps prior to riveting the aileron together.

  Aug 27, 2023     More bottomleft aileron const. - (7.5 hours) Category: Controls

Continued to fabricate, drill and assemble, disassemble, deburr, reassemble and drill and assemble some more, this the second of four ailerons required.
I had initially been looking forward to building these corrugated aluminum surfaces as I had previously built a VAn's RV6 and felt fairly confident working with sheet metal.
That is, until I read a magazine article featuring an award-winning Hatz Classic. The builder (I've forgotton the names and magazine) was giving the author the walk-around tour pointing out his ailerons which he was very proud of. He stated he had built SEVEN (7!!) to get four!
Huh? Building these without a twist was going to be more of a challenge than I was expecting and would have to pay attention.
So I pretty much tiptoed through the first aileron fabrication, but I didn't take any notes other than photos, and was working from memory now building this second one. I spent some time the last two days trying to enumerate the steps I used fabricating the first one and put them to paper, in hopes of making the process a bit more efficient building the remainder of them. Though "efficient" may not be the right term to describe this process... maybe "less painstaking".

  Aug 24, 2023     Bottom left aileron construction (cont) - (13.5 hours) Category: Controls

Continued the construction of the lower left aileron. Same process as the right one, but seems to be going smoother so far. Topskin is completely drilled and deburred, Spar and ribs are fitted as are the steel tabs and the hinge is fitted and drilled . Next steps include cutting and fitting the bottom skin.

  Aug 22, 2023     Starting the bottom left aileron - (6.5 hours) Category: Controls

Welded up The short link for the lower right aileron. Began fabricating the lower left aileron by tapering the spar and drilling the angle/filler strip same as the right one.

  Aug 21, 2023     Attaching the first aileron to the wing - (8.0 hours)       Category: Controls

After riveting was complete, attachment to the wing via a nearly full length piano hinge was next. I used the extruded piano hinge since it is stronger than the rolled eye type of hinge. Drilling the hinge half on the drill press first allowed uniform hole spacing and alignment. Next, I used a straightedge to vertically align the hinge half on the wing aileron spar.
I used a hand drill to drill it to the spar. Care had to be taken to ensure the drill stayed normal to the spar surface since it sits at an odd angle. Could have used a portable drill press, but I think it would have been more trouble for little gain. Hand drill worked okay. First drilled the spar to #8 machine screw size, then backdrilled using a 7/32" angle bit to a depth of 1/4". This allows the shank of the T-nuts which will be inserted from the forward side of the spar to nest in the 7/32" counterbore and the #8 machine screws fit tightly through the spar.
I used an allen wrench and a few socket head screws and washers to seat the T-nuts by drawing them tight after first coating them with JB Weld. These T-nuts only have three sheared "pins" each to hold them into the soft spruce and I wanted to ensure they wont fall into the wing during any assembly or disassembly.
The hinge pin has a 90 degree bend in the inboard end which is trapped against the wing structure safetying it . Removal or insertion requires the aileron to be off the wing.
The #8 screws attaching the aileron to the wing are drilled-head and will be safety-wired during final assembly.
I made measurements to the wing aileron bellcrank from the lower tab of the attached aileron. I fabricated the linkage which attaches the two via a pair of rod-end bearings.

  Aug 17, 2023     Riveting the first aileron skins - (8.5 hours)       Category: Controls

Once all the prep work was complete, nothing left to do but rivet this thing together. The bottom skin is necessarily the first to be riveted due to accessibility. Found a way to rivet and buck the ribs to the skin as well. I had purchased stainless cherry blind rivets to attach the ribs, but managed to buck them with solid rivets instead.

Attaching the topskin began with clecoing it to the structure to ensure proper alignment. Rolling the skin back on itself allowed access to insert a small bucking bar and operating the rivet gun from the outside. The structure was sandbagged flat on the jig during the process.

Once the ribs are riveted to the topskin, the skin is rolled out flat and the structure inverted on the flat jig. Inserting the trailing edge strip and angle then clecoing the trailing edge closed while pressed flat on the jig should ensure the structure remains flat with no twist.

The jig will allow the trailing edge and the leading edge with it's hinge segments to extend past the edge of the jig while sandbagged down, allowing access for the rivet squeezer.

  Aug 13, 2023     Prepping Aileron skins - (3.5 hours)       Category: Controls

In getting ready to rivet this first aileron together, besides the usual deburring, edging, etc. I decided to crimp the ends of the rolled beads along the leading and trailing edges. The early Wacos did this on their ailerons, it looks a little bit more finished. Besides, labor was cheap then as I am now, so why not. Aerodynamically probably doesn't make a whit of difference, but I'm claiming 3 knots if asked.
First step was to notch the ends of the rolled beads. A small pair of snips would do, but Klein tools makes an HVAC tool that makes the perfect v-notch with one snip. Ordered it up from the Home Depot.
To form the closed ends on the beads, I used an old bolt that I filed a notch into, forming a pleasing and eye-catching shape to press onto the snipped ends.
Full disclosure: I'm just copying what I saw someone else do here, pretty sure I can pull it off.
The beads are all fully closed end fore and aft on the topskin, but the bottom leaves every fourth one open on the trailing edge. That's how Waco did it back in the day. Of Note, I saw the new production Wacos at Oshkosh... no closed ends on their ailerons. Labor costs more these days.

Edge forming these closed ends stretched the skin edges a bit making the skins move around a bit, but since I had already drilled and fitted everything prior, the accordion-like skins went right back together when clecoed no worse for wear.

  Aug 08, 2023     Aileron/ Wing attachment - (2.5 hours)       Category: Controls

Aileron attachment to the wings is accomplished via a piano hinge screwed to the wing Aileron spar. T-nuts are inserted on the forward side of the aileron spar in the wing and #8 machine screws are sent thru the hinge half, the wood aileron spar and into the T-nuts. The screws are drilled-head which are safety-wired in place along the back side of the spar.
First issue to arise is the vertical placement of the hinge. The aileron spar flange and topskin sit atop the hinge half riveted to the aileron which comes to about 0.050" thick. So that means the hinge half on the wing aileron spar should be something like that below the top of the wing. There are at least two layers and maybe more of fabric and tapes and fabric finish chemistry wrapped over the top of the wing aileron spar. How thick is that? Dunno.
I think I'll simply screw the wing half of the hinge flush with the top of the wing aileron spar and call it good enough. As long as they are all located the same, it should be okay.
Drilling for the T-nuts presents the next issue. The shanks that get inserted are a few hundredths under 1/4" (0.220") so it's a sloppy fit to drill to 0.250" for which I have a brad point bit. The proper size drill to fit is a Letter "A" bit which I also have. But not in brad-point. The hinge half is drilled #19 as a clearance hole for a #8 screw. Contemplating which bits/size to drill and how. TBD.
Once drilled and inserted, these T-nuts have points that anchor them into the wood spar. Unfortunately, the points do little to resist being pushed out if I get a little heavy-handed driving in the screws which could cause them to fall into an already covered wing with no way to re-insert them without opening up the cover job. Will have to spread some JB Weld on the T-nuts prior to inserting them and anchoring into their holes to prevent pushout.
The aileron hinge pin should be anchored so it cannot migrate out possibly disconnecting the two hinge halves. Several ways to do this. One, I could put a 90-degree bend in the inboard end and leave 1/4" hanging free on the outboard end. Any migration would be limited to 1/4" inboard when the bend would contact the wing structure and stop. Second, I could drill the inboardmost hinge eye, insert a short length of safety wire or cotter pin and secure it. The hinge pin would be trimmed short enough for to accomplish the same thing on the outboard end, trapping the pin between safetied eyes.

  Jul 29, 2023     Aileron jury strut Conundrums - (2.5 hours)       Category: Controls

Okay, hard to see in the pictures below (it's in pencil) but it diagrams and scales the information from the aileron plans. The plans show but do not dimension the attachment of the jury strut attach tabs to the aileron ribs. They appear to be attached equidistant aft of the aileron spars, but if so mounted they sit at different radius' from the hinge points. This means acting at different radius' the upper and lower surfaces will displace differently.

Among the conundrums include how far the ailerons are to displace. The plans show 25 degrees up and 20 degrees down, simultaneously 2-1/2" up and 2' down as measured at the trailing edge. It can't be both. In fact, the inch dimensions are about half of what the angle dimensions will produce.

Locating the correct distance aft of the hinge point for both the upper and lower strut attach point tabs is diagrammed on the scaled drawing in the first picture.
If located per the un-dimensioned aileron drawing, this would produce substantially different displacements between top and bottom ailerons.

I'm not the first builder to address this issue. Some have analytically determined the locations that will result in minimal difference in the throws between upper and lower. Others have observed how Waco addressed the problem and replicated that, using an external attach bracket and reversing them from top to bottom.

Bottom line: Assuming that both ailerons should move in approximately the same manner may be in error.
Dunno where I read about it, but the explanation went something like this: The down going aileron on the lower wing produces a lower pressure area below the downgoing upper aileron. So increased displacement of the upper would be necessary to produce an equivalent rolling force.

So what to do? I'm going with the minimal difference philosophy. From the diagram below, locating the tabs about an inch apart results in the minimal difference between aileron motions. As measured aft from the aileron spars, the lower tab attach pivot point comes out at 6-3/4" aft and the upper tab pivot point at 7-5/8" aft. The latter approximates the location depicted on the un-dimensioned plans.

  Jul 18, 2023     Skinning the first aileron - (18.5 hours)       Category: Controls

Skinning begins with drilling the skins to the spar and rib structure. Keeping everything flat requires drilling it to the jig in the process. Since the topskin is flat, I started with the spar inverted on the topskin drilling it flat. Also aligning the rib structure to the corrugations to ensure the steel attachment tabs won't protrude through one of the rolled beads. Drilling commenced after the alignment was confirmed. Drilling to the spar was first, followed by match drilling the hinge half to the spar.
The remainder of the topskin rivet holes along the trailing edges and rib structures were also drilled and clecoed flat to the jig.
The curved trailing edge segment was also drilled flat to the jig through the topskin.
Once completely drilled, I removed the skin from the jig and clecoed it to the spar and rib structures. The bottom skin was intentionally trimmed oversize for this next step. The bottom skin was then matched to the structure, aligning the trailing edge beads and clamped together using two straightedges keeping everything straight and flat. The straight portion of the trailing edge was then match-drilled to the existing holes in the topskin.
The bottom skin trailing edge was then marked for trimming to size reference the topskin.
Following that, the topskin, spar and ribs were again clecoed flat on the jig with the bottom skin straight portion clecoed on top of the structure as well. The bottom skin was then flexed over the tapered portion of the spar and sandbagged flat.
The bottom skin was then drilled to the remaining structure in sequence: First the ribs and straight portion of the spar, followed by the tapered portion of the spar and the curved trailing edge. All of this was accomplished while the structure was sandbagged flat on the jig.

A second jigging board was made up to allow the clecoed perimeter of the aileron structure to hang over the edge to allow access for riveting. Holes were also bored in that to allow the steel tabs attached to the ribs to poke thru keeping everything flat.

  Jul 06, 2023     Aileron Fabrication - Step one - (13.5 hours)       Category: Controls

So I'm running out of excuses to not build these ailerons. There are numerous ways to screw this up, including building a twist into what should essentially be a flat surface, trusting any dimension on the plans and/or losing track of the whole lefthand, righthand thing like building three left ailerons.

Step one, taper the spars. I bent up the spars with the intention of cutting a taper into them at the tips, then adding an angle along the bottom of the web to rivet the bottom skin to. Having mistakenly trusted the dimensions of the spar length, they're a bit short, even after cutting them long to begin with. See picture one below, the lines to the left of the trimmed spar show where the aileron tip will be relative to the spar. This required adding an extension, resulting in the "hockey stick" angle piece. This adds the lower flange, a couple more inches of spar web and an upper riveting flange to the extension.

Next up, locate and drill the ribs to the spar. Simple enough, but again, the plans dimensions accurate to three places beyond the decimal point might as well be lettered dimensions. Measure from the wing as-built to determine these. Once that's figured out, they can be located along the spar. Oh yeah, scribbled outside the lines again. Plans show the rib flanges notched where they intersect the spar flanges. I joggled them instead and will flush rivet them at that intersection. Should be stronger than eliminating the flange there.

Speaking of coloring outside the lines, the plans call for the spars to be made from 3003-H14, which is really soft stuff (that's what the windscreen frames are folded up from). I used 6061-T4, which is stiffer stuff, but I think it's probably okay.

With a spar and rib framework, time to introduce the skins. I laid the first skin onto the jig only to discover the edge formed a frowney face instead of laying straight along the jig (the opposite edge was a smiley face). I have to straighten the skin before I can lay a cutting template to it. They're about 6 feet long, and a 6 ft straightedge placed alongside showed it had about a 1/4" wow to it. Guess I'll have to cut it or grind it straight. So, how do I cut this stuff without screwing that up? While cogitating my circumstance and the extra steps to get a workable piece, I happened to shove on the high side of the curved edge and behold! It flexed!? With all the beads formed into it, the sheet is just a big spring and will flex around a bit as required... Duh! This could be useful information going forward keeping trailing edges aligned, etc.

So I shoved it straight, laid the cutting template on it and marked it for cutting.
I wound up using my Dremel Max circular saw with a carbide-toothed blade to do the rough cut out of the skin blank. Final trimming was done with a benchtop belt sander. Any edge cleanup can be done with 400 grit sandpaper at this point.

  May 02, 2023     Aileron jig construction - (8.0 hours)       Category: Controls

Returned to work on the ailerons. I have the skins, spars, hinges, ribs and steel arms to rivet to the ribs. Still to fabricate are the trailing edge pieces. Not specified in the plans are the details regarding the thickness and alloy of the trailing edge angles and it's extensions to the curved portions of the aileron trailing edges.
Accordingly, I decided to fab them from 0.050" 6061-T6 and eliminate the wood inserts specified. The angled 6061 should provide enough trailing edge stiffness without the wood inserts. The wood I think would only serve to increase weight behind the hinge line, possibly changing the flutter characteristics for the worse. I'm thinking lighter is better.

The order of assembly will be important to ensure the ailerons get assembled flat with no twist or improper curves.

I'm thinking first steps to assemble involve drilling rivet holes along the spar and top skin which is flat full length. So, I have fabbed a board which will accept the skin beads allowing the top skin to lay flat inverted while drilling the spar to the skin. Drilled and clecoed to the board, the bottom skin can be added after the ribs and trailing edges are inserted. The bottom skin gets curved as it follows the spar taper towards the tip.
Concerns going forward include keeping the top and bottom skins beads aligned with one another, particularly beyond the spar taper point.
The sweeping curve along the outboard trailing edge will also be a challenge. I have a template for the top of the aileron, but the bottom skin will need to matched to the topskin after it is flexed into position.
The final question mark I have is riveting the internal rib flanges to the top and bottom skins. I'm thinking best practice is to use blind rivets to avoid bucking inside the skins as I assemble the aireron. Cherry "N" rivets similar to the ones used to attach the turtledeck stringers should do it. I have 3/32" stainless N rivets with plenty of shear and tensile strength to do the job. I'll use protruding head rivets, but will add a step to fill the tops of them before painting.

  Jun 19, 2022     Aileron skin template - (1.5 hours)       Category: Controls

I continue to advance along a wide front. Which is another way of saying I got sick of doing what I was doing, or frustrated and needed to work on something else in the hopes that inspiration would strike in the meantime.
Anyway, this needed doing and the wings were down and accessible and as a plus, not many deep thoughts required to make a cardboard template.
Cut a chunk of cardboard with a long, straight edge and a right angle corner at one end. Stuffed the square corner into the aileron rib/spar intersection with the straight edge along the aileron spar. Blocked it in place with scrap wood, clamps and masking tape. I used three 1/8" ash strips leftover from the wingtip bows clamped in place to flex around the end to join the trailing edge line of the aileron. Flexed it to match the wingtip sweep and the aileron drawing... seems pretty close.
Of Note: 1) This template fits the lower right wing. (I stuck it up to the lower left wing and it's a pretty close fit there too) Uppers? TBD.
2.) This template matches the upper aileron skin, the bottom skins will be narrower (I think) so cutting from this will allow some wiggle room.
3.) Since I stuffed it into the corner of the spar/rib intersection, it's 1/4" too long in a perfect world. Nobody lives there, but don't build the aileron to this length. Make it fit the wing with a 1/4" gap at the inboard end.

  Apr 22, 2022     Printed knobs and placards - (7.5 hours)       Category: Controls

I needed knobs for the throttle quadrants I fabricated, but the ones I was looking for were out of stock and anything fitting certificated acft were stupid expensive.
Visiting my son and their new baby, he demo'd his new 3D printer and asked if there was anything I could use... well yes! We proceeded to design a set of knobs while he tutored me on the use of Fusion 360 CAD software. With no formal training on the use of CAD other than YouTube University, I pleasantly discovered Fusion 360 way easier to use than the Solidworks software. The result is a bespoke set of knobs.
We also produced a trim handle knob and a set of placards for the quadrants, elevator trim and fuel shutoff. I think I'll be looking for more projects to print going forward.
He schooled me that the plastic used in the printer is not UV resistant, and so needed paint/coating to protect. A coat of rattle-can red or black and all is well. Added contrast to the lettering that was printed into the parts after they were painted. Squeezed some white bathroom tub/tile adhesive caulk onto the lettering with my fingers and wiped off the excess with a wet rag. The stuff shrinks a bit when it dries so it gives a nice concave look to the letters...

  Mar 18, 2022     Aileron Ribs - (11.5 hours)       Category: Controls

After consulting the drawings, made a rib template approximating same. After checking the template's fit to the already-constructed wings, made a couple small adjustments. Next up, cut two hard maple forming blocks to the template size (less .032" bend thickness per edge) and routed 1/8" radius edges on the one block. Sheared the .032" aluminum required into rib blanks, drilled 3/16" dia corner holes where the flange bends will end. A pair of tooling holes were match-drilled from the forming blocks to all the ribs.
I think I counted right. Four end ribs (one for each aileron), six internal ribs (one each for the upper and two each for the lowers). Flange bend direction will be critical for assembly unless I go with blind fasteners. As such, conventional riveting will require some access as the aileron is closed up. TBD.

Oh yeah, I forgot to take a picture of them individually, but the throttle quadrant interconnect pushrods are welded up and powdercoated. They're visible at the top of each picture below. Rigid links connect the two quadrants, then flexible cables connect to the forward quadrant into the engine compartment.

  Sep 17, 2021     Rudder trim Tab - (10.3 hours)       Category: Controls

Decided a rudder trim tab would be a good idea, so chopped a notch in the rudder to accept a ground-adjustable trim tab. Fabbed the tab from leftover aileron spar spruce. Tapered same, then laminated 1/16" birch ply on the outside for added strength and stability. Epoxy varnished and added a piano hinge at the leading edge. The piano hinge will be riveted to the rudder structure post covering.
At the bottom of the tab, a metal tab will be screwed to the tab and a single screw will lock the tab in position on the rudder trailing edge. Fabbed multiple adjusting tabs which will individually adjust the tab in 5 degree increments up to 25 degrees. Test-flying will determine which tab functions best.

  Jul 09, 2021     Throttle quadrants fabrication - (19.5 hours)       Category: Controls

Decided to fabricate the throttle quadrants as they seem to be a better fit than what I've seen commercially available.... and of course way cheaper. Traced the shapes off the full size drawings and glued to 1/4" Masonite, then trimmed away everything that didn't look like the part resulting in a pattern jig the router could follow. I rough-cut the parts with the bandsaw and sabre saw, drilled the template and parts 3/16" to accept -6 (3/16') rivets and stuck them together. A few minutes at the router table for each piece and I had a bunch of quadrant parts.
A note about router safety: I used a foam rubber grout float (pictured) to hold the small bits securely while routing them. Its squishy foam surface grips well and importantly, keeps your digits well clear that bit.
Routing the Internal openings also has it's challenges. It can be less than intuitive which way the work should be moved through the cutter (hence the arrows drawn on the table insert noting cutter rotation) when working in the opening. Take a moment to ensure the cutting edge cuts against the direction of travel of the workpiece, not with it. When approaching an internal corner go slowly, maybe try to trim some off the edge opposite the corner you are approaching. When the bit starts cutting on opposite sides, as it does when plunged into an internal corner, it can get jumpy especially the more material it has to cut, requiring firm control of the workpiece.
The outer plates are fabbed from 1/8" aluminum plate using the same template but cut on the bandsaw and edges smoothed as a single unit. They were then powder coated and match-reamed with the nylon spacers and the rest of the assemblies.
The control levers were also cut out of 1/8" plate on the bandsaw, drilled on the drill press, then slots cut with the angle die grinder using a cutoff wheel. After smoothing them, the innermost and outermost levers were bent at the bottoms per the plans to allow the AN665 connectors room to move past one another. Then polished and began assembly. The lever knobs are out of stock at ACS, may have to shop around a bit more, or turn some of my own on the neighbor's lathe... TBD. Depending on lever knob design, the levers may need some bending on top as well to allow things to pass by one another.
Also fabbed interconnecting rods between the quadrants. AN3 bolts were welded into 5/16" steel tubes, AN665 clevis' were threaded onto the welded bolt ends and the whole works powder coated.

  Sep 12, 2020     Trim Systems - (8.5 hours)       Category: Controls

Fabbed elevator trim handle and mount, installed same. At the recommendation of Chris Bobka, later added a friction disk to the elevator trim handle. It's a pair of 1-1/2" steel disks sandwiching a leather disk. One steel disk is welded to the handle and the other is welded to the outboard support bracket. A knurled knob will allow adjustable compression (drag) on the disk.
Angled weldment with the nutplate installed on longeron aft of the handle is not in the plans. This is used to anchor the trim cable sheath. An adel clamp will bolt into the installed nutplate to anchor it, allowing the trim cable to function.
Thinking of how to install a rudder trim tab. Two flying Hatz's on the field each without a trim tab and both require constant right rudder inflight. Think I'm going to need one, but would rather it looked more intentional than a scabbed-on afterthought. Observed some older Wacos rudder trim tabs and they seemed to be built into the trailing edge of the rudder much like the elevator tab. Think I'll try this, in the photo, the cardboard mockup is about 5-1/2" X 7-1/2". Using the TLAR analysis and because that's the size of scrap cardboard I had available at the time, I taped it in place. It's probably ok. Upon further review, it will be ground-adjustable (And likely left fixed in position following Phase I testing). First prototype will be wood (ultimately fabric-covered) and attached with a section of piano hinge, as it will only need to displace to the left. How to adjust and fix the tab in a particular displaced position remains a question. Caulk would work (and paint it to match) but I'm thinking a control arm on the tab with a rod that goes into the rudder would look more like the real deal. That rod could be made adjustable by cutting threads on the end inside the rudder and welding a floating nutplate to the adjacent internal rib. Then, adjustment would be accomplished by disconnecting the rod at the tab arm, screwing it further into or out of the nutplate, then reconnecting the rod to the tab arm. Voila! Ground adjustable tab, even after fabric covering.

  Jun 08, 2020     Rudder pedals - (13.5 hours)       Category: Controls

Fabbed up rudder pedal bits. Used the old seat frame jig to now jig up the pedals. Once I determined the proper length, ordered pre-fabbed rudder cables with swaged end fittings from Aircraft Spruce. Fabbed a connector link to allow rear pedal adjustment fore-aft + or - 1" from center. Shamelessly copied John Hanson's rudder return spring design, adding a tab to the forward pedals and an anchor for the springs under the floorboards attached to the longerons.
Last four photos show rudder control arm attachment sequence. Rudder is positioned 30 degrees right of centerline and the right control arm is clamped to the tailpost weldment which also serves as the rudder travel limiter. The control arm is then tacked in place to the rudder spar. The rudder is then positioned 30 degrees left of centerline and the process is repeated. Once tacked in place, the rudder is removed to the bench for finish welding.

  May 29, 2020     Elevator pushrods - (14.5 hours)       Category: Controls

Began fabricating the elevator pushrods from the aft torque tube fitting to the elevator bellcranks. Fuselage idler between the two was completed awhile back. The aft pushrod gets threaded fittings for rod end bearings at each end, the forward pushrod gets the same where it meets the torque tube, but where it meets the idler is busier. The threaded fittings slip into the tube ends which have three holes drilled for rosette welds, then in a bit of belt-and-suspenders the threaded fittings will be edge welded to the tube ends as well. The aft end of the forward tube is a round peg in a square hole problem. In order to accept two rod end bearings there it requires the square tubing. First step I drilled and welded in the bushing stock to the square tube. Next, I trimmed the outer length of the bushings, cut the tube to length and cut out wedges to allow the square tube to accept the round tube of the same dimension. I also cut four slots in the end of the round tube to allow a better fit. After tacking the two together, heated and formed the square tube "fingers" to the round and finish welded.
Elevator bellcrank arms are located by blocking the elevators together and at a 30 degree nose up (up elevator) position. Arms were then spaced apart using stacks of washers and bolted to one another. Further they were clocked on the elevator spars to a position off the horiz stab rear spar approx 1/16" and tacked. Once the up-limit was established, the elevators were relocated to approx 20 degrees down and the location for the down-limit stop was determined and welded in place.

  May 09, 2020     Torque tube bits - (23.5 hours)       Category: Controls

Formed torque tube ends from 0.050" sheet heated, tacked and formed over 1-1/2" scrap tube. Tube retention rings cut from 0.065" sheet using hole saws in the drill press. So, I naturally assumed a 1-1/2" hole saw would produce a 1-1/2" hole in my steel sheet using the drill press. Did you notice the operative word there? Assumed. Me neither. Didn't enter the ol wheelhouse. Turns out that sweet Milwaukee 1-1/2" bimetal baby reliably makes a hole of 1.537". Who knew? A smart guy would have maybe made a test hole or two, dressed the saw teeth a bit, or maybe asked his buddy with a lathe to turn a couple of tighter-fitting rings. I did none of the above, got out the magnets and some 0.020" safety wire to space the sloppy fitting rings around the 1-1/2" torque tube (which is 1-1/2") and tacked them in place. Of course Mr. Murphy was still right there as I got them evenly spaced around the torque tube for some sloppy 0.020" gap welds. They are also parallel and 3/4" apart to accept the 3/4" UHMW bearing blocks. With all the aforementioned jacking around, I neglected to ensure they were PERPENDICULAR to the torque tube axis, which they of course are not. I now had swash plates which nicely flexed the forward bearing block every time any aileron input rotates the torque tube, not to mention excessive drag in the aileron control. Sheesh! Took a lot longer than I wished to un____ this issue. Shaved some off the bearing block, lots o selective application of brute force and the plates now minimally flex the block within +/- 30 degrees of aileron stick input. Green Warco bender makes simple work of making precise bends in thick materials. I recommend it. Especially if you can get a friend to loan you his like I did. Has interchangeable bend radius blocks which bolt in place to clamp the workpiece securely. Securely bolted to the benchtop, bending 0.090" bits like the tailpost rudder stop was a non-event.
Last picture shows a 1/4-28 steel nut welded to the aft stick support end of the torque tube. This accepts an AN4 bolt and check nut which will act as an up-elevator stop limit. The bolt will be adjusted upon assembly to contact the base of the aft cockpit stick at full aft stick. (approx. 30 degrees up elevator)

  May 09, 2020     Aileron control arm - (6.5 hours)       Category: Controls

It took most of the day but here it is. According to the drawings and within reasonable building tolerances, it's 0.090" thick and 3.179" from the torque tube centerline to the center of the bolt hole attaching the aileron pushtube rod ends.

  May 06, 2020     Torque tube mounts - (11.0 hours)       Category: Controls

The torque tube mounts were installed per the dimensions on the plans. The torque tube is not parallel to the longerons. it sits at a slight nose-down angle. Dunno why, maybe because the cockpit floor steps down in the forward cockpit. Also simply accepting the plans dimensions has caused issues elsewhere, but I haven't heard/read any complaints in this area so I went with them. White bearing blocks are UHMW plastic bored to accept the 1-1/2" torque tube. The mounts were quickly tacked (while jigged with mount blocks in place) to avoid putting too much heat into the assemblies. Blocks were removed for finish welding.

  Aug 07, 2019     Aileron spars - (5.0 hours)       Category: Controls

Cut up flat stock to form aileron spars. Had access to Chris Bobka's ancient 10-ft bending brake and matching shear. These things date before the Great War I think, shoulda taken pictures... It's all manual operation, built like a steam locomotive, thankfully counterweighted where it matters but you could put eight or nine of your friends on the enormous pedal of the shear.
Made six spar blanks... should only need four if I don't screw anything up. Hope they're enough.
I ordered aileron skins from an old fellow in Wisconsin who has dies for these corrugated skins and sells them. They're beautiful stuff. The plans call for the same profile corrugations in these skins as Waco Aircraft put on their ailerons. Matter of fact, I talked with the folks at Rare Aircraft who rebuild classic Wacos and he produces these skins for them as well.
Some builders have made a press to form these skins but it is challenging to get the proper profile consistently in the individual beads and keeping a uniform pitch between the individual beads adds to the entertainment. Without that, you risk fabricating the ailerons without the top and bottom skins corrugations lining up. Of course, there is an angular concern as well to ensure the skin is formed with the beads also perpendicular to the length of the skin. It looks pretty fiddly to develop a press to accomplish this without several iterations and producing lots of scrap metal. I decided to cut my losses up front and just order some up.

  Sep 29, 2018     Aileron linkage Construction - (22.5 hours)       Category: Controls

From the torque tube to the individual lower ailerons there are a total of three pushrods, an inner and outer which are both internal to the lower wings and a short aileron pushrod that hangs below the lower wing. The system also includes an idler and a bellcrank. From the lower ailerons to the upper ailerons there is another push rod (a jury strut). Began construction of this system with the bellcranks (very important to fab a left and a right...) out of 3/4 X1-1/2 rectangular steel tube and bushing material. Powdercoating and fitup to the wing structure included rod end bearing from the outboard pushrod and inserted bronze bearings for the bolt holding the bellcrank to it's bracket. The idler as designed is a 3/4" square steel tube with more bronze bearings for the center pivot bolt. Instead of more bronze bearings, I opted to install proper bellcrank bearings (steel ball bearings) which I hope to be smoother operating and offer lower breakout forces in the system. Fiddled around with different cardboard mockups of angled idler arms in an effort to "improve" differential aileron action. Finally realized the as-designed straight idler is just fine and differential action is accomplished by "clocking" the bellcrank arm neutral point. Duh! Appropriated the now aluminum and ball bearing idler engineering from Van's RV aileron bellcrank design... Simple, strong and probably lighter than the steel/bronze idler design. Pushrods get threaded plugs welded into the ends to accept 5/16" threaded male rod ends and powdercoating. Inboard pushrods will wait until fuselage-wing mating assembly occurs to get the right dimensions to fit the aileron control arm on the cockpit torque tube. There is a potential interference issue as the inboard pushrod exits the wing and enters the fuse. With a 3/4" pushrod there is only 3/8" additional vertical clearance between the lower fuse longeron and the #1 wing compression tube. At neutral, the aileron control arm is at it's lowest point and at 30 degrees left and right, the arm bolt hole travels vertically that 3/8". Any further or misalignment will result in contact with the compression tubes. Will sort this out later. Of note, inspecting a hangar neighbors Hatz Classic, his inboard aileron pushrods are 5/8" dia steel. His is an early "kit" welded and produced by Makelan. There is no specific dimensioning of this part except to measure the diameter from the scaled drawing and the difference between 3/4 and 5/8 is about the thickness of one of the drawn lines. He had a squeak in his ailerons we were looking for at the time. Narrowed it down to those 5/8" inboard pushrods rubbing now metal on metal on the lower fuse longerons.