Fuselage top skin fit up, starting on rudder fittings and engine re-work quote (aka what is the price of your dreams?)
Another productive day in the shop yesterday. Continuing my work on the fuselage, soon to be taken apart again for debur, prime, reassembly then final rivets. I have some plumbing of wire to do from the front cabin are to the tail section and I've got fit up the rear cabin windows before I close everything up.
Like the bottom fuselage skin, the top skin tapers towards the rear. The large hole in this picture still needs to be flanged, but it is the passthrough for the upper elevator control cable. The hole is covered by the horizontal tail assembly and fairings once the are mounted.
Finished trimming the front upper edge of the top skin at the longeron corners and trimmed the skin across the blue line. With this properly fit, the forward end of the longeron can now be drilled and clecoed. Eventually the rear edge of the cabin skylight window will attach to this front skin edge.
Reaching the top of the cabin was tricky, but there is actually just enough room to stand on the workbench to drill, trim and debur holes and edges.
I've bought a 90 degree aircraft air drill which I will use to back drill the wing mounting plates at the top corners of the rear cabin, just waiting for it to arrive this week. I'll post pictures when I get it, but think of the shape of a large dentist drill and you'll be close. For now I'm holding the wing plates in place with C clamps to check fit as I square up the cabin.
The fuselage currently sits on the bench in a tipped back position, so I needed a way to extend the centreline of the top of the fuselage in order to plumb bob that centre relative to the bottom of the fuselage. I cleco clamped a strip of 093 aluminum extended forwards along the top centreline and strung a plumb bob weight downwards:
I know the fuselage cabin is slightly out of square (leaning very slightly to the pilot side without the other cabin structure in place yet). To adjust the square of the cabin, I borrowed one of Ron's turnbuckles and strung it passenger bottom corner to pilot top corner of the cabin. Tightening the turnbuckle pulls the cabin square. It didn't take much to bring it into line, maybe two or three turns.
For the plumb bob, I used the pipe reaming tool head. It is heavy enough to quickly dampen any swaying of the plumb bob line, but not so heavy as to pull down on the fuselage cabin roof. As added bonuses the reamer can be tied and centred on the plumb line easily AND it has a pointy end for really accurate line up with the centre line of the lower cabin skin.
Here is the original square of the cabin - surprisingly close considering nothing else of the cabin structure is connected yet:
After a couple of turns of the turnbuckle:
Obviously string and turnbuckles won't be what holds it all officially square, I'll bolster it more externally when the time comes to tighten things up. But this gets it in position to measure the cockpit side walls and floor and where it attaches.
Also with the cabin squared up, I finished drilling the top skin to the upper longerons from cabin back to tail. I found it helpful to use a ratchet strap lightly around the fuselage to pull the longerons inwards to line up with the skin edges as I work towards the tail. It's this tension that gives the fuselage it's rigidity once riveted.
Every 3rd rivet hole on the top longerons drilled to A3. Next will all the holes aft of the baggage area up to A4. The picture below really captures how tapered the fuselage actually is. The tail is clamped for now to ensure the longerons maintain their taper curve until I figure out order of operations for the balance of the rivet holes and the bolts that hold the fuselage side rudder attachment plates. The longerons need to be trimmed to match the side skins. The small hole just in front of the clamp is the front edge of a passage slot for the lower elevator cable that runs between the hole and the tail end of the top skin hold for the lower elevator cable. It will be slotted soon:
Super stoked to see the fuselage coming together and that it is almost perfectly square as it sits!
Rough placement of the upper rudder hinge plate - this was one of my earliest pieces I cut from 0.125 aluminum plate using the early cardstock templates. I know I'm on the right track as it fits exactly where it should on the tail:
All four of these longeron ends get trimmed to match the side skins:
A look inside the tail looking forward through the tail bulkheads. This large area gets covered by an aluminum fairing that is attached to the rudder and pivots inside this spot:
I marked where the top, side and bottom skins ends meet the longerons, marked them for trimming then peeled back the skins a bit to facilitate trimming with the Dremel (just like the front ones):
Looks like the top skin is a bit short? It matches at the front edge correctly, so I know that is right, so what's going on here.
I remeasured the entire length of side and bottom skins and they are in correct relative position too. But once I remeasured the top skin, I seems I cut the tail end 10mm too short! Everything else on the top skin including the cross members, the upper doublers, the passage holes - all correct. Thankfully this 10mm shortage has no impact on the function of the tail or the rudder attachment structure. It would have much worse at the front end where the main spar channels are or if I'd cut the longerons too short. Still not sure where I made the mistake, but glad it didn't require replacing the entire top skin, that would have been a major set-back (and expensive!)
As more of this enormous project comes together, more intersections of items to complete start to cross on my list of things to do.
Back in September 2018, I travelled to Mexico Missouri for the Zenith factory Open House Weekend (full 6 part blog story about my trip)
One of the prime reasons to travel all that way was to meet with other builders, get some airframe parts that I couldn't fabricate/bend myself direct from the factory and most importantly have some of my Corvair motor parts assessed by the Corvair aircraft engine authority William Wynne who was also in attendance that weekend (he hasn't missed one since they've been doing them)
William had a look at my cores and offered to take them to his shop in Florida for re-work and at the time my plan was to start that process in parallel with my build. Of course that didn't happen for a number of reasons, cost being one of the them.
Fast forward to last week when I contacted them to inquire of my cores were still available in their warehouse as now I was ready to proceed with the work - four + years of them holding them for me was a lot to ask. Thankfully despite my tardiness in getting them moving through their processes, my cores were in fact still available and sitting in storage awaiting my decision.
I received a quote last week for the required work and in discussion via phone with William I now have a solid plan to get the engine work rolling. It's expensive work, but the value in having the recognized expert and his associates do the required work is great value in having a solid engine to fly behind.
Work includes deep cleaning the cylinder heads and piston chambers, new valves, new valve seats, exhaust value rotators and welding on intake pipes. The engine case I sent unfortunately doesn't make the cut and requires too much work to make it viable, so I'll need to replace that with another core (they are easy to obtain). The core crankshaft I had was too rusty to be ground, so they will supply the core which will heat treated (nitride process), stress relieved, the journals be ground/radiused, bearing surfaces polished, new crank gear welded on and the crank will threaded for the propeller hub safety shaft. When that is done, a 5th bearing is added to the crank, ground concentric and shipped back to me with a 5th bearing housing.
All this work is being done by experts and gets me past the half way point of having a ready to bolt on engine. Again well worth it.
William is a great writer. He often reminds people that none of this is possible if you aren't in the arena. I am in the arena and I continue to participate. It can be an expensive undertaking, but ask yourself honestly if you can put a price on your dreams what would it be?
It has been almost a month since my last blog post, but work continued on the slats over that time. No real need to blog about it as the process was the same for all four with the exception that the outboard slats were slightly longer externally. The internal skeleton and assembly steps were the same.
A pciture of the last slat on the bench awaiting trailing edge bend before debur, prime and rivet.
Also in the last couple of weeks I played a bit more with the 3D printer. It seems I've run into an issue with the filament jamming in the extruder. Very frustrating stepping away to do other things while the printer works on something, just to come back and find nothing coming from the nozzle!
I took the extruder apart and it was clear it wasn't feeding correctly as evidenced by the "knot" of melted filament between the extruder and the hot end.
I spoke to a work colleague who is very invested in 3D printing as a side business and showed him some pictures. There are two things that most commonly cause this are a gap between the hot end feeder tube and the extruder, or worn extruder parts. As the extruder parts are 3D parts themselves from the manufacturer, his suggestion was to spend some money to upgrade to an all metal extruder and hot-end.
Looking further into this, I decided to not to proceed any further with using this printer. The printer is not mine (it belongs to the local library) and I'm not quite ready to invest the time or money to upgrade something that is already esentially obsolete. I still plan on printing parts for the airplane eventually, but this printer is has become a bit of a distraction from the airplane itself. Also, newer model printers are getting cheaper by the minute and easier to use with built in functionality that makes printing exactly what I need more sense, so I'll look at investing in one of my own eventually. I've accomplished what I set out to do - proof of concept and making it functional again for the library. 3D scanning is also functionally feasible, but it too needs more time to getting it working the way I want it so it too will be shelved for the meantime.
A question came up from another builder on the forum on how I've managed to bend the trailing edges so cleanly. The entire procedure of assembling the slats can be seen on a previous blog post but for the sake of explanation, I used a small diameter rod along the inside of the fold held in place with some spacers Ron and I came up with. The are scrap strips of 0.016 aluminum with a a small curled up end.
I used wide painters tape to hold the strips in place, the curl of the strip against the rod. The picture make sit look like the curl is taller than the rod, but it is not. If it were, it would leave a mark on the inside of the skin so caution is warranted here
Strips and tape are cheap, good to have several across the entire width of the slat skin:
The inboard slats (the shorter ones) eventually tuck inside the outboard slat enough to be riveted together once they are mounted on the wings. Here they are back to back and upside down on the bench lined up but not yet tucked together - this really gives the idea how long and wide the wings will be!
Looking at my "completed sections" drawing, I'm pleased to be "mostly done" the control surfaces.....
.... and happy to see an empty bench, even for a few minutes! Now to begin one of the bigger sections both in size and number of parts - the WINGS!
I brought a fresh roll of 0.032 (on the bench) and 0.042 (coiled beside the bench) down from the storage barn, to start laying out the components for the wings. Like everything else, I want all the parts made and ready to use in assembly to minimize the time on the bench.
First up, the wing spar webs from 0.032. The two spar webs are almost a full length section of a sheet and requires accurate cutting so the spar assembly is straight and true. They make up the centre part of the spar between to 6061-T6 angles on the top and bottom (more on later).
I cut the first web using a plunge saw with metal cutting wheel and it turned out fairly decently. The saw isn't as accurate or clean cutting as I would like leaving me some extra work with a hand file to clean up the cut edge by hand before deburring and sanding smooth. With a bit of work, it eventually cleaned up nice and straight. I cut the second spar web by hand using the large hand shears - it took longer to cut, but I found that if I was careful I could be more accurate cutting by hand and it took a lot less time to debur and clean up the cut. I used each side of the factory edges of the sheet to be and edge for each spar web giving me a perfect factory edge to measure from..
With the spar webs cut to size, I measured and cut out the tapers at the inboard ends of the spars where they will meet the wing (the bottom of the spar web faces the ruler in the picture below)
The thickness of the 0.032 and 0.040 sheet make them awkward to roll/unroll, so it makes sense to cut the other pieces out while the sheet is on the bench.
In the picture below you can see the remaining 0.032 sheet after cutting out the spar webs (coiled at top of picture), the spar root doublers (bottom of picture) and the four rear spar channel blanks (middle of picture). The two thinner strips on the right at 0.040 blanks that will be bent into angles as inboard rear channel doublers.
The 0.032 rear spar channels and the 0.040 doublers are too long to bend at our shop, so I've taken them to the same shop who bent the flapperon spars for me previously. I'll get them back this week.
I also needed to cut out the left and right 0.063 strut support brackets (bottom right in photo below). So while I had the sheet on the bench I also cut out some of the other 0.063 parts for the fuselage - the fuselage parts will be put into storage until I need them, but at least they are done. I ran out of space on the 0.063 sheet I had to layout/cut the spar web doublers, so I'll have to get some more from storage to get these done.
So despite no blog updates, I have been working away. Control surfaces are "done" and work on the wings is underway. Looking at the completed parts picture I posted above I'm very pleased how far I've come since starting. I'm not sure I can put a concrete answer on how much I've got done, but of the approximately 275 aluminum parts to make, I've got about 145 done which is very roughly 53%. Understand that's just parts made, not bent, assembled, drilled, debured, primed, riveted.
As always, thanks for following along.
After a much too long break from working on the airplane, I'm back at it again. Not much has happened over the last couple of months in the shop. Returning to shift work has been harder to adjust to than I anticipated. Add to that the passing of my Mom, Linda in October and all the things to process both emotional and tangible - it's been tough to concentrate on anything else.
Mom was always one of the biggest champions of my dreams, including flying. She was my first passenger when I got my licence in 1995. I told the story of that day at Mom's Celebration of Life as it was one of my favourite memories of many during times I spent with her.
We went flying on a beautiful early spring day in a Cessna 150. Typical first passenger type of flight, showing off my newly minted licence by taking a tour of local sights from above. It was beautiful.
Mom always appreciated a good joke. When we were turning base from downwind, I pretended to look around the cabin like I'd lost something. Of course, Mom asked what I was looking for, to which I quipped "There should be a landing checklist in here somewhere, I might have forgot to bring it".
The look on Mom's face was priceless as she went from surprise, to fear to sly recognition that her oldest son was just trying to pull a fast one. Fast transition! She punched me in the arm and reminded me that landing checklists are important and I should have it memorized. I'm not sure she ever truly forgave me, but she probably did. She was that kind of person; kind, forgiving and loving. I miss her very much.
I also know she wouldn't want me to delay getting my plane built, even if she never got the chance to see it or fly in it. So this week I got back at it.
Work continues on the elevator and horizontal stab. There are lots of little things to complete, but it's coming along nicely. In order to mate them up, I had to finish adding the fences on the stab. Here they are lined up where they will be fastened on the stab. To ensure that both ends are exactly the same, I taped them together and dry fit them, marking out the rivet lines:
Quick fit check on the other end, before drilling A3 pilot holes through both
Pilot holes drilled then clecos to hold it in place to confirm measurements are correct and fence is equal all around the stab aerofoil:
The fence is 063 thick, same as the original outer hinge plates which are attached at the trailing end with A5 rivets, so I'm doing the same here (where the black clecos are). The A5 holes are already in the tip rib, so I used the rivet hole duplicator to match drill them on the fence. The balance will be A4 rivets. This combination will only improve the strength of the whole assembly.
Happy how the fence cleans up the whole end of the stab:
I flipped the stab over to make getting at the A5 holes easier
Once flipped, I noticed how tight the fence is to the tip rib skin rivets. I made a note to remind me to river the skin first!
With both fences attached, the stab looks real good!
With the stab fences in place, now I could place the elevator in line and see how they line up:
Even without the elevator nose skins on, I was real pleasing to see them "together" for the first time. Have lots to do yet, but it feels good to see the sum of the parts looking close to what they will be once done.
Also important was seeing that the measurements of the centre hinge is correct! It's a tight fit tolerance but I nailed the measurements perfectly! (Picture is not very clear, sorry. Just noticed the camera focused on an errant rivet stem)
I placed the elevator horns temporarily in place to confirm the alignment - all looks good.
BINGO! Correct spacing for the hinge bolt and bushing. So satisfying to know everything is correct!
Next I decided to take care of the elevator cable pass-through hole. It starts with drawing a centreline on the leading edge of the stab and a measured horizontal where the cable guard angle will be riveted on. Thank goodness for flexible rulers!
Sketch out the lines where the slot will be and draw the circles that make up the ends of the slot:
Pilot hole to prevent tearing of the aluminum - that would really suck!
A small step drill bit used carefully does a great job. With both holes done, simple straight cuts from edge to edge on the new circles to open up the slot.
The leading edge of the stab has a slight curvature to it where the cable guard mounts. So once I had the guard angle bent, I rounded it out a bit to match. This will be primed before riveting to the stab:
Not a bad prodcuctive couple of hours. Like I said above, it's nice to see the sum of all the little parts I've done and it's motivating me to get back in the shop.
Next up, nose skins and tackling the trim tab. I've managed to write some good code for the trim tab Arduino computer that will control the servo.
Thanks Mom and thanks to my wife Brenda for getting me moving in the right direction again :)
July was a washout with regards to getting anything done in the shop, so not much available content for the blog....
A home project to replace the shingled roof on our house with metal took up 2 weeks of my July holidays and work travels took up a good portion of the rest of the month. Day trips with family need to happen too. This Monday to Friday temporary assignment I'm currently doing at work is good that the work is both challenging and really interesting, but it only leaves weekends to enjoy the summer. As of last week, I've been advised that I'll be returning to shift work at the end of September. I don't want to go back to the communications centre, but on the bright side, my schedule during the week gets freed up substantially (4 days off every week), allowing me more shop time.
Speaking of work travels, I had a chance to check out the Chapleau Ontario airport. Although there wasn't much to see (MNR fire base was quiet), I did notice this cool sign posted by the local flying club:
July and the beginning of August hasn't been a total loss I suppose. I did manage to get some work done on the elevator and horizontal stab.
When I fastened the skin to the stab skeleton, I marked out where I needed to trim the trailing edge. The extra was on purpose - it allowed for proper length and square fit. Now that fitting is complete and correct, I can trim it back:
With the trimming done, the rear slot is cut. This is where the elevator cables pass through the stab:
I notched back the spar doubler a small bit, leaving clearance for the rivet. Everything was deburred, cleaned up and primed after this photo was taken. Fortunately only had two places where this was an issue.
With the stab skeleton ready, I deburred the stab skin holes on inside and outside - there are a ton!
Cortec primer on the rivet lines was next. I really like how it applies - next to no smell, easy clean up and cures almost clear:
With the primer curing, I turned my attention to the elevator skeleton. Some final measurements to ensure it's built square and it is ready to taken apart again for final debur and prime.
The elevator skins are made of 016 aluminum sheet, folded at the trailing edge and fastened to the top and bottom of the spar. It consists of two sheets of equal length meeting a the centre:
To allow the rudder to move left and right, the skins are cut out at the centre box where the rudder hinges are. It's difficult to perceive in this picture, but once folded the cut out makes sense.
It's important to radius the corners of the cutout, so I started with a centre punch then a pilot hole and followed that up with a 3/8 drill hole.
Cut outs complete for the left elevator skin. Easier to see how this will look when folded. Round file and debur tool to clean things up. This is a exposed edge, so I final sanded it with 360 grit:
Careful use of the bending brake got the fold most of the way, then I used a small diameter aluminum rod to finish the fold to the 5 degree bend called for in the plans:
I used the same piece of pipe to curve the elevator nose skins that I had used for the horizontal stab - much easier this time.
By this point the primer has cured on the elevator skeleton. Re-assemble and check for square - all good to final rivet. I'll wait to final rivet the tip ribs once the skins are on and I can align the elevator and stab hinges:
With the prime cured on the stab skin, it is reinstalled for final riveting. I've decided to river the curved side (lower) and leave the flat side open for inspection. It's kind of weird order - first place the skin over the spar pick ups and cleco everything down tight:
Flip everything over and cleco down the flat (upper) side:
Flip it back over and complete the riveting on the curved (lower side). Really happy how everything is coming together and how straight everything looks :)
The stab is essentially complete at this point. Remaining items to be done are final rivet the hinge assembly (waiting elevator match up), cable pass-through slot in leading edge and fairleads (rub strips). I've also decided to add wing fences to the stab tips which have valuable aerodynamic benefits and really cleans everything up. More on the fences later.
Next up, get the elevator skins fitted up, then cut the trailing edge for the trim tab and install the servo.
Thanks for following along, more to come soon!
I'm finding it more and more difficult to keep my blog up to date - I've accomplished much in the last few weeks. A lot of it has been routine fitting, drilling, cleco stuff so I haven't been taking many pictures. There are a few updates to share though.
With the one side partly secured with clecos, I moved the stab to the other bench. A large square steel tube was placed on the top to gently bend the skin partially into position before we tightened the ratchet straps to pull the skin down tight around the nose and upper surface.
Long strips of wood help spread the strap loads across the length allowing for fine adjustment. You have to be real careful here, too tight and the skin can collapse at the nose, leading to damaging kinks.
With the fit confirmed, I made a few reference marks, then it all comes apart and I can start the process of measuring the skin for holes. This is the only way to make sure the skin rivets are centered on the ribs as I don't have the luxury of pre-drilled skins.
Measure twice and then twice again, using the stab skeleton as a reference.
Again, I don't have any photos of the assembly, but the process is the same as above - weigh down the skin with the metal tube, use the straps to draw the skin down tight. The only thing that's different this time is drilling through the skin holes and into the structure below. I worked from the nose back to the rear edge (right to left in the photo) and from centre section out to the tips. Each hole gets a cleco until the rear most holes, ensuring a tight and bubble free fit.
Spar lines front and rear are drawn and rivet holes drilled. These don't have to be done with the skin off as the spar is a straight line and on this side the spar isn't pre-drilled. Again, measure 3 times - it's important the spar holes are centred on the spar flange:
I'm happy with how this turned out. Next step was using the template I made earlier to start laying out the slots for the horizontal stab brackets
This cutting is very delicate. The skin needs to be trimmed to be flush with the spar so the brackets sit flat and vertical against the spar. Cutting the skin is fairly easy, but any damage to the spar will be fatal!
I traced out the approximate location of the slots using the template and confirming with the plans started a pilot hole
I used a Dremel tool and rotary burl bit to slowly expand the hole enough so i could see where the rivet holes in the spar for the bracket are:
With a confirmed visual and measured slot location, I redrew the hole on the skin and slowly used the burr and some gentle hand filing to get it to the correct shape and location, ever mindful not to cut or mark the spar. Round files make a perfect corner:
Eventually with patience, the stab bracket fits nice and straight in the hole and perfectly vertical and flush with the spar underneath (it's sitting a little low inside the stab here as I couldn't hold it and take a photo at the same time!)
With that experience, the second slot went well too. I cleaned up the ragged edges a bit using a Dremel sanding/cutoff disc. The slots still have to be deburred properly, but that will come when the skin is off for full deburring:
On another note, Dad and I travelled to St. Hubert airport outisde of Montreal to attend the first flight of a C47/DC3 know as C-FDTD. We've been following the epic journey of Mikey McBryan (of Ice Pilots fame) and his Plane Savers team as they restore to flight a WW2 D-day survivor - a DC3 that dropped paratroopers over Normandy on D-day and during operation Market Garden, and that was sitting derelict, falling victim to vandals and the passage of time being slowly destroyed by neglect.
Here are a few personal pics of that trip - motivational for sure! For a full experience and to see what an amazing accomplishment this is, checkout www.planesavers.ca - of particular interest, watch the YouTube segments from the beginning - awesome and well worth your time!
Here is a copy of the flyer they were handing out to guests:
What an honour to be there and share this with Dad and the thousands of others who followed the restoration was unbelievably amazing..... what a great feeling watching it take to the sky again! All I could think about were are brave young countrymen that participated in the D-Day invasion exactly 75 years prior - God bless them and thank you for our freedoms!
I was so happy to share this adventure with Dad. As I post this blog on Father's Day, I'm reminded how much influence Dad has had on my life, particularly a love for aviation history. Thanks Dad!
While in the Montreal area, I also picked up a left/right set of fibreglass wingtips for my 750. These retail for $160USD a piece and I grabbed this uncut pair for $100CAD. Steal!
So, it's been a productive couple of weeks. Next up, I'll finish the stab skin, get the stab brackets installed permanently and proceed to skin the elevator. Once I have it skinned, I begin the process to line them up together and drill the mount holes for the hinge points.
Thanks for reading, more to come :)
It's finally "done", the 701 wing repair/extension was completed a couple of nghts ago, but I'm just getting to the blog now. Here's a quick update of what happened Thursday night to finish it off.
Off the table and to be prepped for storage. Ron and I will add some plastic sheeting wrap over the ends to keep any birds out while it's stored in the barn.
I'm so glad to be done this repair/extension, but I can't deny how much I've learned. Now the table is clear and I can focus can be on building my 750!
Stay tuned more to come!
Once again, I find myself disappointed that I haven't been keeping my blog up to date. Almost a month has gone by - if you've been following along, thanks for staying with me.
The last couple of weeks have been busy in the shop, I can honestly say I think we are coming to the end of the 701 wing repair/extension. It's been a very VERY long road, but worth every minute learning how to read Zenith blueprints, bend metal, plan ahead and correct mistakes (both my own and those of the original builder).
In my last blog post, I mentioned we were going to try using the router to cut the 040 thick aluminum sheet. I have to cut 3 strips that will be bent to make up the corner supports of the horizontal tail frame box, and using the bandsaw or scoring method would be difficult at best because of the size.
I laid out the 040 sheet on the table. Unfortunately, I didn't take any pictures of the set up, but essentially I planned to use the same method as I used for cutting the nose skin slots - a long straight edge to guide the router along.
What I didn't expect was the router bit to snap immediately on contact with the aluminum. Frustrating as I was very careful in set up, feed speed, etc. In the pics below you can see it snapped up close to the shank, not down by the tip where it contacted the aluminum. I'm guessing it can't handle the stiffness/thickness of the 040 despite cutting the 016 very easily:
I decided to put this testing away for now - I'm going to have to obtain a replacement bit anyhow. I'll do some more reading/research to see what I can do to improve my chances. I'll have to get back at it soon, I need these pieces for my tail, the first thing going on the bench when we're done this 701 wing.
Back to the wing.
Using the same method as the inboard nose skin, straps and wooden strips are used to bring the skin down tight to the spar and nose ribs. It actually wrapped a lot easier than I thought it would, but careful even tightening of the straps was key.
With the skin in position, I used the hole duplicator and matched the nose skin holes to the spar. Surprisingly, the rivet hole spacing is correct - at least the original builder got that part right.
With the bottom of the nose skin secured, we flipped the wing over to get at the top side. Same process here, straps, blocks and careful tightening.
If you look at the picture above, it's clear I need to trim the wingtip nose skin. It's a complicated curve, even more so than the upper and lower wing tip ends because it also curves from top to bottom to form the shape of the nose.
Adding to the challenge is that the original fiberglass wingtip can't be installed yet as we are using it as a template negative mold to make more.
So, how to cut the skin to match the wingtip nose, without actually installing the wingtip nose? There are a couple of things I can look at for reference.
First, the other wing for this 701 is in much better shape and the wingtip is still intact:
Unfortunately, I'm not going to take the nose skin off the good wing, just to make a template for the wing repair. We also can't assume it's correct - remember, it came from the same builder!
Second reference, the plans! Only problem here though is the plans reference measurements from the last wing rib to various points on the nose skin curve, where X is the distance from the spar line, and Ynose is the distance from the last rib to the point on the curve:
Seems simple enough, but we've added an extension and added two more ribs. So where to measure from, hmmmm.
With the skin in place, I marked the skin where it overlapped the upper spar cap - essentially this marks the end of the upper spar cap and is the X=0 point in the table above.
The nose skin was removed again - clecos from both sides, straps, blocks, and all (the skin had to be deburred anyhow). Now that I had a good X=0 point, I measured back from there 505mm, simulating where the outermost wing rib rib would have been. I made a scribe line from top to bottom at the 505mm mark, then marked out each of the X points. From these I could now mark each of the matching Ynose points on the curve.
To make the line a smooth curve, I connected the points with a french curve drawing ruler. Once i was satisfied I had the measurements correct and the curve was a smooth as possible, I used hand snips to carefully cut away the excess skin. I left it a bit long as it's always easier to trim it back once the fibreglass nose is in place.
Before putting the nose skin back on, I ran a pair of wires from the root to the tip, leaving enough to work with at both ends and correctly labelled. The wires are secured firmly (but not tightly) to the nose ribs by a dual wire tie standoffs.
The other thing we wanted to do before fastening the nose skin permanently, was to rivet in a backer plate behind the wrong slot I had cut. This backer will give us a surface to place body fill putty in the slot.. When it dries, the holding rivets will be ground flush and the nose skin sanded smooth.
The wing skins go back on, the straps are tightened again and the skin lines up perfectly. Clecos are added, and the final riveting is completed on the lower side of the nose skin. The wing finally looks substantially complete!
The next step to finish was to replace the damaged lift strut pickup support bracket. I made a new one out of 032 (the original builder used 025), drilled and clecoed for fit
So, what's left to do? Finish installing the fuel bay cover and rivet the upper side of the nose skin. The upper wing root skin will be done once the wings are installed and wing incidence/dihaedral is set (more on that later).
Very happy to see this wing going away for storage by the end of this week.
Next up, my horizontal tail. Here are the frames for two other 701's Ron is working on. I'm getting my parts gathered and will be building my tail alongside these ones:
A productive couple of weeks. Hopefully my followers here will finally get a chance to see me working on my airplane. I wouldn't be able to even begin without the skills I've learned here on the wing repair/extension. I'm very thankful for the opportunity to learn - that's what it's all been about :)
Been a while since I posted, but the new job is taking up most of my days and weekends are escaping us because now the outdoor work around the house begins. Excuses aren't welcome, but the grass doesn't stop growing.
Much earlier in this blog (my first post actually - click here) I spoke of all the work my mentor Barry Morris and I put into trying to promote and develop the South River / Sundridge Airport. Unfortunately, Barry passed away before seeing the local municipalities get their acts together on this important community asset.
I honestly thought all was lost regarding the airport. Three times the municipality almost sold the property to non-aviation interests who wanted to turn it into a number of non-aviation purposes. How disheartening.... however....
I'm ecstatic to say the property was sold to a couple of business men that are enthusiastic aviation people who want to continue to develop the property PROPERLY as a municipal airport, including paving a runway and installing lighting. "Build it and they will come...." is a quote from the 1989 "Field of Dreams". How perfectly appropriate!
On the 12th of May, the new owners, in conjunction with COPA and the local flying club hosted a fly-in pancake breakfast. Ron, his wife Donna and I attended and joined the fun.
Over 40 aircraft from all over southern Ontario attended, it was wonderful! The new owner couldn't wipe the smile off his face! There are a bunch of photos on the airport Facebook page. I was way to busy chatting with friends to take a bunch of pictures but here are a few:
Of course one of the more interesting planes that arrived was a newly kit built Zenair 750 STOL, just like I'm building. Spoke at length with the owner who has about 80 hours on the airframe after completing it last year just south of us in Emsdale. The biggest thing he recommended was keep at it. There is a ton of stuff he still wants to do cosmetically (more paint, etc) but he's having way too much fun flying! He let me sit in it too and I'm even more convinced that I've made the right choice :)
The chance to see another completed 750 was a real good motivator!
The 701 flap repair is almost done. Some final trimming to be done, but the skin wrapped real nice and the joining patch turned out real smooth. Happy to be moving on to building my own flaps shortly and not fighting with other people's mistakes.
Ron has never been very happy with the pinched trailing edge design of the wings and flaps on the 701. The original builder (as I've been saying all along) never really paid attention and the trailing edge isn't nearly straight enough. The pinched rivets called for in the plans really add a lot of drag too.
The plans in the 750 model I'm building wraps the skins forward to the spar, making the trailing edge much cleaner both in appearance and more importantly aerodynamically. Every little bit helps!
To clean things up, we'll be adding a trailing edge strip and attach it with flush rivets. Here, we're fitting the trailing edge "cover". The first one worked real well, I'll add a picture when the one is done.
We plan on building flaps and slaps at the same time for three new 701's and my 750 and new slats for this repaired 701. This sounds like a ton of work and it is, but there are huge time savings because they are dimensionally the same, meaning we only have to set up jigs once.
I spent a couple of hours the other night bending my slat ribs on the forming block. The 750 slats are identical to the 701, so I didn't need to make my own forms for this. The only adjustment needed was one tooling hole on the tail end which is different:
So they turned out ok, but will need some clean up. Not a big deal, but not a nice as I would have liked.
Next up, finish skinning the 701 wing extension. Here is a graphic of what I have complete and ready to assemble (highlighted in blue). Lots of stuff ready to be bent still.
Thanks for reading :)
I had every intention of spending the entire day in the shop today. I'd taken the time last week to mark specific "shop days" on the calendar - days that are set aside for the shop and my build. A discussion with Brenda and our girls regarding my build led us to an agreement that these days are next to untouchable on the schedule so that I can make real progress this year. Obviously if something special comes up that can't be scheduled somewhere else my shop day can be compromised by moving it to another day, but the goal is to maintain a regular shop presence.
So, I discovered that "something special" can also includes those days when I physically can't go. Today was one of those days.
Last night at Natalie's Scout meeting, I tried to prove that I could still play volleyball like a 20 year old. A "I-used-a-could-do-that" type of thing. Needless to say I slept poorly last night and felt like I'd been run over by a Russian cargo plane today, so I missed the shop.
After some rest and feeling sorry for myself, I decided I didn't need to go over to Ron's and could at least get something done here in my own shop.
I pulled out something simple to work on - the flaperon rear ribs. These are simple flanged parts, really just smaller versions of the elevator rear ribs I made before (see my previous blog post here).
It starts with lining the forms up on the metal template. Unlike other templates, due to their size they don't have bolt holes for the forms. Just line them up and place the entire sandwich in the vice:
The soft faced dead blow hammer is used to gently form the flange over the edge of the form:
Turns out the flanges are a bit wider than the thickness of the form. With the short top-to-bottom height of these ribs, I had to devise a way to protect them when I inverted the form to bend the opposite flange. To do this, I added two blocks on each side. One of them had a small groove cut in it to make room for the opposite flange but still enough area to hold the forms:
As per the plans I need 8 left hand and 8 right hand rear ribs and I made a conscious decision to do only six right hand ones first in case I mistakenly made a right hand one when making the left hand ones. Hate to end up with extras - that would mean making replacement templates for each one I screw up. It's easy to see how this could happen, glad I thought of it ahead of time. Good trick to remember for later when I start working on all the wing ribs!
It's amazing! With a bit of attention to detail, I managed to bang out 16 flaperon ribs, all of equal dimensions and quality. Really cool.
16 complete ribs.... not bad for a day I didn't feel up to doing anything :)
I also got a new 14 tooth-per-inch blade for my band saw. Installing the new blade was challenging, but I learned on YouTube how to properly set the tension and blade guides for my model. Once I make some of the rougher cuts on the plate aluminum using the big industrial saw at Ron's shop, I can use my fine tooth band saw to make the final cuts.
I've said it before.... a little shop therapy goes a long way :)
p.s. Photo credits to my daughter Natalie.... thanks for making me look good!
One of the things that I'm really enjoying about being in the shop working on airplanes is it gives me a great way to decompress from work as a 911 dispatch supervisor.
With new technology arriving every day at work, it becomes very difficult to champion change as a team leader in the communication centre. We're all feeling a bit overwhelmed and morale at work isn't the greatest right now. I think too that we all feel we were robbed of the summer as the leaves are already changing here in our part of northern Ontario. Winters tend to be fairly sedate (we don't use the "Q" word - that's how you summon death and mayhem in emergency services) and as a result nightshifts feel longer. It's no fun going to work in the morning when it's dark and coming home when it's dark.
Going to the shop for some plane therapy helps, so that's where I headed tonight.
I made working on the 701 wing extension a priority tonight as Ron wants to get that finished up so we can concentrate on both my 750 build and finishing off his Scout. Once they are complete I'll be able to get some stick time in both while we fly off the required post inspection hours. We're aiming for spring and that should be around the time I'll need use of the workbench for my wings and fuselage.
I've been working on the wing tip extensions. We decided to extend them by 18 inches and this requires extending the wing spar caps as well. These will be extended out to the tips, giving a much stiffer extension that what the plans call for.
Here I'm using the rivet pitch guide to centre punch mark the rivet hole locations.
After marking, and using the drill press to make the holes in each of the upper and lower cap angles, I backdrilled each of the spar cap extensions through the spar web extensionm adding clecos as I went to ensure the spar web cap remained in the correct place.
Take it all apart and debur all the holes on each piece (my new tool works great for that!). Then reassemble with clecos and test fit in position at the end of the wing spar. Perfect fit, tight and level!
Fit the front side spar web extension doubler and back drill through the web. Disassemble, debur, reasemble for final fit:
I've made the spar caps match the angle of the spar tips. Really like how they look and how they will secure the tip skins:
Great progress tonight...... not bad for 3 hours of therapy :)
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Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.