Sunday was a good day in the shop, and both Ron and I can see the finish line with the 701 wing repair and extension. Just a few more small items to go.
As Ron gets close to covering his Aeronca Scout with fabric, we've been discussing his plans to make a fabric/pain rotisserie rig for the shop. You may recall from way back in this blog an engine stand I bought for my Corvair. With my engine parts in Florida for rework, we're going to modify my engine stand and Ron's engine stand to become the end pieces for the rotisserie. This rig will allow us to mount any fuselage, wing or other large parts for priming and painting and being able to rotate them will be very helpful.
The inboard nose skin is ready to be installed. I clamped the skin in place, lined up along the spar. To draw the nose skin tight, ratchet straps are used, pulling the skin tight across the ribs. It's important to place the straps directly over the nose ribs to prevent caving in the nose skin before it is riveted.
Straps are equally tightened until the nose skins lay tight against the nose ribs and spar:
Folded protectors distribute the force across the trailing edge, thin scraps of wood protect the surface skins from the ratchet and strap hooks.
Using the hole duplicator, I matched the new nose skin to the original spar holes on the upper side of the wing. These were drilled to final size, the nose ribs to A3 until final fitting. The 3rd rib is drilled, but missing clecos so I can fit the outboard nose skin where it will overlap the slat pickup.
Once measured up, the outoard skin needs to be slotted to allow the slat pickups to protrude through. The easiest way to do this is with a trim router and spiral up-flute milling bit. I laid the outboard skin out on the table and set clamped a straight edge in place as a guide. Two strips of plywood under the sheet on either side of where the slot will be cut support the thin aluminum sheet and are thick enough to raise the bit above the table
After cutting all 3 slots perfectly straight, a valuable lesson learned - even if you right down the measurement, that is no guarantee that what you wrote down is correct :(
I measured the first slot as 395mm from the inboard edge, but for some reason I wrote down 595mm. From that point on, every time I double checked before cutting the slot, I measured/checked it as 595mm. Bringing the sheet back to the wing, my error was immediately obvious.
After pacing around the shop wondering how I could have possibly messing up the measurement, Ron told me he could fix the error fairly easily with a simple patch - go ahead and cut the right slot. This is part of learning and too much sheet metal to start over.
With the correct slot cut, all the slots lined up perfectly with the slat pickups - minor crisis averted.
Before working on securing the top side of the outboard nose skin, we thought it best to finish securing the inboard nose skin, that would give us a solid reference point for the outboard skin. We flipped the wing over and end for end on the bench. To get the nose skin flat, a thin strip of wood is placed under the ratchet straps. Once lined up and tight against the ribs, I again duplicated the spar holes and drilled the ribs to A3 size. Everything lined up excellent.
Even this nose skin, as small as it is lengthwise makes the overall wing so much more rigid. A good sign.
While waiting to discuss my slotting error I also unrolled my 040 sheet and start marking out the 3 horizontal tail doublers I need. I was initially really surprised at the amount of tape Aircraft Spruce used to secure the roll, but quickly understood why! There is a bunch of pent up spring energy in that roll, and I had to be real careful about wrangling it onto the flat floor for measure/cutting. The longest piece I need from this sheet is 1440mm long, so it was safe to cut that length off the end of the 12 foot long sheet. I marked and rolled the balance back up (that was a task!) and put it back into storage.
Aircraft Spruce ships all their sheet aluminum with a protective plastic sheet coating on both sides. Depending on how long the sheet has been on the shelf, room temperature, and other factors determines how easy it is to remove this coating. I think next time I'll gently warm it with a heat gun or hair dryer - this stuff sticks too good. For now, I've only removed a few inches from the edge I'm cutting from.
Even cut down to length, this sheet is awkward to put in the bender for scoring, and it's thick enough to making scoring a very long process. Instead, Ron and I think we are going to try using the router we used on the nose skin slots to accomplish the long cuts. If this works as we think it will, we'll use the same process for the wing spars (032) and maybe the fuselage sides/tops - anywhere a long straight cut on a large piece of material is needed. As I said above the tool makes really clean cut edges that require little in the way of deburring.
One other thing I've been doing is adding some of the complex shapes from the plans into CAD. Like my smaller parts (ribs, plates, etc.), these will be printed out to provide templates. One example is the wing root nose skin. I use a free downloadable 2-D CAD program called LibreCAD - it is very simple and more importantly it will accept the X/Y co-ordinate system common in the Zenith plans:
If you like doing things in 2-D CAD, you can download a free copy of LibreCAD here.
For those that have been asking, my finger is healing up nicely :)
More soon, thanks for reading.
Previously on part one.....
Without the resistance of the blower fan and suction of the vacuum filter assembly, this motor spins way faster than what the label states. So fast in fact it wants to tear itself apart while merrily dancing across the shop floor despite being mounted on springs (or maybe because it's mounted on springs?)
So, I need to figure out a way to slow the motor down or reduce the vibration component.
My first thought is to reduce the size of or modify the shape of the metal strip I added to the motor axle.
I think doing this only reduces the vibration. The motor will still be spinning way too fast and determining the right size of strip may be hit and miss to get exactly right.
How about controlling the motor speed? I think this will be the easier route.
Digging through my box of household electrical stuff, I found two incandescent dimmer switches that should work. They are designed for AC power (as is the electric motor) and this would add the ability to fine tune the vibratory effect for best results.
Before that however, I need to finish creating the parts bowl. First I inverted the bowl and traced a circle on a piece of spare lucite (plexiglass):
Cut the circle out using my bandsaw...... that's when I realized the centre section of the bowl sits above the rim:
To secure the new lid, I used a piece of hollow threaded rod. I screwed it into the top plate of the tumbler and l left it long enough to add a cap to hold it down tight to the bowl:
To hold the lid, I found an old powder scoop that fits perfectly over the bowl centre. That and a washer and nut hold everything down nicely:
Now that everything is built, back to slowing down the motor.
I added in the rotary dimmer switch. It has an off position when turned counter-clockwise all the way. I'll tide up the wiring once I figure out if this is going to work as designed. The picture was taken prior to creating the lid. Using the dimmer works!
Time to test the machine....
First, add the tumbling media, in this case a couple of scoops of clean clay cat litter. Then add some dirty, greasy and rusty test parts:
Close and fasten the lid..... all secure and "go for power-up!" The vibrating of the tumbler makes it hard to get a clear picture, but the media very quickly envelops the parts. As it tumbles, they occasionally come back up the top:
The tumbler is NOISY! I suspect the bolts between the levels of the tumbler are vibrating against the bowl. That should be easy to fix. Perhaps it might have to be run outside. After letting it run for about five minutes, I decided to have a look at the progress. Even after only 5 minutes, the parts are obviously cleaner and devoid of the grime they entered with:
Although the parts come out a bit dusty, clearly this method and machine I've built works very well, even at a short duration. I'm planning on running a longer test this afternoon and will post more details.
What used to look like this:
Now looks much, MUCH better:
The biggest change is floor space. I'm no longer tripping over stuff to work on other stuff. Most of that is from better organization and better work surfaces. And a personal commitment to put stuff back where it belongs.... HA!
It's certainly not perfect. I still have some decisions to make on some of the smaller items and some stuff to get rid of (bonfire anyone?) I doubt it ever will be perfect, but it's a darn sight better than what it was!
On another note, I picked up a digital calliper on sale at Home Hardware during their no tax sale this weekend:
Like the dial indicator I bought a couple of weeks ago, this will be an invaluable tool to measure the engine components as I pull apart the core engine.
Off tomorrow to look at 2 cores that should be acceptable for conversion! Now I have space to work. Very motivating :)
Used some of these t-nuts....
...that I salvaged from the old desk I recycled for the workbench top. I drilled the mounting hole and used the bolt to draw the t-nut....
....tight into the underside of the bench-top. Now I have a way to temporarily secure my vise and drill press. Mounting bolts go through the top of the desk and hold nice and tight in the t-nuts:
These will come in handy at some point I'm sure.
I'm almost ready to share some pictures from the re-organized shop, but not quite. Here is a sneak peak of my re-organized tool board. I bought a new set of pliers today on sale at Canadian Tire. I never seem to lose screwdrivers, but for some reason I can't hold onto pliers...
Brenda says she is thankful because now she doesn't need to go digging around to find a tool that she might need. Power tools are in the bin under the workbench.
The other tool I picked up today was a dial indicator ($15 at the local hardware store). They actually told me the other day I was the first person to ask in many years for one and when I went in today to buy it they knocked $5 off the price.... sometimes it pays to shop local.
This simple tool will be invaluable in measuring some of the running gear of my engine turns straight and true. It will also be helpful in determining the suitability of the salvage parts (crankshaft, cam, etc) being sent for rebuild.
Hopefully the shop muck out will be "complete" this week and I can start actively purchasing a core engine to work on.
Storage and workshop solution building continues. I finished attaching the top to my new rolling workshop table:
The top is recycled from an old office desk, sturdy and solid. I left if overhanging the frame on all sides giving me plenty of space to clamp things to the table without giving up stability. Frame is 2x4 lumber. Locking casters on opposite corners prevent it from rolling away while working.
Still to come:
Haven't had a ton of time this week to work in the shop for more than a few minutes at a time, but I've been puttering around in there when I could.
As stated in an earlier post, I've been looking for a way to save space. I discovered this link on Instructables.com for a fold down workbench.
I'm certainly no carpenter (sorry Grampa Sword), but I think my version turned out well enough:
Aside from a buying a couple of wood screws, it is made entirely out of scrap 2x4 lumber I already had and an old large cupboard door as the top. Not heavy duty, but an excellent table to work on light weight projects.
I think I'm starting to see the light at the end of the tunnel :)
Next up... a rolling workbench for heavier items and a place to store some of my tools....
Shop muck out continues.
You may recall, this picture is the before. It really can deceive the viewer as to much space we actually have to work with... what a mess:
Now, after sorting the mess and trying to put stuff together that belongs together, I'm well on my way to making space:
It's a pain as I feel like I'm moving stuff around to move stuff around, but it's getting there and it really is my own fault anyhow.
One of the main goals is to create space with, well, better utilization of the space. We are fortunate that the shop area has a fairly high ceiling to work with (open joists as well). Brenda came up with the idea to build a hanging rack from scrap 2x4's to move our long pieces of trim, moldings and tongue & groove boards:
The old closet doors in the corner are going to be sent to the re-build store, but are out of the way in the corner for now.
Another project (every project leads to another!) I've been putting off way too long is insulating the lower wall.
An short amount of time later, voila! Insulated and sealed!
The other walls need work too, but are fine for now. No more bare concrete sucking out the heat.
Off tomorrow to look at a core engine.... fingers crossed!
As I continue to read and digest the information in my conversion manual, the more I realize I've got a ton to learn. But that's what I'm here for (see Motivation).
One of the main items that the conversion manual refers to is the original General Motors (parent of Chevrolet) "green shop manual". This is the manual issued to dealer service centres and covers pretty much everything bumper to bumper on how to service and repair a Chevrolet Corvair. It contains bolt sizes, torque values and disassembly / assembly procedures.
Of course for my project, I'm interested in the sections of the shop manual that apply specifically to the engine assembly and perhaps some of the chassis stuff where the engine is attached. This will be a huge help if I obtain an engine still in a chassis or attached to a transmission.
I did some research online and these manuals are actually still available from Corvair parts suppliers and on EBay.
Further Googling (if that's a word) led me to a PDF copy.
Print, punch and put in a binder. Not green like the original but perfect otherwise! More reference material for the build in my shop.
Time until takeoff
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.