[79FT]: Building Things
|On:||Feb 17, 2020|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, exhaust|
So finally, The Thing That Took Since November and That is Finally Done. Done?
Wait, what? The cowling's back on? Am I.. am I.. done?
You see, one of the things I wanted to fix prior to putting the plane back in the air was this.
Wing root fairing
You're looking at the bottom right wing root fairing, all oily and burnt up, with paint flaking. It is bad. Really bad.
Because it is bathed in the exhaust, and because Glenn added the smoke system on top of that.
Here's the best couple pictures I have to illustrate what's going on.
Glenn's "Smoke On" picture
Old exhaust tailpipe
You can visualize what happens using the second picture. Black shading on the paper shows the original tailpipe. You can see how in the slipstream this will hit the wing root and the side, which is very much evidenced by the stains, oil streaks, and, well, burnt up paint on the fairing.
I wanted to fix this very, very, very much.
As much as I am absolutely not afraid of electrical systems, I am very afraid of exhaust systems (and a few other things). I just don't know enough or have enough experience.
What turned up to be even worse was trying to find someone who does know what they're talking about. I poked around, and couldn't find anyone around or in our Chapter that knows this stuff well to be able to tell me "do this, and I got a TIG machine in the corner to weld up whatever you need".
So, I did the second best thing I could.
A couple years back, I met a gentleman at Oshkosh at our Biplane Forum gathering, Mr. T., who wrote a series of articles on motors, including exhaust.
He agreed graciously to listen to me (well, "read", technically) rant, and maybe guide me a bit.
So, to the drawing board!
I had to put the system back on, and hang the cowling back on the airplane as well, so that I could check everything in place.
When I took the exhaust system off, I plugged the stubs coming off of cylinders with duct tape. Big mistake!
Duct tape on the stubs
Cleaning that crap off took GoofOff and about an hour.
That's the head on picture of the old stub.
The first and the easiest possibility was, what would happen if I just extended it straight out?
Straight extension - head on
Straight extension - side view
I used a piece of paper to mock that up. Mind you, that'd be about a 10" extension! Lots of pipe, considering that the original tailpipe was maybe 16 inches long total.
It was obvious that doing this would move the exhaust outboard way more than moving it down. Why is this bad? Well, the bulk of it was hitting the aluminum side of the fuse and the plastic (okay, okay, fiberglass :) ) root fairing. Moved out this way, it would be hitting the fabric-covered leading edge. Somehow, that didn't sit well with me, and Mr. T. concurred.
So, I went on a scavenging run, and borrowed a nice piece of exhaust grade 3" SCAT from Mr. Dick G., my friendly neighbor, and attempted to mock something up with that.
Now that went way better!
Approx 45 degrees
That moved the exhaust point downward, and I realized that I could play with it even more by bringing it closer to the airbox via cutting progressively more off of the old tailpipe (at this point with SCAT I haven't yet cut anything, because I was just playing and wasn't committed).
That seemed like a way to go. So, next step was to mock this up with a real 45 degree bend.
I got the cheapest slip-on 45 degree mandrel bend from Summit.
At this point, I had to commit, because using this slip-on would require some cutting.
I was committed!
And some more cutting
And then, the fit with the bottom cowl on.
That looked just perfect! A total of about 8 inches of tube added overall, and the exhaust actually moved inboard, and way down into the slip stream.
All that was left to do was to buy the actual 45 degree bend I'd be using, and find a welder.
I was looking around for welder who'd be willing and able while playing with the geometry. Asking around the airport didn't yield much.
Backup plan was Seth from Marioshop - the guy I take my cars to (his boss is a dragster, and Seth welded a lot of tube and exhaust - although, automotive, much thicker kind, with MIG).
I contacted folks from another EAA Chapter, the Waco 59, a great and dynamic EAA Chapter which I am also a member of, and scored - their very experienced Tech Counselor and metalworker Mike M. agreed to help me with the project. He welded himself, and also knew a gentleman that was "very artistic with his welds", as he put it.
I just had to get the material, jig it up to position it, and come over to weld everything up.
My tailpipe was 3 inches in diameter (jumping a bit ahead of myself, unusual for a motor of my size - too big). I measured .049 with my dial calipers, which translated into 18GA, and ordered the nicest shiny new bend from Summit. When it came, I realized...
It was the wrong thing.
Way thicker than what I had.
I think I mis-measured. Maybe I was asleep when I did it, maybe there was a lot of crud on the old pipe and I didn't pay attention, maybe .. but I needed 0.035 material. 20 gauge.
Quick Internet search - nothing.
More Internet searching - nothing.
I could buy all kinds of bends in smaller diameter tubing with 0.035 wall thickness. I could buy 3" tubing with 0.049 wall. I could not find 3" 45 degree bend in 0.035.
One company offered to sell me a straight piece. That was a good backup - we could've mitered and welded up the 45 degree bend in sections, but I wanted to see if I could find a bend. That same company offered to make me one - at a low price of about 600 bucks. Yikes!
Attempting to Hail Mary again, I posted on the Biplane Forum. Guys came back with a bunch of phone ##s of their contacts, and I started calling around!
Nope, nope, nope. I don't remember who it was, but one of the guys I called suggested contacting Custom Aircraft Parts.
A nice lady answered. "You gotta talk to Clint", she said, and transferred me.
Clint picked up. I asked if they could sell me the bend. Clint asked, "What are you trying to do"?
He asked for pictures. A bit weirded out, I sent them over.
"I have two things I wanna tell you", said Clint.
"Buy yourself a bottle of soap and a nice rag".
"Be careful what you wish for".
Clit knew this 4-into-1 setup with a muffler in between very well. He told me that even with me trying to keep the extension as short as possible, I was running a risk of it cracking off at the muffler. Would it for sure? He didn't know. But the risk was increasing a lot.
I called my old friend and a Grumman aficionado Ben the same night. Grummans have this style mufflers (mine didn't by the way because it was sporting Powerflow - a very different system).
"Hey, do you recall welding cracked off tailpipes?"
Damn! Damn damn damn.
More mulling over ensued. I did not want to risk a tail pipe cracked off at the muffler. No way. That puts hot exhaust into a very tight cowling. On a biplane. With my having elevated fear of any in flight fire. Remember, I embarked on the electrical rebuild because I judged this airplane to be a flying fire hazard.
I talked with Ben more. I talked with Mike from Waco 59 more.
The attempted fix solidified.
I would put a ball joint somewhere close to the muffler, with one end on the old pipe, and one end on the new extension that includes the bend. That ball would isolate the extension from the existing system, and allow them to move relative to one another.
I would then hang the new extension to the oil sump on some kind of hanger with a clamp - likely, a kind of tube with ends flattened and bent as required.
I sent this schematic to Clint. Well, no, not this one. This is a nice one I did when writing this post, over a picture I took when mocking up this solution. The one I sent to Clint was this. But, same idea.
Schematic I sent to Clint
Clint's response? Verbatim:
Adding a ball joint and brace solves all of my concerns, you are free to do anything you want to the tailpipe. If you weld the bend on as your latest drawing shows, looks more reasonable. When adding a support brace it is imperative that it stabilizes the tailpipe to the engine, they must move together.
WOOT! Did I find a way to do what I wanted?
One thing to absolutely ensure was that the ball joint would fit.
We went back and forth a bit, me asking about dimensions. Then, I threw together a quick drawing of the widest part of the ball joint - the clamp holding it together - and tried it next time I was in the hangar.
No way. No way it hell it would fit. Airbox would get in the way.
Here's probably the best picture I have of why.
That little triangle of "air" in between the cowling (bottom), exhaust pipe, and airbox is probably 1 inch on sides. No way a ball would fit in there. No freaking way.
So, what am I left with?
I gave up.
Called Clint on the way back from the airport, and asked him to sell me a straight length of pipe with a slip fit on one end.
Got it a week later.
Called Mike, got a contact for his welder, and went there.
The gentleman didn't like the fit - too loose - and wanted to make sure I pinned it exactly where I wanted (and actually, I should've done that in the first place, because the opening in the cowling is very tight, and just a degree of being off would make it interfere with the cowling). He also wanted me to clean all the gunk off.
So, back to the hangar, and fun fun fun with a die grinder, deburring wheel, wire brush... This 40 year old exhaust is gunky!!!
Back on for tailpipe fit
Put new section of pipe on, clocked it just right, drilled a couple of holes thru, and put in a couple screws.
Putting a nut on the inside of a 3" pipe about 10 inches "in" is .. exciting!
Nuts on the inside of the pipe
Then, pulled it off and put in more screws, to be absolutely sure that if it had to come apart, it would come back together in the exact clocking I needed.
Mike's welder fell thru, and that cost me a couple weeks at least. I focused on some other work - panels, compass, etc.
One of those days, I was on the phone with D. when a gentleman I didn't recognise walked over from the hangar next door housing a PT-19, and asked to borrow a hex key. When I hung up, I walked over to introduce myself.
"Hi, I'm M."
M.?! The M.?
He's somewhat of a local celebrity, having built a ton of airplanes, and having worked on more. I met him on a couple occasions in passing, but not really, and I didn't remember his face when he walked over. He's a sheet metal and generally a metal guy. He was working on the PT-19's electrical (ha, fun coincidence, eh?)
A lot of hangar flying ensued.
He looked over the biplane. He told me of his building a replica Hughes H-1. Of his own design basically.
When parting ways, I asked, "Hey, do you have a welder by any chance?" Asking doesn't hurt right? "Yep, I got a TIG machine".
Ha! Of course :) I meant to ask if he knew a welder. But he was one. I should've thought of that myself.
He agreed to help me weld the damn thing back on, of course. He asked for me to clean the insides. It kinda made sense, too - you want full penetration when welding, and you don't want all that crud on the inside of the tube to "float up".
So, lots more of a die grinder time, with flapwheels, with a compressor barely large enough to run the damn thing for a minute straight.
Then, drove to M's shop, drooled over the H-1 and the MP-14 that he had on it.
And then, the final fit of the tailpipe to put it where it was when I cut it off.
We put the exhaust back on the plane,..
Back on the plane
...put the cowling back on, and I started fiddling around with things to try to figure out how to mark an even line to cut it off on.
Rubber band maybe?
Rubber bands actually worked quite well. The kind I had was too tight, and I was playing with it trying to make it work and considering running to a nearby Office Depot, when I was offered a schematic to help guide me.
Exhaust cutoff schematic
But prior to emptying local stationery stores' rubber band supplies, I tried something else - pieces I cut off from the old pipe. Had to trim them a bit more to fit them over the new pipe, but that worked quite well in the end.
Using chunks of old pipe
Starting the hacksaw at this shallow an angle is... annoying? Is that the right description?
Starting a cut
I suck at hacksawing.
My punishment? 30 minutes of grinding.
And so, I am back to where I have started with this little project. My supply of rags is large, and my soap came in a 5 gallon pail (okay, okay, I do have some old stock is all :) ).
But, on the other hand, I think this is the Hump. It's when in a project, there are no more unknowns. You now just have to finish doing everything you've started.
Fuel in the tanks is limited. Gravity is forever.
...fuse blocks, and oil cooler bowden
|On:||Feb 16, 2020|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, electrical, cables|
A couple things have been always on the back burner - fuse blocks, and finishing up the oil cooler bowden hookup.
In between waiting for completion of The Thing I Am Yet To Write About, finally, checked those off the list.
Location was figured out a long time ago, and I just clamped them in place, center punched the holes, and drilled them.
Clamped in place for hole marking
One little bit was to figure out the exact fastener lengths and washer stacks, because the right one had it's right (forward most) end riding on top of a reasonably thick aluminum placard you will see much better in the following picture.
Fuse blocks: mounted
You are forgetting, my Dear Reader. We here are in the misery business. Look carefully at the curvature of the fuselage. Imagine the side panel, open on the pictures, closed over our "conduit", on which the fuse blocks are installed. Do you see how the available "depth" will be bigger in the middle of the conduit as compared to the top?
Of course, the panel won't close. With fuses installed, they would rub on the side panel. Not Good.
But relocating them down? What's the problem? Bowden cables, of course! I'd be too close to them, and I wanted very much to isolate my wire bundle and my bowdens; but even if I didn't, I still won't have enough room there for a terminal, and a nice 90 degree "turn" for the wire to go sideways (either towards the panel, or towards the firewall).
Well.. there weren't any good ones, so I ended up taking the best of the crappy ones.
Final fuseblock mount locations
Not ideal, because they're flipped over - so technically, condensation can run down and into the fuse socket. Not a good situation to be in, but I can't do anything here. I guess, inspecting this area for corrosion is going to be on my Regular Maintenance List.
Oh, and I ended up with four extra perfectly drilled and deburred holes, right in the passenger's cockpit. That's what is on the other side of that "conduit".
I guess, I will attach a placard to them stating that those are "hole samples" or something (my friend Dick Gossen placarded a missing screw in his instrument panel once, so I figure I am allowed as well).
When headscratching about, and later installing the voltage regulator, Oil Cooler Air Shutoff Valve bowden was relocated (and because of that, I had to use a longer Bowden, which, gladly, I had an extra of after removing the Rotec's Throttle Body Injector).
All that was left was cut it to size, and install it into the valve's pivot arm.
Cutting bowdens? I don't know, I think it's easy. Pull out the actual control wire, and use bolt cutters. Push the wire back in, and trim to desired length.
Here's the pivot arm.
Oil Cooler Air Valve Pivot Arm
Notice the gap between the washer and the arm? Yep, the arm's too thin for the little bushing that's used here.
Pivot Arm Wire Bushing
No worries, we can file that shoulder down....
The other minor problem? The hole that clamps the "eye" that holds the bowden's outer housing in place was drilled too close to the place where the eye begins. Result? Flat washer was too big to lay flat.
Put everything together, a bit of TorqSeal, a cotter pin, and we're done! (TorqSeal applied by a steady hand of a four year old, so please easy on your judgements, gentlemen!)
By the way, beats me why that oil cooler would need a shutoff.. It's way too small to begin with; and the SCAT feeding it is the whole 2 inches. I feel that I will excitingly find out how hot my oil gets in a Texas summer very soon....
Takeoff's are optional. Landings are mandatory.
...placards and switches
|On:||Feb 04, 2020|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, electrical|
Since all my tools were already in the vicinity of the back hole, decided to finish doing everything around the panel in preparation for actually running the wires (which will come at the very end).
They were done quite some time ago. I center punched the holes in the panel for the #2 attach screws when test-fitting the placards, and left them at that.
Well, 't was the time!
That is a #2 tap, mind you! Tiny! I used a ratchet adapter; and didn't even need a ratchet - was just rotating it with my fingers. 1/2 turn in, 1/4 turn back. Slooooowly.
..and the placard went on nicely, too.
Placard set up.
Switches will be coming out one by one one last time later, to get wires attached to them, and to get all the hardware locked with washers/Loctite.
In the original setup, switches and fuses were on opposites sides of the panel (now both sides are occupied with switches), and the harness ran kinda loosely in between those sides.
I didn't like that bunch of wires not having any kind of support, and wanted to add something.
Having all those gauges clustered right above the harness, I wouldn't have had any room for the "raw" clamps attached to the panel in any reasonable way.. but, if I put together some kind of "standoff".. kinda like...
Clamp on the bracket
that! (This bracket courtesy of my Polish friend Mr. Wojciech.)
I made another one, and took some weight reduction measures, too.
Brackets - cleaned up
Then, located and drilled the holes in the panel for them.
Using tape to mark out the holes
And, here they are. Notice how harness will end up below the gauges, not interfering with them.
Brackets test installed
Here is how they look from the back, with some "test wires" run from the switches thru the ADELs.
Test installed with wires.
Nice, short, concise, and almost no misery this time!
Experience is a hard teacher. First comes the test, then the lesson.
|On:||Jan 29, 2020|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, electrical|
While waiting for someone else to get back to me to help me finish <the thing that took last month and a half and is yet to be written about>, I decided to work on the panel a bit.
Lighting strip seemed like a nice place to start.
It's a simple LED strip that I planned to glue right behind coaming on the underside of the eyebrow. This way, it'd be invisible from pretty much any angle.
But, the wires! The wires in front of the panel, that have to go to the behinds.. No worries I thought, I'd make a small hole / slit in the top of the panel, also invisible - and fish the wires thru there.
That was the plan.
Reality, of course, decided to disagree.
The plan was to take out all the screws that went around the top of the panel, and tilt it "down" - so that I could use a drill comfortably to make the little slit for the wires.
Couple screws came out nice.
I think the third one came out like...
Did I just bust a screw? I looked into the hole. Empty?!
Upon further examination, I found... glue? What? The screw head was... glued into the hole? That's a first.
After taking the rest of the screws out, I realized what happened.
Backside of the panel
This is the back side of the panel. The panel is attached thru those little tabs and nutplates.
Notice the nutplates using rigid (not floating) style nuts? A slight misdrilling of the holes in the panel, and screws won't go in at all.
So, there were two "screws" that were just heads glued in - yep - and two more that used #6 screw in a #8 nut - the TPI on those is the same, and the holes were drilled sufficiently close enough to let a #6 screw pass thru; but not a #8. Le.. Sigh.
To top it all off, the panel won't fold down for me to get access to where I wanted to be, and to fish it out I'd have to take out the carb heat bowden cable that was attached to it. Too much trouble if I can avoid it (that carb heat cable would've been a 3-4 hour affair just by itself).
Plan B solidified; but first the panel had to be put back.
I ended up putting #6 screws into all the misdrilled holes (sorry, but glueing heads into holes is.. not my thing :)); but I installed nuts on them on the back. Effectively, set up like this the nutplates don't do anything - just add weight. See the picture above - it has the nut over that nutplate. That nut, by the way, was a pain to get in - see how close another nut is to it?
I think all the fiddling with the panel, screws, nuts, washers (losing a few of them and going on fishing expedition to pull them out of the guts of the plane included, of course), and trying to get it back in right took what.. around 6 hours?
The plan B, now executable after the panel was back in, was to route the wire under the eyebrow, and fish it thru behind the coaming to the "top" side right in the middle, where the compass was to be. It then would join the compass light wire, and go to behind the panel land.
So, the strip was glued, and the wire attached to under the eyebrow with HVAC duct sealing tape, ahem, aircraft grade glue backed aluminum sheeting from the local friendly Aerospace Depot.
Strip glued - looking up
That picture's taken "from under, looking up". Ugly? Well, not too easy to make it pretty doing it basically blind with an inspection mirror the only view. Like this:
The only way to see it
The wire was fished thru to the "top side", and it was time to test.
Pretty, huh? :)
Since I was working on that area, I decided to finish it off. Compass was prepped...
Screw those zipties!
... and installed.
The compass bracket is pinning the compas lighting wires there, and ...
Other side (see the red wire)?
... the fished thru wire for the panel lighting strip (see the little red wire? that's it).
Done, and done.
You start with a bag full of luck and an empty bag of experience. The trick is to fill the bag of experience before you empty the bag of luck.
...the biplane way
|On:||Nov 23, 2019|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, electrical, placards, etching, SWX|
This is all your fault, you know who!
Way back, when working on the new layout for switches on the panel, I was thinking about how to re-label them.
I had a nice Brady label maker, and was thinking about just printing and sticking some tags over existing, painted, lettering, on the switch placards.
One of the nights, when I was tired enough to do anything useful, I was playing with the stickers, and posted this picture here:
Playing with placards
The you-know-who-you-are, of course, wasn't happy (this gentleman is an actual friend of mine, not a silly voice in my head). "They will fall off", he said. "Can't you do something a bit more professional"? "Can't you draw them up, and order them to be custom made"?
No. This whole exercise in airplane handling is to put yourself thru as much misery as possible. So the placards had to be made, not ordered. I mean, I could've ordered my electrical redone too, right? :)
I recalled that I read somewhere on Vintage Machinery that someone figured out a neat way to restore old data plates on old lathes and such. Looking it up, I remembered.
The idea is basic - make a mask, transfer it to a piece of metal, soak it in acid, paint, sand - your recessed (etched) areas will keep paint, while the elevated (masked out) areas will sand out. This way, you get metal-on-paint look, and it's nice and pretty.
So, it has been decided - I will etch out my switch placards!
First, though, I had to figure out...
Obviously, SolidWorks would be instrumental in making the actual pattern. I wanted to make the placards out of brass, so that lettering would be yellow, and I'd paint them black, for the yellow on black final result.
First, the mask.
Searching around, it seemed that the most reasonable way to go about it would be to use Toner Transfer technique. Laser printer toner (at least on a good subset of laser printers) is basically powdered plastic. Printer warms it up, which makes it sticky - and toner then fuses itself to paper. It can be re-softened (and made sticky again) by a normal household iron or a laminator. I had both - an iron, obviously; but we also had a great "office grade" laminator in the office.
A lot of folks had success with glossy paper (glossy paper doesn't absorb melted toner, it sticks, but stays on top), but I, looking around, found a lot of good reviews of the PCB Fab in a Box system.
Not only the guy makes a very nice toner transfer paper which "releases" the toner when soaked in water (it works just like your model decals in plastic models, you soak the paper, and the top layer comes off), he also seems to have researched and cleaned up the process to minutia. For example, the toner itself is porous (indeed!) so he uses an extra layer of plastic to "fuse" the micro-gaps between toner granulas as transferred with another layer called "TRF Foil". He also did a lot of research into printers, toners, application techniques and such - and published a great handbook. Just for that alone, I wanted him to have my money.
So, I ordered the transfer paper (the one you print your mask on), and tried the first step - transferring it to a small strip of brass in a laminator.
Laminator with envelope with the workpiece
What's wrong with that picture? Riiight! I forgot to mirror the pattern :). Damn.
I messed around quite a bit with density, too. Just default settings were crap, obviously. Bumping up the density to max didn't help much. I installed a new toner cartridge, and that improved the density dramatically - while not perfect, it would've been workable, hopefully, with the addition of the TRF foil (and, if I saw any obvious holes, I could fill them with a sharpie).
Okay. But the basic test worked! The pattern transferred nicely.
Second time, I threw together another test mask with a couple of different fonts about the size I'd want on the placards - I was gonna transfer those to a small chunk of brass bar stock, and try etching.
With the help of child labor, patterns were cut out, and transferred successfully to the brass bar stock. I then applied the green TRF foil (that stuff that fuses the pores between toner's grains) to it.
Side note: the process manual from PCB Fab in a Box notes explicitly that Brother printers have a kind of toner that requires much higher than usual laminator's temps to melt. I have a Brother printer, but since I was able to do my first transfer successfully, I kinda decided to not bother - it worked, so I must be the lucky one right? Though I admit, I did entertain an idea of a new printer... ;)
On one of the evenings, I had a block of a few hours, and the weather was nice. I had all my chemicals (ferric chloride PCB etching solution and boxes of baking soda to neutralize it afterwards), so I decided to try the actual etching process.
I hooked up the test plate to a piece of closed cell foam (to float it on top of acid)...
Brass with mask hooked up
...set up a small plastic table outside the hangar...
...and went to town.
The idea was to try to get the ferric chloride to about 100 degrees F to speed up the process, so I did a hot water tub (hence, the little camp stove in my setup).
I'd have a large tub with hot water, and a small tub with etching solution in it, with the workpiece floating on top, hooked up to the foam.
Etch, etch away!
It took about 40-50 minutes, I think, till I was comfortable with the depth of etching. Every 10ish minutes I'd pull the piece out, and brush it with etchant to clear the debris that, I thought, would collect in small nooks and crannies (I saw a guy do that on one of the videos I watched).
After a decent etching depth was achieved, I pulled it out, and dunked it in soda to neutralize the acid.
Then, lots of rinsing, while catching water into a tub. Acid, even neutralized, will contain dissolved copper, and just dumping it is not good. I was planning to keep the tub and let water evaporate, at which point I could just wipe off the powdery residue.
All cleaned up
After that, a rag with acetone wipes off the mask, and...
The edges on the letters (basically, the edges of the mask) are very rough there. On these test ones, I started with a maroon pad, but quickly went to a 120 grit non-woven deburring wheel, which cleaned it up nice (and of course, messed up the letters - well, lesson learned, I won't use that aggressive a method on the real thing).
Later, when painting, I noticed that the mask was still porous, letting some acid in (I had some tiny "cavities" in random spots). It looked pretty good when applied. This would become obvious later, when I started adding color. I suspected the old drum, and decided to get a new drum for the printer - though in hindsight, I think this is, after all, the problem of me having the Brother printer (read on ;) ). Meanwhile, I ordered a new drum and a new cartridge.
And then, the paint.
I wanted "golden" letters on "black" background. I wanted to make the whole piece black, and then sand it on a flat surface - everything that was masked would have the black sanded off, and the rest would keep it, achieving the effect.
I wanted to try a couple different "make it black" approaches. One would be forced oxidation with something like a gun blueing acid, and the other would be plain paint. I had two test areas, which would allow be to try both at the same time.
So I blued one side....
Blued with Brownell Oxpho-Blue
... and sanded it down.
Couple notes on blueing. I tried Brownells Oxpho-Blue, and then later Birchwood Casey Brass Black. Both produce a layer of black oxide on the brass. There are a couple of problems, though.
First of, the etched surface is not perfect - and those imperfections are not really hidden by oxidizing, obviously. Second, and bigger, problem, is that that oxide is powdery, and can be rubbed off easily with even a paper towel, given enough elbow grease. I was afraid I'd have adhesion problems with the top coat (I was gonna coat the whole thing in clear to prevent tarnishing of letters), so I decided against it.
The other side I decided to put just your basic schedule of Rustoleum - primer, and flat black.
My kick-ass paint booth
I waited for about a week with the Rustoleum side, and then sanded it down.
Rustoleum sanded down
I liked that side much better. However, the primer, being white, would show in between the paint and the letters, being noticeable. I decided to find some black primer - and meanwhile, coated the whole thing in lacquer, which I decided to use as a top coat.
Mistake! A few weeks later, lacquer started flaking off. Yeah, I learned the "no lacquer on top of enamel" rule. But it was flaking off on plain brass too, so.. lacquer was no way to go.
Just typing that, in hindsight, maybe there was some acid residue after blueing... but acid was dried, and I used acetone to clean up the blued side. But again, clear brass had lacquer coming off as well.
Worse part is, the enamel lifted and was coming off in pieces.
So instead, I did something that in hindsight I think was a mistake. I decided to look for a better paint solution, and very quickly arrived at epoxy, specifically, Klass Kote. It seems to be used by a lot of RC builders very successfully, I saw successful reports of brushing it, and talked to them, too. I was sold. Again, in hindsight... I think this was a mistake. But, read on. :)
To make the actual mask for the actual plates, I used my scan-and-draw-around-it Solidworks trick. I scanned the old placards, and sketched around them.
I very quickly discovered that on one of them, the sides were not parallel; and the holes were all not on one line, and not evenly spaced! :). So, I made two versions - one all nice and even, and the other just like the old placards.
Using a bit of cardstock, I tried each of them on to make sure the holes are okay and such...
Trying on the pattern
Guess which ones fit better? Yep, the crooked ones! Straightening them out made holes not line up with holes in the panel, and one of them would interfere with some screws on the panel. Oh well.
Then, came quite some hours (that I didn't log to be honest) fiddling with the font and the layout. I decided to use "Magneto", the kick ass italic font out of the four I tried on my test etch.
Plates with the cool font
But, the same gentleman who made me undertake this endeavor, argued that while these would look grand on a Cadillac, they have no place in an airplane. "Use standardized fonts!" he said. He did have a point. If it was not me in the back hole, and it was an emergency, readability, not style, is a prime factor. So, I had to remake them.
Plate with the boring font
Before actually committing to etching them, I wanted to do the final size and looks check with actual metal. So, I printed the things on regular paper, spray glued that paper to some scrap aluminum, cut them out, and drilled the holes.
One thing became readily apparent - the lettering was too high up and rows were too close. Well, that was an easy fix on the model, I just moved the bottom row a bit down.
The hour X was quick approaching. I now had the twice tested model that fits, and all the kinks were worked out.
For material, I picked up a sheet of brushed "Marine-Grade" 464 .032" thick brass from McMaster (remember this, "brushed" - one side is brushed, the other is not).
On the final drawing for the mask, I replaced hole outlines with little "donuts" - thinking that those will make nice initial "center punch" marks for the holes.
When printing it, the toner flaked off the transfer paper immediately. "Bad sheet of paper", I thought. I also found the "Improve Toner Adhesion" setting, and enabled it. That made a nice print-out.
The final mask
Prepped my brass with good clean and acetone wash...
Prepping the brass
..made a nice pouch for feeding it thru the laminator..
..drove to the office, and started feeding the laminator with it.
Food for the laminator
On my test piece, I did 10 passes, so I did the same here. Pulled off the pouch, and...
What?! It worked before! A bunch of thoughts went rushing thru my head - more metal? Not getting it hot enough (but it was hot!)? Bad toner? Wait! YES! This time I used a completely new toner cartridge and new drum unit - to make sure my pattern has as little of those pinholes as possible (remember, I ordered a new drum and toner after my initial test etch?)
I went home, and compared the serial numbers on the toner I had success with with the new toner. The first few letters were different, as well as the few digits in the tail, which made me think it was a different brew of toner, and toner problem. So, I printed the mask again with the toner that worked before.
I also started thinking that the "Improve Toner Adhesion" setting I used might've caused mayhem. I also read a bit about that setting, and it seems that Brother recommended using it if the toner flakes off and if setting the paper type properly (ie, "plain", "card-stock", "thick", etc) does not help. So to prevent flaking off, I set the paper thickness to "thick", removed the "Improve Toner Adhesion" setting, printed it again using the toner cartridge that worked before, and went back to the office...
This time I didn't use the "pouch" of paper I typically wrapped around to protect the brass and help the laminator pull it thru (the laminator I was using had a problem with feeding first 2-3 inches of brass - it wouldn't pick it up - so I used paper as the "carrier", which alleviated the problem). I thought that maybe paper was preventing some heat from being transferred well, and got rid of it this time.
What the hell?
I took the laminator home, determined to run a bunch of tests (it was Sunday ;) ).
I had a couple of old masks left (I printed double the amount then, in case first try didn't work - so that would cover the toner/drum combo that I know have worked). I printed a couple of new ones - new drum/old toner, and new drum/new toner.
I also changed the settings again, for the two new prints I made.
As I mentioned before, when first printing the final mask (the one that didn't transfer), I had it's toner literally flake off the paper in some spots. "Hmm, I thought", and re-printed it, using the "Improve Toner Adhesion" setting enabled. That made the paper go thru the printer much slower, it came out much hotter than usual, and the toner adhered well.
On the second try (the one that didn't transfer either), I read a bit about the "Improve Toner Adhesion" setting, and decided to instead try to change the paper type to a more appropriate one - so blaming whatever "Improve Toner Adhesion" did for not transferring of toner, and blaming "thick" not being set on the first try causing toner to flake off, I set "thick" for paper type - which, again, caused the same effect - slow feed, hot paper, good adhesion.
And then, when finally doing a systematic attempt to figure out what's wrong, I remembered that on the very first test masks (the ones on the test piece of brass buss bar stock), I didn't tweak any paper settings at all.
"Slow Feed", "Hot", vs "Fast Feed", "Colder". This time, I started guessing that maybe, higher temp did something to the toner that would then prevent it from being re-melted when fed thru the laminator. I decided to try my luck with "plain" paper type (fast, cold feed), and count on my luck in the toner adhesion department.
I lucked out - test pieces came out fine, and, with three test masks, thru the laminator we went again.. And again... 10 times total, as before.
This time, things definitely changed! First of, all three transferred equally, but they transferred equally... crappy.
So, we knew that we were onto something with the feed/temp settings of the printer affected by the "Improve Toner Adhesion" and paper thickness settings.
But, transfer was still crap.
And then, I realized one more thing.
I was transferring to the "brushed" (remember, I had a "brushed" brass sheet?) side of brass? Those "brush marks" are noticeably deep when you drag your fingernail across them. I suspected that, effectively, whichever pieces of the mask were above the marks, wouldn't touch any of the metal, and therefore won't stick.
OKay, but I can use the other side! It was cruddy, but a bit of the deburring wheel...
Wait. Go to the airport to polish the other side? Ugh.
Found a piece of steel wool we use to scrub dishes. Phew. That, under water, made the other side of brass nice and clean on short order.
OK, the moment of truth. Printed the pattern again, using the new toner/drum, now, when we know that toner/drum aren't causing my transfer problems, but rather, the temp and the feed rate of the printer are.
Will this be final?
Attached to brass
Soak after the laminator to remove the transfer paper
Phew. Okay. So, I guess, after all, Brother toner is finicky, just like the Fab-in-a-Box guys tell you, and mine is not special. I don't know why fast feed / low temp would even keep it transferable.. but... Well, the lesson I take from this is that I will be carefully considering the toner type when buying a new printer, when that time comes.
And then, the foil. I'll admit, I did a couple attempts with the foil. Yeah, and when I didn't like what happened on the first attempt, I had to re-do the mask (toner transfer, that is) yet again!
My laminator has serious feed issues. The foil is very finicky, and keeping it straight requires laminator to feed nice, smooth, even, and straight. My laminator needs to be "helped" sometimes with pressure pushing the plate "in".
Oh, well. After the second attempt, I realized that I probably won't achieve ideal results on such a big piece, and instead, used Sharpie to fix as much holes in the foil as I could find.
Final mask, and lots of Sharpie.
So, bottom line. If I want to make perfect, non-porous etches, I need to get me a good printer that will do what I need, and a good laminator that actually feeds things nicely. Later, later :).
I was planning to etch the following morning.
The weather was great, and I relocated to the airport, setting up my "camping setup" outside the hangar...
..put the plate attached to the foam into the tub, and went counting my 10 minute chunks..
Plate in the tub of etchant
Etching is visible here
..it took about 90 minutes at 100F etchant temp to get about .010 depth.
To neutralize, this time I used soda with water, to make it get into all nooks and crannies better.
And cleaned up!
Nice! I liked it! The etched sections ended up a bit too thin, but workable still. I cleaned them up with maroon scotch brite by hand this time.
Next day, I cut them out, drilled the holes, and tried them on.
I liked them! The only step left was the paint. But first,
I touched on the subject a bit already.
I was afraid of Rustoleum now, even learning that I messed it up myself with lacquer - it peeling off the base in sheets didn't give me confidence. Rustoleum has clear enamel; but my reasoning was that if it peeled off with primer, clear enamel without primer on relatively sharp edges of lettering will just come off almost immediately, given that my hands will always be around the switches when operating them.
I settled on epoxy. It made sense. Klass Kote had good reviews from RC guys, and folks reported it brushable.
I completely stripped my old sample with brass wire brush and acetone. Wire brush cleaned it out nicely and smoothed some roughness still left, so I wire brushed the new plates too. It helped, and seemingly worked better than the maroon pad! Noted.
And then, I set up in the kitchen.
Set up for painting.
Klass Kote needs to be mixed, and reacted for at least 30 minutes prior to application. My plan (approved by Klass Kote) was to do base in black, then bake it after initial flash off for 30 minutes at about 100 degrees Celsius. That will cure it enough to make it sandable, after which I'd sand down the letters, and clear coat it. I won't need to bake the clear, 'cause I'm then done for the night, and it can take it's sweet time curing.
Klass Kote is really thick when mixed!
Trying it straight on my test coupons left horrible brush marks.
Straight Klass Kote black
I tried it on my test plate as well - just to play with the baking process.
Meanwhile, mixed up a new batch and wanted to try it reduced with a lot of reducer to see if that would make it flow better.
Nope. That left the same brush marks, but just watered down, if you will. Multiple coats just made it uglier.
Hmm... Meanwhile, I had a batch of clear mixed too, and tried to see how the clear would look over my test plate that was now baked and ready to be sanded down. Maybe, the brush marks would get better / a bit more hidden with extra brush marks of clear?
Not bad, right? Well, you're not looking at it right.
Frustrated, I dumped my thinned batch of black into the tray I was using for garbage, and sat down thinking. My eye fell on a foam brush I had in the set of brushes I bought. I mindlessly picked it up, and started smudging the dumped paint around the tray.
It flowed! Very nicely!
I then remembered how much I hate brushes in general. I was never able to get anything remotely approaching good with brushes. When I built my kitchen cabs, I used cotton pads over foam brushes and achieved very smooth, mark-less results.
I think, this random act might've just worked!
I cleaned up my other, flat, coupon (the one that wasn't baked, so the epoxy would still come off with some wiping with the reducer).
I was now planning to mix the final batch of black I'd reduce. I'd try it on the coupon first, and then, if I liked the results, on the actual pieces...
...it went on smooth, but fish-eyed a bit. I thought that that was due to some crud on the coupon (I wasn't cleaning the coupon too good).
So, I put it on the actual plates.
It fisheyed! A lot of eyes flowed together, but some big ones stayed. I quickly dabbed them out with the corner of the brush with some paint on it - too late, damn it! It didn't flow out. The whole thing was also rough-ish... thinned paint was flowing around imperfections of the etched surface, as well as my dabs were messing with it, probably. There were also areas that had visible marks of me lifting the brush.
At this point, I should've stopped, dunked it into the reducer, washed the whole thing off, and called it a nite.
But, I was too focused on getting there.
I thought, I might be able to get a uniform "rough" look.
Solvent was flashing off, and paint was getting thicker.
More paint, but this time gently, not to rub old paint off. Then, dab-dabbidy-dab the foam in and out.
That looked acceptable, and I decided to let it flash off the solvent. Meanwhile, went to Walmart for more foam brushes (I only had two in the set).
Got back, mixed a batch of clear and left it off to react. It was looking good, with "rough look", and I was thinking I might just be able to pull it off.
After the paint stopped being tacky, put the whole thing into my oven.
What's for lunch, ma?
Yep, that's my toaster, repurposed as epoxy bake oven, and calibrated at 100 degrees Celsius :).
I forgot about solvent pop.
See, when you have too thick a layer of paint (which I did, when doing my "rough look" pass), and the top of it skins off, some solvent might get trapped under it. What happens then is the trapped solvent tries to evaporate, and can't: pressure builds, and it "pops" the paint, making a tiny little pinhole.
So after 30 minutes, I pulled the plates out of the oven. Yep, I got the pop a-plenty. Some areas of paint that were especially thick got a ton of them.
I decided to stop then. Screw it. Rustoleum it is, as much as I hate the idea. This epoxy stuff is great (no, really, it is); but I need to spray it. So, I took a rag, wetted it with the solvent, and tried to rub the paint off.
Nope! It cured enough to no longer rub off with the reducer! Crap. Now, the only way to get it off is with Methylene Chloride stripper... :(
Oh well. What's the best second option for a frustrated guy who failed at a paintjob at around 2 in the morning? Stop? Go to bed? Strip and start anew?
Nope! I thought, "well, I had a batch of clear right here. I can see if I can rub out the worst uglies with something, and try to clear it to see if it'll hide the rest".
Admittedly, it did hide pretty neat.
I rubbed out the worst popped parts with maroon scotch brite, and sanded down the lettering.
Left's not rubbed, right's rubbed
Bottom's rubbed, top's rubbed and sanded
And then, I clear coated them with two coats, cleaned up, and went to bed.
So, did they come out okay?
They look okay if looked at like that. I don't know. They're ugly, if looked at in the right light.
With the right light
On the other hand, it matches the "rough style" of the old school plates. I really don't know.
What I should've done from the get go is either used Rustoleum, or got myself an airbrush. With an airbrush, it would've worked much nicer.
Maybe, I will strip them and re-do the paint. Maybe not - that kind of light is unusual in a cockpit. Maybe I will file this under the "don't be an idiot / don't rush a paintjob / use the right tools" section, and keep them as a reminder - until I have to make another set.
I don't know. We'll see.
Meanwhile, the Chairman says, "Come Fly With Me!"
If you’ve got time to spare, go by air.
(More time yet? Go by jet.)
fixin' and bleedin'
|On:||Nov 04, 2019|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, Annual, brakes, wheels|
So this one turned into a month long project, give or take. Sure, sure, I was doing other things, too: last one of which was completed October 9th... after which I was finishing this one exclusively, pretty much.
Damn. One month to finish putting the brakes together. Granted, I had a hiatus for a week and a half, dealing with fixing up bad (non-aircraft) plumbing and cutting (non-aircraft-grade) trees.
Regardless... Shall we?
After having finished making the new brake line, I naturally wanted to install it and call brakes done.
Some of the disassembly work documented here actually happened prior to the new line being bent up, but hey. Putting it all in one place makes for a better narrative in one context.
... one of which was cracked due to someone having overtightened the bleeder adapter. Oh well.
... and pull
Brake pads were soaked in brake fluid. For that matter, the disk was covered in brake fluid that hardened to molasses-like consistency (which mineral milspec fluid does, apparently).
Intermission. By the way, it seems that this smudge didn't come from the dripping bleeder, but rather, judging by how the pads were soaked, from under the brake piston. Probably the o-ring was bust, and it was weeping from between the caliper and the piston. It seems that it had been a feature of the plane for a while.
Jumping a bit ahead of myself, on the other side, I discovered the brake disk somewhat dirty with oil - crankcase breather hoses are routed into the _left_ side wheelpant and terminate near the disk - clearly, spraying a bit of oil on and around it. You'll see those hoses on the pics of the left wheel below.
I think Remo's idea was to prevent oil on the belly from the breather. My friend's Ben contention was, this was a brake lock-up prevention measure; and when he brought it up, I immediately realized... leaking piston on the _right_ caliper was a lock-up prevention measure as well - to make sure both brakes are equally slippery - right one with brake fluid, left one with motor oil... At any rate,..
I will admit, this was my first caliper job ever, and anchor pins presented a bit of a problem. They're press fit in the caliper, and I didn't have an arbor press. Well, I used an old 1/4 nut that I banged on (gently!), and finished with a drift punch....
Tapping out the pins (aka anchor bolts)
With the caliper put apart, I tossed the old body, and took maroon scotch-brite to the rest of the pieces to clean them up.
Cleaning up the parts
Now, I tried tapping the anchor pins back in, but was too afraid to mess them up. Finally, that was an excuse to go get me an arbor press!
Pressing the pins back in
One final bit was to put the nuts back on.
Ready for nuts
Question: how many wrenches does it take to put on an aircraft grade nut properly? Answer: three.
Answer: three. Ratchet to work the nut before it's torqued. Small torque wrench to determine the free torque. Large torque wrench to torque to spec.
I pulled off the other caliper, and cleaned it up, too.
Left caliper, cleaned
Put in new piston o-rings, cleaned up AN flare adapters, put the calipers back together, and put them away.
Next step was,
That little doodad was leaking for a long time, too. It seemed it was leaking from the little cam arm that rotates, but I wasn't sure, so I decided to put it apart and rebuild it completely, too.
It's under the passenger's seat on the Charger.
Pulled it off
On the bench
First, I pulled the "cam arm" out - the little arm pivots, and pushes valves open (or lets them close) inside the box.
Cam actuating arm
O-rings were in reasonable shape, but looked a bit.. old. I decided to change them and disassemble the rest of the contraption, to change all the other o-rings in it.
Now, the middle two "straight" fittings are straight threads and o-rings under them. No problems there.
The two 90 degree elbows on the sides are NPT. One came out just fine. The other... Well, the other decided to leave a chunk of itself inside the valve body...
Bits and pieces - valves, springs, and actuator plungers
You can see the chunk of the male thread galled and stuck in the female NPT hole of the body.
Chunk of thread
Damn damn damn! I need a new parking brake valve now?
That new valve is how much (search.. search.. six hundred and sixty five!?!?!?!?! $#*@(&(2@@#!). No way I'm paying that.
There are alternatives. Cheapest one is like what, hundred fifty bucks; and I'll have to work around it's plumbing (which is different than mine); and the "direct fit" "homebuilt" cheapest one is over $300? No way. No way in hell until I try to fix this.
What is the hole? 1/8 NPT? McMaster sells taps for $25, two new fittings are what... under $30, and a handful of o-rings, which of course I didn't have (I have a bunch of o-rings in a ton of sizes for fuel applications, but not for brake applications).
We'll try to re-tap that hole; hopefully braking the piece of the thread left in there by the fitting while keeping the female thread intact...
... the tap and the o-rings got delivered a few days later. Made myself some nice soft jaws for the vice to hold the thing without scratching it.
That's aluminum angle and leather.
Tap, tap, tap (not that kind of tap!)
Slowly, slowly and gently, breaking the chip every 1/4 turn and adding cutting fluid. It worked out great! The hole was deeper than needed, so I tapped the threads a bit deeper, arguing that if the female portion of the threads got chewed up a bit, I'd put a fresh surface on them too.
Well, we'll have to wait to see how well this works out. If it doesn't leak, I just saved me a boat-ton of money.
Putting it back together
New o-rings, new elbow fittings, re-tapped hole. Threads on the busted hole felt good, no hesitation and "catching". We'll see how that works out...
Pads on the right brake (the one with leaking piston o-ring and busted caliper) were soaked in brake fluid. Cleveland says contaminated pads are a cause for replacement, so I decided to do it, since I was already in there. Besides, excuse for another tool - this time, the brake rivet set!
Punching old rivets out
... and putting new ones in
And with that, the last bit before we could put everything back together was,
Again, since I was already there, I decided to do the wheels at this time too - re-pack the bearings, that is, and give the disk contaminated with brake fluid a real good cleaning.
Jacking the plane
The axle nut comes off with finger pressure
I admit - I made a mistake here. I did not remember what kind of resistance I felt when spinning the wheel on the axle before I took off the nut and took everything apart. It would've been important, especially since this was my first time doing these wheels, and wheels in general....
All the grease seals (and bearings)
Crap! What, the felt seal is bust!?.. Looks like it is. Okay, not finishing this part quickly (because of yet again, another "order parts / wait" cycle).
Flushed, and drying
Do you see the other mistake I made? Yep. I mixed up the bearings ("front" and "back"). Bearings should always stay with their races...
Oh well. After some research, seems that the worst that will happen is wear will get accelerated.. since the bearings and races looked squeaky clean, I decided to keep them as is.. for now. And just Hail Mary the position (since I have a 50% chance of getting it right :)).
I decided to replace all the felts because I was changing grease from I didn't know what kind but likely red Mobil grease to Aeroshell 22.
Ironically, I apparently didn't take a single picture of the bearings being greased - probably because my hands were too greasy doing them :). Oh well.
The new felts came, and got coated in grease.
One of new felts
And, I put the wheel back together. And then... And then, I couldn't tighten it back right. I have to align the hole in the axle nut for the cotter pin... I could either get it under-tight (with perceptible play in the bearings - not good), or a bit over-tight (so that the wheel will spin, but with some measure of resistance). Remember, I said that my mistake number one was not checking how freely this wheel spun prior to pulling it off? Now, I was paying for it.
I tried flipping the bearings around (because I didn't note their original positions), thinking that maybe that will help. Nope. No change at all.
Oh well. I couldn't do anything about that at that point, so decided to settle on "a bit tighter" option.
With the other wheel, things went much smoother (the second time you do the job, it takes you 10% of time it took you to do it the first time, right? :) ). It came off, was cleaned, and got back on, with new felts and bearings in the original positions. Nut got tightened to super tight, loosened, and tightened to finger tight - and the wheel was perfect. No play, and no "drag".
Le double sigh.
So finally, it was the time to put things back together!
That was almost pleasant, after all the mess-aroundary with bearings. I cleaned up the pins' glide bushings, and lubed them with Dri-Slide (graphite + moly) lube Parker recommends.
And then... Calipers on, slide the bolts in, torque.
Putting calipers back on
Even a child could do it! By the way, that's the left wheel - remember I was mentioning the breather hoses routed to that wheel? There they are, in their awesome oil-spraying glory...
Parking brake back on
Put the parking brake back on.
Phew. Now, finally, we can bleed and test!
Now, there are two approaches to bleeding brakes - either bottom up (push fluid up thru the bleeder valves), or top down (sit in the plane and squeeze the pedals while the other guy opens and closes the bleeder). Bottom up is inherently simpler.
Some time ago, my buddy Dick was showing off his fancy bleeder he got from ATS.
ATS Brake bleeder
Hmmm.. What is that reminding me of? Aha! Bug sprayer! That's right
Now, a few minor modifications, and...
DIY brake bleeder
Pump it with air, open the valve, and the brake fluid gets pushed out thru the line that attaches to the bleeder valve on the caliper. Child's play.
For bleeding, I dragged my good friend Nick S. to give me a helping hand. I could've done this by myself, but having someone watching over the "other end" (it either being the end that pushes the fluid in, or the end out of which the fluid comes out) makes the job much more pleasant.
Now, the way brakes are plumbed on the Charger is, each side goes from it's caliper up the gear leg to the parking brake valve, then to the Master Cylinder, and from there both Master Cylinders are plumbed into a tee, from which the single line (the one I was re-making earlier) goes to the reservoir on the firewall.
We decided to bleed each side up to the tee first - to minimize the amount of air ending in the "common" line between the tee and the firewall. After bleeding each side up to the tee, we'd attach the "common" line and bleed each side up to the reservoir, letting at least a cup of fluid to flow thru, ensuring that we push all the air out.
The plan went without a hitch, aside from the fact that I initially forgot to open the parking brake, and was trying to figure out why the hell the fluid won't flow. Hehe. Nick called it, too!
Nick holding the fluid line from reservoir
Finally, the moment of truth. The brakes were firm and nice, held well, and no leaks nowhere! Now, I need to double-check this - next time I'm in the hangar for a good few hours, I'll set the parking brake to keep the pressure in lines, and see what happens - but initially, everything held just fine! Phew.
So finally, the last bit was left.
Now, the new line was finally in place, and all that was left was to install some ADELs to hold it.
That one took ... an hour! Very nasty spot and hard to get to. I had to find a better way...
Now, there are fancy mods to ViceGrips (or you can buy them for sizeable chunks of cash pre-made) to hold ADEL clamps together while you're inserting the screw and starting the nut. I don't have them.
Some people use safety wire.
I decided to try...
It works great, too! Just double up and "noose" it around - it holds a clamp like a charm in the "closed" position while you fiddle with the nut! Even Jack came out to see that.
Jack inspecting the work
With those clamps installed, I had to tie a bundle of wires going across the tube to the front stick's PTT switch. That one was one hell of a contortion exercise, under the front seat's front edge and behind the stick, but I managed after a couple of tries.
Lacing the wires to brake fluid line and structure
And finally, a couple more clamps along the length of the line on the fuse to hold it in place there. Some TorqSeal, and we're done!
I worked out a method to these, finally, I think. I use a long (~2 inches) AN3 bolt first to "thread" the clamps on, and then close them with a wrap of lacing cord using the "noose" method ("Method 2" here). I then remove the long bolt, install the final bolt, and start the nut. When the nut brings clamps almost to a close, I cut off the nooses, and tighten the nut. Works like a charm!
So, there. A pretty big job now complete - brake system rebuilt, re-bled, and ready to go.
PS: I was considering where to put this - under "2019 Annual" or "Electrical Rebuild" category... decided to pile it into the "Electrical Rebuild", because basically as a part of this rebuild I'm doing a bunch more stuff.. This is basically becoming a "minor restore" project... But still, the main theme is "Electrical Rebuild", and I'm keeping it under this section.
If it doesn't work, rename it; if that doesn't help, the new name isn't long enough.
... mounted, and pretty!
|On:||Oct 09, 2019|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||electrical, 6781G, MA5 Charger|
Prior to mounting the newly finished brake line, I wanted to finish fastening everything that's around it - so that I minimize wrenching around the brand new line.
Voltage Regulator is one of the bits that will go right there, so it was to be done.
I was working on it's mounting, on and off, and eventually got stuck with attempting to solder a short grounding strap that was to go under one of the "standoffs" for the regulator.
And then, I was making the new brake line - but now that is done too. I also figured out how to make that ground strap. So. nothing prevented me from completing the voltage regulator install.
But, we're getting ahead of ourselves.
First, the holes.
How do you drill real good, round, quality holes, you ask?
Well. All those tools were participating in making of those holes, in sequence. Here's a game: name that sequence!
And then, the mounts. The regulator was to be on standoffs, to "raise" it above that rivet line. The regulator wants two grounds, which will go under two of the standoffs. I also wanted to have a ground strap go under a standoff.
Now, I have to explain the ground strap. I already mentioned spending quality time trying to make it.
I want to set up good grounding architecture in my all new electrical. This side conduit, to which the regulator is mounting, is key.
It's continuous, and aluminum - so it presents a really nice grounding point. I am planning to add jumpers between it and the firewall, and it and the instrument panel, tying it all up nicely. Loads will be grounded to the conduit, firewall, and instrument panel only.
Since the voltage regulator is right next to the firewall, it's very logical to have the ground strap under one of it's stands. And besides, there is already a convenient hole right next to it for the firewall side of the grounding strap - which is why the strap is very short.
At any rate, those three terminals under three out of four standoffs for the regulator are making hardware stacks of varying thicknesses per standoff, so standoffs need to be individually sized to keep the regulator overall "level" above the conduit.
Another fly in the ointment is that "jog" created by one portion of the conduit riveted on top of another - that has to be accounted for, too.
So four individual standoffs.
Calc and standoffs
If I had a lathe, I'd do them on the lathe; but my lathe is pickled, waiting for the shop - so, tubing cutter and a bit of luck made them all within 5 thou of the right size.
All set up
Here are the stacks, just to give you an idea of the mess I got into :).
Top and bottom left:
Nuts there are temp AN315 nuts.
And now, for the final mounting.
First, scrape all the paint from the side conduit, to ensure good contact (top right doesn't have anything electrical so didn't need to scrape the paint there).
Then, make the ground strap.
And then.. Well, I wanted to clean up and make sure I mount the bowdens and the engine analyzer harness at least semi-permanently. So, started doing that - discovered that screws in some places, sticking up, were getting in the way of my clamps.
Who said forceps are a doctor's tool?
Mounting an adel
At any rate, after making sure that I'm happy with bowdens and probe harness, it was go time!
Everywhere I take a nut off, I replace it with MS21042. Half the size, and it supersedes the default AN365 and AN363.
And by the way, often times it's convenient to use a "grabby thingie" to start them.
Set up the hardware stacks, crimped short lengths of wires into the terminals, hooked up the ground strap...
Starting to mount
...and finally, got to use my TorqSeal! I think this is the first fastener I have torqued to it's final state in this project. Milestone!
First dab of torqseal
Next, trimmed and crimped the ground wires.
And that was it! Two more dabs of torqseal on the bottom nuts, and installed all the plugs for the holes left over from removing old lines. I'm using AN-6 plugs here.. nice, light, and pretty.
Why not top ones as well? Well, I have this pesky gutfeeling that I will hook up an adel to at least one of them to hold the main wiring harness to it. It's just too convenient a spot not to do it.
And to top it all off, did a couple of nice placards to remind myself of things :).
It's easy to make a small fortune in aviation. You start with a large fortune.
... the answer is NOT solder?!
|On:||Oct 08, 2019|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||tools, electrical, soldering|
A while back, I wrote a note on my failures at getting good crimps with the hydraulic crimper I had.
My conclusion then was, "solder".
Well, I tried :). I had to make a little bonding strap, maybe 5 inches long.
First time, I cowboyed it - just stuck the strap into the terminal, and soldered away.
In. My. Face.
Second try.. I think
I was soldering, de-soldering, soldering again, etc. Trying different positions, and different heating methods (butane torch worked best).
One of the better ones
I eventually started using the "wedge" trick - to wedge a piece of thick wire in between the wire strands, so that the wire gets packed into the barrel of the terminal.
All that yellow crust is rosin flux
My main problem was, I was trying to prevent solder wicking as much as I could. And I couldn't. It would make 1 inch or more of the wire perceivably "crusty", and I still won't have the barrel filled in. Remember, I was trying to make a small, short grounding strap, that had to be flexible to bend almost 180 degrees. I was trying to achieve a "crimp quality" break between solid metal and strands, and could not.
When I started thinking about it like that, I realized that what I'm trying to do is likely impossible.
Solder will wick - you can control how much with technique and practice, but you can't prevent it. So my current thinking is, if you solder your large lugs, be ready to support first few inches of wire really well, so that that "crusty" portion of it doesn't move.
So, I tried to Hail Mary the crimps again. Previously, I had them just damn ugly (I linked the article above).
I got a small anvil tool (the kind you insert the barrel of the terminal and whack a pin with a hammer) from Spruce. Thought, 25 bucks was worth a try.
Those crimps were even uglier. I don't know what I expected - I guess that was an act of desperation? I didn't even take a single picture.
But then... I had a minor epiphany.
With the Harbor Freight Crimper, dies are not properly ground for wire sizes. But. But.
Just like with hammering, we can crimp progressively until we "flow" all the strands and the barrel into one solid piece!
Here's the approach (okay, this is the final procedure, first try did not include turning - but I did it (admittedly, accidentally), and liked the results a lot).
Pretty, ain't she? And, no "wings".
If you don't do the turning trick, it'll still be pretty; but with just a whiff of those "wings" present:
All all this was what... five and a half hours?
Well, I guess, that's the "education" part of the "Education and Recreation" charter of E/AB aviation ;).
When you’re sitting in the rubber raft looking up where your airplane used to be, it's too late to check the flight plan
... and fitting in place
|On:||Sep 30, 2019|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, Annual, brakes, bending, tube|
So, yet again, last few weeks turned into working on lots of little bits simultaneously.
But, finally, one of them is done - and therefore, something to log.. ahem, pardon, b-log, about :).
The brake line.
The old brake line
I needed to relocate this bad boy to free up room for the Voltage Regulator. This is the older picture - I have long bent it out of the way and cut off a chunk. It was to be relocated to run below the conduit.
Well, first, we had to locate the hole in the firewall. And that depended on the line to the reservoir, firewall forward.
After having thunk a bit about it, decided to replace the 90 degree fitting in the reservoir with the 45 degree; and the firewall bulkhead fitting with a 90 degree. That'd minimize the amount of bends and make for a neat job.
So, firewall forward we go first - that will locate the bulkhead fitting and the hole.
This is with old fittings in the firewall and the reservoir. The clamp on the mockup line is using an existing hole in the firewall - nice happenstance; I'd have to plug it with a "blank" bolt otherwise.
Then, "project" the tube onto the firewall, roughly mark the center, and drill!
And now, to the most fun part. Making the tube.
This was another first - never done tubes and flares before, so first of, had to figure out how to flare them properly.
Question: by how far does the tube have to stick out of it to arrive at the correct size flare?
Answer: 0.035. For the -4 tube. :) Yeah, those practice flares are not ALL the ones I made. Just some of them.
OKay, so the next question was how to actually make it fit.
My first thought was,
Bottom hooked up, top not bent yet
The tubing bender has alignments marks for where the marked CL should go for different angles of bends.
What I didn't realize is that on this short a run, even a little error (bend being off of the ideal centerline by as little as 1/16") would cause a total misalignment.
It did, of course.
Okay, second try.
I pulled out the roll of the new tubing, too. Partly to motivate me. Partly because I ran out of the chunk I've cut off of the old line.
This time, the idea was to bend it first and get the bend angle just right. Then, trim to correct length.
Bend angle first
Trim, flare, hook up the bottom and mark the top
This actually worked.
Question. If you have a fitting with a flared end, where to place the cut mark, so that after you cut, and deburr, and flare it, while it's sticking out of the flaring tool (un)-precisely 0.035", it fits?
Answer? I don't know. I think I got lucky :)
It fits perfect. I have no idea why the fitting there looks crooked - probably weird camera angle. It's straight :).
Okay. Time for the Big Kahuna - the actual long line, running along the conduit, and under passenger's seat.
Under the seat it goes..
See that line? It goes down, turns, turns again, and again, and then goes to the center of front seat's front, and goes under.
It was rubbing against structure in a spot, too - so I wanted to clean all that up.
~30 minutes of head scratching yielded clamping arrangement that would work.
By the way, I am stealing this arrangement shamelessly from my friend Mr. Gary Vogt of AuCountry Aviation fame. He uses similar arrangement to organize wires along motor mounts. Genius, really - and I have never seen this before (but I likely am a total idiot, anyway).
One final mock-up, and we're good to go.
Safety wire for mockup
BTW. How do you make safety wire straight? Chuck it into a drill, and spin a bit :). It'll work harden a touch, and straighten out.
Okay, now, let's do the actual new line.
Unbend a long enough piece of tubing from the roll. Pull out the old line. (and use it as a template!)
First two bends
Old line on the top, new on the bottom. I made the "tip" (that first section on the left) longer and planned to flare it later - can you guess, will that bite me or not? ;)
Once I got to the point where the complex section (the one that goes from under the seat, to the side of the plane, and then up, and down again to run parallel to the conduit), it was time to try it on.
Maneuver it in.. it fits! Perfect! Bends clear all the right spots and fit in all the tight places.
Okay, now, time to actually attach it to the fitting under the passenger seat, hook it up with temp clamps, and do final bends and trim to final length in place.
But first, I need to flare that end - the one to go under the seat, where I left somewhat a longer stub to be trimmed later.
I trim it. Perfect length.
Crap! It does not go into my flaring tool now. It's way too short for it. WAAAY too short.
See, the flaring tool has some thickness to it. The sleeve has to fit on the tubing before you flare, and takes up another 1/4" of it's length. And, it won't go thru the bend. So there's a certain minimum length of straight tubing required for you to be able to flare it.
And, I already cut it off :( And I can't unbend it - it'll just break.
Okay, I'll admit to this. I did try to unbend it. I annealed it back to soft (torch + sharpie as temp indicator) and actually did succeed at it. But, bend flattens the tube some - and the sleeve still won't go over it.
Besides, bending this big Kahuna was actually not that hard - much easier than I thought, with old line acting as template. And, I had enough tubing. So, I decided to re-bend a new one.
Second try, I flared first. And then, I realized that Remo has probably bent his with a different kind of bender, or had a different kind of flaring tool - my bender would make that first section a bit longer than what the original line had.
Well... it wouldn't interfere with anything (I checked). It'll make it run a bit at an angle, and stick out from the seat a bit more... a bit uglier, but not a big deal (and I'll try to massage it into a bit more parallel run during final install).
First bends - the first section (with sleeve and flare) is longer than original
Finished bending it, and installed it into the plane.
Seat to side...
...and up the side
By the way, this is how this looks from under the plane.
The "front" of the plane is on the bottom of the pic. Can you find the line? (hint - it feeds the T with hoses attached to it. Hoses go to master cylinders under rudder pedals).
OKay, so now to final bends and trimming.
Still needs to be bent and trimmed
There'll need to be two more bends - "down" to follow the conduit and "out" to hook up to the bulkhead fitting on the firewall.
That geometry would need to ensure that I have enough straight tube to successfully flare it - learned my lesson there :).
So, our little safety wire mockup to the rescue.
First bend made, marking / eyeballing the second
What I didn't realize is that this long line is much easier than a short stub. Even if you make a mistake, you can massage the line into compliance, "smudging" your mistake over the whole length - mistakes like wrong angle, a bit short here, etc.
Though, marking precisely does help. :)
Two new tubes, all ready
I guess, mounting and bleeding is next; but for that, I need to replace the busted cylinder on the wheel, attempt to fix the leak in the parking brake, and re-pack the wheels (or I'll be re-bleeding the brakes later). I want to install the voltage regulator first, too, because that will minimize me messing with fasteners in the vicinity of this line.
PS: at the time of this writing, I am actually more than 50% thru with both of finishing up brakes, and voltage regulator. :).
If something hasn't broken on your helicopter, it's about to.
...misery turned happy times!
|On:||Sep 10, 2019|
|In:||[Chickenhouse Charger] Electrical Rebuild|
|Tags:||6781G, MA5 Charger, electrical, panel, drilling|
...this is important. Stick a pin in it.
Remo had these nice placards all over the airplane. Professionally done. Very well looking. He probably ordered them somewhere, or used a technique I am not aware of.
These placards are mostly glued on, and do not come off.
How do I know?
Well, I needed to remove one, in the side conduit. Here it is,..
..to the right of the future fuse block. It gets in the way - there will be another fuse block there to the right of the one on the picture. And I can't rip it off! I can't remove the conduit to immerse it into whatever solvent will cut the glue without some major surgery, so I guess the new fuse block will go on top of it.
Why am I telling you this?
You have probably figured by now that I have a taste for misery, and for ranting about how miserable that or this was :). If you read a few notes in this Dear Diary, you will notice a trend - that I tend to come up with ways of making myself aggravated, very consistently and reliably.
Well, this time it was the "anti-rotation" holes for switches in the panel; and the plan was to drill them from the back side of the panel not quite all the way thru (yay, no access and contortionism again!)
Every switch, circuit breaker, and certainly, a dimmer, comes with a "keyed" washer to prevent it's rotation. That means you're drilling two holes - one for the appliance (switch, or whatever), and the other for the little tab that's on the washer.
Picture explains this better. Here is a little hole template I quickly drew in Solidworks, properly dimensioned, with washers from (left to right) the circuit breaker, switch, and the dimmer.
See, Remo didn't have those "secondary" holes on the panel - so I had to drill them (especially for the dimmer).
But wait, you ask. If you drill holes, that will be ugly - a hole next to every switch?
Yup. Aha. Agreed! Though the nuts are supposed to cover them, they, I'm pretty sure, from my testing at least, wouldn't have...
No problem! Remo made the panel from 1/8" thick aluminum, and I needed maybe half that much for the tabs to go in. So the plan was to very carefully drill them just deep enough to house the tabs.
Made me a nice little set of templates...
Templates in the making
...out of a small piece of aluminum, drilled holes using my paper template, and cut them up...
Templates, cut up
...and cleaned up the holes and edges.
The plan was, to put a template like a "washer" around a switch/CB/..., and center punch the secondary, small, hole, thru it. Then, I'll have punch marks to drill, and will have to either get to them from the side of the plane, or, more likely, from the back of the panel while sitting in the seat and not seeing where they are while drilling, using a mirror to position the drill first.
Like I said, I have a taste for misery.
So there we went, punching the back side.
Center-punching on the back side of the panel
Cling! Ding! Ding dang dong.. it sounded like a chunk of metal just fell off the plane and dropped on the cockpit floor.
!??!?@??!??! What the h... did I break?!
I crawled out from behind the panel and looked into the cockpit.
On the floor, looking at me, and almost smiling, was...
...this. Remo's placard that went around the switches. Like so:
Placards - in place
Wait, wait wait wait. It came off. But it will be held back by the switches' nuts when the switches are in. And.. cover the holes! That means, I don't need to drill the holes from the back side and worry about punching thru (or not going deep enough) - I can comfortably sit in the cockpit and drill them from the front! All the way thru! The placard will cover them! In my search for misery, did I luck out?! :)
In retrospect, this (and the opposite side's) placard were probably not glued. No need - switches' nuts hold them just fine.
They were stuck because Remo probably installed them on top of the paint that didn't fully cure - and it just stuck to the backside of placards over the years, under the pressure from switches' nuts.
I stuck my nail under the opposite side placard, and it came off with a little force.
Well, it was smooth sailing from there...
Marking from the front
... relatively speaking, of course. I still had to hold up the vacuum with my knee, and maneuver the sharp drill, making sure to be extra careful not to poke it into anything important (like, fabric on the sides).
The ones on the corners were annoying; but I already had the drill bit installed into one of my hex drill adapters - so a 90 degree adapter was not an issue. Didn't even need an angle drill.
Angle adapter for the side hole
That sucker has 1/4" diameter threads; and all the holes I have in the panel are 1/2... Without some serious bushings, or other mods, or a new hole.. ugh.
Possible pot locations
I was hoping to stick it into the old "Master Circuit Breaker" hole (marked (2) above), but it was waaaay too big.
Looking around, looking around.... aha! Here's a number 8 or 10 screw plugging a hole! I can enlarge it and we'll be in business! (marked (1)).
Yep. Good luck, buddy. That was an even bigger hole that was plugged with a #8 screw in a countersunk finishing washer... hmmm... maybe that will work out for the pot too?
You know, drilling a #10 countersunk washer to have a 1/4" hole in it is... hard? Annoying? You can't really grip it in any manner without damaging it, you can't hold it in your fingers... I think I lucked out on my third try, with combination of a Unibit and light clamping of that washer in a vice.
With that re-drilled countersunk washer, the pot mounts just fine in hole #2. And #1 got plugged back :).
Well, after all that excitement compass mount was almost anti climactic. I toyed with the idea of putting it into the panel (and relocating G-meter into a new hole I'd cut around where the ignition switch was - see, after having failed relocating Hobbs there, the idea of still making a bigger hole in the panel keeps nagging me :).
No good. When that much down, too much steel around it confuses the compass to the tune of about 30 degrees... No need to add extra problems in already a magnetically problematic plane.
So, top it was to be. The windshield will get in the way, but I really, really didn't want to take it off (~20 #6 screws and nuts in a tight spot is no fun).
Eyeballed the bracket alignment with the fuselage centerline and put it in the right spot...
Damn! Sharpie's too tall to get in there to mark the holes vertically. "Angle Sharpie Adapter"... hmm..
Angle Sharpie Adapter
A bit of disassembly and forceps do the trick ;).
Holes punched and drilled, I added a bit of rubber foam under a portion of the mount to "eat up" uneven surface created by combing...
Vertical card compass!
Side note to attentive folks: yes, I know I need brass hardware - those CSK washers and SS CSK screws are temp fasteners I used to test positioning. It will be brass, I promise :).
Oh, by the way, the best accompaniment (score? ;) ) for working on a biplane is...
... The Chairman, of course!
"Put your compass on 'E' and get out of my airspace."
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This website only shows how I did things in my various projects. These pages are for information and personal entertainment only and not to be construed as the only way, or even the perceived correct way of doing things. You are responsible for your own safety and techniques.