[79FT]: Building Things

Tagged with "6781G":

Placards for Switches

...the biplane way


On: Nov 23, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 20.7
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

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"?

Order?

Ha!

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.

Etching!

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...

The Process

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

Laminator with envelope with the workpiece

Transferred!

Transferred!

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.

Second pattern

Second pattern

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

Brass with mask hooked up

...set up a small plastic table outside the hangar...

The setup

The setup

...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!

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.

Neutralizing

Neutralizing

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

All cleaned up

After that, a rag with acetone wipes off the mask, and...

Etched!

Etched!

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....

Masked

Masked

Blued with Brownell Oxpho-Blue

Blued with Brownell Oxpho-Blue

... and sanded it down.

Sanded down

Sanded 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

My kick-ass paint booth

All done.

All done.

I waited for about a week with the Rustoleum side, and then sanded it down.

Rustoleum sanded 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. :)

The Actual Mask

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.

Sketch

Sketch

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

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

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

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.

Test pieces

Test pieces

Left side

Left side

Right side

Right side

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.

Applying the Final Mask

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

The final mask

Prepped my brass with good clean and acetone wash...

Prepping the brass

Prepping the brass

..made a nice pouch for feeding it thru the laminator..

Pouch

Pouch

..drove to the office, and started feeding the laminator with it.

Food for the laminator

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...

Second attempt

Second attempt

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.

Same problem!

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.

Test pieces

Test pieces

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?

Will this be final?

Attached to brass

Attached to brass

Soak after the laminator to remove the transfer paper

Soak after the laminator to remove the transfer paper

Transferred!

Transferred!

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.

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 Etch

The weather was great, and I relocated to the airport, setting up my "camping setup" outside the hangar...

The setup

The setup

..put the plate attached to the foam into the tub, and went counting my 10 minute chunks..

Plate in the tub of etchant

Plate in the tub of etchant

Etching is visible here

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.

Neutralizing

Neutralizing

Pulled out

Pulled out

And cleaned up!

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.

Left

Left

Right

Right

I liked them! The only step left was the paint. But first,

Intermission

Knipex!

Knipex!

Paint

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.

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

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?

Test plate

Test plate

Not bad, right? Well, you're not looking at it right.

With light

With light

See?

That's horrible.

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.

Rough look

Rough look

..on both

..on both

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?

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

Left's not rubbed, right's rubbed

Bottom's rubbed, top's rubbed and sanded

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?

Finished

Finished

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

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!"


It's a good landing if you can still get the doors open.


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Tagged with "6781G":

Brakes and Wheels

fixin' and bleedin'


On: Nov 04, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 23.1
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.

First, the Calipers

... one of which was cracked due to someone having overtightened the bleeder adapter. Oh well.

Drain

Drain

... and pull

... 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).

Ugly smudge

Ugly smudge

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....

Tappy-tap-tap!

Tapping out the pins (aka anchor bolts)

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

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

Pressing the pins back in

One final bit was to put the nuts back on.

Ready for nuts

Ready for nuts

Question: how many wrenches does it take to put on an aircraft grade nut properly? Answer: three.

Wrenches!

Wrenches!

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

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,

The Parking Brake Valve

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

Pulled it off

On the bench

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

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

Bits and pieces - valves, springs, and actuator plungers

Busted elbow

Busted elbow

You can see the chunk of the male thread galled and stuck in the female NPT hole of the body.

Chunk of thread

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.

Soft jaws

Soft jaws

That's aluminum angle and leather.

Weapons ready!

Weapons ready!

Tap, tap, tap (not that kind of tap!)

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.

Done!

Done!

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

Putting it back together

All done

All done

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...

Next,

The Pads

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

Punching old rivets out

... and putting new ones in

... and putting new ones in

And with that, the last bit before we could put everything back together was,

The Wheels

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

Jacking the plane

The axle nut comes off with finger pressure

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....

Temp

Temp "wheel"

Cleaning bearings

Cleaning bearings

All the grease seals (and bearings)

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

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

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.

Cotter pin

Cotter pin

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!

Putting the Brakes Back On

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

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

Parking brake back on

Put the parking brake back on.

Phew. Now, finally, we can bleed and test!

Bleeding

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

ATS Brake bleeder

Hmmm.. What is that reminding me of? Aha! Bug sprayer! That's right

Bug sprayer

Bug sprayer

Now, a few minor modifications, and...

DIY brake bleeder

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 setup

The setup

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

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.

Finishing the New Line Install

Now, the new line was finally in place, and all that was left was to install some ADELs to hold it.

ADEL One

ADEL One

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...

Lacing cord!

Lacing cord!

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

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

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!

All done!

All done!

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.


Definition of 'pilot': The first one to arrive at the scene of an aircraft accident.


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Tagged with "6781G":

LR3-C

... mounted, and pretty!


On: Oct 09, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 6.6
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.

Holes

Holes

How do you drill real good, round, quality holes, you ask?

Tools!

Tools!

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

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

All set up

Here are the stacks, just to give you an idea of the mess I got into :).

Top and bottom left:

  • Bolt head
  • CAD Plated Washer
  • <side conduit>
  • SS washer
  • Ring Terminal
  • Standoff
  • SS washer
  • <volt reg flange>
  • CAD Plated Washer
  • Nut

Top right:

  • Bolt head
  • CAD Plated Washer
  • <side conduit>
  • SS washer
  • Standoff
  • SS washer
  • <volt reg flange>
  • CAD Plated Washer
  • Nut

Bottom right:

  • Bolt head
  • CAD Plated Washer
  • <side conduit>
  • Ground strap lug
  • Standoff
  • SS washer
  • <volt reg flange>
  • CAD Plated Washer
  • Nut
Test mount

Test mount

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).

Holes prepped

Holes prepped

Then, make the ground strap.

Ground strap

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.

Boo!

Boo!

No matter.

Pretty!

Pretty!

Who said forceps are a doctor's tool?

Mounting an adel

Mounting an adel

At any rate, after making sure that I'm happy with bowdens and probe harness, it was go time!

Intermission

Everywhere I take a nut off, I replace it with MS21042. Half the size, and it supersedes the default AN365 and AN363.

Just nuts!

Just nuts!

And by the way, often times it's convenient to use a "grabby thingie" to start them.

Grabbie

Grabbie

Back to it

Set up the hardware stacks, crimped short lengths of wires into the terminals, hooked up the ground strap...

Starting to mount

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

First dab of torqseal

Next, trimmed and crimped the ground wires.

Ground wires

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.

Installed!

Installed!

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 :).

Placards!

Placards!


Better to be on the ground wishing to be in the air than in the air wishing to be on the ground.


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Tagged with "6781G":

Bending Brake Lines

... and fitting in place


On: Sep 30, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 12.5
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

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.

Mockup one

Mockup one

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!

New hole!

New hole!

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.

Flaring tool

Flaring tool

Question: by how far does the tube have to stick out of it to arrive at the correct size flare?

Practice (evidence)

Practice (evidence)

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

Bottom hooked up, top not bent yet

  • Hook up the long portion (bottom)
  • Mark out the centerline of where the bend should be
  • Bend

The tubing bender has alignments marks for where the marked CL should go for different angles of bends.

Marking centerline

Marking centerline

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.

Real material!

Real material!

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

Bend angle first

Trim, flare, hook up the bottom and mark the top

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 :)

All done

All done

Installed

Installed

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..

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.

Clamps

Clamps

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

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

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? ;)

Getting close

Getting close

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

First bends - the first section (with sleeve and flare) is longer than original

Oh well.

Finished bending it, and installed it into the plane.

Seat to side...

Seat to side...

...and up the side

...and up the side

By the way, this is how this looks from under the plane.

From under

From under

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

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

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. :)

All done

All done

Two new tubes, all ready

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.

Oh well.

PS: at the time of this writing, I am actually more than 50% thru with both of finishing up brakes, and voltage regulator. :).


Do you see that propeller? Well, everything behind it revolves around money.


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Tagged with "6781G":

Drilling the Panel

...misery turned happy times!


On: Sep 10, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 5.9
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,..

Placard

Placard

..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?

Ha!

You'll see.

Read on.

Switch Anti-Rotation Holes

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.

Holes template

Holes template

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

Templates in the making

...out of a small piece of aluminum, drilled holes using my paper template, and cut them up...

Templates, cut 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

Center-punching on the back side of the panel

Click-clickity-clack.

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...

Placard!

Placard!

...this. Remo's placard that went around the switches. Like so:

Placards - in place

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.

Ha!

Well, it was smooth sailing from there...

Marking from the front

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).

Curlies!

Curlies!

All drilled!

All drilled!

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

Angle adapter for the side hole

Happy end!

Dimmer Pot

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

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 :).

Compass Mount

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..

I know!

Angle Sharpie Adapter

Angle Sharpie Adapter

A bit of disassembly and forceps do the trick ;).

aaaand, mark!

aaaand, mark!

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...

Mount mounted

Mount mounted

...and voila...

Vertical card compass!

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 :).

PS

... playing with new switch labels...

Labels

Labels

PPS

Oh, by the way, the best accompaniment (score? ;) ) for working on a biplane is...

... The Chairman, of course!


Some pilots will make an emergency out of a bad magneto check. Others, upon losing a wing, will ask for a lower altitude.


Up ↑
Tagged with "6781G":

FWF, Side Conduit, and Panel

...messing around trying things


On: Sep 08, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 21.5
Tags: 6781G, MA5 Charger, electrical, fwf, panel

I was on the fence about making this entry as multiple separate ones versus just one giant one... After all, it covers quite a few, mostly unrelated, things that I did in the last few days, and it would've made sense to keep them separate.

However; finally decided to make just one big article with all of them. None of them are finished; but somewhat a decent chunk of work is - I think I have mostly figured out where everything will go and how it will all come together.

I guess, what I'm trying to say is, if you clicked on the "Panel Layout" entry in the Log, and are trying to figure out why are you seeing notes on Firewall Forward, just keep scrolling :).

Diagram

I have updated the electrical diagram, version 2 is here.

  • Main Connector is gone. I was convinced that reliability concerns outweigh the benefits of having it. Plus, I have very little precious room to work with.
  • Physically, it's easier to hook up the LR3C Sense wire to a different spot - on the Shunt stud rather than to the Master Contactor/Starter Contactor jumper directly. It makes no difference, it's the same circuit - just a different hookup spot to it.
  • I also fixed some typos, and cleaned up a bit.

Firewall Forward

I started trying things around firewall forward while figuring out routing and lengths for carb control cables, and continued afterwards.

Contactors and Beefy Wires

Contactors

It became obvious fairly quickly that I won't be able to use the nice B&C Starter Contactor because of it's mounting holes not being the same as a very common SS581 Starter Solenoid that was set up by Remo. Also, the way terminals were set up on the B&C Starter Contactor would have made them closer to the carb control cables. And, I didn't want to drill more holes in the firewall.

B&C Contactor

B&C Contactor

SS581 Contactor

SS581 Contactor

So I decided to go with SS581-style and ordered one from Vans. While waiting for it, I used the old one just to mock things up.

And because it doesn't have the spike catcher diode, I had to get me a couple IN5400s, and soldered an extension lead to one of them.

Extension lead

Extension lead

The other leg will get a crimp ring terminal. I had to do that 'cause the diode leads themselves weren't long enough.

Battery and Starter Wires

Those are the thickest wires, and routing them is more complicated than the other ones. In addition, the battery + -> master contactor wire is the only wire that can't be turned off, and therefore needs to be very well thought out and as short as possible.

Here's something else, too. The Charger was set up to ground the battery to the motor. So far, so good - starter is by far the largest consumer in the electrical system. However, nothing was done to ground the motor to the rest of the airplane!

So the rest of the system was probably grounded via whatever metal to metal connections there were on the motor. Control cables and braided fuel and oil hoses? ;) Airbox bowden "carb heat" cable... I can't think of much more else.

Initially, I was planning to run a ground strap braid from the battery negative to one of the bolts holding the battery box to the firewall, but with fuel system components and control cables around, just couldn't figure out a good way to run it and support it. I had to end up settling for running it to the engine mount instead.

So the bottom line is, the negative 4GA cable is gonna go to the motor, and parallel to it a braid will go to the motor mount. I also figured out a clamp arrangement with some standoffs that will keep the wires neat and organized.

Beefy Wires - side view

Beefy Wires - side view

Beefy Wires - top view

Beefy Wires - top view

Negative leads and grounding

Negative leads and grounding

Oh hey, and I practiced my lacing on those ignition wires. One of my plans is to excise all the zipties I can get to, and replace them with lacing cord ;).

Laces

Laces

ANLs and Shunt

ANLs and the Ammeter Shunt will go to where no man had go... 'cuse me, to where the old Voltage Regulator was. Like this:

ANLs and Shunt placement

ANLs and Shunt placement

I will need to make a backplate for them to re-use the old voltage regulator mounts, and not have to drill new holes in the firewall. I used my Solidworks templating trick, and made me a nice template...

ANL template

ANL template

... and a mockup (with material, as usual, courtesy of USPS).

Mockup backplate

Mockup backplate

The shunt is offset "down" due to the top hole in the backplate (which will have one of three holddown screws to hook up to the old voltage regulator mounts), and I couldn't use buss bar stock to connect the stud terminals on the shunt and ANL bases - if I were to do that, it would not let the ANL covers to come on. So, before doing anything drastic, I decided to check to see how it would look with the wire jumpers

Crimper

Crimper

One side done

One side done

Second ring on the jumper

Second ring on the jumper

Done

Done

On the firewall

On the firewall

I liked the way jumpers came out a lot, and will probably keep them that way. They do add just a bit of weight, but not enough for me to worry about.

Side Conduit

The Voltage Regulator and the Main Terminal/Fuse Block were to go to the Side Conduit running alongside the fuselage.

Rough component locations

Rough component locations

I had to relocate the bowdens lower to free up some space. The Oil Cooler box on this plane is all sorts of weird, including a flapper valve controlled by one of those bowdens that closes up the airflow to it (which is not enough to begin with; being a 1.5" SCAT takeoff off of back baffle.. but don't get me started on that). That cable turned out to be too short when relocated - but I lucked out - Glenn had a bowden going to the Rotec TBI that I removed for "prime" function, and that bowden was plenty long. I'll trim it to final length when I'm done in that side conduit.

The brake tube was running inside the conduit, and I will have to relocate it to run below the conduit and be supported by adel clamps. For now, I unhooked it and used it to somewhat mock up the new run. Tube and fittings ordered, and tubing bender already here!

Fuse Block

I was gonna use a 20-position fuse block from B&C. Well, that didn't go too well.

Fuse block

Fuse block

Tight! I basically lose the whole top row of fuses with it. Not enough room....

After poking around the Internets for a bit, came to these nice fuse blocks made by Blue Sea Systems. Longest ones they have are 8 fuses, so I will need two (if I recall correctly, I have 13 fuses in the diagram currently, and I want some spare positions for later if I need them).

Blue Sea Systems fuse block

Blue Sea Systems fuse block

Much better! Plus, they use ring terminals rather than tabs - and while tabs are light and simple, I don't like them. Removing them is hard, and, when removed, the terminal loses a lot of it's grip. It's almost like an "assemble once" type deal.

Voltage Regulator

With how the wire harness is gonna go in that conduit, and with bowdens being where they are, the best orientation for the Voltage Regulator would've been "upside down", with terminal strip up.

Upside Down orientation

Upside Down orientation

Damn you, the yellow sticker on the regulator! DAMN you! (hint: read it :) ).

Mounting it sideways, I'd have a line of rivet heads under it - which I didn't want to deal with.

Sideways orientation

Sideways orientation

And mounting it down... Down was annoying because of the clamp for bowdens and bowdens close there. That would also complicate wiring.

Down orientation

Down orientation

Upside down would've been perfect... except for that yellow sticker :). So, I decided to Hail Mary and asked nice folks at B&C about what they thought.

See, the problem is I know why they wanted the terminal strip to be pointed down. It's so that water won't get into the box in case of condensation accumulating on it. But I thought, maybe I can seal it somehow?

The answer from TJ at B&C was a resounding no. Right side up, sideways - but not upside down.

So I mocked up the right side up mounting...

Right side up mockup

Right side up mockup

Yuck. Yeah; it'd work; but it's ugly as hell.

The only other option would be sideways, but on "standoffs" of sorts to clear the rivet heads. I mentioned that to TJ, and he said that that could work, but I should check if I can access the voltage adjustment screw on the top of the box.

Damn it! I forgot about it. On the top of the box there's a plug over a hole that opens up access to a tiny screw to adjust buss voltage - basically, to fine tune how much volts the battery sees. Not something you do often, but you want to be able to do it.

But then, TJ mentioned that he saw the holes in the firewall and that might be the saving grace.

Bingo!

I tried it out again in vertical, now with mocked up standoffs

Vertical

Vertical

With just enough aggravation due to bad access (mandatory in aviation pretty much), you can undo the bolt covering the hole in the firewall (this hole was left over from the brake line relocation), pop the plug on the voltage regulator, and just have enough access to the adjustment screw.

Adjustment screw - firewall side

Adjustment screw - firewall side

Adjustment screw - conduit side

Adjustment screw - conduit side

We got ourselves a winner, I think!

Panels

Hobbs

Hobbs was on the front panel, probably because of space issues on the rear panel.

Hobbs meter

Hobbs meter

"Aux Generator", eh? :) (read what the gauge says).

Well, I had this unsightly hole left over after removing the ignition key switch...

Unsightly hole

Unsightly hole

... and I thought, maybe I could put the Hobbs back there?

My initial tests with one of the 2 1/4 gauges I have removed seemed to have been okay: there was just enough room in there to get another 2 1/4 gauge in.

So, I got me a very nice panel punch that could make a nice, round, clean hole in place.

Instrument Hole Punch

Instrument Hole Punch

Well, next was to remove the Hobbs from the front panel. That was an hour of contortionism. The Hobbs is held by an aluminum backplate and four nylock nuts, so I had to have a wrench over them the whole time. Oh, the screws are way too long BTW, so taking all them out took about five times more turns than it should've, while I was wondering if my wrists will take this much flexing, twisting, and bending any longer.

Mounting ring

Mounting ring

This is a pic from the fuel quantity gauge held in the same manner, but here he's using brass flat type nuts that you can hold with your fingers. On the Hobbs, it was nylocks.

Anyway, I got it out. And then, started setting up for punching that hole. Removed VSI to give me a bit more room to work with.

I tried to reconstruct exactly what happened next in my memory to write it down here, and could not. I was basically fiddling, checking clearances, making sure I'll be able to hook up the punch and center the hole, have enough room for the mounting ring in the back and clear everything I had to clear, when I discovered that...

The Hobbs was not a standard 2 1/4 inch gauge - it was a touch bigger. So the hole that I would've made would've been too small for it. And that if I punched the hole, I would've been just left with a bigger hole and nothing to put in there.

Damn, damn, damn! Damn you, assumptions that every "small" gauge on an airplane is 2 1/4!

And I had the expensive punch that I had no use for :(.

Oh well. Thanks God I actually did not do it - only to have a larger hole to plug up. I guess, that Hobbs is (thru more contortionism) going back to the front panel.

As they say, Le Sigh.

Switches

Finally, something fun! I put in the switches to play with layout. Here's the first, and (after playing with moving things around and pretend turning them on and off), the best, layout.

Left side

Left side

Right side

Right side

On the right side, I might clump the switches together, or leave them as on the picture, to "match" the placards (those are left over placards from fuses that were there in the old electrical system). The little brass knob on the right is gonna be panel lighting control pot.

Compass

I am going to replace Pilot's whiskey compass with a vertical card one - yes, I am directionally retarded :) It's not that expensive a mod in the grand scheme of things; and is the only directional instrument available to pilot on this plane (no DG ;) ).

It's a bit taller than the whiskey compass, so I'm playing with different mount locations. I think this is what it will be; with shock isolating rubber pad under the mount where the gap is at the moment.

Compass

Compass

Fuel Sender Crimps

One of the evenings, I wanted to make sure the Fuel Gauge was still okay (I had a suspicion that it wasn't - turned out to be false).

But first, I wanted to clean up the wiring on the tank sender.

Before

Before

Before

Before

The terminals on it are "automotive" style, without insulation support.

After

After

After

After

There. No zipties, good terminals, and marked :)


"How far behind traffic are we?"
"Three miles."
"That doesn't look like three miles to us!"
"you're a mile and a half from him, he's a mile and a half from you...that's three miles."
-ORD ATC


Up ↑
Tagged with "6781G":

Carb Control Cables

...just measuring


On: Sep 01, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 9.3
Tags: 6781G, MA5 Charger, carb, throttle, mixture, cables, controls, engine, fwf

Even before Oshkosh, I have decided to replace the Rotec TBI the Charger had when I got it with a good old MA4-SPA carb. In short, I do not trust the damn thing - especially with it being the sole component providing two out of three vertices of the proverbial fire triangle to the motor. That reminds me, I need to summarize my thoughts on Rotec...

Regardless, one of the things I got at Oshkosh was a rebuilt MA4-SPA from Spruce, and it was sitting in the hangar waiting it's turn. I knew I would need to order new control cables for it, so I decided to get that going, after all the alternator business was finished, because getting those cables will take me a bit.

Here's a fun aside. I knew this motor had a MA4 carb and Glenn "upgraded" it to the Rotec TBI. What I didn't know was precisely what kind of MA4-SPA it had (and there are quite a few models of that carb).

No problem. At Oshkosh, I went to nice folks from Tempest (which now owns MA Carbs) and had a very nice conversation with them. I asked if I should buy the carb from them, and they recommended Spruce instead, because it would be cheaper that way. And, they mentioned the $600 core charge (I'll spell this out - you must provide a good "core" (old carburetor) or get charged extra six hundred bucks). Ouch.

Ha! thought I. I am at Oshkosh! What could be easier than getting an old carburetor, especially since it's one of the most widespread models? No problem at all!

Laughing, I ran that by guys from Tempest. They laughed with me, and actually were very very very helpful, telling me what to look for when picking up an old carb.

No cracks in the body. Control arms should be present. Threads nice and not torn up. Venturi present. Etc etc etc.

Well, to the FlyMart we went, and sure enough, on a bench there laid a number of MA4-SPAs present, ranging from $250 to $450. Of course, I picked up the $250 one (it was yellowtagged by the way! In 1995, if I recall), dragged it over to Spruce, ordered a new carb, and handed them the old one I just picked up. So, $350 saved in about half a mile of walking. Not bad!

Here it is, in all it's glory, hooked up to my motor. You guys should admire my "economizer design" gasket. Hmm... I need to patent that and start selling them for $100/pop. Your fuel costs will go to 0! Now, you might not be going too far... but.. Fuel costs! Zero! With all the benefits, not going anywhere is such an insig.... Ahem.

Economizer Gasket

Economizer Gasket

Carb

Carb

Well, okay. The carb was on, and cables came next.

The Rotec had it's control cables for mixture and throttle done completely differently than the carb. Glenn reused Throttle cable for Mixture on the TBI - it worked out well. He added a new cable, routed completely differently, for the TBI's Throttle.

Since this motor was originally carbureted, all I had to do is reverse engineer a bit the way Remo did the hookups.

Hehe.

Well, Throttle on the carb side wasn't that bad.

With a Rod End Bearing

With a Rod End Bearing

With a Clevis

With a Clevis

It actually worked out a bit better with a Clevis, having the cable end centered nicely on the throttle arm. So I decided to do the clevis.

Next was confirming the "throw" - making sure that the throttle control range of motion, whatever it is, is sufficient (in fact, it must have some extra "padding" in it) to move the throttle stop to stop. Boy, was I in for a treat.

This Charger has reversing throttle quadrants, meaning that when the throttle goes forward, the actual control is pulled backward. Since forward on the control must translate into forward on the carburetor, the Charger has bellcranks to reverse the motion once again. These bellcranks are also a nice spot to tune out the range of motion.

Control linkage

Control linkage

See, the relative distance of the top and bottom holes on the bellcrank to it's pivot point "convert" whatever range of motion is on the control (throttle quadrant) side to an appropriate range of motion on the carburetor side.

And Glenn changed them.

Not a surprise. The Rotec TBI had it's controls set up very differently as compared to a carb. Notice how in the picture the color of those bellcranks is somewhat off from the rest of the fuselage? That was my first clue...

My second clue was finding one of those bellcrank plates (minus the bearing) in the box of parts that I got with the airplane.

My third clue was me not being able to get the full range on the throttle.

Crap!

I am absolutely not set up to redo the bellcranks. Though they look simple, unless I want to make them from 3/16" steel, which would make them very, very, VERY heavy, I'd need a TIG welder. Or to MacGyver things with washers. And do quite a lot of trial and error.

I wanted to see if I could luck out.

Credit goes to Glenn here - he made his new bellcranks perfect for the TBI. The range of motion on them was just right... for the TBI. Because of that, they were asymmetrical - so I thought; maybe, just maybe, if I was to try them in different combinations, I would luck out...

And I did!

Now, these two paragraphs of text and one picture is me describing... about 3 or 4 hours of work - tweaking cables, turning bellcranks, checking, rinsing, and repeating. I think I did find a combination of orientation of these that gave me acceptable (but by no means perfect) ranges of motion. I think I lost about an inch on both of the controls, but that's not so bad, after all - you want extra room in your control's range of movement to make absolutely positive you can move the controlled thing stop to stop.

Okay, Mixture's next.

I hooked up the cable that Glenn used for throttle to the mixture control on the carb, to use as a "mock up", and kinda fished it thru.

Mixture cable hookup

Mixture cable hookup

I had to use a rod end here. The cable wouldn't line up with the control arm on the carb for me to be able to use a Clevis there.... See how angled and offset that hookup is? I think Remo had a solid bowden cable style control there...

Another problem with the Mixture control is that the carb's arm has a 1/4" hole.. the rod ends need a #10 screw; which means that the hole on the carb arm is too large. No biggie though, I'll add a bushing to reduce it.

Yet another problem is that the bolt's head is way too close to the carb bowl, and I had to have it reversed like that (bolt "upside down").

There's not a lot of room on the top either. Planning to fix this problem with using of 1/2 size shear nut, and figuring out the exact bolt length (I ordered every bolt between -4 and -10 sizes).

And now, the routing of those cables.

The throttle cable routing was a given. I did not like too tight a radius in one of it's "turns".

I wanted to try to optimize the routing..... ha. Good luck there buddy! The battery box gets in the way (the battery is in a completely wrong place on this plane... it's reversed with the oil cooler. Oil cooler should be on the left. Battery on the right. This makes controls routing a breeze. But no.....).

I wanted to make sure to keep the mixture cable to not be too close to the beefy 4 AWG cable that will go from the battery to the master relay.

I had to reverse engineer previous routing of the cable, and figure out the best points to hook it up to the firewall.

I wanted to have my ANL fuse bases close to the master and starter relay. Ha! No way, with the control cables the way they would have to be.

All this was an exercise in misery, and lots and lots of time. I wanted too much.

In the end, the routing of the throttle will stay the same; the cable will just be shortened to make one of the turn radiusii bigger. The mixture will go nearby, and curl around the battery box.

I will not be able to use any other arrangement of solenoids and will have to stick to the old one. What's worse, I will not be able to use the new solenoid I got from B&C - it's mounting holes are very different, and, frankly, it's not worth it to drill more holes in already a sieve-like firewall - I'll stick with the classic "style".

Approx. new routing

Approx. new routing

The mixture cable does look like it'll interfere with the solenoids, I know. In the final setup, it will be pulled away from the firewall and clamped to a couple of points I found.

...

More bad news? I long noticed a leak from the left brake bleeder valve; and decided to add a new valve to my next order from Spruce. I thought it was a basic valve problem. Well, went to look for it's dimensions, and found out the source of the damn leak, actually... Looks like someone tried to fix a leak there by making a bigger leak. The fun thing was, I didn't notice this before - the brake was too dirty...

Boo!

Boo!

Damn.. those cylinder housings are $300 each :(

But hey! I got good news too! I was checking to see if the ANL bases and the shunt will fit where the old voltage regulator was, and they fit perfectly, in just a perfect arrangement!

ANL bases and the ammeter shunt

ANL bases and the ammeter shunt

I will reuse old voltage regulator rubber shock isolation mounts (I can't take them out; and they're sufficiently strong), and make a backplate to mount all this goodness to. Frankly, when I found this fit out, I liked it so much I bust out laughing.

And hey! My engine gauges showed up ;) Ain't they pretty?

Engine gauges

Engine gauges


Helicopters don't fly. They beat the air into submission.


Up ↑
Tagged with "6781G":

Alternator Pivot Arm Bracket

lots of grinding


On: Aug 31, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 14.5
Tags: 6781G, MA5 Charger, alternator, 4130, fabrication, drilling, CAD, SWX

With baffle support bracket done, the next step on the path to alternator happiness was the pivot arm.

The Problem

... was that the default B&C's pivot arm did interfere with the front baffle hookup brackets.

Interference!

Interference!

That did actually make me pay attention to the very unusual old pivot arm.

Old one

Old one

Nice dogleg, isn't it?

Well, this bracket did not involve any bending, just needed to make the correct one to fit around all the other stuff there on the nose.

Hmm... so how do we do that? Well, first, we need...

The Template

This is not the real template, because (.. read on ;) ). It's the template for the Template.

Start with a piece of heavy paper

Start with a piece of heavy paper

Cut around the alternator

Cut around the alternator

All we need to do with this template is show the location of the hookup hole (top hole, the one that attaches the bracket to the motor); the location of the slot for the alternator to hook up to, and the general outline of the alternator

Alternator bolt location is being marked

Alternator bolt location is being marked

Bolt imprints along the

Bolt imprints along the "pivot arc"

..and finally, some more "no go" zones to prevent interference with other brackets there:

Done!

Done!

Notice I also added some "imprints" of the B&C-supplied pivot arm in there, just in case I'd need them.

Okay. I'm lying to you. This template is not the one I used. It was done with the long belt that ended up not working out, so I had to redo the template (thanks God, just the template). The new one was done in the same manner as the one I described above.

Here it is:

The *actual* template used

The *actual* template used

Okay. So now, we know critical locations of things and where not to go - so, cue in...

Solidworks!

It's magic, I keep telling people.

So, we take our template, and scan it on a scanner, along with a little metal ruler to give us physical dimensions. Then, we go to Solidworks, start a sketch, and insert the scan as "sketch picture". Using the image of the ruler that was scanned in, we tell Solidworks what "one inch" on this picture is. Boom! The image is now dimensionally accurate.

Then, we start drawing around it.

Initial sketch

Initial sketch

Above, I positioned the top hole, and the four 5/16" holes around bolt imprints. I then sketched a large circle and made it tangent to three out of four of those holes - it defines the "pivot arc". Then, offsetting it 5/16th gives me the other "side" of the slot; and offsetting it more gives me the "sides" of the bracket in the "pivot arc" area.

I also started sketching the "no go" lines around the top portion of the bracket.

More circles

More circles

More circles and lines are added, and off-set. They are not positioned or dimensioned - just made tangent to "no go" lines. You can almost see the outline of the pivot arm, yes? ;)

Now, we take this master sketch; and add arc elements with real lines that we care about.

The arm!

The arm!

Tada! We got the Solidworks Part.

By the way. How do you "measure" the round over of the B&C arm? Radius gauge? Calipers? Hmmm.. Or...

Measuring with Solidworks

Measuring with Solidworks

Nice, isn't it?

Next, we print the drawing of our new part; making sure our holes' centers are marked (we'll use that later to drill them)

Done!

Done!

And, we got ourselves the actual template!

Now, the final test (Many thanks to USPS for providing material for this test)

Spray glue and cardboard

Spray glue and cardboard

I wish I could cut 1/8

I wish I could cut 1/8" steel with X-Acto...

The mockup

The mockup

Tadaa!!

Tadaa!!

Okay, we have the real template now, and we know it'll work. And now, comes...

The Grind

1/8

1/8" steel is no joke

Nice little sheet of 1/8" 4130 showed up from Spruce some time earlier... I used spray glue to put the print out of the bracket on top of it.

Template on steel

Template on steel

First, all the holes had to be drilled. The drill press I have at the moment is severely underpowered, so I had to step-drill them in four steps.

Curlies!

Curlies!

I got to admit, I am starting to become very fond of pretty steel curlies made by nice drill bits.

Also, lesson number one learned: drilling oil (I used TapMagic) gets under the template, and messes up the glue (and unglues it). I need to figure out a better glue.

I drilled the slot's "start" and "end" holes slightly undersized, and reamed the main attachment hole to 5/16ths exactly.

Reamer!

Reamer!

Next, the slot... I rough-drilled small holes around it's perimeter, thinking that a 1/8" shank carbide burr in an air die grinder (basically, Dremel) would work... Ha! It did... for a second ;)

Slot in the making

Slot in the making

Boo!

Boo!

Okay, time to go old school... where's that...

Hacksaw!

Hacksaw!

I cut it out, and cleaned it out with a bastard file.

Cut out

Cut out

.. and cleaned up

.. and cleaned up

And then, more and more hacksaw...

.. my right arm

.. my right arm

.. is beginning to feel...

.. is beginning to feel...

.. it ..

.. it ..

Yeah. The last few inches, I gave up, and used the jig saw. It did cost me 3 blades, but I was too ... done with the hacksaw. I figure, about a blade per 1 inch of cut in 1/8" 4130 with a jigsaw...

.. gave up.

.. gave up.

Cutting done.

Cutting done.

Looks very ugly, right? Well.... to the grinder!

Grind...

Grind...

.. grind ..

.. grind ..

.. grind away ..

.. grind away ..

Three belts I believe is what it took.

Well, now, the final cleanup on the slot. Yes, Dima, I used the rotary file here :).

Cleaning up the slot

Cleaning up the slot

..and, test fit

Tadaa!

Tadaa!

That was two evenings, folks; but I wasn't done.

The Three Brackets

The Three Brackets

Next, I had to prep the edges and sand out all the scratches, and paint. A deburring wheel on a bench grinder helped; and the most nasty marks were filed out and then polished out with the deburring wheel.

Clean edge

Clean edge

It has to be done because every scratch is a stress riser - on fittings, every edge needs to be rounded over, and polished.

Finally, to....

Paint

Every airplane "paintjob" I've done so far was in my makeshift "paintboots". Like this one.

Paintbooth!

Paintbooth!

I sprayed both the pivot arm, and the baffle support bracket I made earlier, with self-etching primer, and some Rustoleum paint. White will make cracks more visible, if they show up.

Painted!

Painted!

So there we go. With this done, I can now install the alternator. Just measly 30 hours to get ready to install the damn alternator! ;)


"Air Force one, I told you to expedite."
-ORD ATC


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Tagged with "6781G":

Alternator Install: Nose Baffle Support Bracket

...I am Bender, insert girder


On: Aug 25, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 9.5
Tags: 6781G, MA5 Charger, alternator, 4130, fabrication, bending

As I have thought before, I would need the new nose baffle support bracket, to replace this one:

Old baffle support bracket

Old baffle support bracket

...because it would have to now be shorter, fitting in front of the new case mount alternator bracket, over it's right "ear" over here:

Alternator mount ear and starter

Alternator mount ear and starter

However, prepping to set up to do it, I found this.

Gap between starter boss and alternator bracket

Gap between starter boss and alternator bracket

See that gap between the starter boss "ear" and the new alternator bracket?

Hmmm, methinks.. Maybe, maybe, I can get away without bending up a new, 0.090 steel bracket with weird geometry (it's not a simple "couple bends and you're done" - you'll see later).

Well, let's see.

Old bracket fits nicely in that gap

Old bracket fits nicely in that gap

But it was just a touch too "low". Didn't fit right - and I couldn't raise it (that would raise the holes to which the nose baffle itself attaches, and make the whole thing just not work).

Oh well, I guess we're bending steel after all.

Around that time, my strip of 4130 I ordered from Spruce some days back showed up.

I needed a vice, and a couple more pieces of steel for bending block and such. Picked those up at big box stores (and I will admit, that included a trip to Harbor Freight..).

I also fished out my old small belt sander, and air grinder, from the storage (all my tools are packed up aside from simple hand tools - I am rebuilding my shop; and thanks God I had them close so that I didn't have to rummage thru boxes).

Cutting off a small chunk of an approx. 1/4" thick strip for a bending block is no joke...

... Cutting

... Cutting

My compressor would run out of air, and I'd have to stop, and, while waiting for it to get back to pressure, use hacksaw ('cause I didn't have anything better to do).

Then, I attempted to get away with shoddy bevel grind on the bending block...

Very poorly made bending block

Very poorly made bending block

I hoped that that little "cavity" in the middle would work enough to handle bending spring-back - the roundover was fine, just the bevel was uneven.

Ha! Bending a couple of test bends proved me wrong; and that one never gets away with shoddy workmanship.

I re-ground the block to have a nice, even section (all that on a 1x30 belt sander by the way - which I have discovered is perfectly adequate for handling steel with a ~40 grit belt).

A much better bending block

A much better bending block

Cut my 4130 strip to width:

Hacksaw!

Hacksaw!

... and clean up that edge

Edge to be cleaned up

Edge to be cleaned up

I kinda gave up on it, frankly - got too tired to get it straight and even; and decided to temporarily switch my mind to something else.

Instead, I cut another, test strip, of 4130, without making it to proper width - and attempted to replicate the bracket's geometry on the now much better bending block.

Thinking about how to replicate bend lines, I couldn't think of anything better than... just roughly folding a piece of paper over the old bracket.

Old bracket, test bend, paper pattern, and strip prepared for the new bracket

Old bracket, test bend, paper pattern, and strip prepared for the new bracket

It worked!

The key was, rather than bending the strip over the block by hand, instead, start the bend by hand, and then finish it with the hammer. I used another piece of 1/4 strip that I cleaned up as an "interface" between the hammer and the material bent, to avoid hammer marks. This way, the bend was much tighter radius (equal to about material thickness, which is what you need for steel), and much easier to control and nudge in the proper direction.

The geometry of the bracket was close enough; the angles were off a bit, but those could be tweaked.

All that bending was one day. I felt done, and left.

Next time I was over at the hangar, I thought, "to hell with it", and decided to use my real strip that I cut out for final bracket.

Used a nice square to draw a reference line, and cleaned up and straightened that edge left over from cutting, marked the first bend line using the paper template left over from my test bend:

Bend mark one

Bend mark one

... put it into the vice

Bend one

Bend one

and bent, using the old bracket for angle reference. That worked out okay, so marked and bent the second bend

Bend two

Bend two

See the problem? Yep, the first bend is not right on the mark - I did not clamp it right for that first bend. No problem though, I had enough spare length on both ends, so I just moved the location of the second bend accordingly.

Final tweaking by hand

Final tweaking by hand

The hole is made, the

The hole is made, the "ear" is about to be

The hole was drilled with a Unibit, and all the cutting off of small pieces was done with a 3" cutoff wheel on an air die grinder, followed by final tweaking on the 1x30 belt sander.

The ear

The ear

And now, the first try.

Did it... work!?

Did it... work!?

Wow. It might've worked!!! Maybe.. just maybe.. the final test will be if I'll be able to make the holes for the baffle in it.

But for that, we need to position the baffle, and then mark out the holes.

No problem.

Bolt on the old bracket, and hook up the baffle to it. Use anything, whatever, for reference (I used the starter conveniently sticking thru the baffle):

Reference marks set

Reference marks set

Then, unbolt old bracket, put the new bracket in, and mark out the holes, while having the baffle back to position marked by reference marks.

Marking new bracket

Marking new bracket

Okay, here it is. The final test.

The Two Brackets

The Two Brackets

Not bad! Given the messed up geometry, me using the paper pattern, my first attempt at bending, it's not that bad at all! Hey, my holes are also not on the center; but the old bracket doesn't have it's holes particularly centered either (and it won the Golden Lindy ;) ).

I guess I'm keeping mine.

I pulled out my nice Cobalt bits I got at Oshkosh to make those holes. At that point I have obtained an old small drill press for the hangar (I had to drill the first, large, hole in the "ear" free hand - even with Unibit that was very annoying).

Sweet metal shavings

Sweet metal shavings

Final check

Final check

... and, trimmed to size

... and, trimmed to size

Emery cloth the whole thing, and it's done.

By the way - you must say - but it's just two bends! How come your holes are not lining up nicely, and such?

Well, this thing has a very messed up geometry. It's two bends, at a non-even angle. This picture probably illustrates this best:

Geometry

Geometry

Meanwhile, I also had to figure out the alternator's belt length - to make sure it clears all the brackets, and holes in the nose baffle.

I wrote a bit about it in the previous post. Initially I thought that just mocking up the belt, measuring the length of the mockup, and ordering the right size would work - ha!

New belt was too long, and didn't clear the newly made bracket.

Ooookay. Well, I had the belt that's too long (the one I ordered after making the mockup of belt length with a chunk of wire). And, I had the belt that was too short (the one that came with the alternator).

So, I bought all the sizes in between.

Belts!

Belts!

The one that worked? 7320 :).

... and just to make sure that everything will fit with the new bracket, I ended up putting the nosebowl back on. Didn't want to discover that the nose baffle was sticking out, or not fitting in any other way, when putting the cowling back on.

Bracket - final cut (still temp hardware)

Bracket - final cut (still temp hardware)

Fit check with nosebowl

Fit check with nosebowl

OKay. Next - the pivot arm! No bending here. Just lots and lots of grinding.

Meanwhile, all my electrical hardware started showing up! It's like Christmas in August!

Switches

Switches

Components

Components


Navy pilots regards Air Force formation flying skills:
“Same way, same day.”


Up ↑
Tagged with "6781G":

Alternator: Initial Fit-Up

...I almost decided to make new nose baffles


On: Aug 16, 2019
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 4.8
Tags: 6781G, MA5 Charger, electrical, alternator

So most orders have been placed, and a lot of them have arrived already. (Note to self: need to take pictures of all the stuff).

The first thing to be worked on is the heart - the alternator.

Look at this little beauty!

B&C L-40

B&C L-40

Tiny, light as a feather, and cute as a button! No, sir, this thing has to get attached to the nose!

The old one needs to come off. Pivot arm bolt undone. Pivot bold undone.

Wait. The pivot bolt can't get out, because the flywheel gets in the way...

Pivot bolt and interference

Pivot bolt and interference

Hmm.. No, I can't believe Remo pulled the flywheel off of crank just to install the alternator. There must be a better way.

The better way - bracket attach bolts!

The better way - bracket attach bolts!

Aha! This is case mount, and the bracket is attached to the motor case. Let's see... Yep! It came off.

Now, the new bracket... centers nicely!

New bracket

New bracket

See that ear on the right, that touches the starter boss? That one needs to attach to the starter, to prevent the bracket flexing left and right. It lines up great, but, problem number one (but I knew this one), the old alternator bracket didn't have that. Remo used that hole on the starter boss to hook up the front of the nose "ramp" part of the baffle:

Baffle attach bracket

Baffle attach bracket

No matter. I will just bend up a new one, to account for the thickness of the new bracket's "ear" that will get sandwiched between this baffle attach bracket, and the starter boss. Material already ordered!

Now, let's test fit the belt, and the new pivot arm. The belt, the belt.. oh wait. Yep. The prop needs to come off - but this is a non-event now (and I am not leaving the prop off again - learned that one already). I'm becoming quite good at this prop pulling business....

Belt on and prop back on, test-fitting the pivot arm... CRUD!

Pivot arm

Pivot arm

That black bracket to the left of it holds the hose "ramp" portion of the baffle..... and, it won't let the damn pivot arm go in! No way. And no easy modification here - it's interfering, seriously...

Frankly, at that point I went home (this whole note covers quite a few days of work), with thoughts of remaking the front baffle; and spent the evening researching how baffles are done on planes with similar nosebowl... Frankly, I don't like how this front baffle is done on this plane (see Cowling Conundrum), and thought of this as being a good chance to fix it. I moaned about this to my buddy and colleague Dima D (who's helping me here quite a lot with notes and advice)...

But next nite, I thought that maybe I can get away with remaking just the arm... I am absolutely not set up to do complicated sheet metal work at the moment...

The old alternator had this weird pivot arm that now made way more sense. It "doglegged" around the bracket with which the standard pivot arm interfered:

The old pivot arm

The old pivot arm

Notice how it has this portion that goes down, and then the pivot arm "turns" left to go under the nose baffle ramp attach bracket?

That corner is definitely a large stress riser... but this arm held a much heavier Delco-Remy alternator for almost 40 years... Granted, it's made out of 0.190 steel as opposed to 0.125 steel used in B&C bracket... but I can make a similar one for the new alternator...

We'll see if we can smooth out that corner so that it's arcing better, reducing stress. If I can, I will use 0.125 steel. If I can't, I'll settle with 0.190 - just like the old one. We know this works.

Thanks Dima! You were right. For now. I will redo this nose ramp when I'm redoing the motor, later :).

... and now, to the belt. Let's get this nose ramp back on. It has an opening for the belt to pass thru, and a fairing for the alternator pulley....

Damn. Yep. That one doesn't fit right, either.

Nose ramp back on

Nose ramp back on

If you look real careful inside the red circle, you can just see the belt there. It will rub on the left edge of that hole. It has to go right, which means the alternator has to go down, which means longer belt.

I used a piece of wire to mock this up. Here are a couple of pictures from the back side.

B&C supplied belt - interference

B&C supplied belt - interference

Wire mocking up a longer belt - so that it's centered in the hole

Wire mocking up a longer belt - so that it's centered in the hole

I ordered a couple of longer belts from the same series, to try them out and see how they will work in the end...

So, where are we at?

  • I will need a new, smaller, bracket for the front support of that nose baffle ramp (the bracket will attach to the starter, same place as before)
  • I will need to design and make a new pivot arm - and to learn how to make nice slots with hand tools
  • A different belt

Meanwhile, folks at B&C were extremely helpful and generous with their time, reading my long, ranty, emails, and responding to me with their thoughts. I really appreciated that!


A terminal forecast is a horoscope with numbers.



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