[79FT]: Building Things

Wiring - Pt III

...part three: done!


On: Sep 07, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 16.6
Tags: 6781G, MA5 Charger, electrical, panel, instruments

... and the only bit of wiring left was the gauges at the panel.

It was not interesting in any way - mostly, lots of tying in awkward position.

A lot of stuff had to be done thru the front hole's headrest, while standing on a wing, and trying not to get "tangled" in the flying and landing wires.

Oh well.

I realized this was another mistake. Since all the gauge wires started at their transducers or sensors (amps, fuel and oil pressures, oil temp, and the like), I ran them "backwards" as one piece, and was planning to put on the corresponding D-Sub connectors in place.

What I didn't realize was how much pain it will be if I had to work in close quarters. And unfortunately, the 3-in-1 gauge - with the fattest of the connectors - required that.

What I should've done was cut the transducer and sensor's wires and made "whips" for them with connectors while on the bench. Then, I should've spliced them somewhere on the side of the airplane - yes, I'd have to do a lot of soldering, but that would've been better than what I ended up having to do...

Instrument wires - and the back side of 3-in-1

Instrument wires - and the back side of 3-in-1

You can see the DB-15 connector there - that's the 3-in-1. Sticking the wires thru the instrument hole, doing all the stripping and crimping from the panel side while sitting in the cockpit, and then tying the extra length up... maybe was possible, but seemed to me like it would be too much extra, producing ugliness and possibly rubbing on the structure nearby, so I decided to make that connector as close to the actual gauge as I could...

I tried it on the bench first, figuring out where I would put heatshrink, how much of the length is necessary for the connector, and the like.

Another interesting tidbit was that one of the connections had to feed two transducers off of the same one pin. Both wires were 22GA and I couldn't put them into the pin no matter how I tried - too much wire for one D-SUB pin's barrel. I'll show you the solution I used for that.

So, I bunched up the wires, put a round of heatshrink on, and prepped those power wires.

3-in-1 bundle

3-in-1 bundle

I bent the two power wires for transducers backwards "out" of the connector, and pigtailed a single 20ga wire to them. That looped back into the connector and hooked up to the pin.

Then, I set myself up on the wing, slouching over the front hole's combing, took my stripper, and stripped a wire... bam! 2/3ds of the strands came off...

What the..?!

I think the stripper pinched the wire when closing on it, and since I was so much out of position - practically upside down - I didn't notice...

And since I effectively just destroyed ~1/2 inch of the wire, and the wires were cut short....

I lucked out. The wire I was stripping was a standalone ground wire. Moreover, I had two more tails coming from the same source - for the other two gauges, and the unintentionally shortened tail I just made was just the right length for another gauge.

Phew. Only having to cut two knots, I re-routed the shortened wire to the other gauge, and that gauge's wire to the 3-in-1 bundle.

Tested the stripper multiple times. Yes, I think I just missed the right hole.

Making dead sure I was on this time, I tried again - phew. All worked out.

Slowly, everything got crimped.

3-in-1 gauge pins

3-in-1 gauge pins

You can also see that "power loop" in the above picture.

Then, I installed the pins in the housing, and checked the 3-in-1 out. Used a plumber's gauge to pressurize pressure transducers with some appropriate amount of air and made sure the correct arrow went up on the 3-in-1, and by the right amount.

Testing pressure transducers

Testing pressure transducers

The other three gauges were much easier - because they were further from the 3-in-1 and tie point, for each of them I could trim and crimp the wires from the cockpit side. I had some fun times with the housing of the tach connector - a DB-9... UMA shipped me a weird sheet metal shell for it I've never seen that I think needs a special crimper to install, so I ended up replacing it with a regular cheapo plastic after spending what feels like a few hours trying to find out what the hell that shell was... Failed at that.

At any rate.

The final result? Well..

Beind the panel: done.

Beind the panel: done.

And with that, the re-wiring of the Charger was...

Complete!!!


"It's too late for Louisville. we're going back to O'Hare."
-ORD ATC


Up ↑

Wiring - Pt II

...part two


On: Sep 06, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 18.21
Tags: 6781G, MA5 Charger, electrical, soldering, fwf, magnetoes, p-lead

Well, we're continuing happily with wiring over here :).

Wingtips

SkyBeacon and SkySensor were to replace the existing nav lights. Yes, I know, SkySensor is probably a gimmick. But what the hell.

Remo ran nav light wires in a -4 tubing along the front wing spar, using it as kind of a "conduit", exiting the wires around the wingtip, and just soldering them to the nav lights he used. Wires were ~3 ft too long, which is a fine "service whip", but they were just laying on top of the inside of the fabric of the wingtip. There are no access holes on the wingtip, so no way to get in to tie them up.

Oh well. We work with what we have.

I was going to shorten the wires, and because the lights are on the top wing, I didn't want to solder them - I'd be doing it off of a ladder, very near if not on the wing's fabric... lots of things to go wrong.

The other thing I didn't want to happen was to have the connection points between the light's wire pigtails and wires in the wings to "rattle around" the wingtip (with no way of tying them down).

So I had this brilliant idea. The pic is post-realizing the idea was a mistake, with HST cut off....

SkySensor, and cut off HST

SkySensor, and cut off HST

The lights had this plastic tube coming out thru which the wires were routed. I would shorten the pigtails as much as I could (like on the picture basically), hook'em up to the wing wires with barrel crimps, and put a long piece of my favorite glue-lined SCL tubing over them - with it glueing itself to the plastic tube and to the wires, creating one rigid "tube" coming off of the light...

Boy was that a mistake.

The tubing glued itself to the wires alright - but not to the plastic tube. So the whole thing created a rattly "lever" that would pull the wires thru that tube when vibrated - loading the soldered joints on the PCB of the SkySensor.

Not Good At All.

So that idea had to go to trash, and I had to cut the heatshrink off, carefully, with all the glue, without damaging the wires...

And ended up having to do exactly what I was trying to avoid - having rattling connections between the wing wires and the light, and to solder them. Why solder? Well, because the barrel crimps are heavy, relatively speaking, and I didn't want those heavy "bumps" bouncing around inside the wingtip, even with HST around them.

So, solder.

From the ladder, on top of the wing, covered in fabric.

Soldering setup

Soldering setup

You can see the heating station on top of the ladder, and the light ready on some layer of paper towels on top of the wings.

As usual, I used the Nuckolls Splice.

Prepped for soldering

Prepped for soldering

All soldered

All soldered

HST, and ties

HST, and ties

The other side got the same treatment, and...

Let there be light!

Let there be light!

The other fun part? On the left side, Remo had standard 6-32 tapped holes in whatever the backing of the light socket for the navlight was made out of. I couldn't really see - maybe a nutplate, maybe just tapped sheet metal.

But on the right side, he used sheet metal screws. Which, of course, I didn't know about till I started putting the lights on - because I took apart the left side when checking if SkyBeacon will fit, and assumed the other side would be exactly the same. As usual, rookie mistake. By now, I should know to check everything.

Well, that was a minor delay. Spruce / AN standard doesn't have screws with the right size head (#6 AN screws have heads too large to fit on the SkyBeacon and SkySensor), so McMaster-Carr had to be resorted to to get the right size and length sheet metal screws.

P-Leads

The Charger has the Bendix mags, and the P-lead connectors on those are not ring-terminated; instead, using a "screw in" type deal.

Bendix type p-lead connector - old wire

Bendix type p-lead connector - old wire

Basically, the shielded wire goes thru the outer bushing. The ferrule is a "T"-shaped sleeve, and shield get spread out over the "shank" of the T. It's squished between the outer bushing's base and the "flat" of the T of the inner ferrule.

The center wire goes thru an insulating spacer (that brown piece), and thru a washer on the other end - with a "button" of solder built on top of the washer to create a contact point.

The whole contraption gets screwed into the mag's receiving hole with the nut - ferrule rests against the mag's casing, pushing on the insulator and the solder button to contact the contact point inside the mag, while the nut pushes on the outer bushing and clamps the shield between it's base and the inner ferrule.

Now, that works with something like 16GA wire, and it's too big with my small 20GA P-leads. Also, notice how beat up the shield on that setup is? That's the old P-lead.

Folks make adapters for these to go to ring terminals, but they run something like $100 per, which is just silly, so I was determined to make this work.

Here was my idea, and what it looked like on the right mag. Note two P-lead wires - one of them goes to the front cockpit's tach.

We pigtail the shield.

Shield pigtail

Shield pigtail

That gets heatshrunk - and the diameter is just right to go thru the ID of the ferrule.

First layer of heatshrink, thru the ferrule

First layer of heatshrink, thru the ferrule

Then, the second layer of heatshrink goes over the ferrule, "sandwiching" it between the two layers of HST.

Second layer of heatshrink

Second layer of heatshrink

And with that, the bushing would slide over the outer heatshrink... but wait. Not so fast! The hole in the bushing's too small, maybe just by .010 too small, to fit over that layer.

Damn.

After playing with various heatshrinks for the outer layer, and trying to slide the bushing on while the HST was hot, I gave up, and...

... just enlarged the hole in the bushing. Yes, I know. The bushing seems to be CAD plated, and I surely took it off (the bushing was magnetic). We'll see how it fares - if I see rust, I can always buy the adapters for silly prices.

Bushing over ferrule covered in HST

Bushing over ferrule covered in HST

And the rest is easy - fish the center wire (well, wires in this case, but same deal) thru the insulator, washer, and put the solder button on. Except that this is FWF ... hmm...

Soldering setup

Soldering setup

Another exterme soldering setup? Well, not as much as the wingtips were...

Solder button on and cooling off

Solder button on and cooling off

All done

All done

And, screw the whole deal in.

P-lead attached to the mag

P-lead attached to the mag

FWF, finishing up

And then, the rest of FWF. The only other interesting tidbit was my thinking about the Starter Warning light wire. It's one that goes off of the "I" terminal of the starter contactor - which goes "hot" when the starter contactor closes - to indicate "starter engaged" with a light. The whole shebang is probably superficial, but I convinced myself that I wanted it if for nothing else than to maintain "symmetry" of lights on my panel.

Silly.

Anyway, that wire needed a fuse - though it's an intermittent wire, and I'll admit to thinking about maybe not having a fuse on it, decided to do it, because it wouldn't harm a thing.

Used a 1A "legged" type PCB mount fuse there.

Inline fuse for the

Inline fuse for the "starter warn" wire

The rest of FWF was nothing interesting to write about... Contactors, fuel pump, monitor harness, and the like. Tons of knots.

Got rid of all the remaining zipties and plastic "coils" around the ignition wires, too.

FWF - right side

FWF - right side

Right side - engine monitor harness

Right side - engine monitor harness

FWF - left side

FWF - left side

Left side - ignition harness, and battery wires

Left side - ignition harness, and battery wires

Underside - starter, and alternator wires

Underside - starter, and alternator wires


A male pilot is a confused soul who talks about women when he's flying, and about flying when he's with a woman.


Up ↑

Wiring!

...part one


On: Jul 26, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 95.6
Tags: 6781G, MA5 Charger, electrical, soldering, fwf, panel

Well, damn. With almost a year (no, more than a year!) of my being a caretaker of the Chickenhouse Charger, I finally was about to actually begin what I have started - which was, putting in my wires.

I decided to start at the switches, and run from the panel forward. Some wires will terminate at the fuse blocks (power feeds), and some will go forward - to the front panel, voltage regulator, and firewall forward.

Then, I was planning to run a few wires backwards - the ones that were pre-terminated on my transducers (fuel, oil pressures, oil temp, and mag pickup for the tach).

Immediately, I will admit: that was a mistake. While the harness turned out alright, it could've been much neater - if I ran in one direction. I could've made sure the whole thing is wire to wire and perfectly clean. So I should've run front to back, because my pre-terminated wires all "started" upfront.

In other words, prop to tail. Well sigh. Next time. On the other hand, this approach would've made terminating switches at the panel a nightmare. That was, initially, the reason why I wanted to start at the panel - so that I'd pre-attach wires to switches, tie them up, and then trim them at the other end.

At any rate.... Shall we?

Prep

Couple things to knock off before I started wiring was to complete the back panel. One thing that was left was the compass correction card bracket. No problem, drilled and tapped a couple holes for #2 brass screws.

Here's Mr. M. installing it:

Compass Correction Card Bracket

Compass Correction Card Bracket

The other one was the inertia switch for the smoke system. Glenn had it in for "safety": in the event of a shock (crash?) the switch breaks the circuit. I am.. not sure why he would have it, but he had it.

I considered not putting it back in, but what the hell.

Here's the switch:

Shock switch

Shock switch

The problem was, it sat tightly between other switches in the panel. With old layout, that barely worked; but with the new layout, and Honeywell double throw switches, the connector plug was getting in the way. So I had to resort to some vandalism. :)

Removed the connector and the shroud

Removed the connector and the shroud

Epoxy around the tabs

Epoxy around the tabs

Solder!

Solder!

And the switch fit nicely. Here it is, tucked between the switches. You can see how that connector would've interfered.

Shock Switch between other switches

Shock Switch between other switches

The final prep thing was enlarging two holes for ground points to #10 and cleaning the back side up to expose nice shiny aluminum.

Panel

Now ready, I decided to install the switches first, and then wire them from the back. I needed a couple short jumpers though to connect them, and to set up some wires to be the exact length. That'd be impossible with switches installed in the panel (too little access), so I set up an old placard plate, installed switches into it, and worked on those jumpers and terminations on the bench before moving them to the airplane.

Switches on the bench mockup

Switches on the bench mockup

Here's a couple more pictures of soldering and terminating fun pics:

Warning light socket

Warning light socket

(that flux got cleaned off, of course).

Tagged and shrunk

Tagged and shrunk

The heatshrink I'm using for these and in fact all my soldered joints is special strain relief kind with glue in it, specifically, Raychem SCL. It's 3:1 and it is very rigid - almost completely rigid. It definitely adds more support than the typical PIDG crimp used everywhere.

Pigtailing shielded p-lead

Pigtailing shielded p-lead

Finished with rings, HST, and tag

Finished with rings, HST, and tag

And then, switches went in, got tightened and straightened up, and I started running the wires.

Somewhere in the middle of running the wires

Somewhere in the middle of running the wires

I think it happened when I was yet again sitting in the cockpit, clicking the switches and enjoying the very well done Honeywell's action.....

Engine starter engaged position - note that I can hit the starter and hold the throttle with the same hand

Engine starter engaged position - note that I can hit the starter and hold the throttle with the same hand

...when it dawned on me...

My three most important switches, L and R Mags, and Master, were set up with lockouts - you couldn't turn them on just by clicking them, instead, having to pull the lever first to move it to the "on" position. I mostly did that to protect from accidental too playful a kid in the cockpit.

But they weren't locked out in the "on" position!

Why is that important? Well, the Smoke and the Fuel Pump - the most operated switches on this plane - are right there. Note how their levers are shorter? If I accidentally hit the longer levered Master, or a Mag, switch, that would turn it off - with me potentially shutting down the motor. While a remote possibility, improving the situation would amount to just replacing the switches to the ones with lockouts in both on and off positions.

I don't know how I missed that when designing the original setup...

I decided to do it.

So out came the switches, I had to un-wire the terminals from the back. In went the order for three new switches with now correct lock-outs.

About a week later, I had them, and could proceed.

With left side wired up, I could tie it down. Mind you, access there is tight and from all kinds of weird angles :).

Tying left side

Tying left side

Some of those knots I did from the side. Some I did while sitting in the cockpit, using mirror as reference

Look in the mirror!

Look in the mirror!

Then, some "extreme soldering" to extend the panel lighting wires, that turned out to be a hair too short.

Extreme Soldering

Extreme Soldering

For those lighting wires, and for the turn coordinator, routing took some fiddling with. My initial plan would've had them rubbing against the sides of the gauges, and I decided to bring them "out" and away - that's why I had to extend them, by the way.

Lighting, and turn coordinator wires, test-tied

Lighting, and turn coordinator wires, test-tied

Note no padding on that pitot line: this is a temp, "sizing" pass: I am yet to finish assemble the back panel, and will add the right padding then.

The right side of the panel was much easier - it held much smaller, and simpler circuits, for lights and turn and bank.

Right side

Right side

You can see the beginnings of the ground strap to bond the panel with the "side conduit", holding the fuse blocks and being one of the grounding points. In my original design, I had firewall, motor, "side conduit", and panel, as ground points - all bonded with those straps.

Here's the right side:

Right side

Right side

and the bonding strap

Panel bonding strap

Panel bonding strap

(the bonding strap got enclosed in super flexible heatshrink just for neatness: this is a fit-up picture).

I also had some fun with ADELs right where the wires turn from the "side conduit" towards the panel. I had to clear and negotiate a couple bowdens, and the engine monitor harness was unwieldy.

I think that took a number of hours, just trying various setups, the final one that I really liked was this:

Engine monitor and carb heat bowden.

Engine monitor and carb heat bowden.

I replaced all the ugly zipties with lacing, of course :).

Meanwhile, on the outside, to keep the wires nicely separated, I spread them out in kind of a "fan" in the order they ran, back to front:

Wire fan

Wire fan

A day later, I replaced the tape with a comb. Yep, a cheapo $1 comb :) Worked out great.

And finally, before committing and continuing, I checked each wire for gauge, and proper circuitry.

Side Contuit, Part I

With all those wires sticking out, it was now time to start figuring out routing in the side conduit. All the wires that had to go forward had, well, to go forward.

After lots of fiddling, I ended up with this:

Initial stab at the side conduit routing

Initial stab at the side conduit routing

I had to clear all the brackets, and other sharp things. Ended up adding a couple more ADELs (and drilling holes in the conduit to accommodate). Also, reused some existing holes, made a few standoffs for ADELs and such.

Another angle on the side conduit

Another angle on the side conduit

And that was it for now. Now, all the other wires needed to join the main harness in the side conduit.

Front Panel

The most interesting piece in it was a Westach tach, that fed directly off of a P-Lead and required a .25A fuse. Glenn used a 1A classic glass fuse, but I decided to do it right. See, the thing is, if it fails "short circuit", that'd turn off the mag - I guess that's why the fuse is in there.

The tach would get another 20GA shielded wire, just like a p-lead, and I decided to join it to right mag's p-lead at the magneto - instead of splicing it into the p-lead running front to back in the side conduit.

But, back to the fuse. I figured, I'd build it into my connector that hooks up to the tach. Then, if blown, the connector could be rebuilt. Yep, it's more annoying than a regular replaceable fuse, but that circuit is not critical, and I had no room for a "regular" fuse block or holder.

So I got me a "legged" .25A fuse with a massive voltage rating (I forget what it was, but definitely above what a mag makes), and hooked it to a regular Molex pin.

Inline fuse

Inline fuse

Finished with SCL, it's encased in a plastic tube and is not moving anywhere. There's two layers there, actually: one around the fuse and the pin, and another around the housing and the inner layer.

All finished

All finished

The final connector got set up like this:

Inline fuse and connector

Inline fuse and connector

... and it goes on the tach like this:

On the tach

On the tach

The lead is just a regular pigtailed P-lead, of course. Notice how I like using SCL around individual Molex pins for added strain relief - that's because I can't produce good Molex crimps that I like; and I end up post-soldering them in addition to crimping. That strain relief ensures that soldered joint is firmly held immobile. Takes a bit of extra time, but I actually like that better than straight Molex crimps.

The rest of the front panel wasn't interesting, just annoying. There's only three circuits there: nav lights wires from the left wing run along the back of the panel to the right side where the conduit is, and then there's hobbs and tach, and that's it. It was just very annoying: with very little access, not being able to see things, and, being in the front hole, having to climb out and in every time I needed a tool I forgot to put close (when in the back hole, I can roll up a cart to it and have all my tools there).

Mirror was absolutely required.

The only way to see things

The only way to see things

I will admit to asking my dentist right around this time if he had a trick up his sleeve for this kind of mirror work. Of course, he said. Practice. Lots and lots of it.

Okay, so the front panel got done, and it's wires merged with the main harness.

Front panel sub-harness joining the main

Front panel sub-harness joining the main

There, see, it's that small bundle going up and disappearing from view right in the middle of the "conduit"? That's the front panel sub-bundle.

Firewall Forward

The final set of wires to join the main harness were all the wires coming from the firewall side - mainly, transducers and other instrumentation wires, but also a couple wires for the voltage regulator.

This was precisely when I realized the mistake I talked about in the beginning - and ended up with less neat, and more tortured harness. Oh well.

I started up front, trimming and terminating my fat wires for the starter and alternator B-feed. Some more extreme soldering (to cap them), this time with a torch.

More extreme soldering

More extreme soldering

I tied up, and clamped the fat bundle to the motor: and apparently, didn't take a single picture.

Then, I had to figure out the diode for the Starter contactor - first of, it needed longer leads. There, instead of soldering, I used small barrel crimps from Molex along with heatshrink (I do use them where soldering is impractical, and I decided not to have soldered joints FWF).

Diode with leads

Diode with leads

And all enclosed

And all enclosed

And then, a simple ADEL to hook it up and hold it

Diode all hooked up

Diode all hooked up

And then, the ammeter shunt, and the sense wires. Those needed fuselinks - in liew of an in-line fuse. Simpler, and cleaner this way.

I tested them a while back, and am confident they'll work.

First, we take a wire 4 "gauge steps" thinner than the fused one (so 24GA for 20GA fused, etc). That goes into the "source" terminal.

Beginning of the fuselink

Beginning of the fuselink

Then, we hook it up.

Hooked up to the protected wire

Hooked up to the protected wire

Then, some heatshrink over the splice, for strain relief.

HST

HST

Then, a bit of fiberglass sleeve to contain the "fire" when (and if) it does it's job, as in, burns thru the thinner wire that acts as a fuse in case of a short.

A bit of marking too. And a "cap"

Capped and labeled

Capped and labeled

And finally, a couple knots to hold the sleeve better.

And laced

And laced

And finally, I finish installed all the engine transducers: pressures, and oil temp; and routed all their wires back into the side conduit and thru it back to the cockpit, adding them to the main harness. And that was that, for now - I plan to terminate them later.

Tail Light

I got rid of the belly strobe on the plane, because it was too heavy and too.. useless. Wingtip lights are gonna be the SkyBeacon and SkySensor from uAvionix (my ADSB mandate compliance :) ), and they have strobes: but they're not visible from the back. So I decided to replace the tail nav light with an LED nav/strobe.

Problem number one: no ground wire going to the tail light. For whatever reason, Remo decided to basically use the fact that the tail light is hooked up to the rudder with a pair of screws thru sheet metal of the rear rudder bow... I don't even want to begin to think what the ground path would be: hinges? control cables?

So, I needed a second wire.

Problem number two: it had to be one neat cable, and it had to be of a smallish diameter (Remo had an old 20GA wire, which is thicker than modern 20GA tefzel wire).

I decided to use a chunk of 20GA shielded - same ones I used for p-leads. Technically I guess you're not supposed to do that, but it's very far from all the antennas and I'm crossing my fingers that it won't create too much problems. Thickness was spot on.

So, I soldered the new piece to the old wire, and fished it thru using old wire as a pull. That part was scary - if that didn't work, I would've had to cut holes in the rudder to get a new wire thru.

Fishing a new wire thru

Fishing a new wire thru

The tail light shipped with a small Molex. Why not?

Connector terminated

Connector terminated

The other end went onto the light, and everything got hooked up

All hooked up!

All hooked up!

On the other end (on the tail fin side) the wire went into a hole on the inspection cover, and had to join the wire coming from the front. And I had to have the ground there. You can see that area right behind the elevator on the "fishing wire thru" picture.

Problem number three: nothing to hook up the ground to in that area. The only option I figured out was to use one of the rivnuts that are attached to the tabs welded to the frame, hoping that there's no corrosion there between the aluminum rivnut and steel fuselage. I figured I'd use a way too long a screw thru one of the rivnuts when attaching that inspection cover, and then pull the ring terminal onto it, and secure it against the back side of the rivnut with a nut and a washer. Ugly? Yes; but I didn't have any more options. Really, the right way to do that would be to run two wires from the pilot panel all the way back, but.. I'd have to start cutting fabric for that.

So, I attached the positive to the wire that was already there, terminated my ground, hooked everything up, hooked up some power, and...

Nothing.

A bit of debugging showed that... ground was the problem. Damn! I picked the wrong rivnut, I guess - it had corrosion. The one right on the other side though showed the right voltage when measured against the positive lead, so I just moved everything to the other side, and...

Let there be light!

Let there be light!

Intermission

Happy Birthday, America!

Happy Birthday, USA!

Happy Birthday, USA!

Side Conduit, Part II

At this point, the main harness looked something like this:

Main harness: complete, but not terminated

Main harness: complete, but not terminated

Now was the time to go thru it, cockpit to firewall, and terminate all the fuseblocks, and tie and zip everything up.

First, conduit, cockpit side. Lots of crossing things, lots of padding for bowdens where they cross the wires (I used the right sized vinyl tubing from my local friendly Aerospace Depot, and lacing to tie it).

Engine monitor harness got covered in tube for quite a distance - there was no way to keep it off and not rubbing on the conduit.

Cockpid side conduit

Cockpid side conduit

Fuse blocks got their placards. No, Mr. D., I am not doing brass placards again!

Fuse block covers placards

Fuse block covers placards

And then, slowly, methodically, every power wire got it's ring terminal. I added a bit of a "service loop" and used a ruler to try to keep each next wire exactly the necessary amount longer to reach the next terminal screw... Didn't work out too well, but close enough.

Rings!

Rings!

Tied up and hooked up

Tied up and hooked up

Another side got the same treatment, and then...

?!?!?!

?!?!?!

Did I just strip a terminal block hole?? Yep. I did. I blamed a bad block and definitely, positively, absolutely not my overtorquing the screw. Nope. No overtorquing. For sure!

So, had to get a new block. They're $35 so I figured I won't try to repair this hole to use an upsized screw....I'd spend more money on shipping small-headed #10 screws (the screws in the terminals are #8 but with small "oval" rather than "pan" aviation style head, so I'd have to get me some decent screws from McMaster.. by the time I'd be done, it'd be close to those $35).

So, fuseblocks. From there, it was just turning everything pretty.

Both fuseblocks done and tied

Both fuseblocks done and tied

Mid section

Mid section

Voltage regulator

Voltage regulator

The whole thing

The whole thing

Sorry, couldn't resist doing a "before" picture.

Before

Before

Jack likes this!

Jack likes this!


The Law of Gravity is not a general rule.


Up ↑

Engine Monitor Wires

... firewall forward


On: May 01, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 7.6
Tags: 6781G, MA5 Charger, electrical, fwf, engine monitor

This was a small project to wrap up everything I could do firewall forward before moving on to the panel and main wiring.

I wanted to clean up the engine monitor probes harness. When Glenn installed it, he used zipties everywhere (and actually everything on the plane was ziptied). Nothing wrong with that, except where zipties were used around motor mount and the like without any cushioning.

Probe wires with zipties

Probe wires with zipties

But last I checked, zipties weren't used in the 1930s. No, in the 1930s grass was greener, trees taller, water wetter, and Real Men used wire lacing to tie their wiring harnesses together.

And using adel clamps on round tube is just good karma.

So, I re-did one side first.

Properly laced and mounted

Properly laced and mounted

Much better isn't it? Those wing nuts are temporary - I will replace them all with real ones when finishing up FWF much later.

I did the other side, though didn't tie it up yet - there will be more wires joining that branch later, and I had to wait until they were done. But, I did set up all the adel clamps - about 4 pairs of them total.

Next, came the carb temp probe. I had to extend it's wire, and hook it back into the main harness. I repositioned it a long time ago because I ditched the Rotec TBI, and the old wire was just a touch too short.

I spent quite a bit of time making sure that it's a thermocouple, and that I can reliably extend it - with same material and type thermocouple wire. I did some basic tests with extending it and making sure it shows reasonable numbers. It did.

I thought a couple times about ditching it; but decided to keep it if I could, and my tests showed that I could do that.

Mounting and routing ended up looking something like this:

Carb temp probe wire

Carb temp probe wire

From there, it'd go straight to the motor mount (towards the firewall), and join the engine monitor harness.

When extending the thermocouple, the easiest thing to do is make sure that the joining thermocouple wires mesh together - this way, you're not introducing a section of a dissimilar metal between two segments.

To do that, I used simple Molex "barrel" butt splices that allow you to put one wire on top of another and crimp around. You then heatshrink the joint. In fact, I'm starting to like them, and am thinking about using them instead of the usual AMP butt splices with nylon insulation. They are much cleaner and compact, and heatshrink I use here (SCL) provides ample strain relief (it shrinks to hard plastic, and glues itself to the wire).

Extension being put on

Extension being put on

I shrunk each crimp individually, and then another chunk around the whole thing. The whole thing was set up to be held by a second clamp (you'll see it in the picture a bit further down).

Back when I installed the CGR-30 on the Cheetah, I encapsulated all the probe wires into fiberglass sleeve, and here it'd fit perfect - to support the lonely wire spanning about a foot to the motor mount.

Fiberglass sleeve

Fiberglass sleeve

I also used CGR's "barrel connectors" to hook up to the harness end. They have the wires "mesh" together, and fix them with a grubscrew, making the whole thing removable. Not sure when I'd want to do that, but I wanted to have an option.

Barrel connectors hooking up to the main lead

Barrel connectors hooking up to the main lead

Before closing it up, I tested everything. The probe had to be in the carb, so the best I could figure was to check if the ambient reading was good, and then heat it up and make sure that was reflected.

Testing

Testing

That was good enough for the test.

All closed up

All closed up

Turned out pretty nice methinks - and I didn't have to lose the probe. The joint between the extension wire and the probe wire is very close to the adel clamp holding the fiberglass sleeve to the airbox, on the right side - and remember, it's in hard plastic that the heatshrink that's under the fiberglass sleeve turned into - so I'm not concerned about the joint failing there.


"The first officer says he's got you in sight."
"Roger, the first officer's cleared for a visual approach runway 27 Right...you continue on that 180 heading and descend to three thousand."
-ORD ATC


Up ↑

Fat Wires Firewall Forward

basic setup


On: Apr 30, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 29.4
Tags: 6781G, MA5 Charger, electrical, alternator, starter, contactors, fwf

Fat wires firewall forward. Battery leads, shunts, alternator, contactors, and the like.

I was doing them along with the fuel hoses mostly, in between waiting for shipments to arrive.

Mounting the Current Limiters and the Shunt

They were to take place of the old voltage regulator, onto the same mounting pads. I needed a backplate...

Pattern

Pattern

...and a very basic one at that. Basically, a "hole pattern adapter".

Cut

Cut

Mounted

Mounted

I also needed to plug the nearby hole left by the removed mechanical tach cable. That one needed a large plug, and, as before, I decided to use a pipe plug with straight threads. It's nice, light, and aluminum.

Tach cable hole plug

Tach cable hole plug

There, the black one. Above the grommet with a couple wires.

That washer took a couple tries to make BTW. First one was functional, but too ugly.

The washers

The washers

Plugging the Holes

There were some more holes left after removing some old things. They were for #6 or #8 screws; and I could barely access the other side (fuel tank that's right behind the firewall makes it super hard).

Instead of attempting to maneuver nuts back there, I wanted to try something along a rivnut.. but a bit better. Steel.

Spruce sells these steel "nutserts", which seemed to fit the bill. Got a set, with install tooling.

A nutsert with an installation nut

A nutsert with an installation nut

I had to enlarge the holes on the firewall a bit to fit even the smallest nutserts; and used #4 screws to "plug" them.

Nutsert installed

Nutsert installed

Nutserts with screws

Nutserts with screws

Fat Wires

The contactors got mounted and torque sealed (of course I forgot to add a diode jumper to the starter contactor, will have to add later). Next, came figuring out the alternator wire and battery contactor -> shunt jumper (main buss feeder from the battery basically).

Initially, I thought I could route the alternator wire on the right side of the motor; keeping the starter on the left (remember, the firewall layout on this plane is reversed of sorts - with battery and oil cooler having their locations swapped and producing all sorts of grief due to that).

While not bad, holding the alternator wire on the firewall would've required more holes, and it'd go straight down, at 90 degrees to the main harness on the firewall (going left to right), kinda "crossing" it under. So I gave that idea up pretty quick, instead deciding to run it along that main harness - neatness and 1 less hole/clamp instead of a shorter by about a foot run.

Initial alternator and starter hookups

Initial alternator and starter hookups

Alternator wire is the white one going into the ANL current limiter, and starter wire is the red one joining it after coming off of the starter contactor (black) there.

And then, I needed the battery -> starter jumper. That was the spot to hook up the buss feeder too, with other end on the shunt.

I made this fancy thing...

Contactor jumper and buss feeder

Contactor jumper and buss feeder

... and of course, a mandatory pile of shame...

The Pile of Shame

The Pile of Shame

Clocking of terminals is critical on these fat wires. If you're doing two wires, relative position of them in the terminal is critical too. You lose concentration for one moment and clock them wrong; and you're redoing the lead.

The first one I didn't like the crimps on.

The second one I messed up the clocking on.

The third one (bottom one) is the good one.

Mr. Max made a comment that it's the music that's distracting me (he was busy building his "water system" out of the old fuel system hoses and fittings I took out at the time).

The initial setup

The initial setup

I did not like this. See how tight that Master <-> Starter contactor jumper is? It was very tight. The rigid alternator wire hooked into the ring on the master contactor side was too tight too (that adel clamp that I needed to hold stuff under the starter contactor had to be there - there will be other wires bundled there later). It was so tight that it bent the ring when I attempted to set it up.

No, that wasn't good at all.... hmmm..

Aha! I did a similar trick with the gascolator! Reverse the flow.

Flow reversed starter contactor

Flow reversed starter contactor

Much better! All I did was swapped the jumper from the Master contactor, and the starter lead on the starter contactor; and, while that made the fat red wire jumper much longer, it made the whole setup much, much cleaner. It made the buss feed wire a bit less pretty, arguably, with that weird "dip", but there's no avoiding it. I'll live with that.

The pile of shame grew.

Growing Pile of Shame

Growing Pile of Shame

By the way, here's how a crimped end looks up close.

Crimped ring

Crimped ring

Even with heatshrink, I had these thoughts of water weeping in between the strands on the ring end, and staying there, and slowly eating up the wire. Probably a non-issue; but it didn't sit well with me. So I used that as an excuse to whip out my small soldering torch, and add "solder caps".

Solder cap

Solder cap

Much better and neater, don't you think? Solder here acts as a filler between the strands and to "tin" the bare copper wire of the welding cable I'm using for those fat red wires. Much; much cleaner and prettier this way.

Ground Strap

This plane didn't have any. The battery was grounded to the motor (good - the biggest current demand is from the starter). The motor wasn't grounded to anything else at all, making the current flow thru probably the control cables and fuel hoses to the rest of the plane. Not good.

So, one was needed. That took more thinking and fiddling. I had a plan initially to ground the battery to the motor and the motor mount (Grummans do something similar - battery to firewall; and motor mount to motor) - but I wasn't sure about how good a connection there is between the motor mount and the firewall. So I decided to jump the motor to the firewall - a very common setup.

Simple braid will suffice.

Braid - one end

Braid - one end

Braid done

Braid done

I used a super flexible Raychem SFTW tubing and heatshrunk it. Doesn't affect the flexibility, but protects the strands a bit.

Braid installed

Braid installed

Random Soldering Picture

Filling the end with solder

Filling the end with solder

Battery Box

Battery leads were easy to make. Had to fiddle a bit with grommets (holes in the box are much larger than wires, and I had to use a "hose section around a wire in the grommet" trick to keep the wire tight and nice.

The battery box was another matter though.

Glenn had replaced the original large ("standard") battery with a small Odyssey - and took out the space with a bunch of chunks of random foam...

Foam

Foam

The box had "dimples" for the battery to stand on, lifted off the bottom (the bottom was made into a funnel of sorts that ended in a drain - setup for an old school battery that could leak acid). Those dimples were sized for a full size battery, so Odyssey couldn't stand on them.

So, .. ahem.. the solution was?

Bottom

Bottom

Yyyyeah. No. Come on now.

Proper bottom

Proper bottom

And that chunk of whatever it was? Belongs here:

Right there

Right there

Now, the checks...

I hooked up the leads, routed them out of the box, and closed it up, only to realize that the battery was loose in the "up and down" direction. Not good at all, but the solution was simple.

Mock up

Mock up

I mocked up something quick out of some foam I had around, and closed the lid. Much nicer! No more bouncing. See, I didn't want the battery to hit the top and be bouncing if the airplane all of a sudden went to <0G (in turbulence, trivially possible - and it is aerobatic after all!)

Ordered some foam from McMaster, and padded the top of the box, and the battery sides.

Battery sides padded

Battery sides padded

Box top padded

Box top padded

Now, the battery was sitting solid. No more bouncing.

And with that, I moved on. The main layout was done - the rest of tightening, tying, and strapping has to be done when all the wires are in, close to the end of this rebuild.


Assumption is the mother of all screw-ups.


Up ↑

The Fuel System Redo

...hosed!


On: Apr 29, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 31.5
Tags: 6781G, MA5 Charger, fuel system, fwf

Trying to Get off Easily

After having mounted my transducers, it was time to hook'em up.

I also needed a new engine pump -> carb hose, because the old one was too long.

The old pump -> carb hose

The old pump -> carb hose

And since I was dealing with hoses, I figured I'd clean up this monstrosity of the electric pump -> engine pump hose.

Ugly hose.

Ugly hose.

There are a few options of course. Pre-fabbed hoses - you gotta measure carefully and they'll be made to the exact sizes you want. You can buy fittings and make your own. You can go with different styles - integrated silicone firesleeve or "crimp on", rubber or teflon, yada yada.

I decided to go with pre-fabbed. I did the math a number of times; and a pre-fabbed hose was cheaper than making my own.

TS Flightlines has a great reputation on the Biplane Forum, and are pretty much the go to guys.

So, time to measure!

I had to re-clock the fittings on the engine fuel pump, so I loosened the jam nuts...

What? .... Jam nuts backed off, and fittings won't turn easily?! They should just unscrew!

Fittings moved with a wrench - and I discovered .. my favorite, The White Schmoo of Death. The teflon dope.

For some inexplicable reason, whomever undid the plumbing last time, re-plumbed it with the sealant everywhere. Okay, NPT fittings need sealant (though, a choice of a crumbly drying type stuff is questionable - because when it's left in a female fitting, getting it out without it getting it's crumbs into the system is almost impossible). But o-ring boss? Where there's a straight thread fitting with a nut and an o-ring? No sir! The o-ring seals it just fine! Siiigh.

Here it is. That lovely sealant.

Sealant where it shouldn't be

Sealant where it shouldn't be

I already had a ton of questionable fun when trying to get it out of the TBI. Frankly, I was glad I tossed the TBI altogether, hoping that that was the only place I'd find that sealant... Only to.. Oh well.

I had to take the pump out. No way I could clean out that damn stuff out of the hole w/o getting it all inside.

Slowly and steadily, with the hole pointed down, I scraped and scraped and scraped it with my dental pick, followed with a brush wetted in Goof Off that kinda softens it. It was.. hours. For two holes.

Clean.

Clean.

Phew. The pump went back on, and finally, I could clock the fittings how I wanted them.

I used a few old hoses I had lying around, and chunks of safety wire to mock up my new ones; measured the mockups, and made a bunch of pictures like this:

A drawing of a hose

A drawing of a hose

Next morning, I called TS.

Tom, the owner, is the guy who answers the phone. A quick email with pictures, a quick conversation about various hose ends (we ended up doing a few -3's instead of -2's as I had before), etc etc - and the order was in.

And, a few days later, a box showed up at my door!

Next time at the hangar, I tried them on. The hoses were perfect! But, something I haven't considered before...

Tee to engine pump

Tee to engine pump

There's a tee. Right side is connected to the gascolator. Left side - to the electrical pump. Both horizontal sides of the tee are connected with aluminum tubing. Notice the adel on the right holding onto the flare nut. The adel on the left, barely visible, is holding onto the tube - motor mount geometry isn't allowing it to grab onto the nut.

And the whole thing is aluminum, and the hose is creating a ton of leverage onto that tee.

It's not the problem with my hose. I should've realized this before I even ventured there. The old hose had the same problem, of course.

Aluminum has fatigue life. The motor shakes. The whole thing shakes, connected by the hose. How that tee didn't crack is... anyone's guess. On top of that, how the tube didn't crack is even more miraculous.

I showed it to Deene Ogden - one of our Chapter's very experienced guys. He agreed with my hunch. His suggested fix was to attempt to tie that hose end somehow into the firewall, so that it doesn't create that much leverage.

Well, easier said than done. Firewall on this thing is .035 - and not rigid at all.

I showed it to Tom (the TS Flightlines guy). He thought that even the fact that there's aluminum tubing between firewall and engine mount is a bad thing - though there the relative motion is small, it still might crack a tube or a flare.

Top that with my general dislike towards the non-firesleeved sections of aluminum tubing firewall forward (I admit, I actually attempted to figure out a nice way to sleeve them), and incorrectly plumbed fuel transducer (it was on the "suction" side - before all the pumps - and it is a restriction - and a restriction on a sucking side is a potential for vapor lock) - and I, in my usual manner, decided to, of course, rebuild the whole thing.

Disassembly

Well, that was easy - except for my favorite white crap everywhere. All the fittings were aluminum, and most of the fittings weren't AN.

Now, similar to a conversation of which sealant to use on NPT threads (you can start a fight amongst best friends by bringing it up!), there's a massive holy war on aluminum vs. steel FWF. I am in the steel camp.

And there's another, smaller holy war, about using "racing" fittings. Folks that do say "if it's good for NASCAR, it's good enough for us". I don't know. I don't buy that. First of, those fittings are of extremely varying quality (AN level all the way down to cheap Chinesium). Second, race cars are rebuilt all the time - and in an airplane, I bet some of those are 40 years old. Or 20. You get the idea.

So I am firmly in the "AN, steel" camp. Even though they are $20 a pop.

Transducer was the hardest to clean out, because I needed to make sure none of that white crud went into it. My friend and hangar neighbor Dick G. suggested running a tap with flutes filled with grease to pick up the crud... hmm... I didn't have the right size tap, and that sounded a bit too extreme.. but the idea..

The Schmoo Cleaner

The Schmoo Cleaner

I filed a few grooves into one of those fittings I took out.

It works!

It works!

It worked! See it picked up some grey stuff? Of course, I used it for final scrubbing after fishing out most of the crud with my dental pick.

Thankless work.

Gasolator

Gasolator

So. Much. Of. It. On the gascolator, I didn't care about it falling inside - I could flush it.

Cleaning the gascolator

Cleaning the gascolator

Absolutely thankless work.

The Plan, and the Mockups

So since we're redoing the whole thing; first thing I was gonna do is dump the parallel plumbing of the pumps. I guess, Remo's idea was that in case the electric pump fails in a mode where it blocks the flow of fuel thru it, the gas will still be able to go thru the "alternative" branch and still reach the mechanical pump.

Not sure about that. I am very used to Grummans, which are plumbed in series (electrical -> engine pump -> carb), and I have not heard of a single failure there. I have heard of this type failure on an RV, which used a solid state Facet pump that Facet tells you not to use on airplanes.

Okay, actually, this whole Facet pump situation is interesting, apparently. Bendix used to make these electrical pumps, but then Facet bought that part of their business. Nowadays, they explicitly tell you not to use their pumps on airplanes!

But, Dave Fletcher of Fletchair fame buys batches of particular Facet models, and runs tests on them. He sells off the ones that don't pass (apparently, flow rates vary wildly), and tags the ones that pass. He then sells them to Grumman folk.

Hey, good enough for Grumman - good enough for me! I can have my much simpler series system (less hoses, less connections, less fittings, less space), and trust the pump. And they're cheap! (Well, relatively speaking).

So, I got a pump from Fletch and bolted it on.

Transducer was the next big ticket item. It had to go between the engine driven pump, and the carb - the "last step" in the chain.

I needed something to mock things up. I needed hose ends.

... now, what's with those racing hose ends?

I called Mario - a great guy who fixes my cars when I don't want to :). His thing is drag racing.

He knew a place.

Couple hours later, and with a lighter wallet, I had a bag of fittings that were close enough in size, and a chunk of hose to cut up.

One of the first x-cer mockups

One of the first x-cer mockups

This was the first. Followed what Fletcher did on the Cheetah back when we installed the CGR-30, but on the Cheetah the hose went back towards the firewall and did a nice 180 u-turn, and came back to the carb. Here, I had to go "sideways" to do this "hanging" style if I wanted it. It produced a weird low spot in the loop that I didn't like.

Next!

Could I maybe still have the x-cer on the firewall, and reuse some of the holes?

Second mockup

Second mockup

Much better I thought. I ran those by Tom of TS Flightlines. He thought the second setup was better, and recommended using one of his fancy "u-turn" fittings to save on the hose length. He gave me dimensions. I realized that I suck at mocking things up, and asked him if he would be able to send me the fitting (I would gladly pay for it). He said, of course. He could send me whatever fittings I wanted, and just figure the cost in the end. I'd make mockups and send them to him. Heck, he'd send me the hose too - and I'd cut it to size, and make the hoses - then send them back to him, and he'll crimp and firesleeve them.

Wow.

And he was a treasure trove of information. Basically, hand-held me all the way. And I took it, and am very grateful. This was my first plumbing job - so I needed the help.

One big fear I had was running bent fittings before and after the transducer, because they can induce turbulence in the flow. Tom said that they ran them in whichever configuration, and they work fine with the setup he was suggesting. That was a great relief too.

So, I made my "shopping" list, and he put the fittings in the mail.

I got them, and ran over to the nearby auto parts place to get some hose for the mockup (I decided not to fiddle with cutting braided teflon hose). The guy took me back, we found the right I.D. stuff. I asked for ten feet. "This is fuel hose, it's expensive", said the guy. I asked how much. "Two-something a foot", was the response.

I almost cracked up. I then told him that the fitting I brought in to check, that one fitting, was probably twice as much as 10 feet of that hose. We then had a very nice conversation about everything airplanes :).

My final mockup, with fittings from Tom, looked like this:

The Final Mockup

The Final Mockup

The gascolator hookup looks funny, doesn't it? It's "reversed" - because otherwise, I had no room for hoses at all.

And then, the mock hoses were sent back to Tom for final fabrication.

The Gascolator

Somewhere in between all the mocking up and messing around, I had to figure out what to do with the gascolator. See, it had no mount. None.

It was basically "hanging" on the fittings coming into each side, and rigid aluminum tubing. Yeah. Ugh. But that's besides the point - with flexible hoses, it'll be bouncing in that "ring holder" that isn't holding it at all, apparently.

I'll admit, buying a new gascolator with mounting options crossed my mind. But then.. I thought, maybe some kind of latch..

Something that will hook to the bottom of the ring on the gascolator, and the top of that "bracket" and pull it up.

I search McMaster and other catalogues and couldn't find anything... An idea crossed my mind.. maybe..

Worm Latch!

Worm Latch!

That's a worm clamp I cut up, straightened, and bent a couple of hook ends in.

Side view

Side view

The felt prevents the worm mechanism housing from scratching the gascolator, and the heatshrink makes the hooks non-marring.

Installed!

Installed!

It worked! I made two more - planning to have them at 120 degrees to each other around the gascolator.

The diameter of the gascolator's top was a smidge undersized for the ring it was in - Glenn had some kind of a sticky foam in there. I replaced it with proper, aircraft grade felt :).

Felt pad

Felt pad

And then, the drain.

The quickdrain on that bowl was leaking. I found that a looong time ago, and attempted to replace it. Obviously, I had to take the old one out....

... only to discover that the threads on the bowl were all chewed up.

No problem, thought I, and ordered a new bowl from Spruce.

The threads on that one.. looked even worse.

I contacted Spruce. No problem! They sent me a new one.....

... slightly better, but still chewed up!

Here's one of the pictures I sent to Spruce back then, just for illustration.

Bad threads

Bad threads

They said, they will talk to the manufacturer, and have them direct ship one to me. Then, they got silent for a long time, and then I somehow ended up with two? I think? All with bad threads.

All and all, I ended up with five bowls. That happened almost a year ago, and frankly, I don't exactly remember how exactly the fifth happend, but I ended up with five. And Spruce didn't want them back. And they refunded me the money.

But that was then. This was now. Now, I had a tap just the right size, and was set up in the hangar.

This is a 1/8" NPT thread - so tapping it just a hair further would re-cut the bad parts and remove a bit more material, fixing the threads.

So I took one of the bowls, re-tapped the hole, and started putting in the quickdrain. Ha! Not so easy. There's nothing on the bowl to grab onto, and I had to tighten the quick drain pretty tight (1 1/2 to 2 turns past hand tight).

I kinda tried to use my vise to help me - holding onto the round thing isn't easy but I tried, using my hand too... Clack! The wrench slipped, and the bowl went bouncing on the floor.

A bit of damage surveillance showed a nick on the lip where it contacts the rubber seal on the gascolator top, and my better part decided that I need to be punished and re-do it. Heck, I had FIVE bowls!

So, I tapped the second one. The quick drain went in. It was annoying, but I managed. 1 1/2 turns.

Hmm.. Why does it look so weird... and not work? Hmm.... Did the torque and compressing the hollow quickdrain with "wedge" action of NPT thread mess it up? Evidently.

But I turned it 1 1/2 turns!!

Idiot me, of course. The 1 1/2 turns is probably too much to begin with (though Vans recommends it in their manual). And besides, they talk about AN plumbing fittings. Not special fittings like this quick drain.

I googled "Curtiss Quick Drain Torque"... Sure enough. Tiny. 40 inch pounds if I remember correctly. Way to be an idiot, dude.

But I have three more bowls to mess up!

Okay, bowl number three.... tap... attempt to hold... slip.. fall... DING! Damn.

This is stupid, I know. I had to stop and figure out a fixture to hold the bowl while torquing the fitting after the first one slipped out of the vice (try holding a round object in a vice w/o a fixture?! Idiot). This was the ... "try to get away with it" mode.

Enough. See, I was in such a weird state of mind I didn't take any pictures?

And the solution was simple and right there, of course.

The solution

The solution

A 2x4 and a hole saw.

Holding!

Holding!

See? Not even pretty. Not even the right diameter. But it worked, of course.

So, yeah...

Ugh...

Ugh...

BTW, see that quickdrain all bent out on the second from the left bowl (numbered 1)? That's the overtorqued one.

But hey! I got a pile of bowls to talk about on my bench now. "How not to be an idiot and what happens when you are".

The Pile of Shame

The Pile of Shame

The Hookups

Well, the rest of this was fairly uneventful.

Hoses!

Hoses!

The hoses showed up, and I already had the fittings arrived earlier from Spruce.

I messed with the transducer a ton. That was another hard part to hold - and I'll admit to bending it's outside box (that's non-sequitir but annoying). This transducer is weird - it has it's body and it's brains all in a very thin sheet stainless "box", making it virtually impossible to hold onto and screw the fitting in. But the bend in that body doesn't affect anything - it's like a "cover".

I'll admit to thinking I overtorqued the transducer fittings, too - and removing them to check for cracks (only to find that no, I actually didn't overtorque them - the manufacturer's spec was higher).

But in the end, it all worked out for the initial hookup. I'll have to tighten everything and clean up the angles on the fittings a bit when getting closer to the engine start; but the initial fit up worked great. Tom did a great job!

New hoses

New hoses

New hoses

New hoses

Oil perssure transducer hose

Oil perssure transducer hose


The three best things in life are a good landing, a good orgasm, and a good shit. A night carrier landing is one of the few opportunities to experience all three at the same time.


Up ↑

Skookum Choocher

... aka The Mean Beast


On: Mar 21, 2020
In: [Blog]
Tags: Texas, smoking, bbq, brisket

I've had a problem.

Well, two problems to be precise.

Problem number one: being an alien Texan, I had to ensure that I stay on the good side of our local BBQ police. Did you know that if you move to Texas, you get deported if you can't pull off a passable brisket on an offset stick burner? You probably didn't!

My other problem was 20 inches wide, 40 inches long, and had a 3" stack.

My Other Problem

My Other Problem

It was too small, which resulted in inability to make more than one brisket...

Loaded to the brim

Loaded to the brim

That's one brisket and some ribs - and they all are in suboptimal spots on the pit. It's just too small!

My son's fourth birthday I had to admit defeat and get a couple cooked briskets at Brett's Backyard BBQ. Nothing wrong with Brett - his briskets are grand; but I need to cook for my son's birthday!

On top of that, that pit was all choked up, with such a small stack that it couldn't handle any real size firewood. I ended up having to fiddle with the fire every 10-15 minutes, and feed it with kindling.

So, after going thru all the smoking for New Years; I decided that I outgrew my pit, and had to upgrade.

The usual suspects - Klose, Gator, and JJ were all on the list. They're all in Houston, and I was gonna make a trip on January 2nd, and talk to each one of them. I was thinking about 24x48, and possibly talking about getting a 30x48.

I considered a Lang for a while; but decided against it - I kinda like the simplicity and basic-ness, if you will, of a straight pit.

And in parallel, I was browsing Craigslist. Hey, if someone was dumping a good sized pit, I would've taken it off their hands.

And that's how I found...

Tim

There was a pit for sale that looked basic; but was everything I needed, and for just 1800 bucks. A lot? Well, a 20x40 Klose sells for more, and this one was 24x60, I think; and on a trailer. It was.. dirt cheap.

It seemed that the guy selling it was in the business of making them. He had a website, and there he said that he can custom build. Hmmmmm... I gave him a call.

... we met the same day. Mr. Tim turned out to be a rancher, welding pits up out of propane tanks as a side gig. "Helps me feed the cows", he said. They started as a group of buddies and helped each other make their pits; and then decided to make this into a paying side gig.

Tim's approach was simple and easy; and he was very open to tolerating my obnoxiousness and making a pit for me. We bounced ideas back and forth, and none of those seemed to scare him too much.

That evening, I went home way over-excited, and started mocking things up ...

The Design

Just to make sure to illustrate what I wanted from Mr. Tim, I drew the key parts of the pit up in SWX and sent it over to him. We did a few rounds of back and forth...

I wanted a baffle between the firebox and the cooking chamber that was adjustable from the outside; because I felt like with that, I wouldn't need to tune it with tuning plates, which are much more annoying to deal with in a hot smoker (moving them around in a hot smoker is no joke). I played with a baffle a lot on my old smoker, and wanted it easily adjustable on this one too.

Baffle

Baffle

I wanted a "Franklin Style Collector Stack". Like this:

Franklin Style Stack

Franklin Style Stack

I wanted a base on casters and leg levelers. See, I wanted it permanently installed - but I had to install it first; and a monster pit is no joke weight-wise.

So the idea was, to have casters to move it around, and then remove the casters, and level it with leg levelers in place. So I designed a funky base arrangement:

Base

Base

Levelers and base detail

Levelers and base detail

Mr. Tim was fine with all of those after asking some very pointed, and very good, questions, and offering a lot of suggestions and detail and his take on things.

We settled on the final design, I put up the deposit, and Mr. Tim proceeded to ...

Build

He took about 2 months, which, given that he's a one-man, part time, show, was blazing fast. He was feeding me a good diet of pictures :).

Tank, and firebox

Tank, and firebox

I asked him if he could not paint the tank. He wanted to make sure I wasn't making a mistake. The paint is ugly, he said. Am I sure, and very sure, he inquired? I said, I thought it was beautiful!

At some point he said that it's the wife who needs to approve, and a wife would not generally approve of an old propane tank in the backyard being an eyesore.

Well, my wife thought it looked great! :).

The base

The base

Mr. Tim thought that doing A-style legs would be better. I agreed! I wanted the A-frame type legs initially, but decided against it given all the funky geometry involved - but he offered! Of course!

On legs

On legs

Stack on

Stack on

It was progressing steady. That funky adjustable baffle was the last bit; and I made a visit to Mr. Tim's ranch and we poked around the pit a bit discussing options on how to hook it up.

He said, he might be ready in a week. I got very excited!

And then, exactly in a week,

The Delivery

What's that far out?

What's that far out?

He showed up Friday evening.

We spent most of the rest of the daylight having fun unloading the Beast.

Jacking to put the casters on

Jacking to put the casters on

A little come-along winch, a jack, three guys, and a four-and-a-half-year-old is all that's needed to maneuver a pit that's heavier than my biplane!

Off the trailer, now to turn and slide in...

Off the trailer, now to turn and slide in...

We rolled it to it's final spot, raised one side, dug some holes in the dirt, and put pavers down to have a solid footing for leg levelers. Then, we took that side off the casters.

Setting up on pavers

Setting up on pavers

The other side then got the same treatment. We used the levelers to level it then, and confirmed with running water inside the cook chamber. It's very important to level the pit right, so that all the grease won't go into the firebox and light on fire!

Next morning, I took an angle grinder to the pit to knock some rust off. Then, lots of soap, scrubbing, and hosing down. I hurt the day after BTW!

She cleaned up nice!

She cleaned up nice!

And then, the moment we all have been waiting for...

The Fire!

I oiled the firebox and lit a blaze to burn off all the bad smell.

First fire!

First fire!

Once the pit started coming up to temp, I was just rolling on layers and layers of peanut oil everywhere on the outside to burn it on.

Oil patina on the firebox

Oil patina on the firebox

That yellow is no rust - it's oil burnt on. Kinda like a cast iron skillet.

I burnt the fire for as long as I could and as hot as I could.

Man, this pit drew! I could throw anything at it. 5-6 large logs? No problem! No choking. It just gets hotter and hotter! Man, what a beast!

I kept her at about 450-500 for a few hours, and let it die down overnight.

The next morning, I washed the insides out of all the soot from the first fire, oiled the insides, and now went slowly. Now, it was the time to season the insides with oil, and to do a quick check of temps.

Oiled and pretty

Oiled and pretty

My TelTru gauges I've installed into 1/2 NPT ports we welded onto the pit in strategic places were dancing around a happy 250-275. The top shelf in the middle was hotter with the baffle full open, but the pit evened out when I closed the baffle down a bit to deflect incoming hot air from the firebox down. It worked! No tuning plates and I'm within 40ish degrees everywhere! Wow. Just.. wow.

I wanted to probe various parts of the pit closer to the firebox. I stuck in my thermocouple probe.... 350. What the hell? Too close?

I was messing around with it, with thermocouple showing me numbers that didn't agree with TelTrus at all. Finally, I did this test.

Two probes

Two probes

The top is a TelTru mechanical gauge. The bottom is the thermocouple. They're within 1 inch of each other. 250 on the TelTru. 330 on the thermocouple. At least one of them is lying. But which one?

Hmm... how does one test a thermometer...? hmm.. aha! Boiling water! That's a nice reference.

Pulled all the 4 TelTrus and my thermocouple, and stuck them in the pot. All of then shown.. 212?! What the hell?

Weird cosmic rays affecting thermocouple crossed my mind, I admit. I talked with Ben. I talked with Alex, and Nick. No ideas.

Dammit!

I had a hunch then. Maybe, just maybe, the stick-out on the mechanical TelTru's was not long enough? To confirm, I did a couple things.

First of, I became somewhat of a aficionado of the Mad Scientist BBQ channel, thru which I found out about Fat Stack Smokers. I checked how long were their stems. They used 4 inch TelTru's. I was using 2.5 inch ones.

Second, well.. I could confirm which gauge was lying by using paper thermometers - those little strips of paper with squares that turn black in 10 degree increments.

I ordered some strips, and some 4 inch stemmed TelTru gauges - and meanwhile, decided to do another test - the biscuit check!

That's a fun one. You fire a pit, and fill it with frozen biscuits. You let them sit, and watch the rate at which they brown - to figure out where the smoker's running hotter, and where it was colder.

The Biscuit Test

The Biscuit Test

With the baffle tuned to where I thought it'd be in the right spot, the test showed almost perfect results! The hottest spot was the middle of the top shelf. The coldest was the middle shelf near the smokestack. Center middle and top near the smokestack were almost the same, and all biscuits were reasonably evenly cooked - with crispier side to the firebox. That's the perfect offset distribution!

You see, brisket is thick on one end and thin on the other. The way I feel about it, you want one end to be hit by more heat than the other. I actually like this temp gradient - if you have the smoker full, bigger pieces can go into hotter spots, and smaller pieces can go into the colder ones; or you can rotate to cook everything roughly the same amount of time. I feel like that gives one more options rather than an oven-like perfect environment. One of the reasons I didn't want a Lang BTW.

Those frozen biscuits turned out to taste like baking soda, by the way :(. Oh well. They were dirt cheap.

The following weekend, I set up the temp test with temp strips.

The Temp Strips

The Temp Strips

The results

The results

330! So, it was the TelTru that was lying. My long-stem ones showed up, and I installed them to find perfect indication now.

4 inch stem on the top

4 inch stem on the top

Now, they agreed within 5 degrees or so. Notice how much further the top, TelTru, probe now protrudes.

The TelTru Gauges, in their final spots

The TelTru Gauges, in their final spots

And so, now, the only thing that's missing is the first cook. Which, by the irony of circumstance, might turn out to be a high-pressure one. My neighbors' daughter's wedding caterer ditched them, and I very well will very much likely end up cooking for that wedding. Fingers crossed!


Regards engine power: Lots is good, more is better, and too much is just enough.


Up ↑

Brackets for Transducers

fun litte project


On: Feb 23, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 5.1
Tags: 6781G, MA5 Charger, fabrication

Pressure transducers. Those little doodads that take liquid pressure and transform it into electrical pixies on the wire...

The ones I got are from UMA. I'm replacing the mechanical engine gauge with electric - same 3-in-1 (oil temp, pressure, fuel pressure); but the fluids stay under the cowling. Pixies run in the wires to the gauge and rat those fluids out to it.

Ahem.

Well, this was always a part of the plan:

Pressure transducer on adels

Pressure transducer on adels

but this never felt like sufficient. Only rubber (will harden up pronto) and screw torque (well, not too shabby, but still) prevent it from rotating. Plus, a single point of failure - and I am probably over too sensitive to a probability of dangling fluid hoses with transducers at the end under the cowling in flight.

No sir, we can do better!

Long time ago, I have installed a CGR-30 onto my Cheetah, and back then I mounted the transducers on two adels - but those were different style transducers, much longer than the ones UMA makes.

But they have that threaded "neck" and a nut on it.. hmm... Let's see if we can make some kind of a bracket?

Marking the hole

Marking the hole

Start with our good old friend aluminum angle. Now, the "tab" on the bracket will screw with another adel on the motor mount; that was the idea (so the bracket basically was replacing a second adel around the transducer that didn't fit). Therefore, the tab off of my bracket would have to be co-planar with the adel. It did not have to be super precise - I figured, 1/32" of mistake was fine.

A bit of black sharpie transferred the imprint quite nicely.

The bracket taking shape

The bracket taking shape

And then, bandsaw and sander. Had to break out my good files to clean up the "fillet" that remained after cutting off one side of the angle under the nut (otherwise, the nut won't fit).

Pferd and Grobet, the two buddies at work

Pferd and Grobet, the two buddies at work

OKay, now, let's add a bit more fanciness to it. Using the nut to draw out circumference and to make sure to stay well clear for now

Now, make it

Now, make it "flow"

This above picture also shows the filed area real well - bottom left.

Finally, need to drill the hole for the adjoining adel in the horizontal portion - that one needs to be somewhat precise too, if the transducer is to sit straight. So, we'll test mount it on one adel, and mark out the second hole using the second adel.

Marking hole location

Marking hole location

Okay, drill it, and then clean up, deburr, round over all the corners, yada yada - the usual drill.

Tadaa!

Jack likes the bracket very much.

Jack likes the bracket very much.

But we have another transducer. That one's bracket will have to be "mirror image" of the first one.

I used the first bracket to kinda "estimate" the second.

Now, both brackets.

Now, both brackets.

Are they the same? Hell no. But I wasn't trying to make them the same. Just close enough to do the job.

Second, fuel pressure, transducer

Second, fuel pressure, transducer

Fun little Sunday project, and I broke in the new fancy files :).


Pilots are just plane people with a special air about them.


Up ↑

Carb Controls

...finished!


On: Feb 21, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 15.95
Tags: 6781G, MA5 Charger, carb, throttle, mixture, cables, controls, engine, fwf

Quite a while back I have measured the control cables and ordered them.

They took a long time to show up, and then I was working on this amongst other things. Just finished now :).

So, right to it, shall we?

First things first was to get thru the firewall. I had these fancy penetration trims for cables called 'CableSafe' from Spruce

Cable Safe

Cable Safe

Throttle cable with it

Throttle cable with it

Hmm... problem one. Washers clearly won't fit given the old holes in the firewall (Remo had grommets there, but I wanted something a bit more substantial).

No worries - we'll make me a special washer!

Special washer

Special washer

Here's how this looks from the "airplane" side (ie, opposite the motor side of the firewall).

Cabin side of the firewall

Cabin side of the firewall

And then, came fiddling. Most of it was done before ordering the cables, but I still wanted to check and re-check everything.

Hooked the clevis ends to the control cables, and the cables to the carb to verify everything.

When measuring, I figured I'd need a rod end for the mixture arm due to misalignment of the cable rod and the control arm. And the damn bushing, too - because the hole in the carb is 1/4", and the bolt is #10. I got some bushing stock from McMaster, but it was too long - had to shorten it with some creative sanding.

Mixture rod end hardware stack

Mixture rod end hardware stack

Fun hardware stack, isn't it?

Bolt -> Large Washer -> Rod End -> Shim -> Bushing (inside control arm) -> Washer -> Shear Nut + Pin

Bolted together

Bolted together

Throttle's clevis looks way more dull.

Throttle arm

Throttle arm

Then, the airbox went on and I noticed something.

Airbox - do you see it?

Airbox - do you see it?

See how it's tilted to the right (clockwise)?

I spent quite a bit of time there trying to figure out what's wrong. I put the cowling back on!!

With cowling

With cowling

Still crooked.

I kept thinking and thinking. It's motor -> oil sump -> carb -> airbox -> filter. That's how everything's bolted together. The first three are not "home buit", so I didn't think they were off. So it must've been the airbox and / or the filter mount.

Upon closer examination, I realized that the airbox was welded together way off, and is crooked itself. And the filter is mounted even more crooked in the same clockwise direction.

To confirm, searched all the pics I could find online of the plane prior to my having it (and disassembling the front).

It was hard to tell, but.. I think it was like this from the very beginning.

Phew.

--

Meanwhile, we had a night of a kind of weather when it rains without actually raining - you know, as if you are in a cloud with large droplets. Everything in the hangar got soaked, obviously. Including my clevis ends.

Rust on a new rod end?!

Rust on a new rod end?!

Aren't they supposed to be cad plated? Oh; and that was the first time I really noticed how cad plating sacrifices itself to prevent rust on steel - a lot of my hardware was covered in little white stains, which were cadmium having corroded and saved steel.

At any rate, I double checked the order paperwork. "Cad plated". Hmmmm. They definitely were not.

Called Spruce. She checked and doublechecked - and confirmed that indeed, their vendor stopped doing cad plated clevis forks specifically in that dimension - #10 end, #10 rod. They refunded my money, and let me keep the forks.

Called SkyGeek, asking about the clevis forks they sell. The lady goes, "yep, plated". I ask her to triple-confirm.

She takes about 10 minutes, and gets back to me - nope, not plated. She's sorry. No longer made.

John F., a local IA, confirmed. Only plain steel now, seems that cad plated forks are unobtanium. Crap! Oh well, I guess, paying attention and making sure to put oil or something similar on them from time to time is in my future.

--

Glenn had a carb temp probe in the Rotec TBI I am replacing, and I decided to try to keep it. Wire was cut way too short for how everything's on the carb (vs. the TBI), so I spent a bit of time pondering if:

  • The probe was a thermistor, or a thermocouple
  • If latter, could I successfully extend it

Pouring thru (mostly AeroLectric Bob Nuckoll's) notes on thermocouples, realized that some are magnetic. Let's see.. score! Magnetic indeed.

Got some multi-strand thermocouple wire of the same kind (red/yellow - I forget which metals those are :) ), and did some "back-bench" testing.

  • Hook up the probe direct to the gauge
  • Pour solvent onto the probe tip, watch for rate of temp change and lowest point
  • Extend the wire now, do the pour again
  • Subjectively decide if the indications were "roughly matching"

They seemed to have been indeed matching, so I decided to attempt to keep the probe.

But, problem. It'd interfere with the airbox'es mounting bracket (and for some reason, I didn't take a picture of that :( ).

So first, let's cut a slot that will let that bracket clear the wire.

Slot

Slot

A bit of drilling, a bit of hacksawing, and a bit of filing.

Then,

Trial fit

Trial fit

Nope, still not good. The carb temp probe there is the little thing that looks like a bolt with a wire sticking out of it - and it's hex was interfering a bit. But we cleared the wire now.

So, a touch more cutting was in order.

A touch more cutting

A touch more cutting

... and it fit.

---

Since I was messing with the airbox, needed to finish one last thing on it.

Carb heat bowden bracket

Carb heat bowden bracket

That bracket holds the carb heat bowden cable. Notice something weird? Yep, castellated shear nuts and pins. And, no, they weren't tight either, so the whole bracket business was wobbling around.

I spent quite some time pondering why would it be set up like that. Castellated, pin, not tight, wobble - all of that adds up to "he wanted that bracket to move around". It adds up really well too! The setup makes total sense if he wanted to have this arm move around - but there is absolutely no reason for it to do that! In fact, it's not good at all - steel bracket with steel bolts moving around holes drilled thru aluminum airbox - that would elongate and tear up those holes!

I decided that no. It should not move around, in fact. So,

Hardware replaced

Hardware replaced

--

And then, the final hookups of everything after a long break. Routed the cables, and hooked them up with adel clamps where necessary (doing that conforms them to their final shape, which causes some changes in positions of the cable and controls and the range of motion).

Then, fine-tuned positioning of the controls, and tightened the pivot bolt on the bellcranks. Clevis pins might still need to come out - and that's why cotter pins aren't bent yet - just in case I'll need to unhook them again.

Bellcranks all done

Bellcranks all done

Then, the penetrations.

Fancy caulk!

Fancy caulk!

Who said caulk guns have no place in aviation?

Sealed the big gaps

Sealed the big gaps

I wanted to stuff all the gaps with as much of this stuff as I could. I'll probably come back later with much more of the FireBarrier to put a good layer of it around this and other firewall penetrations.

And then, and then... Oh yeah! I could torque the throttle arm nut, and pin that in place!

Throttle arm nut pinned

Throttle arm nut pinned

And finally, add more light machine oil to the carb bowl, so that all the rubber stuff won't dry out - all that moving of throttle back and forth pumped most of it out by now via the accelerator pump, I bet.


If you’re ever faced with a forced landing at night, turn on the landing lights to see the landing area. If you don't like what you see, turn 'em back off.


Up ↑

Exhaust...

...full circle


On: Feb 17, 2020
In: [Chickenhouse Charger] Electrical Rebuild
Time logged: 17.25
Tags: 6781G, MA5 Charger, exhaust

So finally, The Thing That Took Since November and That is Finally Done. Done?

Tadaa!

Tadaa!

Wait, what? The cowling's back on? Am I.. am I.. done?

Ha!

Nowhere near.

You see, one of the things I wanted to fix prior to putting the plane back in the air was this.

Wing root fairing

Wing root fairing

You're looking at the bottom right wing root fairing, all oily and burnt up, with paint flaking. It is bad. Really bad.

Why?

Because it is bathed in the exhaust, and because Glenn added the smoke system on top of that.

Here's the best couple pictures I have to illustrate what's going on.

Glenn's

Glenn's "Smoke On" picture

Old exhaust tailpipe

Old exhaust tailpipe

You can visualize what happens using the second picture. Black shading on the paper shows the original tailpipe. You can see how in the slipstream this will hit the wing root and the side, which is very much evidenced by the stains, oil streaks, and, well, burnt up paint on the fairing.

I wanted to fix this very, very, very much.

Research

As much as I am absolutely not afraid of electrical systems, I am very afraid of exhaust systems (and a few other things). I just don't know enough or have enough experience.

What turned up to be even worse was trying to find someone who does know what they're talking about. I poked around, and couldn't find anyone around or in our Chapter that knows this stuff well to be able to tell me "do this, and I got a TIG machine in the corner to weld up whatever you need".

So, I did the second best thing I could.

A couple years back, I met a gentleman at Oshkosh at our Biplane Forum gathering, Mr. T., who wrote a series of articles on motors, including exhaust.

He agreed graciously to listen to me (well, "read", technically) rant, and maybe guide me a bit.

So, to the drawing board!

I had to put the system back on, and hang the cowling back on the airplane as well, so that I could check everything in place.

When I took the exhaust system off, I plugged the stubs coming off of cylinders with duct tape. Big mistake!

Duct tape on the stubs

Duct tape on the stubs

Cleaning that crap off took GoofOff and about an hour.

Old tailpipe

Old tailpipe

That's the head on picture of the old stub.

The first and the easiest possibility was, what would happen if I just extended it straight out?

Straight extension - head on

Straight extension - head on

Straight extension - side view

Straight extension - side view

I used a piece of paper to mock that up. Mind you, that'd be about a 10" extension! Lots of pipe, considering that the original tailpipe was maybe 16 inches long total.

It was obvious that doing this would move the exhaust outboard way more than moving it down. Why is this bad? Well, the bulk of it was hitting the aluminum side of the fuse and the plastic (okay, okay, fiberglass :) ) root fairing. Moved out this way, it would be hitting the fabric-covered leading edge. Somehow, that didn't sit well with me, and Mr. T. concurred.

So, I went on a scavenging run, and borrowed a nice piece of exhaust grade 3" SCAT from Mr. Dick G., my friendly neighbor, and attempted to mock something up with that.

Now that went way better!

Approx 45 degrees

Approx 45 degrees

That moved the exhaust point downward, and I realized that I could play with it even more by bringing it closer to the airbox via cutting progressively more off of the old tailpipe (at this point with SCAT I haven't yet cut anything, because I was just playing and wasn't committed).

That seemed like a way to go. So, next step was to mock this up with a real 45 degree bend.

I got the cheapest slip-on 45 degree mandrel bend from Summit.

At this point, I had to commit, because using this slip-on would require some cutting.

Some cutting

Some cutting

I was committed!

And some more cutting

And some more cutting

And then, the fit with the bottom cowl on.

Front view

Front view

Side view

Side view

That looked just perfect! A total of about 8 inches of tube added overall, and the exhaust actually moved inboard, and way down into the slip stream.

All that was left to do was to buy the actual 45 degree bend I'd be using, and find a welder.

Unobtanium

I was looking around for welder who'd be willing and able while playing with the geometry. Asking around the airport didn't yield much.

Backup plan was Seth from Marioshop - the guy I take my cars to (his boss is a dragster, and Seth welded a lot of tube and exhaust - although, automotive, much thicker kind, with MIG).

I contacted folks from another EAA Chapter, the Waco 59, a great and dynamic EAA Chapter which I am also a member of, and scored - their very experienced Tech Counselor and metalworker Mike M. agreed to help me with the project. He welded himself, and also knew a gentleman that was "very artistic with his welds", as he put it.

I just had to get the material, jig it up to position it, and come over to weld everything up.

My tailpipe was 3 inches in diameter (jumping a bit ahead of myself, unusual for a motor of my size - too big). I measured .049 with my dial calipers, which translated into 18GA, and ordered the nicest shiny new bend from Summit. When it came, I realized...

It was the wrong thing.

Way thicker than what I had.

I think I mis-measured. Maybe I was asleep when I did it, maybe there was a lot of crud on the old pipe and I didn't pay attention, maybe .. but I needed 0.035 material. 20 gauge.

Quick Internet search - nothing.

More Internet searching - nothing.

I could buy all kinds of bends in smaller diameter tubing with 0.035 wall thickness. I could buy 3" tubing with 0.049 wall. I could not find 3" 45 degree bend in 0.035.

One company offered to sell me a straight piece. That was a good backup - we could've mitered and welded up the 45 degree bend in sections, but I wanted to see if I could find a bend. That same company offered to make me one - at a low price of about 600 bucks. Yikes!

Attempting to Hail Mary again, I posted on the Biplane Forum. Guys came back with a bunch of phone ##s of their contacts, and I started calling around!

Nope, nope, nope. I don't remember who it was, but one of the guys I called suggested contacting Custom Aircraft Parts.

A nice lady answered. "You gotta talk to Clint", she said, and transferred me.

Clint

Clint picked up. I asked if they could sell me the bend. Clint asked, "What are you trying to do"?

I explained.

He asked for pictures. A bit weirded out, I sent them over.

"I have two things I wanna tell you", said Clint.

"Buy yourself a bottle of soap and a nice rag".

"Be careful what you wish for".

Clit knew this 4-into-1 setup with a muffler in between very well. He told me that even with me trying to keep the extension as short as possible, I was running a risk of it cracking off at the muffler. Would it for sure? He didn't know. But the risk was increasing a lot.

I called my old friend and a Grumman aficionado Ben the same night. Grummans have this style mufflers (mine didn't by the way because it was sporting Powerflow - a very different system).

"Hey, do you recall welding cracked off tailpipes?"

"For sure".

Damn! Damn damn damn.

More mulling over ensued. I did not want to risk a tail pipe cracked off at the muffler. No way. That puts hot exhaust into a very tight cowling. On a biplane. With my having elevated fear of any in flight fire. Remember, I embarked on the electrical rebuild because I judged this airplane to be a flying fire hazard.

I talked with Ben more. I talked with Mike from Waco 59 more.

The attempted fix solidified.

Exhaust hanger

Exhaust hanger

I would put a ball joint somewhere close to the muffler, with one end on the old pipe, and one end on the new extension that includes the bend. That ball would isolate the extension from the existing system, and allow them to move relative to one another.

I would then hang the new extension to the oil sump on some kind of hanger with a clamp - likely, a kind of tube with ends flattened and bent as required.

I sent this schematic to Clint. Well, no, not this one. This is a nice one I did when writing this post, over a picture I took when mocking up this solution. The one I sent to Clint was this. But, same idea.

Schematic I sent to Clint

Schematic I sent to Clint

Clint's response? Verbatim:

Adding a ball joint and brace solves all of my concerns, you are free to do anything you want to the tailpipe. If you weld the bend on as your latest drawing shows, looks more reasonable. When adding a support brace it is imperative that it stabilizes the tailpipe to the engine, they must move together.

WOOT! Did I find a way to do what I wanted?

One thing to absolutely ensure was that the ball joint would fit.

We went back and forth a bit, me asking about dimensions. Then, I threw together a quick drawing of the widest part of the ball joint - the clamp holding it together - and tried it next time I was in the hangar.

No way. No way it hell it would fit. Airbox would get in the way.

Here's probably the best picture I have of why.

Clearances

Clearances

That little triangle of "air" in between the cowling (bottom), exhaust pipe, and airbox is probably 1 inch on sides. No way a ball would fit in there. No freaking way.

So, what am I left with?

Putting it Back Together, the Way It Was

I gave up.

Called Clint on the way back from the airport, and asked him to sell me a straight length of pipe with a slip fit on one end.

Got it a week later.

Called Mike, got a contact for his welder, and went there.

The gentleman didn't like the fit - too loose - and wanted to make sure I pinned it exactly where I wanted (and actually, I should've done that in the first place, because the opening in the cowling is very tight, and just a degree of being off would make it interfere with the cowling). He also wanted me to clean all the gunk off.

So, back to the hangar, and fun fun fun with a die grinder, deburring wheel, wire brush... This 40 year old exhaust is gunky!!!

Back on for tailpipe fit

Back on for tailpipe fit

Put new section of pipe on, clocked it just right, drilled a couple of holes thru, and put in a couple screws.

Putting a nut on the inside of a 3" pipe about 10 inches "in" is .. exciting!

Nuts on the inside of the pipe

Nuts on the inside of the pipe

Then, pulled it off and put in more screws, to be absolutely sure that if it had to come apart, it would come back together in the exact clocking I needed.

Mike's welder fell thru, and that cost me a couple weeks at least. I focused on some other work - panels, compass, etc.

One of those days, I was on the phone with D. when a gentleman I didn't recognise walked over from the hangar next door housing a PT-19, and asked to borrow a hex key. When I hung up, I walked over to introduce myself.

"Hi, I'm M."

M.?! The M.?

Yep.

He's somewhat of a local celebrity, having built a ton of airplanes, and having worked on more. I met him on a couple occasions in passing, but not really, and I didn't remember his face when he walked over. He's a sheet metal and generally a metal guy. He was working on the PT-19's electrical (ha, fun coincidence, eh?)

A lot of hangar flying ensued.

He looked over the biplane. He told me of his building a replica Hughes H-1. Of his own design basically.

When parting ways, I asked, "Hey, do you have a welder by any chance?" Asking doesn't hurt right? "Yep, I got a TIG machine".

Ha! Of course :) I meant to ask if he knew a welder. But he was one. I should've thought of that myself.

He agreed to help me weld the damn thing back on, of course. He asked for me to clean the insides. It kinda made sense, too - you want full penetration when welding, and you don't want all that crud on the inside of the tube to "float up".

So, lots more of a die grinder time, with flapwheels, with a compressor barely large enough to run the damn thing for a minute straight.

Then, drove to M's shop, drooled over the H-1 and the MP-14 that he had on it.

And then, the final fit of the tailpipe to put it where it was when I cut it off.

We put the exhaust back on the plane,..

Back on the plane

Back on the plane

...put the cowling back on, and I started fiddling around with things to try to figure out how to mark an even line to cut it off on.

Rubber band maybe?

Rubber band maybe?

Rubber bands actually worked quite well. The kind I had was too tight, and I was playing with it trying to make it work and considering running to a nearby Office Depot, when I was offered a schematic to help guide me.

Exhaust cutoff schematic

Exhaust cutoff schematic

But prior to emptying local stationery stores' rubber band supplies, I tried something else - pieces I cut off from the old pipe. Had to trim them a bit more to fit them over the new pipe, but that worked quite well in the end.

Using chunks of old pipe

Using chunks of old pipe

Starting the hacksaw at this shallow an angle is... annoying? Is that the right description?

Starting a cut

Starting a cut

I suck at hacksawing.

Ugly cut

Ugly cut

Ugly edge

Ugly edge

My punishment? 30 minutes of grinding.

Finished edge.

Finished edge.

And so, I am back to where I have started with this little project. My supply of rags is large, and my soap came in a 5 gallon pail (okay, okay, I do have some old stock is all :) ).

But, on the other hand, I think this is the Hump. It's when in a project, there are no more unknowns. You now just have to finish doing everything you've started.


Any pilot who does not privately consider himself the best in the game is in the wrong game.



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