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More odds and ends

April 7, 2013 / posted in Electrical, Firewall Forward, Panel, Wings / No Comments

4 hours.

A few things here and there. I installed the MAP tubing and put a couple of heat shields on the pipes to protect the throttle and mixture cables. I also installed the canopy seal, which is going to need some assistance from some RTV or proseal. I do think firewall forward is just about done, though. The cabin heat SCAT tube rubs on the engine mount a little, but some UHMW tape should fix that. The two things I did that were of major importance were the autopilot test and getting that ridiculous piece of lead off the flange of the left elevator counterweight rib.

A while back, I’d balanced out my elevators, or so I thought. You’re supposed to put the elevator tips on, then drill holes in the lead weight until the elevator balances. Well, guess what? You’re not supposed to have the elevators connected when you do this. I discovered this, freaked out, then riveted a flat piece of lead (cut from an extra counterweight) to the outboard rib.

When I put that away, thinking I was just about the smartest cat in the whole barn, I started imagining the kind of beating a control surface takes in flight. So what happens to a little piece of lead riveted to this structure with a couple of Cherry countersunk blind rivets? The piece of lead comes off and somehow jams the elevator in the dive position and I go screaming downward like a holed Stuka, straight into a busload of orphans on the 405. This has bothered me for months, but I could never find a good opportunity to fix it until Saturday. I drilled out the rivets and put the lead back in a drawer. I also read about a neat trick you can do when balancing your elevators: Pour some lead shot into the tip through the tooling hole in the rib until th elevator balances out, then stick it in place with epoxy resin. Even if it’s not perfect, bias it a little heavy, because paint will change the balance.

I also mounted the MGL GPS antenna on the top side of the glare shield. It works; I get an intermittent GPS position while still inside the guest house.

Oh and one other thing: I dragged the wing cradle over to the shop and tested out the bank servo of the autopilot. Since I actually followed a wiring plan and wired the fuselage-side and the wing side according to it, I was able to test out both servos simultaneously. I do need to make a new ground connection though. The ground from the servo bracket sucks and I was only able to get a good ground by cleco-clamping the ground terminal to a wing rib.

The Skinner

February 18, 2013 / posted in Firewall Forward, Fuselage / No Comments

3 hours.

And yes, it’s a shout out to Neal Asher, whose writing has gotten me through a tough couple of months. When you’re having horrible-seeming things happen to you, reading about truly horrible things happening to somebody else and the truly horrible people who cause them getting their comeuppance is very therapeutic.

As far as this aircraft project goes, yesterday was not horrible. I actually might have the temerity to call the firewall-forward process almost done. The only two things missing from the equation is a 2″ hose clamp for the cabin heat SCAT tubing (which is actually missing, I can’t find it right now) and the manifold pressure sensor fitting and tubing, both on order from McMaster-Carr. I can look at the engine installation and say with fairly high confidence, yes, this engine will turn the propeller repeatedly. Today I’ll go through my periodic shop purge/clean ritual and see if the clamp turns up.

I also took a long look at all the stuff just behind the firewall and ahead of the subpanel, to make damned sure there was nothing else I needed to put there, because as I’ve mentioned before, once you rivet that top skin on, you can’t get to anything below it without a flashlight, a mirror, and possibly tentacles. Satisfied to the limits of my ability with such things, I began riveting the top deck skin on. This is hard. This is hard because you have to have a rivet gun on one side and a bucking bar on the other, separated by a 3-foot sheet of metal and ‘awkward’ only begins to describe the process. There are two holes in the subpanel support capable of taking my hand holding a bucking bar through them, and it’s a little like the reverse of a monkey trap. There is much maneuvering into position, then there is riveting, whilst holding the bucking bar perpendicular to the rivet without being able to see it. This process enabled me to do the center row of rivets, and the canopy hinge support bracket, but failed on the outboard subpanel support rivets because to get my hand into the right position, I had to bend the skin away from the surface it was being riveted to, causing a gap. I couldn’t get the leverage I needed and the skin ‘pillowed’ on the support rib. Bah. Curses. Foiled. I’ll need to enlist a helper for this step, but as soon as it’s done, I can put the canopy back on and officially list the project as ‘more parts assembled than not.’

The endless detailing.

February 11, 2013 / posted in Firewall Forward / No Comments

5 hours.

I’m getting real tired of posting about loose ends, but at this point in the build, that’s pretty much all there is. I spent the day safety-wiring and adel-clamping various things firewall forward. Oh, and I did get the blast tubes done for the magnetos and alternator. These are pieces of ribbed conduit that go through the baffle wall and blow air directly on things that tend to heat up. I installed and safety-wired the tachometer drive cap, the oil drain plug, the governor clock screws, and a couple of other odds and ends. Safety wire is crazy stuff and hard to work with, especially in tight spaces, but after a while you get the hang of it.

I secured the wiring bundle on the right side behind the firewall with Adel clamps. It was loosened up to do something, I forgot what.

Oh, and the wonderful news is, we’re now ready to rivet the top deck skin on!

Checklist for firewall forward close-out

February 4, 2013 / posted in Firewall Forward, To Do / No Comments

Fuel pump overflow tube – figure out how to drain this somewhere that won’t set you on fire. Buy some high-temp fuel line, maybe a flare-to-barb connector.

MAP sensor – Going to need a connection from the port in the center of the sump to the RDAC. Again, high-temp fuel line, and some interesting fun with an angled NPT fitting.

Cooling blast tubes for mags and alternator – still need to drill the holes for the mag tubes, but the hard part is positioning the one for the alternator.

Safety wiring – tach cap, drain plug, anything else I can find.

Back on track.. Kind of.

February 4, 2013 / posted in Firewall Forward / No Comments

2 hours.

Been a rough week. A friend passed away last Saturday, so building an airplane has not been the first thing on my mind. Our plan to take my Aliens-dropship-painted RV7 and fly over Detroit playing Front 242’s “Circling Overland” is postponed indefinitely.

But today I got some of the FWF stuff back together. The only fly in the ointment was one of the baffle connecting rods. I can’t find it. With all the moving around of crap to get things out of the way of our downstairs remodel, I think it got put in a throw-away pile instead of a “keep this stuff” pile. I don’t have time to order another length of that crap from Van’s, so I did it oldschool: I used some .041 safety wire with some plastic tubing around it to tie the baffle together. Not bad. The fuel pressure sensor is also done and connected, the throttle cable bracket bolts are safety-wired, and the air intake is reinstalled and safety-wired. I need to spend some time safety wiring things like the oil drain, the tachometer drive cap, and the oil fill tube, but that’s minor.

Then the exhaust goes back on and we do the top deck skin.

Fiddly bits.

January 14, 2013 / posted in Firewall Forward, plotting/planning/deciding / No Comments

8 hours.

So yesterday, I joined EAA 723 at Camarillo airport. I dunno why, but I’m drawn to Camarillo. Maybe it’s because my cousin finished and flew that little hot-rodded Vari-EZE out of there many years ago, maybe it’s because it was the first place I took passengers when I got my private ticket, who knows? But I like Ventura county, and I like KCMA. It also doesn’t hurt that the EAA hangar is right near the Commemorative Air Force hangar, where there are a multitude of interesting flying machines to gawp at. Everyone seems friendly, and the guest speaker for the meeting was an FAA official, who gave us the rundown on ramp checks and a few FAR’s that are very much misinterpreted by the likes of you and I.

The goal of this is to find a nest for my bird where I can final-assemble, certify, and test fly 313TD. Currently, there isn’t any room in either of the hangars, but one gentleman is 20 hours into phase 1 on an RV7A and another is getting ready to go fly, so maybe a spot will open up soon.

Another benefit to membership is that the chapter has a flatbed trailer suitable for moving a project to the hangar, which I will hopefully need very soon. Yet another is several more sets of eyes looking at workmanship and assembly techniques.

As for actual work on the plane, I got the left intercylinder baffle and the replacement fuel pump installed, which is nice. All the wiring is re-secured where it was, and the fittings on the sensor are properly installed with thread seal.

Today, the morning was spent with my neighbor’s vast crew-cab contractor truck, schlepping stuff to and from two different Ikea stores, one in Carson, one in Costa Mesa. We’re doing this kitchen remodel, and our designer was a complete monkey: he ordered a ton of stuff we can’t/didn’t use and failed to get a bunch of things we need, so Shelley and I had to kill our morning putting everything right in preparation for the final cabinet install tomorrow.

I did get some work in on the plane, but it’s cold in Los Angeles right now, down in the 50’s during the day. You East-coasters, Northerners and Midwesterners chuckle all you want, but the little space heater in my shop wasn’t able to take the edge off, so it kind of sucked to be out there today. Cold hands bashing on metal structures when wrenches slip reminds me way too much of college street surgery, changing out a part lying on my back under a car in an icy parking lot. One of the many reasons I moved out here and stayed.

So no, it didn’t go well. First event of the day was an oh-shit moment, when I snapped the head off one of the bolts holding the throttle bracket on. That was a study in anger manangement, and I had the presence of mind to self-soothe through the initial impulses of throwing the torque wrench through the sliding glass door. Tantrums do not fix airplanes.

Fortunately, there’s an O’Reilly Auto store not a city block from my house, so I picked up an EZ-Out (sorry, screw extractor- generic) and through some miracle, managed to get the offending bolt out of the sump. I guess I’m now 1 for 5 using those things. At least I didn’t snap the drill off inside the broken bolt like I did with the wing attach adventure from a couple of years ago.

I installed the breather tube and safety-wired the mixture bracket bolts after torquing them with a different torque wrench (A Snap-On dial-type I bought used) and those are fine. I’m hoping I’m nearly done messing around with Adel clamps. Space is getting tight.

More firewall forward progress… And regress.

January 7, 2013 / posted in Firewall Forward / No Comments

5 hours.

The latest load from ACS allowed me to finish a couple of things. I got the oil pressure line/oil line adel clamp securing done, I finished the purge valve bracket assembly, I got the fittings installed on the oil cooler, and I actually got the prop governor installed, and the front center baffle reinstalled. I painted the throttle and mixture brackets and put them back on, and I re-secured the current sensor to the alternator wire. This is where it all went south.

I also finished attaching the fuel hose to the throttle body, and securing it to the intake pipes, but this is where it all went horribly wrong. I had purchased a steel 1/4″NPT-AN6 elbow, but I was using one of the blue aluminum ones to get my fit and mount done. The Floscan is on the firewall, and the elbow points toward the intake pipes on the left hand side of the engine. I had the fuel line connected to this. Somehow, in backing out the AN6-1/4″ NPT elbow on the output side of the Floscan fuel flow sensor, I managed to cross-thread the fitting as I was taking it off. Taking it OFF, not putting it on. So what it did was essentially pull on one side of the threads but not the other, kind of just bending the whole thing. Long story short, I completely destroyed the threads on the Floscan and it will have to be replaced. That was a very expensive ($210 from MGL Avionics) lesson in not connecting loads to dry-fitted NPT fittings loose enough to jam up. I did finally manage to extract the threads left in the Floscan housing and re-tap them, but I don’t trust the connection anymore, especially not with high-pressure fuel running through it. Now would be the time to switch to the Red Cube, except that now I’m reading about failures of these units, plus my firewall mount is drilled specifically for a Floscan. The time for experimentation is pretty much over.

I also got a tube of red RTV for sealing the baffles and putting some blobs wherever things might rub that I didn’t get with Adel clamps.

I still have to track down a hose from PHT (throttle body to fuel spider), but that’ll have to wait until tomorrow. My intercylinder baffles are on their way, and once those get installed I can permanently reattach all the baffles. I can also rivet the firewall to belly skin, because I’m giving up on making an exhaust fairing for now.

Adel clamps, and lots of them.

December 31, 2012 / posted in Firewall Forward / No Comments

5 hours.

Today was another iteration of finding the best way to keep things from rubbing together. I did a lot of hemming and hawing about zip ties, reading the horror stories on the Internet of that one guy who had a zip tie saw through his engine mount, and that you’re never supposed to use them on the engine mount or hard lines, and that’s all fine. Supposedly they’re big time savers, and for wiring, you bet. Lacing cord? No way, I don’t have the patience or the skill and zip ties are easy. Firewall forward though, it’s a different story. Conditions are murderous up there, and the regular Home Depot 500-for-$10 pack ones will go brittle and snap off in the heat and vibration of the engine bay. Still, there are a lot of folks who use zip ties up front with no ill effects, and there are all kinds of cool tricks to make standoffs, joins, and other fastenings, but you need to use a tie gun, and my tie gun is shite. I think I bought it at Fry’s for around five bucks, and it shows. I’m not shelling out three figures for a Panduit tie gun though, that’s just crazy. What I did do instead, is finally master the horror of Adel clamps.

Take a look:

That’s the neat little visegrip hack I bought a while ago, but never quite got the hang of. Now I’ve got the hang of it. The way this thing works is you jam a pointy thing that looks like an icepick through the holes on both the Adel clamps you’re trying to put together. Then you try to get the flanges close enough so you can wrap the forks of this gizmo around the icepick, then squeeze the clamps together as if they had a bolt throug them. You pull the icepick out, and you can put a real bolt through the holes. Problem is, the forks on the visegrip thing are pretty thick, so I ground off a couple of 32nds from each side. This way I could use a shorter bolt and not as many washers. At this point, screw it, washers are cheap and I’m not using more than 3 on a side, so this setup works fine.

I did as much as I could on the right side of the engine, where the 1 and 3 cylinders are. This means the alternator wire, the fuel pump input line, the purge return line, and the oil pressure sensor line, along with some miscellaneous wiring, needed to be isolated from the airframe, the engine, and each other.

Above my head, you can see the throttle and mixture cables, as well as my homemade steel brackets, and on the left, the double Adel-clamp assembly keeping the starter wire from rubbing on the mount.

I didn’t take a lot of pics, because I was too busy fiddling with clamps, and that makes my hands hurt, especially the knuckle on the middle finger of my right hand, where that stupid cow knocked me off my motorcycle with the door of her minivan this summer. I did get some, like this one:

This is the purge line, all secured and isolated.

This one:

shows the fuel pump feed and the purge return, held off from each other and the mount. Also clamped up here is the alternator wire and starter wire.


Gratuitous Adel clamp porn of the alternator wire.

Gonna do the rest of it this week. Happy new year!

Cables, hoses, pipes

December 29, 2012 / posted in Firewall Forward / No Comments

6 hours.

For a “simple” engine this thing sure has a lot of frippery. Today was spent optimizing the routing of various members and employing different methods to insure they don’t chafe on each other, or the multitude of hazards awaiting the unsuspecting flammable-liquid-carrying hose beneath the cowl. Oh, and heat. There’s lots of heat down there. The control cables, I wrapped in some Thermo Tape I bought a while back for that very purpose. I think I’ll also use the heat shields that clamp onto the exhaust pipes as well, but I’ll do those later.

I actually wound up dropping the exhaust so I could get better access to things that needed to be secured. I’m also debating hooking up a fuel pressure sensor, since thanks to an error in my PHT hoses order, I now have a firesleeved hose that will work great as an oil pressure line.

I also spent a good chunk of time chasing down the intercylinder baffles for my engine. There are about three or four different variants, some with the hole drilled for the fuel injection hose, some without. I finally wound up just ordering the ones the book calls out for that engine, and I’ll drill the hole for the injector feed line later.

“He fixes the cable?”

December 28, 2012 / posted in Firewall Forward, Panel / No Comments

8 hours.

Yes, the title is a line from “The Big Lebowski.” You’ll find a few of those in here. Saturday, Sunday, Monday, Got some solid work in during the Xmas holiday, at least up until Christmas eve. My ACS order containing a bunch of suppplies came in during the week, so this involved making the firewall penetrations for the throttle, mixutre, and governor cable.

Since I got to firewall forward, I’ve pretty much been on the “here be monsters” part of the map, so drilling the firewall where it says to on Van’s plans was a non-starter. For one thing, the governor’s up front. For another, the Superior Cold Air sump and the AFP servo pretty much negate the use of any standard Van’s bracketry or control cable lengths.

In a way, it’s a kind of freedom: Since the plans don’t apply, you’re not bound by them. What you must do, however, is follow the rules, and that means keep things from chafing, don’t glom fuel lines on to wiring, keep things from flopping, and whatever you do, insure free and correct travel of all controls. I got some good cable routing for the throttle and mix by bringing them down through the angled part of the firewall recess. This has the effect of lifting the cables up over the rudder pedal crosstubes, then a smooth S downward and slightly to the left, which lets me bring them in more or less right behind the engine above the exhaust. I’ll show pics as soon as I get them off my phone.

I used the eyeball-type firewall pass-throughs from ACS, but in this case, even the biggest one they had wasn’t enough to accommodate the fat green cables from Van’s, so they had to be drilled out. Installing them required Shelley’s help, since getting these things in requires the holding and alignment of more things than I have hands, and putting in fasteners as well. Smashing success though, the cables work smoothly with full travel.

Here, you can see the one for the governor cable, doing its thing:

You can also see the purge valve cable, running alongside before taking its right turn. The bracket for the purge valve cable and the number 2 injector line is an idea I stole from somebody on VAF: A piece of aluminum angle bolted to the case and drilled for Adel clamps in 2 places. Of course, this means replacing the case bolt with an AN4 one of a length I don’t currently have, but I guess that’s why it’s good that ACS is only an hour’s drive and 2 days’ delivery away. That brown hose snaking out over the baffling is the fuel purge return line, which will get a corresponding hole drilled in the baffles.

Once the cables made their way through the firewall, they needed to be attached to the quadrant. Somehow. I knew there was going to be some metal fabrication (yay!), and way back when I built the rails for the quadrant, I figured there would be some sort of hare-brained rig holding it all together, and this weekend was the time to actually build the thing.

This is the shape it wound up in:

This started out as 3 pieces of 2x2x1/8″ angle. Through a series of moves that involved cleco-clamping, measuring, marking, and finally cutting, I came up with a structure that gave me a bracket with 3 holes for the cable ends, each with enough room to turn the nuts on the cable. I managed to get the measurement for the attach angles by securing the cables into the part with the 3 holes, then drilling the attach angles to the angles holding the quadrant itself.

In its final form, it looks like this:

The clevises on the cable ends are special ones with 10/32 thread, and finding them was kind of a bitch. They give you the range of travel you need, but it’s a bit of a puzzle to get them all installed without them interfering with each other. As it was, I had to squeeze the middle one in the vise (not much) and come up with an arrangement for the clevis pins that allowed the maximum amount of space between them. I still wound up grinding down the middle one (blue handle, prop rpm) so that it didn’t catch on the left one (throttle), because these things binding on you in flight would be a major downer, possibly literally. But the control cables are in, they work, they’re smooth and functional. One thing I am going to have to do at some point is make some cover plates for the sides of the quadrant, because the levers are basically three little guillotines, hungrily awaiting careless fingers.

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