« Archives in December, 2012

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.

More control cable work.

December 20, 2012 / posted in Firewall Forward / No Comments

9 hours.

I owe you a report from the last two sessions, which were on 12/1 and 12/2, and 12/15 and 12/16. The week of 12/4, we went to Florida for vacation, and nothing got done. Upon returning, I did some work on control brackets. Turns out my fancy bracket that I made for the purge valve cable isn’t going to work, because there’s no threaded part where the engine-side end of the cable is. What I’m doing is using a piece of angle, which will allow me to hold the cable in place with an Adel clamp.

The other thing I did was fiddle around a lot with cable routing. Supposedly the 51″ and 52″ cables from Van’s should work for the mix and throttle, but I wasn’t exactly sure about that, so I ordered the 60″ ones. Those, I’m sure, can be routed to where they need to be on the throttle quadrant. On the engine side, it was pretty interesting. I wish someone had told me I could have had AFP reverse the mixture direction, because if that had happened, there’d be no danger of interference between the cables, arms or hardware. Maybe on the next plane I build. Lol. Anyway, I was able to find positions for the cables that allows the arms to move freely and not interfere through their entire range of travel, and that’s a good thing. Unfortunately, I’m looking at running those things fairly close to the exhaust pipes, so good thing I’ve got heatshields, both the solid kind that clamps to the pipe and some of the cloth-type stuff that can wrap around the cables.

With that solved, it was time to make some bracket, which meant more steel. I’ve more or less made my peace with steel, other than the fact that it burns up bandsaw blades like crazy. I first mocked up the brackets out of .032 aluminum, just to get the angles and holes right, then hammered the mockup flat to use as a template on the steel, which reminds me: Superior Air Parts, you bastards, why couldn’t you have made the bolt spacing for engine brackets on your cold-air sump the same as on the Lycoming sumps? Huh? If it wasn’t for that, there’s a good chance one of the stock Van’s brackets would have worked.

It wasn’t all bad, I was able to obtain a PDF of the dimensioned drawing of the bottom of the sump, and from that I was able to drill the mounting holes in my fabbed steel brackets fairly easily. Of course, I didn’t have any of the hardware necessary to attach anything, so I had to make a fairly severe ACS order. In that order, I got 3 more of the firewall eyeballs (which I’ll have to drill out to fit the fat green marine-style Van’s cable), a bunch of rod-end bearings, and some other bits and pieces, including the 2×1/8 angle I’ll need to fabricate the quadrant-side bracket. If I can ever get away from work, the remodel, and my recovering dog (long story, and not a good one), I should be able to finish up the control systems.

Oh, and I’ve also ordered all the hoses I need from PHT, so I should be able to rock out all the engine plumbing as well.