Sep 12, 2021     Nose Lift - (100 hours)       Category: C13 Nose+Gea

This is a 2-part entry. First, the work done in 2009 by the original builder, then the 2021 work I have done.

2009-07-02 (5.00 hours):

I know it doesn't seem like a big step, or something that should have taken this long. But today I installed the switch for the Wilhelmson nose gear lift. Several years back, when I purchased this unit, I also bought the AEX1 auto-extension module. I quickly came to hate it - every time I turned on the power, it wanted to extend the gear, and nearly caused several accidents in the build process because of that. And I didn't like the standard answer of adding a breaker or switch - what good is a safety device that you can disable? This also came with a big rats-nest of wires, some of which didn't even match the supplied wiring diagram. For instance, "white" for me was actually grey. Blue was purple. It took a while to wire, and it looked like a mess. I never did get it neatened up to my satisfaction.

Today I cut all the wires out of the rats nest, removed the AEX1, and rewired the unit with the bare minimum of wires. I kept everything neat, bundled all wire bundles together with heat shrink tubing, and now I have a clean and simple installation that I'm finally happy with! The only thing I have left to do is replace the LED grommets - they're just sort of sitting there right now. I need deeper grommets for my instrument panel. I'll address all the LEDs at once when I do the full panel setup later. Besides, I'd just have to remove them anyway when I do my panel overlay (which I may do with carbon fiber trim sheets off eBay.

9/12/2021.

I also found a rat's nest of wires, and no functioning auto extension. I built an auto extension unit following the schematic posted by Marc Zeitlin (attached) and removed the wiring of the prior install. I constructed the unit as a panel-mounted module, and located it below the SDS ignition controller, then remade it to have the switches and transit lights in my switch panel, assorted relays on a remote mounted tray. Wilhelmson guidance says the lift is fused at 10 a, and the wire sizing guides say that the installed power leads (18 AWG) are wildly redundant: good to 30 amps over the 3 foot distance. But other builders have found that a fully fueled Cozy with 2 large passengers puts a significant load on the Wilhelmson nose lift. One builder went with a 15a breaker and 14 AWG wire, and believes this is beneficial. I will move ahead with the current installation and then revise if appropriate.

The Zeitling Auto Landing Gear Extension uses 2 relays of 2 circuits each and one relay of 3 circuits. In addition there are 2 pitot pressure activated switches, a throttle position switch and a LIDAR (light detection and ranging) unit to sense AGL altitude. In operation, the unit will auto extend when there are 3 simultaneous conditions: air speed of 40-90 knots, throttle less than 10% and less than 280 feet (85m) AGL. The unit has a disarm switch protected by a safety switch cover. Attached are the LIDAR install manual and the settings I programmed in.

This was a challenging bit of kit to assemble and then install. I started with some basics - I learned to label each of the circuits on the several relays, noting common, normally open and normally closed. I made aggressive use of shrink tubing to strain-relieve the numerous joins, and liberal use of solder sleeves rather than a ring terminal setup. The WIlhelmson unit connects to the panel through a 9-pin Molex using the high power .093" pins (rated to 17 amps per pin). After the ease of DB9 pins the Molex is particularly awful to work with, and I had to find the tools to rebuild the harness. I ended up going with individual connections under shrink tubing, as in the Nuckolls method for DB9 pins in small spaces. Finally, I found and used a lot of (Mil Spec) zip ties to organize a challenging set of wires. The gear lift itself is protected by a cover which is easily removable for service, with wires passing through rubber grommets.

One build note - the Wilhelmson nose lift was installed without use of a violet wire in the #1 position: a white 22 AWG was used in its place. I have marked the pin numbers and confirmed the function of each - otherwise the unit is consistent with the technical guide provided by Wilhelmson's EZ-Lift.

1/18/2024

The Wilhelmson design is the best available for the Cozy, but it had a design flaw addressed by a retrofit kit. See the attached write-up.

  Sep 16, 2020     Pitot heat - (4 hours)       Category: C13 Nose+Gea

The aircraft pitot tube runs from the nose, along the left wall, via an aluminum hard tube. I installed a 12 volt, 12 watt resistive heating tape, contacting the face of the tube as far forward as possible within the nose compartment. In addition to heat conducting adhesive, the tape is secured with 3 safety wire wraps and does not touch the fiberglass structure. The location is not subject to motion and this is fully adequate for securing the heat tape. Since the aircraft is _not_ intended for flight in known icing conditions, a short term test was useful information.

I used a digital kitchen temperature probe of known accuracy. First, I tested the temperature of the tape itself. Under 13.5 volts it heated to 180 degrees, with probe in direct contact with the heat tape. Second, I secured the tape as described above - the tape was tied to the aluminum pitot tube and did not touch the epoxy structure. The temperature probe was placed inside the pitot, touching the side wall at a contact point with the heat tape. At 13.5 volts the tape heated the mouth of the pitot, first from 85F garage temp to 127 (3 minutes), then climbed slowly to 141F over 15 minutes. The adjacent composite surface heated to only 115F. I was surprised the glass temp did not go higher and repeated the measurement with the same result. The heat tape came with 24 AWG leads, which were secured with D-sub pins to 22 AWG shielded twisted pair wire. Each pin connection is secured with shrink tubing and the pair covered in a larger piece of shrink tubing. The draw is 1 amp. Pitot heat is switched at the panel and separately fused at 3 amps, giving the wire significant protection. I again used DB pins for the connections. DB pins are rated for 5 amps in low density loads. This load is significantly less than the rating of the DB pin connection.

Because the heat tape is an untested building practice, I will test again when measuring temperature and amperage draw of the completed airplane.

  May 13, 2023     Tires - (2.5 hours)       Category: C13 Nose+Gea

Tires are
mains - 500-5 Desser Monster Retreads, 8-ply, inflated to 60 psi
nose - 10x3.50, Tire Specialty of America, 4-ply, inflated to 35 psi

Note - at full inflation and tirtes as new, the bottom of the prop extension is 45" above the level surface. After moving to new engine mounts, __ inches.

  Oct 11, 2021     LIDAR - (25 hours)       Category: C13 Nose+Gea

The Zeitlin auto extend unit triggers nose gear extension on a combination of signals - low speed, throttle closed and near the ground. The "near the ground" bit is handled by a LIDAR unit sold by LightWare of South Africa. The programming of unit was straightforward - below 85 meters it sends a 3.3v signal to the auto extend unit. (I'm hoping this voltage is sufficient - the alternative setting is 2.2v.)

My main power runs on the right side of the aircraft: power and ground travel from firewall to instrument panel. This wiring runs on the left side. The installation instructions are specific about providing a clean power supply and routing the wires away from main power lines. I think any EMR sensitivity is about the signal from the LIDAR serial output, which reports altitude 20x per second for use in drone autopilots. Still, I routed the wires in the pilot side (signal side) bundle and put a power conditioner along side the unit, setting it to 5.00 voltage and measuring the voltage numerous times. 12 volts in on 22AWG twisted pair, and the 3.3v alarm signal on 20 awg unshielded.

The fiddly parts of this task were fitting and re-fitting the altitude senor, and the nuts and bolts of learning enough about circuits and relays to have a reliable device. Note that the plans do not include the power converter you need at the LIDAR unit - you have to deliver power to the unit, then step it down to a precise 5v. I bought an adjustable step up step down converter (single circuit board) and adapted an enclosure - seems to work well. I did the step down at the gear leg mounted LIDAR unit - too much voltage loss sending current front to back. Just put the converter next to the device and all is well. Per mfg., max power consumption of 200 mA (0.2a). See manual.

  Apr 20, 2007     Piping the Pitot and Static System - (14 hours)       Category: C13 Nose+Gea

For the pitot, I found a small air compressor blower nozzle on McMaster-Carr that had a threaded fitting on one end. A threaded bushing in the nose provides the connection, giving me a removable pitot. An elbow joint completes the picture by connecting to the aluminum tubing that runs up to the instrument panel.

For the static port I found some small machined aluminum static ports that seem like they'll do the job. They (one per side) get installed in recessed holes just under the outside skin and plumbed the same way.

PK note, November 2021.
1) The removable pitot is an M10 thread, with a barbed front. 6mm Barb x M10-1 Male; Total Length: 1.22"; Hex Width: 7/16ths. I have a pitot length of 7/8th inch, with the lip barely forward of the landing light lens. In flight testing I'll determine any pitot-static error.
2) As described elsewhere I have pitot heat from a thermal tape wrapped around the aluminum tube. The temperature test went well. I still need to test for a self-draining ability in the pitot system.
2) Pitot static plumbing went missing from the project as delivered, and I assume they were retained by Craig W. I bought a full pitot-static kit from ACS ("Avery EFIS System Plumbing Kit" at $132) with lots of hose in 3 colors and way too many fittings.

  Oct 10, 2021     Nose Gear refinement - (12 hours)       Category: C13 Nose+Gea

The project as received had some rough spots, and one was the nose gear. Here are the things I found and fixed:
- The EZ Lift attaches to the nose gear strut with a metal clamp. It was held in place by an AN3 bolt with no nut. Replaced with the correct AN4. Where the installation instructions use a lock nut, I see this as rotating through 15 degrees or so, so I went with a drilled nut, castle nut and cotter pin.
- For the past decade or so the user group has called for a bolt securing the metal clamp to the gear leg. The bolt is to be transverse through the no stress center of the gear leg. (The front of the gear leg is in tension, the rear in compression, the center is neutral.) I installed an AN4. Even as this bolt does not move, for consistency I went with drilled bolt, castle nut and cotter pin.
- One gear door was torn out. I prepared flox beds for small screws and installed the missing door.
- I found and fitted a door spring that holds the door open through taxi and take off, then has the retracted gear pull the door closed. This is a fairly standard design for EAB aircraft with retractable gear.
- I cleaned up the gear door edges so that the doors open and close smoothly. This amounted to some light filing work.

  Apr 26, 2007     Closing the Top and Glassing the Outside - (16 hours)       Category: C13 Nose+Gea

In the top of my nose I have a bigger door than the plans call for. This will make it easier for me to do visual inspections of the brake fluid reservoirs, allows me to install and remove the nose gear cover (it's pretty big), and will give me access to two small storage compartments I built into the nose to the left and right of the nose gear support box. I'll use these for storage of some items, perhaps a spare inner tube and/or tools, or extra ballast if necessary.

The door itself is held in place with two quarter-turn fasteners and the canard cover. The small door in the nose for access to the ballast compartment is held in place with four quarter-turn fasteners.

  Feb 08, 2006     Installation of Box Assembly - (3 hours)       Category: C13 Nose+Gea

2006-02-07 (2 hours):

I didn't go through as many gyrations as some of the builders I've seen. Not to say their techniques are invalid, but I thought this was one of the easier steps I've done. My fuse was sitting on the floor, on carpet. I clamped a SmartLevel with audio beep turned on onto F22's center rail, and shoved some pieces of plywood under the firewall until F22 was perfectly level (vertically). I also leveled the fuse horizontally - it was only 0.1 degree out to begin with.

I then used some foam scrap to position the NG30 assembly at the right height and position. I moved the SmartLevel to the face of F0 for this task, and got IT perfectly vertical, with the bottom edge of the NG30s flush with the bottom edge of the fuse. I also leveled the sides of the NG30s. Finally, I laid a long carpenter's square along F22's center layup (better line than the outside layups) and flush with the centerline I drew on it ages ago (thankfully). I aligned the center of the assembly, which I had drawn onto NG5 and F0, with this square. My assembly was thus perfectly vertical in both directions (to a tenth of a degree), and square to the fuselage.

I filled a small gap between the NG30s and F22 with flox, and made a flox fillet on the back side. My NG30 assembly was slightly wider than my F22 center bar. No problem. I then wrapped a BID tape all the way around from one NG30, across F22, and onto the other. It was faster than cutting two tapes, and about the same amount of cloth anyway. I left that to cure before adding the rest of the tapes, so I wouldn't disturb the assembly's alignment.

2006-02-07 (1 hour):

Today I added the rest of the BID tapes on the insides of the NG30 box against F22, and the inside of the box formed by F0, the NG30s, and F5. It's really a pain to get the tapes in there. I don't know why the plans say it's better to do it on wax paper first. In my opinion, it would be almost impossible to do it properly any other way.

I'm learning about corners, too. I've always tried to make a nice flox fillet, and I've always had problems with little air bubbles around the bends. Today, I tried something new. I mashed in twice as much flox as I needed, making a convex filling instead of a concave fillet. When I laid on the BID tape, I pressed it into the corner starting from the center, and ran my fingers along the corner. This pressed both the bubbles and the excess flox out along the line. I scraped off most of the excess flox as it came out each end, and will clean the rest up when I trim the tapes with the Fein.

I'm also experimenting with putting peel ply into the tape when I lay it up on the bench. Previously, I would make normal tapes, apply them, and peel off the plastic and add peel ply if necessary. This time, I added the peel ply as part of the tape itself. YOu have to be careful to be sure it ends up on the correct side, but it's pretty obvious if you've done it wrong when you peel off the plastic. With some acknowledged hubris, I have to say it would be difficult to forget.

  Feb 02, 2006     Fabricating NG-30s - (11 hours) Category: C13 Nose+Gea

2006-01-17 (2 hours):

I cut the NG30 foam pieces and laid out the holes. I also drilled the holes in the aluminum mounting plates for Jack's nose lift. His instructions, unfortunately, aren't very easy to understand, and they're written for a retrofit, so I've been going slowly, making sure I know what's going on before I do each step.

2006-01-18 (1 hour):

I wanted to get this out of the way yesterday, but ran out of time before I head home. Work and home life have been increasing the time pressure lately, so my build time is less than it was. C'est la vie. I did the BID layup on the NG30 pieces. I had a few dry spots where I over-squeeged at the edges. I'll fix this with an extra layer of BID when I do the BID taping. Just a few small bits along the bottom edges, nothing serious. Be careful using a hair dryer on a layup. You have to pay attention to the type of foam you're working with. I've just finished one wing, so I'm used to working with styrofoam, which holds (and allows the flow of) less air than the stuff for the NG30s.

2006-01-23 - 2006-02-01 (6 hours):

This was a rather difficult piece for me to finish. Work has been very distracting, and I kept making mistakes. I also have a devil of a time getting the skins laid up without bubbles on the outsides of the NG30 pieces, especially around the compound curves.

For the first time, I tried the "LoVac" technique as described by the CozyGirrrls, with mixed results. The technique itself is fine, but since my shop is not at my house, and I had no way to check on the (hot and getting hotter) pump, I didn't want to leave it running all night. I did my best to seal off the bag, but when I came in the vacuum had still gone. No surprise, of course, but it didn't help the layup. Around all of the compound curve areas by the hardpoints I have air bubbles that I'll have to inject.

On the other hand, this is clearly a good technique when you can do it. It produces very fast layups, since you can basically slop on the epoxy - there's almost no working of the material involved. In fact, if not for the compound curves, even removing the vacuum after an hour would still have produced a good layup on a flat part, much as if I had hand-worked it. It just didn't help keep things in the curves.

I put an extra 2 layers of BID in the layup after reading about NG30 failures others have had. I didn't realize until it was too late that another suggestion is to raise the horizontal section 2", and round the corners. But, this middle ground should be a reasonable compromise. There are plenty of Cozies flying with no modifications at all. I won't be as survivable through a pothole as some, but more than others. I'm fine with that.

2006-02-02 (2 hours):

I finished (I hope!) the NG30 pieces today by carving out the area around the MKNG6 mounting point, and glassing it with two plies of BID. Not much to say - it was a pretty easy step, if a bit messy during the carving.

  Jul 11, 2007     Nose Gear - (30 hours)       Category: C13 Nose+Gea

I don't have a great shot here of the nose gear itself. I lost a bunch of pictures during the move
and need to take some new ones.

Here you can see a few shots of the top of Jack Wilhelmson's nose lift. The manual extension rod runs through a bronze oil-impregnated bushing through the face of F22 and through a universal joint to the top of the lift. On the other side, if you look closely you can see where I accidentally broke open the sealing boot on the universal joint on the other side. Unfortunately that's going to be an expensive replacement - those things aren't cheap.

The manual extension rod runs through another bushing installed on the instrument panel. Right now it's hooked to a socket wrench that we use to adjust the gear when the power is off.

I did purchase and install the auto-extension unit (seen below just below the gear extension rod), although I'm not that thrilled with it. It's not that smart. Auto-extending the gear just because I turned the power on is an invitation to tip back, and I'm finding myself leaving its breaker off a lot to avoid that. I may rebuild the unit at some point to require at least a few mph of airspeed before it auto-extends.

  Feb 02, 2006     Installing Worm Drive Assembly - (.5 hour) Category: C13 Nose+Gea

I'm marking this step completed and moving on. I'm installing Jack Wilhelmson's electric nose lift, and it's best fitted a bit later in the build cycle. That's the only way you can accurately drill the holes for the mounting plates.

  Mar 07, 2007     rudder pedals - (9 hours)       Category: C13 Nose+Gea

Installing the rudder pedals was a bit of touchy alignment work. To provide a solid mount for the Matco master cylinders, there are two aluminum angle brackets installed with plenty of fasteners and BID over the top, as you can see in the bottom of the photo below. The rudder pedals themselves are Dennis Oelmann's, and look great. Also in this photo you can see a taped up box over the nose gear lift. I installed Jack Wilhelmson's lift, and wanted a tight seal around it to prevent air leaks. Details in another post.

  Jan 12, 2006     Reinforcing Glass Strut - (3.5 hours) Category: C13 Nose+Gea

I definitely wanted the electric nose lift, so I puchased Jack Wilhelmson's system. I included the replacement MKNG6A bearing, and the auto-extension system. I could probably have built the auto-extension unit myself, but I can spend that time on better things.

Step 1 - Reinforcing Glass Strut

2006-01-12 (2 hours):

This step probably didn't need to take as long as it did, but I wanted to clearly understand what was going on. I have Jack Wilhelmson's nose lift and thus have two sets of directions to read and follow.

Otherwise the work was simple - cut the strut to length, sand it down in some spots, and glass it. At least, it was simple because I have an oscillating spindle sander, which made quick work of sanding down the attach areas to make sure the brackets would all fit. Without this tool this would have been a painful step.

2006-01-13 (1.5 hours):

The other half - laying the BID on the front face. Easy as pie now that I know what I'm doing. The only awkward thing is figuring out a way to set the strut up on your bench so you can DO the layup. I rested mine on some narrow sticks. It makes stippling the layup an annoying job, but I didn't want to bondo or 5-minute the strut down. Not for this little layup, anyway.

  May 03, 2009     Finishing       Category: C13 Nose+Gea

The nose gear was finished long ago, but with the plane in transit and at varying stages of finishing, there wasn't a good opportunity to get any pictures of it. Today we flipped the plane back over onto its mains, and before we did I took these. I'm pretty happy with it. My only complaint is the small flap that covers the nose gear pivot - it warped slightly, and I want to try to patch that up a bit at some point.

  Jul 11, 2007     Nose Door - (22 hours)       Category: C13 Nose+Gea

On the advice of some builders who have had gear-up landings, I went with a plywood nose pad around the front of the gear door. This gives stopping ability, but more wear protection than a small puck. With the fairing around it, it won't add much drag.

John spent a lot of time tweaking the doors to work just right. His finishing work is excellent. You can also see the sealing box here. If you look closely you can make out a small fiberglass lip that extends up from the gear box. The cover fits into this slot, and with some RTV sealant will completely seal the space.