Chapter 26.1: Assembly and Fitting
This covers assorted tasks with getting the Cozy all assembled in the hangar
With all components in the hangar I could now get the wings on for good. Uhh, that's a misstatement. I could put the wings on and leave them on a while, before needing to remove them for something else that needed to be done (see later).
Over the 2018 Christmas holidays I got help from my boys in getting the wings mounted and doing the initial fit check with the cowlings. Pictures to right. Some trimming required on upper cowling/wing interface, but not bad, and lower cowling went right in place, but may need some modification to match lower wing profile AND the upper cowling trailing edge. Update mid January: I have the support tabs now bonded on the upper and lower wing inboard edges and mated with the cowlings. See more detail on cowling completion further below.. |
Nav/Strobe Lighting:
Needed to build up the wing-tip with flox to provide good thickness to bolt the Nav/Strobe bracket's to. The lights attach to these brackets. I'm using the AeroLED's, which were expensive but very low drag and current draw. I ran the green synch wire between the wingtips through the spar to keep it out of the engine compartment. I used some tricks here to guide the wires and avoid damage to Comm antenna coax that's in this same wingtip region. contact me for details... Testing shows all the lights working great. At some point I'll do some more cosmetic smoothing around these lights, but they are good for airworthiness inspection now. |
Pitch Trim:
When I got everything assembled in the hangar, I found an interference between the elevator inboard counter-weight and the Vance pitch trim system I'd build a few years ago to his specs. The problem was the location I'd picked for anchoring the actuator to F22 and would require movement of about 1/2". I'm not sure how I didn't find this before, but part of the reason is that I kept the pitch trim actuator safely stored in a cabinet after I'd done the initial proof that it ran, without connecting it to the elevator push rods coming from the joystick. I should have completely connected everything, but was doing too many things at the time... Lesson: finish things. I'd opened up the hole in the IP a little to enable the trim actuator spring housing to come through in addition to the push rod on the pilot side, but it now looked like needed more clearance here, and I was growing uncomfortable with the smoothness of the actuator motor, which had been sitting for a couple of years. In the mean time, there was significant debate on the list associated with a failure mode in this pitch trim system that might prevent recovery from an uncontrolled full extension of the actuator. Many have been flying with this system for many hours, and I wasn't originally thinking of changing, but after some internal debate, I started pursuit of the Davenport spring approach which would shift the whole pitch trim to the centerline area behind the IP. I got a lot of help from Rick Hall, who'd been through about 4 iterations optimizing the spring recently for his Cozy MKIV. Since work was taking me up near where Rick flies, he loaned me the jigs for making a spring and even made an initial one to his current configuration for me to try. Thanks so much Rick! My implementation shown below. |
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Roll Trim:
This couldn't be installed until the wings were on as it depends on having the full control linkage in place. I'd built the Hanka spring back in Ch 17 (Trim), and procured and wired the Actuonix linear actuator in Ch 22 (Electrical). Here, I needed to get the mounting bracket built and attached to the firewall and complete the connection point to the control rod as shown in the figure. It's a really simple system, but required custom bracket build and I didn't use a real fancy connection between the spring and the actuator. If interested in the details, contact me directly. |
GPS Antenna in TB:
I chose to put the Dynon GPS 2020 up in the Turtleback just behind the bulkhead that the headrests are mounted to. This would get the antenna up high and away from everything else for what I hope will be great satellite reception. It works great in tests just outside the hangar, and we'll see for sure once flying. To mount it there, I built a plastic bracket for it and used 2 plastic screws into the bulkhead, which I locally filled with flox as hard points. It's nice and light, so the loads should not be great. I ran the cables from here down the co-pilot side of the TB bulkhead, down the back of the co-pilot seat back, and then forward through the co-pilot arm rest to the IP/HDX unit. Once I'd confirmed it worked I put a MOLEX connector in at the canopy/longeron interface, so it's easy to disconnect when I need to remove the canopy. Later note: Greg Cross found that he had significant satellite signal reduction mounting same GPS antenna below the IP cover. I checked the satellite strength with my antenna position and it looks great. Remember that I'm between two rows of hangars here so some of the lower satellites are not blocked. |
Engine Exhaust Side Heat Shields:
As I finalized the cowling and had more time to examine the fit with the engine and the exhaust, I needed to deal with shielding the cowling from both convective and radiative heat from the exhaust pipes. These pipes are short, but they will be quite hot. I also want to insure that the cylinder cooling air gets well diverted out back towards the propeller and not swirling around in the engine compartment. To aid in directing the flow aft and shielding radiation exposure from the aileron controls I designed, built and installed custom 6061 aluminum side shields that could attach with 2 of the same bolts used to secure the cooling plenums on either side. A couple of sample pictures are shown below (before/after) without the lower cowling installed. I may use the rubber sealing material typically seen on the upper forward baffling with a Lycoming to reduce leakage of high temp air in the forward/side areas of the engine compartment.
As I finalized the cowling and had more time to examine the fit with the engine and the exhaust, I needed to deal with shielding the cowling from both convective and radiative heat from the exhaust pipes. These pipes are short, but they will be quite hot. I also want to insure that the cylinder cooling air gets well diverted out back towards the propeller and not swirling around in the engine compartment. To aid in directing the flow aft and shielding radiation exposure from the aileron controls I designed, built and installed custom 6061 aluminum side shields that could attach with 2 of the same bolts used to secure the cooling plenums on either side. A couple of sample pictures are shown below (before/after) without the lower cowling installed. I may use the rubber sealing material typically seen on the upper forward baffling with a Lycoming to reduce leakage of high temp air in the forward/side areas of the engine compartment.
Thermocouples:
My UL520is engine has a fully computer controlled electronic ignition and fuel injection system, so there is no utility in adding exhaust gas temperature (EGT) monitoring. The Dynon Engine Monitoring System (EMS) has provision for measuring up to 6 cylinder head temperatures (which I use) and 6 EGT's. I chose to use this EGT monitoring capacity to monitor some other temperatures that may be important as I get to know the Cozy under various flight and ground conditions. I bought K-type thermocouples, which are what the EGT's are, and wired them into the EMC and they are interpreted fine. In the Dynon HDX I simply had to assign the measurements a name (other than EGT's) and give them a place in the display when I want to monitor them. Of note: the thermocouple wire size was too small to wick solder into the 25 pin connector, so I had to use short lengths of 20 ga wire between the thermocouple wire and the actual EMS connector. The temperatures I'm monitoring are: - Left brake (for overheating on heaving braking conditions) - just monitoring one side on assumption that they are roughly even - engine compartment in the upper area where most of the wiring is (between engine and firewall) - Rectifier for the engine alternator (it's air cooled, and I'd like to insure it's getting adequate flow) - Master solenoid - I've been told this can get pretty warm, and by monitoring it over time, I hope to be able to detect degradation before failure. I'll get some pictures of this when completed (have tested one complete circuit already). |
Instrument Panel mod to allow removal without removing the Canopy:
Being able to remove the instrument panel cover is really important when checking electrical functionality and doing the final installation of things like the ELT and trim system and the Autopilot, which I'll cover later. I find that most of the time in the hangar I still have this cover off. However, I like having the canopy installed and being able to close it down and lock the plane. In the plans the IP cover is made in 2 parts and only the small portion that's inside the canopy is easy to remove, but I didn't like having a seam that could leak in this area above the instruments and behind the IP, and built the IP cover in one piece (others have done this too. This piece is installed by slipping under the canard cover trailing edge and locking in place with the piano hinge pins as shown back in Ch 18 step 17 (shown on the Ch18.3 page). The problem is that with a side hinge canopy the fit is too close between the IP cover and the canopy (even with the canopy completely open) on the hinge side to allow slipping the IP cover in place under the lip of the canard cover. To remedy this problem I made an angled cut in the aft section on the IP cover that would allow the portion that can't be cleared with the canopy to remain in place all the time bonded to the longhorn, while allowing the rest of the IP cover to be slid up and back without hitting the canopy, when the piano hinge pins are removed. I'll get a picture of this modification in here soon. Eventually I'll seal this cut line from the outside to prevent water leakage, but it's well away from the electronics. |
See page added called 26.2 for more hangar related work...