I mentioned in Friday’s article that I had flown the Swift early last week – before the major cold front blew through the area.  I had planned on flying sooner but ran into a maintenance problem that caused a few days of delay.

I pulled the plane out of the hangar after my preflight, got in and prepared to start the engine. I turned on the master switch and immediately got all the landing gear warning lights, the gear-unsafe buzzer and an operating hydraulic pump. (This plane has a red light and a buzzer that come on if the landing gear has not activated the down position micro-switches and the throttle is at idle – and the hydraulic pump will run as long as the gear handle is down and the micro-switches are not activated.)

I immediately turned off the master switch, then carefully got out of the plane and inspected the landing gear positions again – I had checked that they were safely down and locked during the preflight.  All looked good to me but something was obviously wrong. I put the plane back in the hangar and up on jacks to test everything again.

With the jacks in place and the tires 2″ off the ground I got into the plane and turned on the master switch again. Everything was normal – no lights, buzzer or hydraulic pump running. Hmmm.  I hate intermittent electrical problems.

After running the gear up and down a few times and pushing and pulling on the retraction mechanisms of both gear with and without hydraulic pressure on the system I found that without pressure in the extension direction the right landing gear could be moved about 1/16″ toward the retract position. That was enough to allow the micro-switch on that gear to indicate unsafe but not enough to actually make the gear unsafe – the hydraulic downlock was still engaged and the mechanism was over-center in the down direction. After sitting for a few days the hydraulic pressure had bled off in the system and moving the plane out of the hangar had put enough side force on the gear to move it off of that micro-switch.

There are recurring Airworthiness Directives(ADs) on the landing gear requiring checking several dimensions for wear. I checked all those again and found all to be within limits. The only thing left to do was to check the micro-switch itself. When I took it out to look it over the switch came apart in my hand. Hmmm, I think I had found the problem.

Luckily, Don at The Aeroplane Factory had a spare used switch that he could loan me to get back into the air. I picked that up the next day, installed it, checked all the AD dimensions again, ran the gear up and down and checked the emergency extension system again (I pretty much did another annual inspection on the landing gear). All was back to normal.

The next day was clear with light winds and about 58 degrees. A little chilly for a bikini, but great for flying. I’m not sure what the occasion was for the photo shoot – probably a calendar or something.  They were out there for about four hours.

I took the photo at the top of the page while I was flying north of Stead. the arrow appears to be drawn with fire retardant. I points to the south face of a ridgeline that has a fairly large burn area on the north side, out of view of the arrow. I’m assuming that it was drawn to aid in the fire-fighting efforts.

Yesterday I got a package from the Swift Association Parts Store with four new-manufacture micro-switches. When the weather turns warm, I’ll replace all of the one’s currently installed – two main landing gear, each with a switch for the extended position and the retracted position.

Another cold front is supposed to come through today – winds only in the 35MPH range this time. Slide Mountain (between Reno and Carson City)  is currently averaging winds of 50 MPH with gusts to 78. Probably pretty bumpy once you get above the ridges.

I haven’t had any actual flying posts lately because I haven’t been flying.  It’s the time of year that the Swift’s annual inspection is due – the end of October to be exact.  I started the inspection a couple of weeks ago and was promptly sidetracked by other projects at home.

So far I have completed the exterior of the tail and the inside of the aft fuselage. Panels are coming off and control bearing lubrication is underway. Lots of little things to do.

And now the transponder/encoder check has expired, so that’s on the list, too.  I’d much rather be flying, but heaven forbid if  all the boxes aren’t checked when I do.

A friend sent the link to this video today. I though I’d embed it in this post so you can watch it. Very well done.

The FE’s Lament by Balleka on Youtube.

Installing an aircraft radio is not as tedious as trying to put your watch back together, but it still seems as though this project is taking forever. My day job is taking up way too much of my time. I checked my logbook  (I use Logbook Pro in addition to keeping a paper copy) and found that I haven’t flown my Swift since February.  With my work schedule in June, it looks like the best I can hope for is a flight some time in July.

On the dismantling side of the project I have removed the fore and aft windows on both sides of the aircraft, stripped the old paint from the cockpit interior, removed the old radio and wiring harness and removed the old antenna and cable. On the put-it-back-together side I have repainted the cockpit interior, installed a new antenna with skin doubler, installed new antenna cable (RG-400) and routed it to the new radio, installed the radio box in the hole left by the old radio, wired it into the existing PM-1000II intercom and successfully accomplished the operational checks specified in the radio and intercom installation manuals. I have also moved the headset and mic jacks from the instrument panel to the underside of the aft shelf behind the outer edge of the left and right seats. The forward location of the jacks was probably acceptable when the aircraft had yolk controls but this plane has a dual stick conversion STC installed and the forward jack location could easily allow interference between the stick movement and the headset cords. While I was working in the cockpit I also took the time to move the fuel quantity gauge for the outer wing aux. tanks from its position aft of the main tank gauge on the little center console to a blank space on the instrument panel. In order to read the aux. fuel quantity with the gauge located in the center console (even with my right hip) I had to turn sideways in the seat. The switch for the gauge that selects either the left or right aux. tank quantity for viewing was located on the instrument panel. Now the gauge and selector switch are next to each other.

The notes on the project progress that I left for myself show that the items remaining to be accomplished include completing the radio box installation by adding a vertical support at the rear of the box per the installation manual, the final wiring of the mic and trim buttons on the sticks and adding the wiring supports, grommets and protective sheaths along the wiring runs as specified in AC43-13. That will just leave the installation of new windows.

Let’s see. That’s about a week’s work so it will probably take two months to complete, especially when you consider I’m currently 4 days into a 14-day airline trip. That day job is getting in the way again…

My time at home in April was split between catching up on the usual home and office duties and working on the interior of the Swift. I bought a new Garmin SL-30 communications radio for the plane along with a new Comant CI-121 VHF communications antenna and RG-400 cable to connect the two. About a month ago we had a nice warm day, so I decided to go out and work in the hangar and to start the new radio installation. First I took the old unit out, a big box com/nav unit that had long outlived it’s usefulness. The next step was to remove the old antenna and install the new one, then route the new cable along the same path that the old cable used.

I won’t say what I found when I removed the old antenna other than to say that it hadn’t been installed using the best practices. In order to correct the workmanship and install the new antenna correctly I would have to install a doubler under the antenna. That would involve stripping the ugly yellow/tan paint away from the area below the antenna before doing the riveting. Stripping the paint in just a small area and then painting a new color wasn’t a good idea, so now I was looking at stripping the ugly old paint in the aft area of the cockpit and repainting the whole thing. Now I needed to remove the shoulder harness installation, the electric pitch trim motor and lines and the rear windows. This list is not getting shorter!

Last week I finally completed the stripping process. That cleared the way to rivet in a doubler for the new antenna and to install a flush patch in the place of an ugly scab patch that had been installed on the top of the fuselage. I finished that two days before I was to leave on my next trip, then spent the next day doing a final cleaning and masking in preparation for the new paint. I chose a medium gray acrylic enamel for the project. First I sprayed on a self-etching primer, then followed with two light and one medium color coat. The blue lines you see dangling in the cockpit are the loop of the elevator trim cable and the power lines for the electric trim motor which is now sitting in the bottom of the cockpit. They are masked off with blue painter’s tape.

The painting directions said to wait seven days for the paint to cure before adding additional coats. That happens to be just the amount of time that my airline trip is taking, so when I get back I’ll evaluate whether the job requires any additional painting. If the paint coverage still looks good, I’ll remove the masking reinstall the trim and shoulder harnesses. Then I’ll get some new window material, make some aluminum frames for the inside of the window, paint them and reinstall the windows with new frames. THEN I can get back to the antenna, cable and radio installation.

Remember, when you estimate the time it will take to complete a project on an airplane, make your best guess then double it and go to the next higher unit. A one-week project will probably take you two months, if you’re lucky.

I mentioned my engine pre-heater in my last post and received a request to explain it in a little more detail. Engine manufacturers and engine overhaul facilities such as Mattituck strongly recommend pre-heating the engine whenever the temperature is below 20° F. and some sources recommend pre-heating when the temperature is below 32° F. However, all the sources I checked agreed that pre-heating before starting in cold temperatures will significantly reduce wear to the engine.

Ben Visser, Staff Research Engineer, Shell Oil:

“Preheating your engine makes a world of difference. It heats the oil so the oil is thin enough to flow through the engine and properly lubricate all of the critical wear surfaces. Preheating also heats the metal parts in the engine. That’s important because aluminum crankcases have a higher coefficient of thermal expansion than iron crankshafts. This means as your engine cools down, the clearance is reduced. And as a result, you may not have sufficient oil film thickness for proper hydrodynamic lubrication at very cold temperatures. In other words, the wear rate is going up. If you’re using [an electric] heater, make sure it’s a system that heats the whole engine, not just the oil.”

I made a small pre-heater for my plane that forces hot air into the engine compartment from below, allowing the warm air to heat the oil sump and then to flow up around the cylinders and out the front of the engine, using the reverse of the route used by the cooling airflow during flight. 

I bought all of the materials for my pre-heater from one of the local home improvement centers like Home Depot. The heat source is a small portable ceramic heater. The sticker says it is a Ceramic Safe-T-Furnace, Model HC-441W (made in China, of course). It has a built-in fan and a plunger-type safety switch on the bottom that will shut the unit off if it tips over. There are both fan speed and heat controls on the front, though I just set both of them to their maximum settings and leave them there. I also have a piece of tape on the bottom of the unit holding the safety switch depressed. As you can see in the photo, the unit is tipped slightly forward and the tape keeps the unit from shutting off.

I used a square to round flange adapter similar to this larger version and tapped it to the front of the ceramic heater to use as a transition to the round ducting, then attached a length of dryer duct to the adapter to direct the heat upward. The duct is a very flexible expandable metallic tubing that is easily molded to any shape that you might need.

I used the pre-heater with bare tubing for a little while, then decided that the unit was transferring too much of it’s heat through the thin-walled ducting, so I bought some self-adhesive insulation and wrapped that around the duct leaving the last 6″ or so uncovered so that it could be squeezed into an elongated oval in order to fit up into the cowl. The adhesive on the insulation wasn’t staying attached to the uneven surface of the duct, so I wrapped the whole duct with aluminum tape that is used by HVAC installers.

I also use 2-3 layers of blankets and carpet remnants over the engine compartment to help reduce heat loss. When I intend to go flying, I plug in the unit, make sure that the fan is operating and then go about my preflight duties. If it’s really cold, I will often make a trip to the local coffee shop for a few minutes and give the unit about an hour to work it’s magic. By the time I return there is a noticeable flow of hot air coming out of the front of the engine and the blankets/carpet over the top of the engine compartment are warm to the touch. The engine always turns over easily during start and the oil pressure indicates quickly.

I don’t know how much the pre-heater cost to make. I do know that I bought more material than I needed for the project because smaller quantities were not available. Two people could probably build units and split the costs. I did notice the other day that you can buy the flexible ducting with insulation already attached. Bigger heaters will, of course, pump out a larger volume of hot air and will do the heating job a bit quicker, but they would also need a larger diameter duct to move the air.

I’m sure other people have made more elegant and more professional-looking pre-heaters, but this one works for me and it seems like it will last for quite some time. It looks like the temperatures are starting to trend higher now, so maybe by the end of the month I’ll be able to put it away for the summer.

Update:I first posted this article on the evening of March 8th after a beautiful, clear day with temperatures in the low 50s (F). It is now 8 am on the morning of March 9th and I am looking at a thermometer indicating a temperature of 22° F with 5″ of new snow on the ground. Maybe I won’t put the heater away this month…