Chapter 17 - Trim system / center console

Landing Brake

I don't have to do all that stuff about the landing brake because I installed an electric actuator in chapter 9. This gets rid of a lot of mechanical arms, levers and brackets. I havent checked, but I'd bet the actuator and switch was cheaper than the hardware for the manual system. Dispensing with the large landing brake pully also allowed me to make leave out the big bump in the center console. (Note: Later I rebuilt the center console to fit the Vans throttle quadrant - see below and chapter 23.)

Landing Light

I originally planned to put lights in the nose during chapter 13 as a couple of other builders have done. Eventually I decided against this and did the plans method of putting the light in the floor under the pilots seat. I found a servo to extend the light when needed, rather than have the mechanical system. As with the landing brake, my theory here is that the electric method is simpler and that failure of either or both of these systems in case of electrical faults is not a major issue.

I couldn't find the Kmart item specified in the plans, but got something similar from an auto store. I'd already bought 4 inch airplane bulbs so I was able to compare the difference. I set up the two lights and viewed a large tree 280 feet away on a dark night. Using the auto light the outline of the tree was just barely visible. With the airplane light the tree was very clearly lit. The contrast was striking. I decided to fit the airplane bulb and made my plywood support 5 inches * 5.5 inches. This is a few inches narrower than the plans. I rigged a clamp to the roof and hung the fuselage from it by the nose gear bolt. I cut the hole in the fuse floor under the pilots seat with a sabre saw. I hadn't trimmed the seat support in advance per plans because I didn't know how big a cutout to make. This was no problem. The sabre saw cut the seat support as I cut the back and front of the hole. I fitted the plywood support using duct tape to hold it in place with a bead of micro to form a good fit, looked at it for a while, then decided to cut a matching hole for a second light under the passenger seat. Now my lights will be balanced both aesthetically and aerodynamically, I'll have a backup, and with both on I'll be able to give people a sunburn from 1000 feet.

A problem with the plans light position is that they'll create a lot of drag at cruise speeds. I'm still going to need some recognition lights somewhere for cruise flying.

I'm still figuring out how to lower the lights. I'm now thinking that I could join the two lights with a 3/4 inch strip of aluminum and use an auto electric window motor to raise & lower them. If I can rig the lever to the alum strip I'll be able to glass and seal the two boxes that the lights will retract into. I have a picture of the plans lever on a plane I saw at sun & fun and I dont like the way it looks. It also looks like it might interfer with the pilot's right leg somewhat.

Much later another builder mentioned that the headlight actuator from a Honda Prelude was light, small and powerful. I dashed out to the local U-pick junk yard and secured one. Getting it out of the Honda was probably harder than installing it in the plane will be. It seems perfect. It's small, has switching built in for reversing 180 degree travel and it only weighs 18 oz.

I spent days trying to figure out how to lower the landing lights with the honda prelude light servo. The servo does a 180 and I found it very difficult to get the lights to go from fully open to fully (and tightly) closed. What you really need here is a spring loaded push pull actuator, not a rotating one. I even built the plans manual handles. I didnt like these either. I've been unhappy with these lights ever since I started with them. I think what's been bugging me is the fact that they'll be a damn nuisance even if I get them opening correctly. I'll still need a recognition light because I can't run these at cruise speeds and they can't be seen from above. The ideal would be a landing light which also works as a recognition light. I considered all the possible places for such a light.

  • In the strake fairings - too much reflection off the canard and too curved
  • In the wing tips - too far from center
  • In the floor - can't use at cruise and can't see from above
  • In the nose - too ugly, and I don't want to remake half my nose out of plexiglass.
  • On the nose wheel strut - nice for landing, added gear reminder at night
  • In the nose's of the wheel pants. I thought of this one too late.

    Finally I've found what is, to me, the perfect landing light solution. Where is the only spot on the plane which is at right angles to the airflow? The very tip of the nose of course! Trouble is that the nose curves off very steeply. I bought two VERY small 55 watt halogen lights from Pepboys. They're 2 inches * 1.5 inches and slightly oval. I hacked out my pitot head (I want to put in a heated one anyway) and cut an oval in the tip of the nose to match my one of the small lights. I build a birch and BID reinforced pad in the bottom of the ballast compartment and mounted the light bracket. Next I got some plexiglass, heated it to 325F in the oven and formed it to match the curvature of the missing piece of nose cone. I made a recess to take the plexi so that it's exactly flush with the rest of the nose. Later I'll mount the other light on the nose strut.

    I've stuck to the plans pretty solidly so far. The landing light was my first real deviation. The experience has been interesting and I'm very pleased with the result. However, I probably have more metal energy, time and effort expended in this minor issue than in some of the major chapters. Follow the plans and everything goes smoothly and relatively quickly. Deviate and you're breaking new ground with every step. In one little detail like the landing lights I've tried all sorts of directions and expended much time which could have been used to proceed with the airplane. The result can be satisfying, but beware - any experimentation will tend to be very time consuming.

    Landing Lights - the final solution

    So; there I was in October 2002 with a landing light in the nose, and two big holes in the bottom of my plane. I still hadn't figured out how to activate the lights. I cut these holes over 2 years ago, and I've been agonizing about what to do with these lights ever since. Last night I found the perfect text on how to install landing lights in a Cozy. The text even comes with full scale drawings and a parts list. Simple, neat and easy to do. You'll never guess where I found the solution.... yep. Cozy IV plans, Chapter 17, page 9.

    I built the plans handles and pushrods (again) and decided that, with an extra 1/2 inch on the length of the handle the travel would be perfect. I built 2 new handles. The movement was almost right, but I like the way the handles go over center and rest against the panel when the lights are not in use. My pushrods were a bit short for that. I wasnt really sure about the maximum angle of travel I'd need, so I decided to make my pushrods adjustable. I cut them in the middle and inserted some threaded rod of just the right size to cut a thread in the inside of the tube. By screwing this rod in and out I could get all the adjustment I could possibly need. I don't see why these lights wouldnt work for cruise as well, except that they're going to be a bit draggy. To secure the handles to my modified center console I Drilled for an AN3 bolt right through from side to side where the handles go, and then realized that a bolt through here was going to interfer with the EC2 computer control console I'd installed in front of the throttle quadrant. This time I was lucky. The bolt passed straight through the middle of the control panel between the board and the mounting plate with lots of room to spare. To give the installation some strength I drilled a similar hole at the bottom of the console and connected the two holes on each side with aluminum plates glassed to the inside of the console. I also used spacers over the bolts. This gives the installation a square structure that seems pretty strong.

    The entire job took 4 hours, and I built two of everything and four handles (five if you count the one I broke trying to bend it :( ). Now there's a lesson learned regarding sticking to the plans. It was such a relief to just read the instructions and make the parts from the drawings. I still like my nose light, but I think the landing lights will come in handy too. An added benefit - on approach, with all three lights on at once, the plane's going to look like a commercial jet and spam cans will clear out of my way. (and the smoke coming from the alternator will look like a contrail :).

    Did I say it took 4 hours? I forgot to mention the cover. Wayne Hicks is into sheetrock nails. Personally I like the fast setting mud. With the headlight doors held firmly closed from underneath I heaped about a gallon of the stuff under the seat and shaped it into a pleasing lump. I tried to make it fairly uniform as it went between the seat supports. Once this dried I carved it into a smooth plug and glassed each section overlapping onto the floor, the seat supports and the heat duct. After cure I cut holes for the pushrods and made lips around the holes to hold some sort of boot. I microed the bottom of the seat supports. I looked in the auto stores for a suitable boot, but couldnt find anything. Watching the pushrod I decided that I needed something quite flexible because the pushrod goes in and out of the hole with a couple of inches of travel. I searched around and finally discovered what I thought was the perfect item. A condom. I could only find lubricated ones, and they kept slipping off, so I washed them in soap and water to get the oil off. Un-lubricated would have been easier, but maybe they don't make these anymore. I found that the little "reservoir" on the end travels with the pushrod and the whole thing seals perfectly. Perhaps it wont stand up to much wind, though....

    You think I'm kidding, right? I'm not. Rolled up condoms make a nice sealing boot. I may even use one on the nose strut, the cold air scoop.... A few days later I found out that condoms don't stand up to the weather very well (I wonder why?), and they split very easily when pricked with rough fiberglass. I went through a pack of six trying to get one to stay put. That's gotta be some kind of record! Anyway, I went back to the automotive store and looked again for rubber boots. Eventually a helpful parts assistant showed me a bunch of CV joint boots, the smaller of which might have worked for my nose-lift but they were fairly heavy. He couldn't think of anything small enough to handle the headlight pushrods. In the end I found a generic rubber boot in Discount Auto which fit the nose lift with a bit of trimming. For the headlight pushrods I found something in a drug store which did the job nicely. Ironically, after all the split condoms, it's a teat for a baby's bottle. You may laugh, but it works just fine. I enlarged the hole in the teat, greased it and used a wire tie to hold the base of the teat to my flange. I spent way too much time getting the headlights and nose lift opening sealed. It's time to move on, once I get through explaining to Char why there are used condoms all over my workbench.

    Later I got a note from Chrissi telling me how to make custom rubber boots...

    BTW, if you make a form out of bondo/whatever and make it super smooth then 
    paint it and wax it,  you can then paint it with liqud latex . It takes many 
    coats but you can also add gauze to reinforce it at clamping edges etc. 
    (bandage gauze strips or cheesecloth work great) After it is all done, peel 
    it off the form and boil it to vulcanize the rubber. Keep out of direct 
    sunlight. This way you can make your own custom HD flex boots. I have done 
    this several times for parts as thick as 1/8"
    There is also a rubber you use the same way to make molds for plaster of 
    paris figurines.
    Ah well. Maybe next time. For now my baby teats are working just fine.

    Trim System

    I came back to this chapter to do the roll and pitch trim much later. I made the funny shaped supports for the roll trim cables and used a rotary metal cutter to carve out the slots needed in the seat supports. It only took an hour or two to get everything ready for the trim handle. That's when I hit my first error. There was no way to get the little compression spring on the bolt and put on a nut. I'd put the heads of the bolds on the wrong side of the birch support so the amount of bolt sticking through wasnt enough. I removed the birch support, made a new one and tried again. This time everything fit fine and moved smoothly. Next problem was my parking brake. I'd mounted it right where the trim cable goes. I decided to move it further into the and work it with a push pull knob I saw in the ACS catalog. Looks like I'm going to have to break my rule and order from ACS. When I came to install the cabling I realized that the swaging I'd done in Chap 16 was just training. Now I had the hang of swaging in a vice fitting the trim cables required me to swage upside down between the fuselage side and the torque tubes. I got one sleeve on too loose and gained a whole new appreciation for the strength of these little nicopress things. It took me 20 minutes and two dremel blades to remove the sleeve. After I [thought] I was done I found that the spring on the right (Char's) side was too loose. I'ts tough to pull the cable tight, hold the thimble in place and swage at an angle all at the same time. By the time I redo the right side I'll probably have the hang of it.

    I don't seem to have a pitch trim handle. This is probably because I'd been planning to fit electric trim. I ordered a Strong pitch trim system. Fitting this wasnt quite the snip that I'd expected. Perhaps I was having a slow day, or maybe the July Florida heat was getting to me. The instructions didnt make it clear (at least to me) and it took me a while to figure out that the trim unit points aft, not forward. The mount goes on the side of the fuselage just under and forward of the canard and it connects to the torque tube right by the stick. When I measured where it should go, I didn't realize that the clip used to connect the trim unit to the torque tube would interfer with the rivets on the end of the tube, and the 1/8 securing pin would hit the adjustable screw for the MM3 swivel point. I sent email to Alex with a few questions, but I guess he was on his way to OSH. I had to "make a few adjustments" before getting everything settled. Next was the wiring. I found a wiring diagram which shows two Radio Shack 275-249a relays. In my electrical naivete, I'd expected the wires from the trim unit to go straight to my stick hat switches, but no - you need these relays to flip the power from one direction to the other. The instructions say to solder the wires, but I've read in Bob Knuckolls's book that it's better to crimp. Now I know how to do this, I can use the same method to control the landing brake. All in all, I think the trim unit is a good piece of equipment and I hear it works very well. I just kinda expected it to go in easier.

    Alex later sent me a note:

    If you have 2 switches, one on each stick, the possibility exist that cross
    control ie; one switch up the other down will cause a direct short. If you
    do I can show you how to eliminate that condition.
    I really dont want to redo the wiring for the pitch trim right now, but Alex makes a good point. I probably will later.

    [Later note: The Strong pitch trim is excellent. I only have 5 hours on the plane, and already I'd hate to be without it.]

    I'm still wondering whether to cut the manual trim bellhorn off the elevator torque tube. It gets in the way a little when I remove and install the canard which, for some reason, I do a lot.

    Center Console

    My first attempt at a center console was too high. Anyone with fairly wide hips was going to find the front seats uncomfortable. I remade the console about 1 inch above the heat duct with aslope up to the throttle quadrant. I built the EC2 controller panel into the slope and made a walnut backing for it. For times when I'm solo, or when it wont get in the way I made a removable armrest which sits on top of the console and hooks into the map pocket.
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