Cargo Door Stiffeners Continued

I finished up the cargo door stiffeners today with the forward stiffener. These stiffeners will allow me to mount a quarter round seal for weather protection.

Switches

I ordered three of the Rocker Switch Pros (Carling) switches to see if I liked them and if they would fit my panel. They came in today and I started playing around with them to see how easy they were to put together and take back apart. Very easy with the right tools. I'll have to give these serious consideration as they are really nice.

They can custom engrave whatever you want on them for a reasonable price. This also means that I don't have to label the panel, the labels are on the switch. They offer a pretty extensive selection of standard symbols, I think over 200 and counting. They are back lit with red LED's, but offer them in blue LED and white incandescent. The switch actuators come in either RED or BLACK. These switches have two LED's, one to back light the labels and the other to show when the switch is ON (the bar on the bottom).

Wing Lifting Tool

Just in from the Harbor Freight Aviation Dept., my wing lifter. Actually, it is a dry wall panel hoist but I'll use it to lift and mount my wings.

Cargo Door - Upper Stiffener

I measured, cut and bent up a piece of .020" 6061-T6 to make a stiffener for the inside top of the cargo door. Mixed up some Hysol and clamped it in place. I used angle bracket on the outside of the door to ensure straightness while the Hysol sets.

Next, I repeated the same process for the bottom stiffener. Got it Hysol'd in place and left to cure.

Seat Pins

I revisited the seat pins today. I mis-drilled the first one I tried, didn't drill it in the correct place. The second one I tried the drill bit broke off in the pin. I could not extract it to continue the hole. So, after ordering two replacements I decided to tackle them again today.

It went much better and I got both drilled out perfectly.

Cargo Door Latch

Decided to tackle the problem of how to latch the cargo door. In my research, I've come across many ways to accomplish this task from very simple to very complex. I've chosen to keep it relatively simple and use a cabinet lock. This is a simple keyed lock for cabinets.

So, the advantages are:

It's simple to install
It's lockable
It's relatively light
It's secure
It has a pretty low profile

The disadvantages are:

It requires a key to operate
It's heavier than some other options
It requires some other parts to be installed

First thing I had to do was make a stiffener for the rear of the door. This actually accomplished two things, to stiffen the door so it won't flex in the vertical axis and provide a little more material thickness for the lock to attach to. A primary concern with stiffeners in general is how to attach them to the door? I really was wanting to avoid using any rivets and thus preferred using Hysol. The stiffeners are not a structural component so Hysol alone will be sufficient.

At first, I was thinking of using L bracket material for this but decided against it because of the added weight. It absolutely would be great for stiffening the door but would add too much weight. Instead, I decided to use .020 aluminum sheet and bend up my own L bracket. This would provide plenty of stiffness while keeping the weight to a minimum. I measured and cut a piece to test it out. Seemed to work perfect so I proceeded to Hysol it in place after deburring, sanding and cleaning the areas to be Hysol'd.

After it cured, I measured and marked where to drill a starter hole for the lock. The lock requires a 3/4" hole so I used a step drill to slowly work my way up to the correct sized hole. Once drilled, I installed the lock to check fit. Worked as it should however, the steel lockbar was operating against a soft aluminum tube. This would require installing some sort of protector striker material.

Initially I thought of a piece of steel or sacrificial aluminum plate, and also considered anti-chafe tape but wanted something a bit more robust. Then I came across some leftover delrin seat track material. This would provide a nice slick, quiet, durable, replaceable striker surface but it is a little thick. Maybe the same material in 1/16"? Maybe I can sand down the delrin I have to the correct thickness? I'll have to try this.

Next, I started looking at how I would mount the delrin. Hysol came to mind but it wouldn't allow easy replacement. Then I looked at rivets. This is when it occurred to me that the fabric wraps around and covers the area where the lockbar will go. This will requre a slot for the lockbar to operate. I can't just cut a slit in the fabric for the lockbar. I would need an actual slot which means I would need a fabric plate to be installed to give the fabric a place to attach around the slot for the lockbar. So, I fabbed up a fabric plate with a slot for the door opening and Hysol'd it into place. This plate will allow the fabric to attach around the slot so I can cut the slot out for the lockbar in a nice neat fashion.

Left Wing Fuel Tank - Bottom Cover

Again, as I did on the right wing, I installed the bottom cover for the fuel tank. First thing was to mark all the rivets that I need to drill out. Once marked I began to replace each marked rivet with a rivnut.

The process is, drill the rivet out with a #30 bit, change the bit to a 3/16" and drill the hole out to the larger size. Check to make sure the rivnut fits. Debur the hole. Use an air gun to blow any debris out. Set the rivnut with locktite. Move on to the next rivet.

Once all the rivnuts were in place it was time to position the bottom cover. I used cleco clamps to hole the piece in place while I measured the corners. I adjusted the panel until it was in the correct position. I then used a #30 hole finder to locate the screw holes and drill them out. Once I had the four opposite corners drilled out, I screwed the panel in place to holed it while I used the hole finder to drill out all the other holes.

After all the holes were drilled I trimmed the panel to size and finished by putting the compression bends on the three sides.

Left Wing Spoilers

As I did in the right wing, I temporarily installed the spoilers in the left wing. They are marked for specific positions being the wings were factory built. I will remove them for painting and then reinstall them before covering.

Auto Pilot Roll Servo Continued

I received my bracket material from Aircraft Spruce to mount the servo. I measured and cut the bracket to length. Using the Garmin servo bracket that came with the servo (I am not using this bracket), I placed them back to back so I could mark the holes for the bolts to mount the servo to the angle bracket. Once marked, I took the bracket to the drill press and drilled the holes.

Next, I removed the plate from the wing and set the angle bracket on it to find the best alignment to the previously drilled holes (in the plate). I also wanted to determine the best placement for the bracket so the servo push rod would not bind.

Once the best placement was determined, I clamped the bracket to the plate and began drilling through holes into the bracket using the pre-drilled holes in the plate as guides. I cleco'd as I went along. Once all the existing holes were match drilled, I used a rivet fan to layout the remaining holes to be drilled. I then drilled all those holes.

After cleaning up and deburring all the holes in all the pieces, I mixed up some Hysol to bond the bracket to the plate. I gooped the Hysol onto the angle bracket and set it in place on the plate. I used a couple of cleco's to align the bracket to the plate and began riveting the holes that would be in the lightening hole on the rib. Of course, I wanted the plate to fit flush with the rib and took care to only install the rivets that would not interfere with the rib to plate fit. Once this was done I mounted the plate/bracket assembly into the wing. I debated about using Hysol for this joint and decided against it in case I ever have to remove the assembly from the wing. Besides, there are numerous rivets holding the assembly to the rib. Plenty strong.

I started riveting the assembly to the rib working back and forth across the plate to distribute the loads as I went. I got all the rivets installed. With the bracket assembly mounted in the wing, I set about installing the servo. The bolts were easy to get in place but the washer and nuts were another matter. Eventually, I got them installed and torqued.

The only potential problem I can see at this point in the install is the wiring connection. It doesn't appear I'll have enough room to mount a straight plug on the servo, I hope there is a 90 plug for this application.