Wings - Slats

Started working on the slats for the right wing. Pulled all the hardware and began first by installing the arms in the wing. The slats were built by the factory, mounted and the arms were adjusted. So, I just had to reinstall them and verify I had all the parts. The arms were engraved at the factory to ensure proper placement on the wing.

First, I installed the rubber arm bumper on the arm bracket. Next, I had to install bearings on each bolt which I pressed on. Once those were all in place I could install the arms into the wing. There are two bearings per arm.

Each slat must be installed in a specific spot. Once I figured the order I started trying to fit each slat onto the arms. There is a trick to installing them which took some time for me to figure out. The manual is moot on this. Anyway, the slat needs to be rotated onto the arm while the arm is almost completely retracted into the wing. I found that it is easier to do this with the wing inverted on the rotisserie.

 

After much trial and error, I finally was able to get the slats temporarily mounted on the wing and check function. They worked as they should. Once installed, I was able look at where the outboard slat tips will be mounted. They will be riveted on to cap one end of the slat. There are also a couple of rubber bumpers that install in the inside tip of the outboard slat that provides a cushion when the slats bump together. The bumper hits against the slat tip that gets riveted on to the opposing slat.

Header Tanks - Fuel Drains

Since the SuperSTOL comes from the factory with only one header tank and I am going with two, I decided to tackle a small project. There is a small piece of steel welded to the passenger's side of the fuselage for a fuel drain.

I needed to fabricate a similar piece on the pilot's side for my second header tank, and Hysol it into place.

So, I found a scrap piece of .040 aluminum and measured it, cut it, and bent it. I test fit it several times, trimming it to get the angles correct. Once satisfied with the shape and fit, I deburred all the edges, sanded the fuselage where it would attach, and then cleaned all the surfaces.

I mixed up a couple of dabs of Hysol. I placed a metal ruler underneath the fuselage stringers and clamped them in place. this allowed me to set the piece into place on top of the ruler, knowing it would be absolutely flush with the bottom of the fuselage. I dabbed some Hysol into place on each end to tack the piece into place. I allowed the Hysol to set up and then removed the ruler. I mixed more Hysol and filled in the seams ensuring a very good bond. I again let the Hysol set up to working consistency and then smoothed out the fillets using rubbing alcohol. Once cleaned up, I left it to totally cure.

I drilled out the passenger's side and test fit the drain and coupler.

Wings - Spoilers

I pulled all the parts for the six Spoilers for the right/left wings and verified I had everything. I cleaned and deburred the edges of each spoiler. I had to ream all the holes in the spoilers and mounting tabs. I then mounted three spoilers temporarily in the right wing. I will ream the holes in the left wing tomorrow and mount them.

Once I get to covering I'll remove, paint and reinstall them.

Now on to the fuel tanks...

Oratex Covering Sample Kit

I received the Oratex Samples in the mail today. I had Paul Mills of Oratex send me a large sample of each Oratex6000 color, eleven in all. Each sample is approx 2ftx3ft so it's a good size to grasp each color. He also included enough glue to be able to test them out for real. I have an extra rudder and aileron to use as test beds.

So, here are the colors from left to right White, Fokker Red, Corsair Blue, White, Cub Yellow, Olive Drab, Orange (new), Sky Blue, Black (new), Silver, and Light Gray. They are bright colors and look really nice.

Here are the back of the fabrics to show what they look like from behind. A few of the colors have white backs and a couple have black. The rest are modeled as in the last pic of the back side of black.

I have an idea for a paint scheme and was originally planning to use the Polyfiber System and paint the plane. However, the more I think about it the more I like the Oratex and not having to paint. However, I really like my paint scheme and could cover the plane in white Oratex and paint it anyway. There are several advantages to Oratex from my point of view: (YMMV)

1. Lighter weight
2. No painting (if you don't want to) However, you can paint the Oratex, I'm told you just scuff it up with a scotch brite pad and clean it off and shoot paint.
3. It's impervious to UV. This is a biggie to me as I live in Arizona. As a side note, how many traditional fabric airplanes have you seen where the inside of the fabric was not painted and/or primed? Tons. Polyfiber is VERY susceptible to UV light degradation. One must coat the fabric to protect against UV or it will degrade, and fast. In this SuperSTOL, I will have a lot of glass area.
4. Much simpler and quicker to apply.

Ok, so that's it for now. I'll post more once I start working with them...

Tail Wheel Access Cover

I didn't like the tail wheel access cover that was supplied with the kit because it was ill fitting and just a flat plate. I had read about several other kit builders that had a carbon monoxide problem when they started flying and traced it back to the ill fitting access cover. So I made another one that fits a lot better.

I used the original to get me close on the size and shape. I got it cut out and bent up on the brake. Deburred and sanded all the edges. I set the rivnuts for it and mounted it temporarily to check fit and finish. I took it apart to let the LocTite 680 Retaining Compound cure overnight. If I don't remove the screws they'll bond to the rivnuts. It doesn't take long to become a real problem. I found this out on some of the early rivnuts I set for the floorboards. I had to drill a couple out and replace them. :(

MOD - Cargo Door

I attached the hinge to the cargo door with solid rivets. Then I clamped the hinge to the door frame to determine where I would have to rivet the door to the frame. The cleco clamps would not allow the door to fully close so the only way to be sure of the alignment was to actually set a rivet at one end of the hinge. This not only secured the door to the frame, it would allow me to fine tune the overall alignment to the frame. The only problem was initially setting the height of the hinge to the frame.

After a lot of fitting and clamping I thought I had the door just right. So, I drilled it and decided to set a rivet. Once the rivet was in place, I removed all the clamps and closed the door to check if I had set the door correctly to the frame? I did.

The next step was to adjust the rotation of the door in relationship to the frame. That rivet acted as a pivot allowing me to adjust the side opposite the hinge up and down to get the perfect alignment. Once I achieved that alignment, I clamped the hinge at the bottom and drilled the very bottom hole. Then I set that rivet and removed the clamp.

Now, the door was attached to the frame and was free to move throughout its range of motion. I verified that the overall alignment was perfect. With the door attached, I was able to drill all the other holes. Also, I will be able to figure out the latching method and get it installed. I'll need to add stiffeners to the back of the door, probably in the form of a bracket to attach a first aid kit. Might as well pull double duty since I have to add them anyway.

Once completed and I move into the covering process, I'll drill out those two rivets and remove the door from the fuselage. After cover/paint, I'll reinstall the door and all the rivets during final assembly.

MOD - Tail Light

After letting the Hysol cure overnight, I fitted the SunTail back into the housing and set it on the rudder to check for rough fit. I think I got the angles correct, it looks pretty good. Obviously, I'll have to spend some time finish sanding/filing to get it ready for paint.

Actually, the next task is to determine exactly where it is to be positioned on the rudder and come up with a secure mounting method, as well as figuring out how I'll run the wiring. At this point, I've decided against permanently mounting the the housing to the rudder because of the extra work that would be involved when covering the rudder. Also, I would prefer to be able to remove the housing and light without having to cut fabric. Anyway, I have some research to do...

MOD - Tail Light

I saw this on Trent Palmer's Kitfox and thought I would like to do it too. So, I sourced the tail light housing kit from Kitfox. I knew when I ordered the kit that it would not fit out of the box on my SuperSTOL. I ordered the kit anyway and the SunTail Light/Strobe from AeroLED's. The SunTail fits perfectly as the housing was designed for it. However, as suspected the housing did not fit.

There were a couple of problems. First, the Kitfox has a flying rudder which means it has airfoil shaped ribs in the rudder. The housing accommodates this by having angled "wings" that mimic the shape of the airfoil ribs. The SuperSTOL does not have airfoil shaped ribs, instead it has a flat rudder. Second, the rudder trailing edges of both airplanes are different meaning the milled angled cut in the housing does not match the SuperSTOL trailing edge which puts the light and "wings" of the housing pointing at the wrong angle. So, I had to figure out how to correct these problems.

The first task was to correct the overall angle of the unit when fitted to the trailing edge of the rudder. I decided to file the milled angles in the housing to fit the trailing edge of the SuperSTOL rudder. Using a large round file and after much filing, I had the correct overall angle of the housing for the rudder. The housing matched the angle of the trailing edge of the rudder as well as the rib angle and consequently had the light pointing in the correct direction.

Second, I had to figure out how to bend the "wings" in to match the flat rudder profile. This was accomplished by cutting off each wing on my band saw and sanding a beveled edge into it on a disc sander. The bevels effectively straightened out the housing matching the straight rudder rib profile. This took quite a bit of effort to get the angles as close as I could, not perfect, but close enough.

The next task was to epoxy them back to the housing. Being that the housing is glass filled nylon, it is hollow or somewhat hollow as you can see in the pics. Actually, this is good because it allowed me to embed some Hysol into the pieces which made the joints much stronger than had they been just smooth. Of course, the down side is it added more weight.

Seat Harness Install

I marked and drilled two 1/4" holes in the two gussets on the upper frame of the baggage area for the upper attach points for the seat harnesses. Once the holes were drilled I deburred them.

Again the manual is of little help here. It doesn't specify how this is to go together. It only lists the (AN4-6A) bolt, but doesn't specify the washer(s) or nut nor does it explain about the bushing (supplied with the harness). So, my first instinct was to do it as in the 1st pic with a couple of big washers and although it might work, it  didn't look correct. Then, I assembled it like the 4th pic and texted it to Jak at the factory and asked it that was correct. He said yes. So I assembled them accordingly.

So the parts for the top attachment are: (1) AN4-6A bolt, (1) bushing, (1) AN970-10 washer and (1) AN 428A lock nut per bracket.

At some point the factory stopped mounting the lower seat belts to the actual seat and started mounting them via cables to the fuselage frame behind the seats. Of course, the manual is light on instructions of how to do this. It states to cut a 7ft piece of 1/8" cable into four equal parts along with the nylon tubing. It doesn't call out the part numbers of either or the specific length of the cables, but it does tell you to cut the nylon tubing into 4 equal 6" pieces.

Actually, after locating some pics from other builds on the net, it looks like the total length of the finished cables should be between 7 to 10". So, I guessed that the cable pieces should be about 12" in length and I cut my nylon pieces about 8" each. No mention of part # regarding the thimbles to be used but it does state "use the bushings provided inside the thimbles to  act as a spacer so the belt can rotate freely." The bushings will not fit inside the thimbles? I think what was meant was to use the bushings inside the belt bracket which is sandwiched by a thimble on each side, then a large washer on the outside of each thimble? How many bushings are to be used? Seven are provided with each harness. So far,I've used one on the top bracket and one on each lower side for a total of three. Where do the other four bushings go?

Based on my best guesstimate, I gathered the materials to make up the four lower seat belt cables. I cut four lengths of 1/8" cable (approx. 12" each), four lengths of 5/16" nylon tubing (approx. 8" each), gathered eight tin swages, eight thimbles, and cut eight lengths of shrink tubing.

I swaged one end of the cut cable using a swage and thimble. I taped up the exposed end of the cable past the swage and slid a piece of shrink tubing over the swage followed by sliding a length of nylon tubing over the cut cable into the shrink tubing up to the swagged end. Once all the pieces were in place, I used the heat gun to shrink the pieces together. I then assembled the other end with the various pieces and swagged that end and finished with the heat gun. This effectively made a short cable with thimbles on either end as shown in the pics. I continued to repeat the process for the three other cables.

The manual does not call out the correct size bolt, number of washers, or nut. "Use the bushings provided inside the thimbles to act as a spacer so the belt can rotate freely. Use AN970-4 washers on each side." So, I guessed at a AN4-13A bolt, one bushing, two AN970-4 washers and an AN -428 lock nut. Waiting to hear back from the factory to see if my guess is correct...