Apr 25
2010

Hours
Logged: 4

I started cutting and adding in some of the new skylight tubes today.

Here is a new chordwise tube. Note that it doesn't really fit just right.


I cut a notch into the tube to make it match the mounting area.
Mysterious note from the future!
I learned in retrospect that the following picture shows a tube that is ground a little too much. It should have been a little bit taller.

Now it fits better.


Here you can see the pair.


Mysterious note from the future number 2:
The above and below pictures show another problem. I put the tubes in as straight tubes, and they should have been curved slightly. Can you see what I mean? They should probably match the curves in the channels at the wing root.

From this angle you can see the new spanwise tubes, and the problem with the chordwise tubes.


While I was there, I welded the seatbelt tube in place.

Here's the completed seatbelt support tube, ready for prep and paint.



Thanks for Visiting! • This Entry is from April 25, 2010 at 7:00 pm 


Apr 24
2010

Hours
Logged: 6.1

Today I finished the back seat covering. Now it’s ready for some airplane noises.

Here's the finished back seat bottom.

It's a front seat, in a seat. It and the engine mount are just having a chat.

Here are some details of how I sequenced the overlaps.

Since our back seat has the added headrest structure, I covered the back in two pieces.

I wrapped the front fabric of the seat back around the back side of the bottom tube.


After I finished the back seat I took a little lunch break. Fellow EAA 731 member Kevin Ball stopped by and we spent an hour or so talking about the airplane, then I went over to Bart’s to take a look at his avionics work and to return his bending brake. When I got back, I started preparing the ceiling structure for the skylight.

The first step was to cut the stringers off. I left them a little bit long for final trimming.


I also cut the old stringer supports down a little bit to effectively lower the roof line about 1/4 inch, after accounting for the thickness of the new tube that will be on top of it. I copied the spanwise tube sizes from the plans at station C (T3, 3/8 x.035), and the chordwise tube sizes from the existing tubes in that area (T2 5/16x.058). I chose that size since the spanwise tube at station C serves the same purpose as my new tube at station N- a forward border for the fabric and an aft border for the other than fabric.

I decided to run the skylight back to the aft spar, which is further back than Pat ran his. I'm planning to have three separate panels that each run the full length. This will help reduce the compound curves in that area.


Bob has also specified that another tube be added between station N and the x cluster for supporting the shoulder harnesses for the front seat passengers, if the shoulder harness is going to attach out in the middle of that big tube at station N.

Note the areas that I've cleaned for welding in the seatbelt support tube.


Since the skylight will move the forward end of the stringers aft, I'll need to cut off these tabs.


In this picture I'm cutting away the old stringer supports.


This is looking mostly forward at what used to be the tab that supported the stringer


Here's a nice overview. The two little vertical tubes that used to be stringer supports will now hold the spanwise and chordwise skylight tubes, and the new forward attach tabs for the stringers. The paint is gone in the middle of the large tube for the seatbelt support tube.


I also did some measuring to decide on how far forward to take the skylight. One certainty is that this is a lot of effort to make a big hole in the roof, and I’ll have to carry sunshades to cover it up for a lot of the time.

I still haven't decided on where exactly to end the skylight on the forward side. Here are some options, with the numbers reflecting the number of inches from the windshield track. This shot is looking down at the top of the fuselage with the nose to the right.



Thanks for Visiting! • This Entry is from April 24, 2010 at 7:00 pm 


Apr 23
2010

Hours
Logged: 8

asting complete on 1, elt brscket on, control sticks done, cast 2, cover front seat bottoms and backs 1800 lunch?

With one aileron balance tube done, the second was easy. I’ll elaborate more on the process this time.

Here's the finished weight of the first lead tube. I will be able to drill some of the lead out once the aileron is covered to get a perfect balance.


I used a thick aluminum pan that Tabitha found at the thrift store, complete with a little pour spout. It was really perfect for pouring the lead.

I used tire weights that were really dirty. I would tilt the pan, and direct the torch at a tire weight. It was amazing to watch the bright silver liquid run out and leave the dirt, oxidation, and steel clip behind. A few passes with the torch helped be sure that all of the good lead was out. From there I would reach in and remove the nasties with needle nose pliers, putting them into a nearby rotel can. I would repeat this process until I had a fairly large puddle of bright lead, then I would reheat that puddle so that the whole thing was molten, and pour it into the tube. I would try to preheat the aluminum tube some too, in hopes that the lead would make it all the way to the bottom. Once the whole thing was cool and finished, I flipped it over and heated the other end. This caused all of the dirt and gravel to float up to the top, so I removed each of those with pliers. That left me with about a 1/4″ lip of aluminum as the lead settled into places that used to have little bits of rock in them.

I used a hammer to shrink the edge of the aluminum tube, so that it will help hold the lead in place more securely.

This would have been especially tidy if the whole tube was full, since then I could have the extra lead security on both ends.

Danny was telling me about an oil cooler that he didn’t use during his RV construction. Bob and others seem to think that it is adequate, and the price is great, so I think I’ll use it.

Oil Cooler donated by Danny

The control sticks are ready to repaint:

Here's the cap on top of the control stick, to support the push to talk.


I used the grinder to remove most of the weld bead around the control stick cap. This is to make sure that the grip will fit over the end, and this is certainly a non-structural piece, so I wasn't worried about removing the material.

I also finished the ELT bracket, except for cleaning and painting.

Here's the top of the ELT bracket, ready to weld to the bottom.


Here's the finished ELT bracket, ready to clean up and paint.

Today was a great productive day, and the weather was nice, so I figured I’d try a little bit of covering. I’m making the seat pans out of polyfiber covering, the same stuff as the exterior of the fuselage. The seats will be different from the airframe in that they won’t have any reinforcing tapes, UV protection, or color finishes.

I copied this idea from Oshkosh. The little cardboard disk helps reduce evaporation and drips.

Here's one of the front seat bottoms with the fabric on.

Today I finished covering the front seats, except for shrinking. I wanted to make this a priority so that I could get the seats ready for upholstery, which also involves cutting the foam cushions.



Thanks for Visiting! • This Entry is from April 23, 2010 at 6:00 pm 


Apr 22
2010

Hours
Logged: 5.3

It’s been a while since the last building entry, but I’ve been out of town more than usual. I just got back from Sun-N-Fun with a new list of ideas and a few new parts.

One of my SNF finds was these LED position lights. If I didn’t already have the aeroflash lights, I would have probably gone with a different setup, but since I do, I wanted to find some LEDs to replace the four incandescent bulbs. I had seen these before in the Aircraft Spruce catalog, and the guy who sells them to Spruce had a booth at the show. His price was a little better, so I got a set.

Here are the LED replacements for the position lights.


I took the cover off of the nav lights and took this picture.

Inside of the Aeroflash


This is the green LED in place


And the aft-facing white


Here's the whole assembly back together again. I replaced the green lens with a clear one, and was actually able to sell the original lens and bulbs to offset the price of the new parts.


On the red side I found that the gasket wasn’t properly installed you can see what I mean at the pointy end of the strobe insulator.

Notice how the black gasket doesn't quite fit right.


The white insulator wasn't quite right either.


When I put it all back together I put the gasket on correctly and also made sure that the white insulator was correct. I wonder if it came from the factory this way.
I realized that I should probably take some documentation pictures of the engine and accessories, because I always find myself with questions when I’m away from home.

The Starter...


...and the ignition wires...


...and the starter ring gear...


...and the carburetor...


...and the carburetor data plate...


I also found a baffle kit for sale second hand. This one wasn’t related to sun-n-fun, but I hadn’t had a chance to go through the kit to make sure that it was complete.

The plans for the Vans baffle kit are on one big sheet


There's all sorts of hardware in there


To change gears again, I finally had enough lead to fill the aileron balance tube. I ran safety wire from the corner of the bench to the tube, then leaned the tube slightly down and to the right as shown in this picture.

Aileron Balance Tube


This is a 1″ tube, which is larger than the 3/4″ tube originally designed in the plans. The diameter change is to improve the aileron if I recall correctly- it doesn’t really matter, since my ailerons have a 1″ hole in them. Back with the old 3/4″ tube, builders had to fill the entire tube with lead in order to get the required 5.5 pounds. I’m glad that another builder pointed out that the 1″ tube definitely does not need to be full. Without this tip I might have not thought about that until it was full of lead. I started to wonder if this uneven weight distribution would be a problem. I asked Bob, and he said to just leave the tube at it’s full length so that it will have more attachment points, and not worry about it. I’ll probably have to drill some of the lead out to actually balance the aileron. If I leave the 1″ hole open during covering, I will still be able to get a long drill bit into the lead. I can make small covers to pop-rivet over the 1″ holes when that is done. This will also come in handy if I need to recover the aileron later.

While I had the torch out, I figured I would also weld a cap onto each of the control sticks. This will make it much easier to mount a push to talk switch on the top. In this picture I’ve cleaned the paint off in preparation for welding.

Control Stick prior to welding


I also removed the paint for the ELT bracket


I don't remember where I got the idea for this holding fixture. It is 16 gauge copper wire and alligator clips. For tacking it works well, but since the clips are soldered it might not hold if it gets too hot.



Thanks for Visiting! • This Entry is from April 22, 2010 at 5:30 pm 


Apr 2
2010

Hours
Logged: 3

Today I was in the mood for some welding. First, I noticed back when I primed the headrests that I had missed a problem with one of them. I had started to cut one of the horizontal tubes, then realized that I was cutting in the wrong place. This left a scored line around the tube, so I wanted to grind the paint off and run a bead around that score mark to remove the potential stress riser.

Fixing a problem with one headrest


Next, I needed to make a welding cart to hold my tanks. I started with this cheap harbor freight hand truck and spent an hour or so modifying it. I didn’t count this time towards Bearhawk building of course.

Starting point for a welding cart


With the tanks safely secured, I started on that ELT bracket. I started with the tube that will hold the fairlead plastic, and a short piece of tube that will locate that tube vertically.

Even with as much practice as I have, I still am not a pro. Note how I didn't get out fast enough with the torch at the edge of that thin 7/8\


My goal was to try and locate the top of the antenna plate just below the level of the stringers, just in case the covering had a little bit of sag between them. The reality is that since the stringers are so close together at that point, the covering probably won’t sag at all.

The ruler is just a straight edge to hold the bracket blank level with the stringers.


Here’s the blank after I’ve bent it. It’s going to be a tight fit with a 90 degree BNC adapter to keep the coax out of the elevator trim cable’s way.

ELT antenna bracket view from the top


Here's the top half of the bracket



Thanks for Visiting! • This Entry is from April 2, 2010 at 4:45 pm 


Apr 1
2010

Hours
Logged: 2

I needed to bend the new aft cable guards again, so this time I took some pictures of the process that I described earlier. Thanks again to Brad and Joel for letting me use their machinery! The weather was nice, so I put the blanks into the car that Dad was driving down to the IPJ airport. His airplane was down there getting a new engine and he was helping them get it installed. He was going to be there all day, so I rode a motorcycle down there at around lunch time so that I could borrow their brake.

3-in-1 Sheet Metal Tool

3-in-1 Sheet Metal Tool


Theirs is the combination brake, shear, and roller from Northern Tool. I’d love to have one in my shop, but I probably wouldn’t use it enough to justify the cost. In fact, I’d rather have the larger version that could handle a 48″ wide sheet of aluminum, but even the cheap Chinese version is close to $1000 and 700 pounds- I definitely wouldn’t use that one enough to justify the cost! This one is very handy, but has some important limitations.
Bending Die with No Radius

This isn't enough of a radius for 2024-T3


The primary limitation is that the bending dies don’t have any radius. As you can see from this picture, they are quite sharp. Since the 2024-T3 Aluminum is so hard, it tends to crack if bent under these circumstances.
Fake Radius

Here's Bob's solution for adding radius to the dies


In this picture you can see the corrective action (as outlined by Bob in the early Beartracks) which is made out of some aluminum flashing. I used one piece on the bottom (just to prevent scratches from the sharp edges) and a handful of pieces on the top. If this were my own brake, I would modify the dies to have a 1/8″ radius permanently, but since it isn’t, I just use these pieces instead. The above picture actually also shows a blank in place and ready for bending. I bent the two pieces as before and enjoyed a fantastic spring ride back home. Everything is really starting to bloom and grow again, and the little two lane roads are full of lots of great yards and gardens to see.
Cabin Air Intakes

Here are the Vans cabin air intakes

Once I got back to the hangar I opened up a box from Vans that included the two air intakes for the cabin air and the countersunk nutplates for the boot cowl. Their price on the nutplates was better than spruce at somewhere around 50 cents each, and I’m going to use them for the parts of the boot cowl that aren’t riveted. The vents will provide fresh air to the two front seat occupants, and there’s no way that I would try to make them myself since Vans sells them for such a reasonable price.



Thanks for Visiting! • This Entry is from April 1, 2010 at 4:30 pm