Carlson Skunk Works

Well, there has been progress on the airplane and on the engine and on the shop and on the bathroom and …

What I am saying is that I have been busy!

So, the airframe is progressing in that all of the long ribs have been assembled. The first of the short ribs has been assembled as well, so we are onto the production of the next set of parts. Therefore, here are some pictures of the airplane parts.

One of the small improvements that I made to my work area is to add “stilts” to my work table. I used some pieces of 2×4 and built extensions for the table legs to sit on. This raised the working height of the table top from 29 inches to 36 inches. This is a real back saver!

Now, on to the engine! Progress has been made on disassembling the RH engine. Most of the external parts have been removed and we are waiting for the arrival of a nut splitter in order to remove the heads.

I got the book “The Classic Corvair” by Bob Helt. In his book Bob suggested using a piece of 2×4 to make a parts holder for use during the engine rebuild. This was a fun and easy tool to build. I decided to make mine a bit bigger than what Bob had suggested and I think it looks rather impressive. It is really fun to have a nice place and method for keeping the parts from the valve train organized. I have a largish nail to hold each of the rockers, balls and nuts for each valve. As I removed each piece I put it on the holder in it’s place. I drilled a 3/8″ hole for each of the pushrods. I do think that one of my pushrods is bent.

Here is where the prop will be installed eventually.

Here is the back of the engine. If you look closely you will see some of the white aluminum oxide that I am finding to be quite common in this core. I will need to be very meticulous in cleaning it up.

But I did mention the shop improvements as well. I needed more workbench space and I needed to start organizing the shop better. So I built an additional workbench. This one is fastened to the wall and is eight feet long. The shelf under the bench top will be used primarily for power tool storage. Right now I have my belt sander and some hand tools under there. I am busy using the scroll saw to make gifts and some tool parts like handles for pusher boards for doing small work on the table saw and router table.

Speaking of the router table, it is done and it works! I still have to finish the fence, but it is usable in its current configuration. This is being used to build the doors for the bathroom cabinet. One thing I discovered is that I really need to have the vacuum port on my fence. Without the shop vac handy there gets to be so many shavings that they get under the part that I am currently working on and it can climb up and throw the cut quite a bit off. Anyway, here is a picture of the router table.

The router table is a homebuilt unit from a magazine article. It was originally intended to be clamped in a bench vice for use, but I don’t have a proper woodworking bench vise, so I build some legs to go under it. I mounted a switched outlet under the table on the left side. This is a switch and single outlet that is a single unit and fits in a regular switch box. I might replace this with a double switch box and put in a double outlet and a regular light switch so I can turn on both the router and the shop vac at the same time. It was a fun project and is proving to be very helpful. I expect that I will be making quite a bit of use of the router table for shaping parts for the airplane.

Now the background project that I have been “working” on since March! THE BATHROOM!!!

Ok, so you can only see the toilet. My camera doesn’t have a wide angle lens and there isn’t enough room in there to get a good picture of the rest of the project. However, the new floor is in, the pedestal sink is in, the recessed medicine cabinet is in, the trim is installed and the cabinet is in. The only thing left is the doors for the cabinet and you can see the parts for them on the workbench if you look closely.

Well, that brings things up to date.

My wife and daughter will be at a women’s thing at church tonight, so my son and I are expecting to get a few more short ribs done. I will post more as progress is made.

It has been a long, busy summer, but some progress has been made since my last post.

Enough of the long wing ribs have been built for one wing. This weekend I will be building ribs at our EAA Chapter 1091 fly in here in Kearney. If you get a chance, come on out to see us. With the amount of time and being focused on building ribs I am hoping to have a significant number of ribs completed by the end of Saturday. Just to be sure that I have enough material to keep working on ribs, I ordered more 1mm plywood. It should be here tomorrow.

The big news is that I have finally located some engines that I can use to build the engine for the Maranda. The pictures show the condition of the engines at present. Before long we should be tearing them apart and cleaning things up.

The engines I am using are Chevrolet Corvair engines. The first one was from a 1963 model and had only 145 cubic inches of displacement. According to the manual I needed a 164 cubic inch engine, so I called the gentleman I bought it from and he said I could trade up. He went through the engines he had and came up with two complete engines that were “stuck” and one block, crank and cam unit. I exchanged the small engine I have for the larger ones and bought a gallon of penetrating oil.

This weekend I was able to put together a stand to put one engine on while we work on it. This gets it up to where we can comfortably get at things and see what we are doing. The stand has wheels so that we can roll it to a convenient location for working on it and then roll it back into storage when we are done.

Take a look at the pictures. I will try to keep the images updated as work progresses.

A Rib Is Born! Well at least the first rib is assembled.

I finally got time to assemble a rib. Things went well. Jeremiah helped me and even took some videos, so I am posting them today as well. The videos are in AVI format. My Windows media player doesn’t do much for them, but my Quick Time player shows them very nicely.

We built the rib as a team. I applied the glue and Jeremiah stapled the gussets in place. Jeremiah got a bit carried away with the staples in some areas, but by the time we finished he was doing very well.

Here is the video of getting started on the first rib:
Building the rib

Here is the video of me showing off the finished rib:
The completed rib

I am now set up to build ribs.

Since returning from Kansas City I have cleaned up my work area in the basement and arranged it for rib assembly. I put a sheet of cardboard over the table top where I will be working and another one on the floor under where I will be working. That way if the T-88 drips it should only drip on the cardboard.

The gussets that I have already cut are in zipper bags on the table behind the rib jig.

I covered the rib jig with a sheet of wax paper to try to minimize the chances of a rib getting glued to the plans. Hopefully I will be working fast enough to avoid that, but it never hurts to be careful.

Now I just need to load up the syringes with T-88 components and work up the nerve to mix a batch of glue.

The Skunkworks has moved to Kansas City for this week. I am setup at a Marriott Courtyard near the airport. The primary reason for being here is to attend a class for work, but since I have some long evenings available, I have taken the opportunity to cut gussets from the plywood that I have available. So far things are going quite well and I should have enough gussets ready to allow construction of the ribs to begin once I get back home.

Last Saturday I cut the sheet of 1mm plywood into strips. This week I have been cutting the strips into gussets. There are two main sizes of strips to be cut for the gussets; 105mm and 40mm. The 105mm wide strips need to be cut cross grain and are used for the nose and tail gussets. All of the other strips should be cut with the grain.

I took a walk yesterday at Lowe’s and found a clamp that I had never seen before. It is a 2 inch plastic hand clamp that has a locking mechanism that is very easy to use. There are softer plastic pads on the tips of the jaws that keep from marring the material being clamped. At $5 each I thought they were a bargain, so I purchased two of them.

We have gusset!!! At this time just one, but that means the next step of this project is under way.

Last night I cut the remainder of the spruce pieces for the ribs. My sockpile of parts looks like this:

And another view:

Next I moved on to my scarfing sander. Here is the vacuum cleaner that I am going to pull the motor out of:

Here is the vacuum after I freed the motor from it:

Here are the parts that I will keep and build the scarfing sander out of:

The only issue that I ran into was that when I tried to take the fan off of the motor I didn’t see that the nut used left hand threads and stripped the nut. Now I will have to work a bit harder to get the fan assembly off of the motor. I didn’t have the time or inclination to work on this issue last night, so I proceeded on to cutting gussets.

Cutting gussets should be a fairly easy issue, but I think I will need another sheet of plywood to finish the ribs. I will be able to tell more after I cut a few more gussets. I started with the gussets for the nose of the ribs. I used a spray adhesive to glue a photo copy of the rib nose to a piece of tag board, then cut a pattern from that. Then I cut a strip of plywood 75mm wide. I traced my pattern onto the plywood and nested the pieces to make the best use of the plywood. I was able to get about 24 rib nose gussets from one strip of plywood.

I am using a utility knife to cut the plywood. After all the plywood is only 1mm thick. It takes a couple of passes foir the cut to make it all the way through, but the cut is clean and there is no waste in the form of sawdust. It is a bit tricky to cut the curves on the back of the nose gussets. Making several passes with the knife and being careful seems to do the trick. I was careful to allow a bit extra around the nose of the gussets to ensure that they will cover all of the area that they are designed to cover.

Next week I will be out of town, so I don’t know if I will be able to make much progress if any. I am toying with the idea of taking the plywood with me. If I cut the strips ahead of time and take them with me I shouldn’t draw too much attention bringing it into the hotel 😉

Over the past few days I have cut a few more pieces for the ribs. However, Tuesday night was EAA and Wednesday was Valentine’s Day and our bible study group had a pot luck dinner, so things have been moving quite slowly.

The EAA meeting was well worth the time on Tuesday night. The club calendars were passed out and a full list of members names and contact information was distributed. There was a presentation about aircraft wiring. I setup the TV and DVD player and we watched several of the segments from the Homebuilt Help DVD “912 Competition”. Fred had the Pober spars mounted on a work table and some of the members worked on assembling the ribs to the spars for one wing.

I have been puzzling over how to scarf the plywood joints that will be needed when I assemble the spars for the Maranda. Several Maranda list members offered suggestions and some provided URLs to information on building a scarfing sander (http://www.seqair.com/skunkworks/WoodWkgMethods/Notes/Notes.html). With this information I have started scrounging for materials to build a scarfing sander. The primary part is an electric motor.

New electric motors run anywhere from $70.00 to $120.00 for a relatively small unit. However, as the horsepower rating decreases the cost seems to increase. The most economical new electric motor that I could find in my area is a 1/3 hp for $70.00. That was too expensive for me. Trying to find a used electric motor was impossible. Then I got to thinking of things that used small electric motors; fans, vacuum cleaners, garage door openers, etc. Goodwill did not have any. The Salvation Army Thrift Store didn’t have any. However, there is a vacuum cleaner store in town and they have used vacuums! I stopped in yesterday and talked to the lady that runs the store and she had an older upright vacuum that has been taking up space for some time. I got it for $10.00! Now all I need to do is take it apart to get the motor. I am good at taking things apart 😉

I cut more pieces over the weekend. The only rib pieces other than the gussets left to cut are A, B, C, M, N, O and P. We are getting there, but slowly.

Purchases of construction supplies last week included a four foot straight edge, some new blades for my utility knife, a couple of large disposable veteranary syringes and a box of disposable plastic gloves. I also got a large 3 ring binder to keep documentation in.

If you’ve been reading on my other site, I’ve been busy learning about casting aluminum at home. I built a burner which uses propane at high pressure to heat a crucible containing aluminum, and for my first pour, used plaster of paris for the mold. This did not work very well, so I proceeded to move on to sand casting. Today I did my first sand casting, and let me tell you, the results are WONDERFUL!! I am very happy, and excited about the quality of the latest casting. It is still not perfect, but the step forward in switching from plaster of paris to sand was a huge leap.

I’m including some photos here and a couple of videos for posterity.

Here you can see me after I’ve mixed up my green sand using approximately 10% bentonite clay and 90% silica sand. I’m starting to ram up the mold here.

After pouring, and letting the casting cool, I broke it out of the mold. In this photo it is still very VERY hot, far too hot to pick up, but I couldn’t wait any longer (I had waited about 45 minutes at this point).

After letting it cool more, and cleaning off the sand, here are some close up photos showing some of the defects in the casting. I’ll be researching what happened, and trying to remedy the problems on the next casting. However, I’m very excited as this casting turned out FAR better than my first!

Last night was more productive. I cut a significant number of pieces of spruce for the ribs. Parts completed to date are F, G, H, I, J and L. I am currently working on K. The vertical rib pieces go quickly since there is only one cut per piece. The diagonals take a bit longer because they require between three and four cuts each. It won’t be long before I start on the gussets!