Cockpit interior Print E-mail
Written by Vidar Fagerjord   
Saturday, 05 May 2012 20:16
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This article will show how I made the different cockpit interior details, starting with the cockpit sidewalls.

Sidewalls

I have created a PDF document with all the drawings for the sidewall panels. It can be downloaded here.

You will need two standard sheets of plywood or MDF, 10mm thick. I have tried to minimize waste when stacking the parts. The drawings includes two of every part; one for each side.

The following image shows the first sheet. Most parts are found here:

On the second sheet, some parts are blue - those are not needed for the side walls; they are the MIP support and the FMC bay for my FDS MIP.

This is a detail image of the sidewall, showing measurements and angles on the "tables" where the map lights, oxygen mask, chart pocket and cup holder goes:

The Google Sketchup model is available upon request, but you should not need it - everything is included in the PDF.

This shows the sidewall with measurements. This drawing can be used as a reference when assembling the parts.

NOTAM: I planned the assembly based on a concept found in boat building, called stitch and glue. Basically, you cut the different parts roughly to size, then use epoxy resin and fiberglass to create a very strong, self supporting structure. This method does not require great accuracy, nor a complex support structure behind the parts. There will be some support needed to stabilize the sidewall, but not much. And since everything is covered by fiberglass and epoxy, the end finish should be superb!

All the joints between the different parts will be filled with epoxy putty, then blended to the neighboring parts by sanding.

I started by drawing all the parts on the plywood sheet, then used a track saw and a multi saw to cut out the parts:

The track saw is an extremely nice tool to have! You line the track up with the markings, then plunge the saw through the material, then push the saw as far as needed.

The above image shows the different cuts I made with the track saw. Dead straight and done in 5 minutes!

The multi saw is perfect for the smaller cuts and to finish the cuts the track saw couldn't. Several parts are stacked against each other, so you need to stop before you cross into the next part. The multi saw finishes the job.

And this is how everything comes together:

Looks like a simulator part to me!

I plan to use a router with a round over bit to create even edges. This is actually mandatory for glass fiber use! The glass fibers do not like sharp edges and corners - and on the real birds, there are no sharp edges where the pilots could cut themselves.

Some adjustment will be needed on the parts in order to make them fit properly. But you do not need to be that accurate! Gaps up to 3-4 millimeters are accepted, and some gap is actually preferred for the epoxy to bond properly.

I plan to build my own boat in the future (I already have the plans for it! 21' pilot house style!), and this building method is used on that boat. And I figured - why not the cockpit as well?

I will update this article when progress is made. If you do not own the fancy tools I have, do not let that stop you! Go get yourself a Japanese pull saw, and you can cut the parts within a few hours! A jigsaw could also be used, but use a fine-toothed blade or you will experience some nasty tear-out and splintering on the plywood!


Update 12. may 2012

I've started building the left sidewall. I'm new to the whole "stitch and glue" method, and I've never used epoxy resin before (only Polyester resin). I ran into a few obstacles, but nothing I couldn't resolve. The epoxy resin is rather "runny", and the first "glue up" got very messy. But - it worked, and the parts are now in one piece:

I taped a small piece of plywood to hold the largest part at a 90 degree angle. Two 45 degree cuts at opposite directions, and you have a 90 degree support piece. The other parts are just taped together (later I used duct tape, which worked MUCH better).

After the resin cured, I used polyester putty to create a uniform fillet with a nice radius. The fibre glass cloth does not like sharp bends, and the real world side walls has a small radius there too.

Since the first attempt did not work very well, I got better resin and micro glass balloons (a filler material made of microscopic glass balloons). The glass balloons can be mixed with the resin to create putty. I glued some plywood to the underside of the table area in order to support the walls extending to the floor, and to strengthen the joint. I then made epoxy putty and made fillets:

After the putty and the epoxy cured, I applied glass fiber tape (just a narrow strip of glass fiber with no adhesive) and epoxied it over the fillets, extending out onto the neighboring wood:

It is important to "wet out" the glass fiber, but not soaking it. It should be transparent with very little resin on top. By "glassing" both sides, this joint should be strong enough to stand on!

Here's a shot of the taped seam on the inside of the 45 degree piece on the lower wall beneath the table area:

Another method of assemble parts is to "spot-weld" the pieces together using a small piece of glass fiber epoxied in place:

Note that these spots needs to be sanded down after the inside joint is epoxied, or you will get visible "bumps". You do not need to remove them completely; when finishing the rest of the joint, you just overlap a bit on the "spot weld" piece. In the end, the whole construction will get a putty coat and sanded to a smooth surface before painting.

I epoxied the rest of the parts to the table area in two steps. The first step was to join the table area part to the frontmost part, giving me something to clamp to the work table later:

After the epoxy and putty cured, I continued with the next parts, completing the front part containing the table.

NOTAM! The drawings might have an error - the aft part on the table area was too narrow!

I order to correct the mistake, I just used a scrap piece from the plywood sheet. I made a small piece that fits between the aft and the side part.

The piece can be identified by looking for the black, horizontal line on the upper right part in the picture. The joint will be glassed over from the back, filled with putty on the visible face and sanded smooth. Then the whole thing will be glassed on the face visible from inside the cockpit. The backside will be "painted" with epoxy then painted in order to preserve the plywood.

This is how the build looked before I mounted the last two pieces (1 and 2)

After the epoxy and putty has cured on the last two pieces (and all seams are filleted and taped), I will use a round over bit on my plunge router and make nice, beveled corners around the table area. The "rib cover" will be mounted (I actually plan to use foam for this, just as a test), then the whole thing will get one layer of woven glass fiber cloth and epoxy resin. I will then spacle the whole construction, sand smooth and paint. I plan to use semi-gloss paint - high gloss is not used in a cockpit because of glare.

The diagonal structure beneath the windows will be constructed using some plywood for the parts that needs to be strong, the rest will be made from foam (dense, small-celled type. Underground insulation pieces is ideal). When covering foam with 2 layers of fiber glass (preferably laid so one layer is laid at 45 degree) and epoxy resin, it will be both light and very strong. The foam is very easy to shape into smooth curves and shapes, giving a very nice look.

All in all, this construction method has proven to be super easy! The structure in the image above doesn't have a single nail or screw in it! Just plywood, epoxy resin, glass fiber and micro glass balloons (in the putty).

Update 14. may 2012

The last two pieces are now epoxied in place, the joints filled with putty and glassed in. I used my plunge router to create a rounded edge - done in a minute! Beats sanding and filing...

I "painted" the backside with epoxy in order to seal the wood from moisture. It just need a light sanding and some paint. I'm going to paint it white just in case I ever need to work inside the side walls. The oxygen mask panel is removable, and the space beneath would be ideal for running wires.

I then applied glass fiber putty on different areas where there was gaps or bumps. After a light sanding, the surface is ready for the glass fiber layer.

In the image above, you might notice the putty on the aft wall (part no. 1). As i mentioned earlier, I had to insert a small piece because part 1 is too narrow. By glassing the piece in place, the structure is extremely rigid. If all errors could be fixed that easy...

The next job will be to glass the entire surface. I'm doing it to get an even surface with minor sanding needed before painting, and the layer of fiber glass will make a sandwich construction in all the joints. There should be no problems standing on the parts when finished.

Now I just need to source the oxy panels...

 


 

Update 24. may 2012

I've made the right sidewall as well - or to be correct: there front parts. The aft portion of the sidewalls, where the flight bags are located, will have to wait. I plan to make the side walls in two pieces, and my focus is on the front parts for now.

I glassed the structures by using narrow strips of glass fiber over the joints. By using thin glass fiber, it is easy to form around the corners. The heavier (thicker) stuff does not like narrow corners - very easy to get air bubbles where the weave lifts off the plywood.

The dark brown stuff is polyester putty with glass fiber threads in it. I started using long-threaded, but switched to short-threaded since it is easier to work with in this case. The fillets are applied with a butter knife (!!!) with a big enough radius - the fillets gets the correct radius, and I don't have to sand as much.

Here's a shot of the piece I had to fit since I cut the parts wrong:

I glassed the whole structure with a long piece of glass fiber. This creates a very strong structure. All joints are glassed on both sides.

I then made the "rib covers" from pieces of insulating foam. I cut three pieces from a sheet of foam, two of which I cut at a 45 degree angle. I epoxied them together, then epoxied them in place and covered with two layers of thick glass fiber fabric. This made a very hard "shell" over the soft foam.

After the epoxy cured, I cut the foam to shape and sealed the top with two layers of the same glass fiber fabric.

I also made a fillet at the bottom with polyester putty. Since the foam was sealed with epoxy, the polyester goo did not dissolve the foam.

I sanded the fillets to a smooth surface and "painted" them with epoxy to seal them. Just because I had some epoxy resin left over from the sealing of the foam pieces. You should try to utilize every drop of the epoxy - it is expensive stuff! I used leftover resin to "paint" the whole back of the structure in order to seal the plywood.

And now for the bigger picture:

The two sidewalls end to end before the last fillet was made. Looks great!

Another example of being cheap:

Leftover resin + micro glass balloons, and the "table" area of the right side wall got a layer of putty - which is FAR more easy to sand! I'm going to use epoxy mixed with micro glass balloons on the entire surface (inside), then sand smooth and flat before painting.

Here's a shot of the two sidewall structures placed side by side. Excuse the mess in the background - the workshop is busy!

This building technique is simply fantastic! VERY easy to do, and very forgiving if you make a mistake. The only drawback is that sanding cured epoxy is hard! But the end result should be smooth and clean.

I just need to make a support "leg" at the back, then I have to start the sanding job - but I need to let the epoxy fully cure first. If you sand epoxy before it is fully cured (which can take up to two week depending on the conditions), you will clog the sand paper very quickly.

I also have to cut holes for the oxygen mask panel, the light panel, the cup holder panel and the chart pocket - but I'll do that when I have the parts I need.

More to come, but I'm not going to bore you with images of me sanding, sanding, and then sanding...

Last Updated on Thursday, 24 May 2012 16:07
 
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