3.4 Hours -
There are a lot of pictures for this post. Some of them may seem a little repetitive on the pitot/AOA portion, but I wasn’t able to find many good descriptions for assembling the Dynon pitot/AOA with the SafeAir1 mast. Hopefully, my description and pictures will help out someone else.
Since deburring doesn’t make any noise that will wake up the neighbors, I started on the project relatively early this morning . OK, it probably wasn’t early by most people’s standards, but I know some people were still asleep in the neighborhood. After about a half hour, I had all the holes on the left bottom outboard skin deburred. Once deburred, I transitioned to dimpling and used my squeezer to dimple all the holes that it could reach. By this time, I figured it was late enough to start making some noise, so I pulled out my c-frame to finish the dimpling process. To wrap up my morning session, I scuffed cleaned and primed the inside surface of the skin.
Me, deburring the left bottom outboard skin.
A bonus picture for the FAA. Me, dimpling the left bottom outboard skin.
After lunch, I returned to the garage. Before I could start riveting the left bottom outboard skin, I needed to finish the pitot assembly. This could be done after the skin is riveted, but doing it now lets me see how things are going together inside the wing. Once the skin is riveted, I’ll just have to attach the pitot tube to the mast and connect the air lines.
The first thing that needed to be done was to match drill the mast and pitot. Unfortunately, neither of these have any holes to use as initial guides. The only indicator of hole location is on the pitot tube itself, where there are areas with thicker metal that indicates the proper location for the holes. I used a sharpie to draw lines on the outside of the tube where these thicker areas were. I could then insert the tube part way into the mast and transfer the lines to the mast.
The pitot tube has to be drilled through the sections that have extra metal...marked with lines here.
I transferred the lines to the mast, since I would have to drill through the mast first.
To drill the holes, I started with the mast. After some careful measurement to determine the proper distance that the holes needed to be from the end of the mast, I center punched the mast and drilled the initial holes to #40. These will have to be enlarged, but not until I know everything is lining up.
I drilled the initial holes to #40. These will be enlarged once I know everything fits.
With holes drilled in the mast, I reinserted the pitot tube. The lines on the tube were visible through the holes in the mast, so I knew the holes were in the right position. The pitot tube was a little loose inside the mast, so I wrapped a couple layers of aluminum tape around it before drilling. These two, thin layers of tape gave the pitot enough extra thickness for a tight fit in the mast.
The lines on the pitot tube are visible through the holes in the mast. This is a good sign, but I'm still nervous about drilling into a $200 part!
I then drilled the holes in the pitot using the mast holes as a guide. I did this extremely slowly because, if I was off, I could easily drill through the tubing inside the pitot. If this were to happen, the pitot would be ruined ($200 down the drain). After drilling the holes in the pitot, I tapped them for #6 screws.
After drilling the holes into the pitot tube, I tapped them for #6 screws. I also placed two layers of aluminum tape around the pitot to give it a snug fit in the mast.
Next, I enlarged the holes in the mast in order to accommodate #6 screws. I opted for flush screws, so I needed to countersink the mast. Since the mast is curved, a countersink cage would not work, and I decided to countersink by hand using a deburring tool. This method doesn’t create the prettiest countersinks, but it gets the job done.
Since the mast is curved, I had to countersink for #6 screws by hand with a deburring tool.
After countersinking the mast, I assembled the pieces for the first time and everything went together easy and the hard part was behind me!
The pitot tube and mast assembled for the first time. This wasn't nearly as difficult as I thought it would be.
I’m using the SafeAir1 pitot/static and AOA tubing kits. These kits use plastic tubing, while the Dynon pitot/AOA has aluminum tubing. To connect the two types of tubing, SafeAir1 provides the appropriate AN and push-on fittings. To install these, I cut the tubes on the pitot/AOA to the appropriate length. For this, I decided to cut them so that the coupling hardware would be partially inside the pitot mast. Once cut, I used my Rolo-Flair to flare the ends of both tubes. After that, it was just a matter of installing and tightening the fittings.
The ends of the pitot and AOA tubes had to be cut to length and then flared. My Rolo-Flair made quick work of that!
The SafeAir1 hardware enables a transition to plastic lines using push-on connectors.
Here's the finished product off the wing. I'll probably wrap the fittings with some tape so they aren't vibrating against each other or the inside of the mast.
To wrap up the day, I did one last test fitting of the assembled pitot/mast on the wing, and then I clecoed the left bottom outboard skin to the wing. Finally, I ran the pitot and AOA tubing into the wing just to see how it would work. I’m planning to run the tubing under the bellcrank, and I may need to install an adel clamp to hold the tubing down and prevent it from rubbing on the bellcrank. I’ll wait to do this until the bellcrank is installed and I can see how things are actually going to work.
Here's what the pitot assembly will look like on the wing.
Both wings are now ready to have the final skin riveted!
Just for fun, I ran the pitot and AOA lines. I will run them under the bellcrank. If needed, I'll install a clamp to hold them down and prevent them from rubbing on the bellcrank.
