I’m finally getting back to building and since I don’t have any workable epoxy hardener at the moment, I thought I would work some more on my landing light and associated stuff. The instructions seem fairly easy. I had already test-fit the premoulded flange into the fuselage and it fit reasonably well. So I cut the hole out around the markings and tried to fit the lens in. Unfortunately it took a lot of fitting to get it close, and then when I put the flange in on the inside, it was obvious that something wasn’t right.
So some other solution will have to happen to get things to fit right.
I’ve been really stuck on this project for a couple of years, and unfortunately I think a lot of it has to do with my ability to document the work I’ve completed. I’ve been recording my work on a GoPro in time lapse mode (one picture every 2 seconds) and then converting them to a video at 30 frames per second, which is nice because it gives me videos at 60-1 time compression. So 1 minute of video is an hour of work time. When I started I had a Windows desktop and used the GoPro software to convert the images to 30 second clips, then used Windows Movie Maker to add text, insert still images, and combine the multiple small videos into a single one. At some point I switched back to Linux as my primary desktop and decided to try making my videos in 4K. The GoPro I use captures in 2592 X 1944 (4/3 ratio) which is less common these days, but still pretty good.
Unfortunately, I had a tough time finding a good video editor to use. Windows Movie Maker didn’t do 4K videos, neither did Apple’s iVideo or whatever it was. After doing a little searching, I found that an app called “Blender” would be able to work with the resolution I wanted and ran on Linux. Unfortunately, blender has a steep learning curve, and I couldn’t get it to do the few simple things I wanted in a way that was at all reasonable. So I kept messing with it occasionally, getting frustrated, then doing other things with my life. Of course this only works with existing video effectively, so I had to convert the images to video beforehand. What I use to make videos out of the still images is ffmpeg and the command I’m using is ffmpeg -r 30 -pix_fmt yuv420p -i pictures/%04d.jpg -c:v libx264 -crf 10 output.mp4
It’s not perfect, but it gets me a pretty high quality video that I can then further edit. Also, GoPro puts the images into a series of folders, so I first have to rename them all and put them in the same folder, which is trivial but just another stupid step I have to take.
Recently I decided to try again, but instead of digging into blender again I did a new search for a video editing app. What I decided to try this time is called ‘kdenlive’. This product seems to be more effective at the things I like to do. (Inserting text and adding still images) I was able to execute all of the features I wanted to in kdenlive in 4 hours, when there are things I never got working in blender in probably 40 or more hours of effort. This is what my desktop looks like (as of about 30 second ago) when trying to edit a video and update the wordpress site.
My attempt at video features can be found here:
In case you are curious, the features I wanted were:
Adding text in various locations
Different fonts and colors is a bonus
Adding still images as an interruption to the video
Adding small images over the main video while the main video is still playing is a bonus
Scrolling text for ‘credits’ style ending is a bonus
Fading in/out of different video clips or stills is a bonus
Things I don’t know how to do yet, and am not really motivated to learn:
How to add an image (clip-art like an arrow) that follows something on-screen that moves.
How to move an image on-screen
I think I know how to do this but I don’t care enough to do it
How to pan&zoom the video while it is playing.
OK, I lied, I just did it although I didn’t update the youtube version.
How to speed up or slow down video clips
How to add audio
I suspect this will be pretty easy
So anyway, now that I can more easily create my documentation, I think I’ll be more likely to get back to building.
Also, the video I was playing with for the demo is from March 2017, I will have an update with that work (that isn’t such a hectic mess) reasonably soon.
Since the Keel access hole and the torque tube access hole and torque tube cover are complete, it’s time to add the keel hard point for the aileron torque tube. I had already shaped the wood to the right shape and knew exactly where it would fit in the keel, so it was a matter of sticking it on with some cab-o-sil epoxy and the covering it with the appropriate layers of glass.
This one actually turned out to be one of the better layups I’ve done so far in my work. The pressure I put on it and the amount of epoxy was just right. If I had to do it over, I’d probably add a small fillet of microglass to the edge of the layup so it wasn’t sharp, or at least figure a way to have the very edge be only one layer of glass thick.
The keel hard point in place, with the microballoon fillets
The glass on top. Note that there is a pretty big step from the multiple layers of glass down to nothing.
And now with the peel ply on!
And after curing:
The epoxy/glass ratio seemed really good to me. No dry spots, no excess epoxy.
My intent was to attach the keel hard point, but the epoxy hardener had crystalized since I last used it. So I put it in the heating pad and let it sit at about 130 degrees overnight. After that it was nearly as good as new.
You can see all the small crystals in the mixed epoxy
They all come from the hardener
Wrap it up and heat it
And it’s nearly as good as new after that.
It looks clean again
There are still some tiny flecks, but I think this will be acceptable.
Reiff came to visit again; we worked on getting the keel access panels attached to the keel.
I started by marking out six equal spots on the (very nicely round) keel access hole cover. Then we oriented it so the ‘center’ hole was up, then drilled through both the top and the bottom layers. Because the holes might not be exactly evenly spaced, I marked an ‘up’ direction on the cover for future reference.
We then used the nut plate tool to cut holes for the rivets, then modified the countersink stop, countersunk the rivet holes, drilled out the bolt hole, riveted on the nut plates, then we were done!
After we were done with the keel access panel, we did the torque tube access cover, then the cut-down keel. It was a good day.
When I started looking at the keel access hole cover I realized that I didn’t cut the hole to the right size to have the access hole cover actually fit inside the hole. Plus the layup was way too dry. So off it came and I started over with a larger access hole on the outer skin.
Some of the things I did on this attempt:
Use the drill press as a lathe to round the keel access hole cover. This went reasonably well but I found that I didn’t have a strong enough grip between the keel access hole and the flat piece I made to hold it.
Use a small piece of wood and a drill and sandpaper as a fly cutter to get the hole for the keel access round. This actually worked out quite well. I would have used the drill press, but I don’t have enough reach with it. (See pictures below)
Part of the reason this took so long to get published is that I decided I wanted my videos in full 4k resolution rather than the 720p that I was able to get out of Windows Movie Maker and iMovie (Actually, I think I could get 1080p out of iMovie, but that’s still a far cry from 4k) so I started looking for options and came up with ffmpeg to create the video out of the still images that the GoPro makes and blender to edit the video and add captions. Blender is powerful but has a steep learning curve and every time I got started on it I gave up after a few hours.
On the forward access hole cover I have a small gap around in some places around the edges of the original piece of keel, so I’ve been planning on mixing up some cabo and jamming it in there to fill the gap as well as I can. So as I was looking at it, I thought that it won’t take much epoxy, so I should wait until I had something else to do then I can just use the leftover for this. So that task is delayed, but I thought I’d go ahead and finish the rest of the cover, cutting out the canard control hole and getting the edges shaped and ready.
After that I started working on the round keel access hole. The instructions say it should be 6″, but the shape drawn on the keel was only about 5 1/2″. I made it a little larger than 6″, then I cut the foam away on the outside and then enlarged the outer skin hole and sanded it down so there is a nice taper. My intent is to vacuum bag this part and have a small section of glass-to-glass contact for the panel to attach to.
There is an additional layer of glass that goes over the forward keel access hole, covering the whole thing. So I did that the next night, and it went fairly well.
One big change in the way I did things was to use a heating pad and then provide a more even pressure by using many layers of towels with a little weight on them. I think that worked out very well and am intending to use this method more in the future.
Now that the access hole is cut out, I just need to build a flange to hold it tightly in place. The instructions call for 4 plies of BID, 1″ on each side. It went fairly well, although a few things I think I could have done better one. Once I took it off, I discovered that the plug that I was attaching to settled a little because it was only held in place with hot melt glue, so I need to go back and fill that in with expxy/cabo. I don’t think it’s a safety issue, but I want there to be no possible gap there.
I also tried adding a layer of absorbent material on top of the peel ply and weighting the whole thing down. In general I think that’s going to be a winning combination.