Still working on the Jupiter Duck. There are some areas of the construction where there are 2 or more layers of foam board. So it’s an old balsa builder technique; building on a building board. Normal balsa building pins are not long enough. Could bea building board of balsa, or a ceiling tile, or foam board. I came across these corsage pins on Amazon. Click HERE to visit the page.
I have been having some luck cutting the Depron foam with a hot wire instead of utility knives or xactos. So I made a poster board template from the plans, then used balsa building pins to hold the template to the Depron. I cut both fuselage sides at the same time. Seemed to work pretty good except when I pushed the foam too fast and not straight, the wire got under the template a bit so that it wasn’t really a square cut. Next time I think that I’ll cut one side at a time.
Now I just need the middle.
After I glued the horizontal & vertical stabilizers together I realized that it was a flimsy arrangement. The vertical stab is nearly 12″ tall with no other means of support other than the glue joint. I saw a few YouTube videos of other 200% Jupiter Ducks that had struts on both the tail surfaces and wing tips. So i came up with this way of adding struts to the tail. Used coffee stirrers and BBQ skewers. The large black triangles pictured hold the vertical stab at right angles to the horizontal stab while the glue dries. How did it work? Way better!
Two Krylon products came in handy for painting the tail feathers of the Jupiter Duck. Easy Tack allows you to make a painting mask, use it, the remove it easily. You don’t want to make a permanent bond. Then for painting I used another Krylon product called Short Cuts paint. Seemed to work well on Depron. I used white craft paper for the mask. And when drawing the mask I just moved the poster board templates around and traced it again.
Took a trip to a local Hobby Lobby the other day to buy another few cans of Krylon ShortCuts spray paint. It seems to work well on Depron. As I was walking up and down the aisles I came across a section with a variety of wooden boxes and containers. One caught my eye. Looked just like a box that you would take to the flying field with your transmitter, batteries, and donuts. It’s about 16″ long and 7″ wide; all wood. Nice box. Stapled together. Also bought some styrofoam sheets that I came across. I feel like I have an R/C Airboat in my future. Scratch build. There are a lot of YouTube videos out there on how to build one. Also bought some craft foam spray primer. Didn’t know there was such a thing. And gesso. Used to use gesso to prime raw canvas in art school. It also works on wood and some other materials. I have some wooden paint stirrers that I may use for the motor mount on the airboat. The gesso will come in handy to prime the wood.
This video shows how to cut slots and tabs in Depron using a hotwire and guides. These are the horizontal and vertical stabilizers for the Jupiter Duck. My thinking is that the slots and tabs will add strength to the joint between the stabilizers.
When I cut out the stabilizers I added tabs and slots to make a stronger joint. The bevel on both the elevator and rudder were cut with a hotwire and guides that I made from yardsticks. I shot some video of that process but I haven’t processed that yet. Since Depron has no paper backing to use as a hinge, I needed to get something. A couple of the manufacturers use a 3M product called Blenderm for electric hinge material. So that is what I used. I usually pin the surfaces down when applying the hinge tape. It just makes it easier to apply. Still using those red balsa building pins.
One of the problems with working with foam is making the control surface bevels. Most builders that I have seen on the Internet just use a sharp knife, either x-acto or utility knife; the kind with the break off blades. I have been having good luck using a hotwire to cut foam so I thought that I would try cutting the bevels with hotwire. I made a few hotwire guides from wooden yardsticks that I bought at Ace Hardware for 99¢. The wood is clean and straight. For the Jupiter Duck I made three. One for the elevator, one for the rudder, and one for the bottom of the vertical stabilizer. They are cut at a 45° angle. The original plans for the Duck don’t show tabs and slots for the stabilizers glue joint, but I decided to add them for strength since my Duck is going to be a 200% version. I’ll probably also add bamboo skewers to strengthen the stabilizers. In the pics below I showed the plan template in the yardstick guide to give an idea of what the relationship between them looks like. I have a couple videos in the works to actually demonstrate the process. Stay tuned.
The Jupiter Duck has 8 degrees of dihedral for each wing panel. On the plans it shows the midrib tilted 8 degrees during construction. With the rib tilted there will be a small gap where the rib doesn’t touch the wing surface. So I came up with a way to make a good gluing arrangement. I made a 3 layer midrib, then created a guide from wooden yardsticks such that the midrib is held at the 8 degree angle. If I would have just cut the angle into a single rib, there wouldn’t be much rib left. Probably could have used just 2 ribs. That would have worked fine. Next time. The first picture on the right below shows the part that holds the rib. I used double sided crafters’s tape for that. Then I used a hotwire to cut the angle. Worked great. Took a little experimenting to get here.