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.
This will be not news to the woodworkers and cabinet makers out there. You can use Forstner Bits when you want to drill a really clean hole in wood. The pic on the left below shows the BACK side of plywood that I drilled holes through. At least with me when drilling plywood I often end up with breakout on the back side; splinters of wood sticking out. Not so using these bits. The bit in the left pic is 1/4″. The other pic has a much larger bit for the purposes of illustration. The bits are available at Menard’s and Home Depot.
This is the Stanley FatMax Utility Knife model 10-481. Up until now I have been using the inexpensive, throw away, plastic knives. The ones I have use 2 buttons; one to lock the blade in position, the other to slide the blade in and out. FatMax has just one button that does both functions. And it has some weight to it. It feels substantial. Spare blades are stored inside. It just seems all around more comfortable to use.
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.
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!
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.
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.
Why didn’t I think of this before? Up until now I have been using a plastic drug store protractor to measure various angles on model planes. On the Jupiter Duck it’s 8° dihedral each wing panel, 5° right motor thrust, 4° motor up thrust. You get the idea. This one is available at Amazon. To view it click HERE.
The Jupiter Duck in it’s original design has a 25″ wingspan. I decided to double that to 50″. So the question came up about what motor / ESC combo to use. The wing without the power pod weighs just under 4 oz. So it’s going to be a light weight. The 200% Ducks that I found on the Internet did not have any information about power. So I decided to try a Park 400 motor. The recommendation is to use a 10-20 am ESC. The Park 400 comes with 3.5 mm bullet connectors while the 10 amp Eflite ESC comes with 2 mm connectors. Now what? As it turned out after a fair amount of internet snooping around I discovered 3.5 mm female to 2 mm male bullet adapters. Bought the last two on Amazon. Almost every 10-20 amp ESC that I found had 2 mm connectors. Just seems like the Park 400 should come with the same size connectors as most recommended ESCs. My 2nd grade teacher, Mrs. Schnitzer, used to say that solving problems make you smarter. They do. Embrace them.