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.
It’s always a good idea to plan ahead. Just in case we have an FAA worst case scenario, which means you need to get out of the model airplane / drone hobby, what next? R/C boats and cars come to mind. Here is an interesting video on how to build a simple, inexpensive airboat.
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.
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 top panel of the Jupiter Duck powerpod needs to have a double bevel where the back part meets the wing. The sander table is set to 135˚ to do this. I marked the angle from the plans and just held the Depron at that angle. I used a Logan Hole Cutter to make a hole in the wing to allow the motor wires to pass through to the fuselage. Then I glued the powerpod and pinned it to the wing. I let it set overnight. Then I pinned the back end of the top panel to the powerpod. The Depron doesn’t flex very easily so I decided to glue it in two steps. First the part where it meets the wing dihedral. Let that dry overnight. Then glue the front part. I don’t have a picture of that yet. Going well so far. Started work on the horizontal and vertical stabilizers. Should have some pics in a few days.
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.
Nearing completion of the powerpod for the Duck. In the pictures below you will see the Logan Hole Cutter that I used to make a hole for the motor wires to pass through. The top view shows the 4˚ right thrust in the firewall. The battery is used for photo purposed to keep the pod from tipping forward. I used blind nuts or t-nuts to help mount the motor. What you don’t see is the bottom of the pod side panels cut at an 8˚ angle to fit for better gluing on the wing. I used a Hot Wire Foam Factory Table to cut the angle. Worked really well. Next time I’ll take some pics.