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.
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.
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.
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.
Needed to make some Depron ribs for my Jupiter Duck. As mentioned in a previous video even with a brand new blade in my knife my cutting is not that good. I had luck while cutting the wing panels using a Hotwire so decided to try doing the ribs in a similar way. I did make lite ply ribs to guide the Hotwire. The ribs need to be sanded as smooth as possible along the edge where the Hotwire travels. When the wire gets stuck on even a sliver of wood it burns a little notch where ever it stops. I made a triple thick rib for the Duck to use as the midrib (root rib). More on that later. You can easily cut several separate ribs using this technique.
Working on a model called the Jupiter Duck. It’s a seaplane. The building material is 6mm Depron. Even with a brand new blade my cutting is not that good, so I thought of cutting with a hotwire. In this video I copied the plans, cut out the wing pattern, then glued it to a piece of posterboard. Then trimmed it to the plan outline. It worked really well and there was no sanding or touch up when I was done. Note: This is a 200% version of the original model which has a wingspan of 64 cm, or about 25″. So this version will have a wingspan of about 50″.
Club member and Safety Officer, Kim Kraft, has been doing some modeling with foam. He made this hotwire cutter from a coping saw and some other parts. It connects to a 12 volt source. One thing that he did that I liked was to add a spring to keep tension on the wire. Nice touch. He is working on a model that uses 1/2″ pink insulation foam. Looking forward to seeing that one.
Just started on my next building project. This one will be all Depron, a material that I never used before. So there will be a learning curve for me. When you find the plans on the Internet they may be in French or German. The designer is Thomas Buchwald. I have the Chrome browser on my Mac that has an option to translate web pages in another language. You may have a similar ability on your computer. The original design has about a 23″ wingspan, which is on the small side for me. So I went to Kinkos and had the plans blown up 200% which yields about a 46″ wingspan. Here are a few links to Jupiter Duck pages.
YouTube video – https://youtu.be/enZOPQGCpmQ