Park Pilot is the Park Flyer magazine from the AMA – Academy of Model Aeronautics. Came across an interesting article on the use of various foams for model building.
It appears that Depron is gradually becoming scarce here in the U.S. I read somewhere that Depron is still being produced but not in the form that we use as modelers. That’s the bad news. The good news is that other foam board products are becoming available. And there are some products that we have come to love that are still available if you search around.
FliteTest has a new product available called Maker Foam. It comes in two thicknesses: 3/16″ and 8.5mm. Why mix fractional and metric measurements? Good question. When you look at the prices remember that you are getting folded sheets 30″ x 40″ bifold. Maker Foam is covered with white paper unlike the water resistant product that is brown. The white paper will certainly take paint better. Once I wrote FliteTest and asked if I could purchase a kit made with white foam board instead of the brown water resistant. The answer was a polite no. Wouldn’t you like to have the choice?
Model Plane Foam offers a 6mm thick product made from extruded polystyrene foam. It’s not paper covered but they do mention it being sandable (sandpaper), so if you miss sanding with the other products and 6mm is the right thickness for your project, this may be a good choice for you. When you get to the product page you will have choices of: Grade A, Grade B, Mixed Box, and Seconds.
There are a number of sellers on ebay that offer various foam model suitable products. I just recently bought a box of 12 sheets of 6mm Depron. It came from the U.K. so the shipping cost was high. But there are U.S. sellers, some that offer free shipping. The problem that you may run into is the size of the sheets. Many are 9″ x 12″ for smaller craft projects. But if you look around and don’t mind paying a bit more for shipping, you can find some of the original Depron in sizes good for model airplanes.
Amazon offers Great Planes Pro-Formance Foam in a few different sizes; 2 & 3 mm in the 47″ lengths. From the product details: “FEATURES: Ideal for building airframes as well as landscape scenery and buildings Edges and surfaces are sandable and can be painted with water-based.”
Just discovered a model called the Jupiter Duck. Free plans are available HERE for download. Went to Kinko’s and had a set of the plans blown up to 200%. Then I stumbled across this one. More on the Jupiter Duck in future posts. In the mean time watch this video. Slowest flying R/C model I have ever seen!
Foam board wheels are not very durable. The question is what to do about it. I came across some 1-3/4″ I.D. rubber O-rings recently and thought they might be useful to add some durability to the foam board wheels. The process begins with gluing the artwork to the foam board. There are places on the Internet where you can buy excellent art work for just a few dollars. Then cut the circles out. I used a Logan WA8001 FoamWerks Foamboard Circle Cutter available at Amazon. Glue the rubber O-rings to the wheel. Don’t forget to use the doublers behind the wheel for added strength. And you may find a Center Finder useful to find the exact place where the axle needs to go though. I bought the O-rings on ebay from Mr. O-Ring. Finally I used some rivet parts to act as a bushing inside the wheel. See my Rivets post HERE. The O-ring is 1/4″ thick so the finished wheel is 2″ diameter. Probably suitable for a smaller model such as the FT Minis. I am looking for larger O-rings or something similar. I fly from a grass field and have found that something more like a 3″ diameter wheel will allow me to taxi and get off the ground.
Finally got the internal servos and pushrods finished. Check the pics below. Included is a pic of the pushrod guide that I installed in the fuselage. I used this method instead of the one shown on the Flite Test build video. The method shown on the video with the foam board keepers bends the pushrods and puts tension on them. So the servos need to work more. This method takes some strain off of the servos.
This video shows how the combo of internal pushrods and the slot in the stick fuselage work. At first the slot seemed a bit on the long side, but it turned out to be just about right.
Several years ago Sig Mfg. sold three old time kits that had profile pilots as part of the kit. You can still buy the kits or just the pilot figures directly from Sig. Click HERE to visit the replacement parts page. Then view the parts for the Antionette, Demoiselle, or Deperdussin. The Demoiselle comes with torso, arms, & legs. The others just come from the waist up. You can order online.
The main point of this post is to show an optional way to mount motors that allows you to adjust down and right thrust. This may be needed to improve flight characteristics of some models. In this example I made a new firewall from aircraft plywood.
These are two ways to mount the motor on the firewall. The FT motors come with an X-Mount that can be set vertical or diagonal. The motors come with tiny wood screws and the firewalls have pre-drilled holes for the wood screws. Over time and with vibration wood screws tend to loosen up and back out resulting in a wobbly motor. For me a better way to mount the motor is to set the X-Mount on a diagonal. You’ll need to drill new holes, use blind nuts (also called T-nuts) and socket head cap screws.
The diagonal mount can be used to provide just down thrust, just right thrust, or both down and right thrust. It is a bit easier than using the vertical mount.
Looking from the front, if you put washers under the top of the mount, you get down thrust. If you put washers under the right side of the mount, you get right thrust. And if you put two washers under the upper right corner and one washer each under the upper left corner and lower right corner, you get both down and right thrust. No washers under the lower left corner. If you decided to make a firewall for the diagonal mount, you will need to relocate the hole that the motor wiring goes through. Click HERE to see what the blind nuts look like from behind the fire wall.
While I was working on the FT Speedster I was amazed to see the skewer fall out on the floor! This is the skewer that holds the back end of the power pod in place. Lucky I wasn’t flying. A couple of short pieces of tubing will hold it in place.
When I am working on a project I often have small parts sitting around. I had been keeping them in a small, plastic cup – probably one from Taco Bell. Only problem was that I kept knocking it over. Quick fix was to hot glue the cup onto a piece of foam board. Now it doesn’t tip over so easy.