FRANCHERIZED SIG TWISTER
A year or two ago I read an article by Ted Fancher about modifying a Sig Twister kit to modernize it. I thought it was an interesting project. I usually do not like building kits but this time I wanted to try it and I happened upon a Twister kit. So here we go.
I started with the wing and made the half ribs and the few other modified parts and the weight box. Then I assenbled the wing on the original Twister plan, but I changed the top and bottom spars from 1/4 in. balsa to birch. A nylon bell crank with adjustable lead-out was added and a 1/4 in carbon fiber main pushrod and ball link were installed. I made new ailerons because the originals seemed a bit weak. Before I covered the ailerons with yellow Monokote I drilled/mortised them for the wire joiner and installed Tyvek hinges. I decided to ditch the standard landing gear infavor of underwing mounted gear and the hardwood inserts were cut and mounted to the underside of the wing Even with the addition of the half ribs and other extras the wing came out very light and strong.
Next, I fabricated the fuselage modifications, lengthening the fuse by 3 inches and adding modified rudder, and balse cheeks to the nose. A 3/4 in high balsa canopy and turtleback were added to streamline the assembly for a more modern look. The maple motor mounts were drilled a 4-40 brass screw inserts were added to accept the Super Tiger motor horizontal stabilizer and elevators were modified per the plans and they were drilled/mortised for the wire joiner. After initial assembly the whole fuse and tail feathers were covered with ight weight Silkspan and given a coat or two of yellow dope and a few clear coats.
After mounting the wing in the fuselage, it was time to cover the wing. I decided I wanted more than just a big yellow slab of a wing, so I chose a three color pattern of yellow, purple and orange Monocote. Patterns were cut out from an old drawing page and used to precut Monocote panels and they were joined together so they could be installed onto the wing in a single piece. It was the first time I had done this and though it took a bit more time to do, it came out nice. One thing I noticed on the first wing panel in that the purple Monocote shrank at a different speed then the orange and yellow so on the other three wing panels I took care to apply the heat to the yellow first then the orange and purple last. Thie minimized any wrinkles by the different shrink rates of the project
The planes hardware package was finished with a carbon fiber pushrodand nylon control horns, light weight 2 in. wheels, 3 oz. uniflow tank and the sweet Super Tiger motor fitte