Free Flight Duration
Louis Joyner [[email protected]]
Moffett attains Model of the Year status
BOB BIENENSTEIN'S Rogue 2
Bob Bienenstein’s Rogue 2 was one of the Models of the Year featured in the 2007 National Free Flight Society (NFFS) Symposium.
The Moffett event began in 1933 to honor Rear Admiral William A. Moffett, who was killed in the crash of the airship Akron that year. The event languished from 1941 until its revival in 1991 through Jim Bennett’s efforts.
The current Moffett rules limit the total projected wing and stabilizer area to 13 square decimeters (202 square inches). The fuselage length cannot exceed wingspan and a minimum cross-section of L^2/150 is required. Minimum airframe weight is 50 grams per 100 square inches of wing area. There are no restrictions on the weight of the rubber motor used. Models must rise off ground (ROG).
Bob Bienenstein’s Rogue 2 evolved from his earlier diamond-fuselage Bandit design. Along the way Bob has tried a variety of things including different wing airfoils, rudder configurations, and wing constructions. Several of Bob’s Detroit Balsa Bugs clubmates, including Bill Shailor and Paul Crowley, also fly the Rogue 2. At this year’s Nats the three were flying side by side, so it was easy to see the subtle variations among the permutations. Having other modelers building and flying the model provides feedback that helps improve the overall design.
“I’ve been learning all my life,” said Bob. (He seems to be learning a lot. He has won the Mulvihill Trophy six times, beginning in 1947, and won the Moffett Trophy four times.)
This year Bob flew his “wet” model that features Union Jack wing and stabilizer construction and Mylar covering for damp conditions. Power is 22 strands of 1/8-inch rubber that is 25 inches long. That’s enough power to allow a VTO (vertical takeoff) launch, which is actually safer than a conventional ROG launch. Motor run is about 70 seconds.
2007 Models of the Year
- The Astrostar 404 — Terry Kerger’s update of Terry Thorkildsen’s 1988 design. Cody Secor used this model to win the Junior FF World Championships last year.
- Jack Emery’s F1G Coupe — uses composite carbon-fiber construction and features a folding-wing DT.
- Graham Selick’s Accorte II CO2 — has accrued a total of eight Nats wins in the F1K and Unlimited CO2 events. The 34-inch-span design weighs roughly 60 grams.
- Marvin Mace’s AMA Gas Super Marval — the bunt version of his 1993 Model of the Year Marvel. Wing construction uses a traditional balsa D-box. A K&B 3.5 powers the 564-square-inch airplane.
In addition, Sergio Montes received a special award for his Free Flight Quarterly. The international publication is now in its sixth year. To order a copy of the 2007 Sympo or for other information about the NFFS, visit www.freeflight.org.
BOB BIENENSTEIN'S Rogue 2
The Moffett rules for the event (see above) set limits on wing and stabilizer area, fuselage length, minimum cross-section (L^2/150), and minimum airframe weight (50 g per 100 sq in of wing area). There are no restrictions on rubber motor weight and models must ROG.
Bienenstein’s Rogue 2 developed from the Bandit and reflects many experiments with airfoils, rudders, and wing construction. Feedback from other flyers in his Detroit Balsa Bugs club — notably Bill Shailor and Paul Crowley — has helped refine the design. Bienenstein has a long history of success in free flight, including six Mulvihill Trophy wins (starting in 1947) and four Moffett Trophy wins.
Colorful Covering
Hank Nystrom has found an inexpensive source of colored transparent plastic film. The brand name is Clearphane, and it is sold at craft stores for wrapping gift baskets.
“Right after Easter is the best time to buy,” said Hank. “It’s usually on discount. It’s really cheap.”
As with many plastic films, the model structure must be coated with a heat-activated adhesive beforehand. The covering is attached using a trimming iron, after which a 300° MonoKote iron is used to tighten the covering.
“I’ve used it for years,” said Hank. “I’ve used it on 1/2As no problem.”
However, as with most plastic-film covering materials, the thin plastic contributes little to a wing’s structural rigidity.
“I used it on an A/B Spacer,” said Hank. “It was too much airplane for this covering.”
Tissue Graphics
I’ve been cutting individual numbers from tissue for years. I stack three or four small pieces of tissue and then tape down a printed paper outline of the letter. The straight lines are easy, but the curves are difficult to do neatly. Then I dope the numbers one at a time, keeping them straight and properly spaced. It’s not one of my favorite things to do.
At the Nats John Pratt showed a quicker and easier method using an ink-jet printer. He designs the numbers, selecting the typeface and size he wants. For the model number on his F1B airplane John adds the “USA” prefix required by FAI rules. He also includes a line of smaller type below with contact information in case the model is lost.
Then John flips the number in the computer to create a mirror image (the command is “Flip Horizontal” in Photoshop). He attaches an 8.5 x 11-inch sheet of white tissue, glossy side down, to a sheet of printer paper using repositionable spray mount. He found this works much better than taping the tissue to the heavier backing paper.
He runs the paper/tissue combination through the printer with the dull side of the tissue up. (Check how your printer feeds; some pull the paper through a 180° half-loop so the up face in the paper tray becomes the back of the document. Just remember that you want the printer to print on the dull side of the tissue.)
After allowing the ink to dry, John carefully peels the tissue off the backing paper and trims the excess with four straight cuts. Then he attaches the block of numbers, right side up, to the model using thinner.
(John covers his model with Polyspan, which requires a dope finish. If you are trying this technique on a model that is covered with plastic film, apply a coat of clear dope in the area and allow it to dry before attaching the tissue numbers.)
John has also tried printing directly on the tissue used to cover a model. For a small sport rubber model he designed graphics for each wing panel and for the fuselage sides, printed them on the dull side of the tissue, and allowed the ink to dry. The model was covered conventionally, misted with water to shrink the tissue, and then doped. The limiting factor is the maximum paper size your printer can accommodate. Be sure to run a test sample since different ink brands may react differently to thinner.
Sources:
- National Free Flight Society
- www.freeflight.org
Transcribed from original scans by AI. Minor OCR errors may remain.
