FREE FLIGHT DURATION
Louis Joyner 6 Saturday Rd., Mt. Pleasant SC 29464
IMPROVED PERFORMANCE is one inevitability of FF competition. No matter what the rules-makers do to reduce performance, modelers figure out ways to make their models fly better.
For example, the engine run in F1C, the FAI large Power class, has been reduced throughout the years to limit performance. In the last 30 years it has gone from 10 seconds to seven seconds, and, for the last few years, to five seconds.
The 2.5 cc engines have become more powerful; gearing has allowed larger, more efficient propellers; and autosurfaces have allowed bunt transitions to maximize altitude. Wings have become longer and thinner, thanks to the use of carbon fiber and other modern materials. A few models even utilize flapped airfoils or folding wings to minimize drag in the climb.
F1J was developed as a smaller, lower-performance Power class, as a parallel to the other mini classes (F1H Towline Glider and F1G Coupe rubber power). F1J models quickly turned into scaled-down versions of F1C models. With a dead-air time of well more than five minutes off of a seven-second engine run, the contest didn't really begin until the flyoff.
For the Junior World Championships, F1J was used as the Power event and F1A and F1B were the Glider and Rubber events respectively. Within the last few years, a new Power event—F1P—has been developed to replace F1J as the Power event at the Junior World Champs. (Juniors can, of course, continue to fly F1J in other Open contests.)
The rules for F1P are simple. Maximum engine displacement is 1 cc (.061 cu. in.), minimum weight is 250 grams (8.82 ounces), maximum projected wingspan is 1.5 meters (approximately 59 inches), and minimum projected wing area is 26 square decimeters (roughly 403 square inches). While most FF rules specify a maximum surface area, F1P requires a minimum area. By restricting the span to 1.5 meters and requiring a fairly large minimum area, the result is a low-aspect-ratio wing. (A constant-chord wing to fit the rules would measure roughly 7 x 59 inches, giving an aspect ratio of approximately 8.4:1. Typical F1J wings have an aspect ratio of almost double that.) Keeping the aspect ratio low increases drag in climb and glide, thereby reducing performance—always a goal of the rule-makers. A low-aspect-ratio wing is also easier to build using conventional stick-and-tissue construction. (Thin, high-aspect-ratio wings require carbon D-box construction to prevent flutter in the high-speed climb.)
F1A, F1B, and F1C are flown to a 180-second maximum. F1P uses a 10-second engine run and is flown to a two-minute (120-second) maximum. The F1P rules allow only one incidence change during flight. By limiting the number of autosurface functions, the rules, in effect, ban bunt, which requires at least three incidence changes in the stabilizer (climb, bunt, and glide).
The two-position (climb and glide) variable-incidence tailplane (VIT) allowed by the rules makes the F1P model easier to build and trim, while still allowing the stabilizer to move once from climb to glide setting. An auto rudder is allowed. The typical pop-up stabilizer DT (dethermalizer) is also permitted.
Although autosurfaces do add a slight level of complication to construction and flying, they make adjusting the airplane much easier and safer compared to a locked-up model without autosurfaces. With a locked-up model, any incidence adjustments affect climb and glide; VIT allows climb and glide to be adjusted separately. An auto rudder allows climb and glide turn to be adjusted independently.
Although F1P is a new event, the rules essentially describe a typical 1960s–1970s Power model. Many designs from that era can make a competitive F1P with only a few modifications. Just make sure that the projected wing area exceeds the 403 square inches and that the maximum projected span is less than 1.5 meters (59 1/16 inches). Any engine up to 1 cc (.061 cu. in.) can be used; there are no special fuel requirements.
To encourage Junior participation in F1P, a number of FF clubs and individuals across the country are contributing to a program that offers F1P kits and engines to Juniors who want to participate in the Junior Team Selection Program.
"This is a very straightforward program," said program administrator Walt Ghio. "If a Junior gets in touch with me, they will get information along with a kit."
After the model is finished, the Junior verifies completion by sending photographs, and then he or she receives an engine. The engine can be used only on an F1P model and must be returned if the airplane is not flight-ready within three months of receiving the engine. A Junior can also purchase a kit, build it, and then receive an engine.
"They really can't go wrong with this program," said Walt.
For more information about the program, contact Walt Ghio by e-mail at [email protected] or write him at 1380 Elkhorn Dr., Stockton, CA 95209.
This is not an inexpensive program. An F1P kit can cost more than $100, and the current price for a Cyclone .061 engine is $190. The program can only continue with the generous support of clubs and individuals. If you or your club would like to make a donation, contact Walt.
F1P Maverick Kit
Joe Wagner has put together a kit for F1P based on the Tom Hutchison–designed 1/2A Maverick from the 1970s. Joe’s version is scaled up to fit the F1P rules. He added a short center panel to the wing that allows an optional two-piece wing. "The original Maverick was a single-piece model and, when enlarged, it needed the extra flat section to get closer to the allowed span," said Joe.
In addition to allowing a more compact model box, a two-piece wing also permits shimming one wing half to adjust washout. "The young fliers need to have adjustments available," he said.
The kit features:
- Laminated elliptical tips
- Balsa–carbon laminated spars
- A preformed and molded pylon
- Full-length balsa and spruce fuselage components
- Covering
- A timer mounting plate
- An aluminum engine mount designed for the Cyclone .06 engine
The kit price is $129 plus shipping. Check with Joe about availability. (The first run of his 1/2A Nostalgia Lucky Lindy kit sold out quickly. Another batch is in the works.) You can write to Joe Wagner, The Model Box, 25804 John Hansen Rd., Chestertown, MD 21620, or e-mail him at [email protected]. Joe also has a couple of other kits in development: a 500-square-inch A/B Maverick and a 1/2A Uranus.
Another F1P kit possibility is the Astro Star 404 designed by Terry Thorkildsen and kitted by Bob Van Nest. The Astro Star features a constant-chord wing with union-jack construction. The kits are available through the Junior program mentioned above. Contact Walt Ghio for more information.
NFFS Membership Drive
If you are not a member of the National Free Flight Society (NFFS), there's an added incentive to join. From now until the end of August, new members will receive a coupon for a $10 purchase of NFFS plans.
The coupon must be used by the end of 2005 and has no cash value. It can only be used toward the purchase of NFFS plans. There will be no partial refunds on plans orders less than $10. For plans orders exceeding $10, you pay the difference.
This offer also applies to former NFFS members who have let their memberships lapse for at least 12 months. A two-year NFFS membership is $48 for US residents. For additional information about membership options, visit the NFFS web site — www.freeflight.org — or contact membership chairman J.P. Kish. His e-mail address is [email protected]. The mailing address is:
NFFS Membership Office 222 Pine St. Homosassa, FL 34446
Go to www.freeflight.org/jlf/NewMembers.htm to find the sign-up form. While you are on the NFFS site, scroll around and check out the plans offerings. The NFFS Plans Service is changing to a digital, print-on-demand system instead of the old system that required extensive inventory. Wendell Russell has taken over responsibility for the Plans Service from Hank Sperzel. (Thanks, Hank, for all the years of work in this area.) Send your plans orders to:
Wendell Russell NFFS Plans Service 1375 Ridgefield Dr. Roswell, GA 30075
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
