FREE FLIGHT SPORT
Gene Smith, 1401 N. Husband St., Stillwater OK 74075; E-mail: [email protected]
Keith Laumer and nostalgic designs
One of my favorite model designers of the late 1950s was Keith Laumer. His sport free-flight designs were unique and downright cute. The ones that keep popping into my head are the Twin Lizzie, the Zoomerang, the Curvette, the Dan'l Boom, the Dub-L Dek-R, and the V Girl.
These models were powered by the 1/2A engines of the day: the Atwood and Cub .049s. Appropriate power plants today would be the Cox Pee Wee .020 or a motor such as the HiLine Dual Mini 6. I never built one of Keith's models as a kid, but I will remedy that this year.
James Caley's Boombox (Dan'l Boom derivative)
While checking out free-flight sites on the Internet, I found an airplane that looked similar to Keith's Dan'l Boom. The builder was James Caley—the man behind JCI tissue. He sent me the following information on the model.
"I am flattered that you would take an interest in my Boombox, and would be honored and delighted to have it shown in Model Aviation. I loved the designs of Keith Laumer also, and I am a fan of his excellent science fiction stories.
"I built the original Dan'l Boom first and it was a fun airplane to build and fly. It finally flew away while flying in a small field surrounded by a residential area. I decided to build another, but made some modifications.
"The Dan'l Boom had polyhedral; I decided to make it just dihedral. The wing planform was changed to a straight taper of 33-inch span. The original 'boom' was solid balsa. I slightly enlarged the cross-section and made it with a 'keel' of 3/32-inch balsa with a couple formers and 1/32-inch sheet wrapped around to give the cross-section a sort of 'football' shape. The fuselage is sheet balsa, and the entire airframe is covered with JCI Japanese tissue, clear doped only.
"The Boombox weighs 7 ounces ready for flight. The DT is just the old fuse type, with the snuffer tube sticking out the back of the boom. The vertical stabilizer is attached to the horizontal stabilizer.
"After the usual test glides, and with the propeller on backward for decreased power, the model flew great from the first flight. The model flies left in power and glide and uses a little down and left thrust.
"I used to fly in a small field. I never went for much power, speed or altitude and always used a slightly larger propeller than the one that comes with the Pee Wee. The model flew slowly and was very stable. The Boombox pictured flew OOS one windy day at my small field! I shall build another soon."
James makes a kit of the Dan'l Boom, which includes Japanese tissue and turned balsa wheels. He sells it for $45 plus $5 shipping. For the kit and JCI tissue, contact James at JC Industries International, 655 State College #19, Fullerton CA 92831, or on the Web site: www.jcimodels.com.
More Sig Cub fans and modifications
Ohioan David Narance has built eight or nine Sig Cubs because they are great for experimenting. He has found that the following changes help his models:
- Add a second 1/8-inch square spar down the main wing, along the bottom of the panels, and located approximately 1 inch back from the top spar to resist wing warps.
- Add extra 3/8- or 3/4-inch square diagonals on tail sections to resist warps.
- Use the provided wing pylon pieces as a template, but recut and add 1/4 inch more to allow the pylon to extend down the side of the solid-balsa fuselage. This helps prevent the wind from moving the wing off-center.
- Instead of using the provided brass or aluminum tubing "bearing," build a beefed-up front end to accept a Peck-Polymers (large) nylon thrust bearing. This allows for smoother power transmission.
David has learned that the Cubs seem to hold up better with these modifications.
A couple of his Cubs have been powered with motors, three have been powered with Telco, Brown, and Modela CO2 motors, and one has been highly strengthened and enlarged to accept a Pee Wee .20 engine. All have flown well.
For more information about the Sig Cub, see this column in the August 2003 Model Aviation.
Go for the silver
There are a variety of ways to obtain silver tissue for that Mustang or similar project. I have seen good results with aluminum powder in clear nitrate dope and with a silver Floquil/nitrate mix.
Hal Schwan advised me of a method I had not seen. He uses Testors Metalizer paints. Made for plastic models, these paints must be airbrushed, but Hal says they cover quickly and are the lightest he has found. They are thin enough to airbrush right out of the bottle.
There are "Buffing" and "Non-Buffing" varieties. When applied to a smooth, hard surface, such as a finished cowl, the Buffing variety can be polished to a high gloss. Seal the silver with clear nitrate. You would use the "Non-Buffing" type for tissue over open framework. Hal sent me a small patch of silver tissue that he had painted. It really looks good.
Greyhawk Embryo
Al Lawton designed a birdlike Embryo, and it has been a reliable performer. Keep in mind that bonus points are awarded for wheel pants, simulated exhaust, and a cockpit.
This model uses a Silly Putty/cocktail-straw timer for the DT. Because of the stabilizer's location, it would have been difficult to raise the entire stabilizer. Instead, Al pops up the elevator and gets an effective DT.
Flying Frogs (FFCU group build)
The Free Flight Cookup (FFCU) group had a group build of the Frog simple series this spring. The models are cute as can be and go together relatively easily. They are all variations on a central theme and include biplane, shoulder-wing, and twin-tail designs.
You can find the plans on Mike Stuart's Web page: www.thestuarts.eclipse.co.uk/. If you do not have a computer, ask a friend to check out the site. Many libraries can help you with computer services.
The tail surfaces are 1/16-inch sheet balsa. One problem with this type of construction is its tendency to warp, but one of the builders in the cookup reminded me of a simple technique to prevent that problem.
Cut a circular piece of balsa from one side of the stabilizer that is approximately two-thirds the width of the stabilizer. Rotate the cutout 90° and glue it back in place. Now the grain of the body of the stabilizer is along its length and the grain of the circle is along its width; this stiffens the stabilizer and helps prevent warps.
Check out the FFCU at www.smallflyingarts.com/index.htm. Click on Flying Model Forum. Then under SFA Forum, click on F/F Sport Builds. Go to Frog Senior Series, and you will find the Frog series thread complete with many building and flying tips.
Raven — brief flight report
The following is a brief flight report on my Raven, which I built to the 18-inch span. I used a 6-inch Peck-Polymers propeller with a 15-inch loop of 1/8-inch rubber, which I anticipated would be a bit weak.
Trimming started with 3° of right thrust and 3° of downthrust. With 300 winds, the model flew straight away roughly 50 feet. I added a shim for more right thrust to get a right turn. Then 500 winds got a nice right turn until the power ran down, and then the right turn tightened. I tweaked a small amount of left rudder. Then 800 winds gave a nice right turn and a slightly nose-down glide.
I will conduct the next tests with a stronger motor, which should move the CG back a bit and give a better climb and glide. The model is diving a bit after launch and may fly better with less downthrust. Your results may vary.
Grandkid's Corner
If you are looking for simple models for the grandkids, check out www.luminet.net/~kbuhl/Darth.htm. In addition to the Delta Dart, the site shows some helpful conversions for improving the Guillows Strato Streak.
The site also plans for a flying wing and the Dennydart, which is a great-flying stick model designed by Neil Dennis, 7940 Cadwell Rd., Bliss NY 14024. He is selling a bundle of three Dennydart kits for $12, postpaid Priority Mail. Pay by money order or PayPal. To contact Neil or to order with PayPal, E-mail [email protected].
Easy Built Models update
Easy Built Models has relocated to Alabama and is actively producing models, including several new additions. A couple of those are the Jimmie Allen Blue Flash Racer, which is a laser-cut kit, and the Luscombe Phantom, which is a short kit. Both are eligible for Society of Antique Modelers competition and a few of the Flying Aces Club events.
A color catalog is $3 or free with an order. You can order online at www.easybuiltmodels.com, and most orders ship the next business day. Easy Built Models' mailing address is Box 681744, Prattville AL 36068.
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
