Author: Gene Smith
Edition: Model Aviation - 2011/01
Page Numbers: 114,115,116
,
,

Build your 1/2A Viking for the Nats

Gene Smith

[email protected]

DON'T FORGET TO build a Viking for the 1/2A One Design event at the 2011 AMA Nats. Plans for the original are available from the National Free Flight Society (NFFS), listed as Viking 1/2A. The reduced-size version is available as a kit from BMJR Model Products.

George White — Dime Scale Comet Curtiss P-6E

George White, president and webmaster of the Pensacola Free Flight Team (PFFT), did a great job on his Dime Scale Comet Curtiss P-6E. He finished it with green Esaki tissue and sprayed glossy wood-tone floral spray on the fuselage. The flying surfaces are doped yellow tissue. The decals were laser-printed onto 20-pound bond paper.

Paul Grabski — Dime Scale Megow Taylorcraft floatplane

Paul Grabski, a fellow Pensacola modeler, built a Dime Scale Megow Taylorcraft floatplane. It weighs 14.4 grams with a 3-gram motor and is finished with red and silver floral spray. That is a real ultralight! Neither model has been test-flown, but they look promising. The Penn Valley Hobby Center sells kits for each. The PFFT web site is a wealth of free-flight rubber tips and information. While you are there, consider subscribing to the PFFT newsletter.

Karl Geis — Buster

Karl Geis, a prolific and talented model builder, completed yet another project from his early modeling memories: a Buster. Gerald Zeigenfuse designed the model; it was featured in the December 1957 Model Airplane News. Karl built a Buster in 1967 and gave it to a kid in his model club who had lost his in a thermal. Karl was leaving California at the time for a new teaching career in Butte, Montana, and has missed his model all these years.

Spanning 30 inches, the pretty Buster flies well. Al Lidberg noticed how thin the propeller blades were and suggested that Karl fiberglass them. Karl thanks Al Lidberg and Al Pardue for tips on how to accomplish that task, because he had never done it. At their suggestion he applied three coats of nitrate dope to the propeller, using that base to adhere 3/4-ounce fiberglass cloth. A few more coats of nitrate dope were used to finish the propeller. Karl was extremely pleased with the results. He is going to make a folding propeller for the model, to see how much difference there is in performance between the freewheeler and the folder. Karl used his favorite covering method: Japanese tissue over 1/4 mil Mylar.

Plans for the Buster were included in Free Flight Quarterly issue 36. You can obtain 3/4-ounce fiberglass cloth from Hobbico or one of its dealers.

David Scigliano — Comet Curtiss Robin

David Scigliano did a fantastic job building his Comet Curtiss Robin. To have this 22-inch-span model come out at 18 grams, he must have used some incredibly light wood. He used a 6-inch propeller with 3/32-inch rubber and a trim tab under the left wing. So far David has made a basic trim flight with the Robin, and it performed great. He is awaiting a pair of 1-inch vintage wheels before taking the model out for a real flight.

Free Flight Sport - 2011/01

Vance Gilbert and the de Havilland D.H.95 Flamingo

Vance Gilbert is a well-known and skilled member of the Flying Aces Club (FAC). His musical and entertainment talents are appreciated at the FAC Nats. Known for selecting unique subjects to model, Vance has exceeded expectations with his de Havilland D.H.95 Flamingo. The full-scale aircraft first flew in December 1939, and it saw service with the Royal Air Force and British Overseas Airways Corporation during World War II and afterward.

Vance's Flamingo spans 35 inches and weighs 54 grams empty. That is exceedingly light for such a large model. Vance built the design to that light weight by using Dave Rees–style construction, with 1/20-inch sliced ribs and spars and 1/16-inch square fuselage stringers.

Despite the fact that the propeller hook-to-peg distance is only 6 inches, Vance can use two loops of 3/16-inch rubber that are 24 inches long in each nacelle. The 8-inch-diameter propellers are plastic from a cottage cheese container. Their pitch is approximately 1.1:1 (pitch:diameter). They counter-rotate, with their tips going out at the top.

The covering is Micro X Old World White tissue, preshrunk and painted on a frame. The silver is Testors paint or aluminum acrylic. The tissue was applied with glue stick and sealed with a mist of Krylon Crystal Clear.

The D.H.95 doesn't like to be overpowered and hauled up into the air. With excess power, flying speed goes up and any flight anomalies are amplified: a previously gentle left turn can become a steep left bank, etc. Easy does it is the rule.

A key fact to remember is that lightweight models can fly slower than heavy models; therefore, light models are easier to trim than heavy models. I agree with Vance that we no longer need to arbitrarily dismiss modeling subjects with short hook-to-peg distances. Despite its relatively short nacelles, the Flamingo flew beyond all of Vance's wildest dreams. Its last flight at the FAC Nats in Geneseo, New York, last year was approximately 73 seconds. It climbed out gently, as usual. Once the model was overhead, Vance did something he never had: he lay down in the grass to enjoy the flight. It was good enough for third place in FAC Scale, which, thanks to Vance's memory of that long, pretty, floating flight, didn't matter much.

Motor selection for twins

How do you select motors for twins, such as the D.H.95? There are several formulas for determining rubber motor size for a single-engine model. Those formulas use the empty weight of the aircraft. Lacking a similar formula for twins, Vance uses the empty weight to give him a basic idea of the model's potential and what it might need for power: the less the airplane weighs, the less power it needs.

Vance knows from experience where to start in choosing a rubber motor. That's why I like to include weight, motor, and propeller used when I feature models in this column. Those of you who are starting out in this hobby or who want to improve your skills can take advantage of the voices of experience.

To learn more about Vance, check out his web site.

Since I mentioned formulas for calculating rubber-motor size for scale models, some of you might wonder what they are. To see a spreadsheet formula for that calculation, go to the NFFS web site. Select "Shopping & Publications" and click on "NFFS Digest Online." There you will find an Excel program by Bob Hodes. Fill in the blanks and it will give you a good starting point for your model's motor. You are given a choice of motor weight as a percentage of empty model weight and a choice of motor length as a multiple of hook-to-peg distance. For sport-flying, pick the lower end of the ranges that the program suggests. Choose the upper end of those ranges for competition flying.

Bill Schmidt — Piper Cub Special PA-11 on floats (and PA-12)

Bill Schmidt is especially proud of his Piper Cub Special PA-11 on floats. The full-scale PA-11 was a result of cleaning up and modernizing the old J-3 in 1947. It featured a revised fuel system with the tank in the wing instead of in your lap. The boot cowling was lowered, and a pressure engine cowling fitted that totally covered the power plant. The cabin interior was changed from doped fabric to metal panels. A new 90-horsepower Continental engine was installed, which gave the PA-11 a tremendous increase in performance over the old 65-horsepower engine that the J-3 Cub had. The Piper Cub Special was built for only a year or so and was then further updated to be the PA-18 Super Cub with a 150-horsepower Lycoming.

Bill built the model from his plans. He finished it in Bahama Blue and Lock Haven Yellow, as were used on the full-scale airplane. The N number is that of the first factory prototype that the FAA certified. The lettering on the model was created with a Dymo tape machine, which is available for roughly $30 at Wal-Mart and similar outlets. Bill had the special tail logos made on water-slide decals.

The PA-11 has a 27-inch wingspan and weighs 49 grams less the motor. The propeller is an 8-inch Peck-Polymers cut to 6-1/2 inches to clear the floats. The model is covered with Japanese tissue, except for the bottoms of the floats; those are covered with Polyspan for added strength and puncture resistance.

The Piper Super Cruiser PA-12 was finished in the factory colors of Diana Cream and Tennessee Red. Color-trimming the curvature of the front end and cowling was achieved using narrow strips of party-store domestic tissue butted together and touched with thinner on a small brush. The finish is non-attenuating nitrate dope. Randolph nitrate dope from Randolph Aircraft Products is item A-1690.

You can purchase the Piper floatplane plans and a set of tail logos for $10; call Bill to do so at the number in the Sources listing.

Sources

Transcribed from original scans by AI. Minor OCR errors may remain.