The Year of the Biplanes

Vintage biplane with a wood frame and colorful markings in flight against a green backdrop.

Free Flight Scale

By Tom Hallman | [email protected]

EVERY YEAR, a couple of models stand out in Free Flight Scale. This past season, however, there were many. I’m going to focus on biplanes that turned our heads at a few of the major contests, starting with Dave Mitchell’s charming 13-inch wingspan Gloster AS.31 Survey.

Silver biplane with orange propellers on a textured surface. — Dave Mitchell’s charming 13-inch wingspan Gloster AS.31 Survey twin biplane was inspired by 1992 Emmanuel Fillon plans. Photo by Dave Mitchell.

Designed by master builder Emmanuel Fillon in 1992, the Peanut model features a dual-geared drive powered by a single rubber motor that is located in the long fuselage. Besides requiring a lightweight, yet sturdy, structure, the added challenge was the creation and development of a strong, efficient, and lightweight gearbox. It needed to be small enough to fit into the rear of the narrow fuselage while being smooth running and reliable to confidently power through many flights.

Before committing to building the bones of the model, Dave worked through numerous gearbox designs, using various gears and bits from little toys and methodically bench-testing each new version. Dave wrote, "My first attempt at the gearbox was a nonstarter, but it gave me insights as to how to approach version two, which was okay, but too big and not free-running, no matter how much I tried to break it in. Version three was a great improvement. It is easily small enough to fit in the Peanut Gloster and free-running, but it wasn’t counterrotating, and it was heavier than I wanted. The key to getting counterrotation was to run the propeller-drive gears in series off the main drive, not parallel. It works like a charm.

"I got my new Tamiya gearbox kit, which provided me with six new drive gears to play with, [allowing me to] finish off gearbox version four, which is counterrotating and .13 grams lighter to boot. Runs nice and smooth, and at 1.52 grams with the propeller-drive wires, is the lightest version yet, nearly a quarter of a gram less than version three."

Model airplane with pink propellers, labeled G-RADR on a green surface. — The Gloster’s thin and efficient flex cables are invisible in flight as they transfer the rubber motor’s power through the nacelles to the 3.5-inch carved spruce propellers. Mitchell photo.

Wooden frame canoe model with internal structure and blue gear. — With a combination of wire, brass tubing, thin plywood, flex cables, and bits from a Tamiya gearbox kit, Dave Mitchell’s miniature gem came in at 1.52 grams. Mitchell photo.

As Dave worked through the gearbox designs, he changed his focus to the framing of the model. "Everything on the Fillon plan is in millimeters, so my digital calipers have been getting a workout. I’m finding enough variation in 1/32-inch and 1/16-inch stock that often a little sanding needs done to bring the sheet wood to dimension—and sometimes none.

"There’s a lot of substance left to make yet—engine nacelles, motors and propeller assemblies, landing gear, struts, and, of course, the tissue. The weight of all the balsa parts, including the gearbox, is 5.7 grams. I ‘think’ I’ll be able to at least match Fillon’s stated weight (15.5 grams). I’m going to be very careful from this point forward. It’s got something on the order of 40 sq. in. of wing area, adjusted for biplane inefficiencies. It would be nice to bring it in at roughly 13 to 14 grams."

The model was covered with white Esaki tissue that was lightly airbrushed with silver acrylic enamel. Dave added, "The model is powered by a well-braided, single loop of 1/8-inch rubber, 21 inches long, powering two counter-rotating flexed-wire driveshafts that run out to 3-1/4-inch carved spruce propellers that must rotate ‘out at the tops’ (toward the wingtips) for stability."

After initial trim flights, the model came in ballasted at 17.5 grams without the motor. Dave wrote, "[The] best unofficial flight so far is about 35 thrilling seconds. I think it can do better, but it’ll require some thermal help to get there. Frankly, anything in the 30-second range with this bird leaves me floating. It’s just so cool, and the noise it makes is indescribable. You want a motor hum device? This baby has it built-in."

Vintage biplane flying in a partly cloudy sky above trees. — Vance Gilbert’s majestic 50-inch wingspan Farman F.60 Goliath came in at 190 grams without rubber and sports a 14-inch propeller that nearly disappears in flight. Photo by Karin Escalante.

Another model that caught my attention was Vance Gilbert’s 50-inch Farman F.60 Goliath with scalelike zero dihedral. This modeling approach was inspired by the late, great Bill Hannan and his classic Boxy Bipe stick model. The Farman’s wide, circling flights were surprisingly stable as the model majestically flew at scale speed.

Vintage biplane in flight with blurred trees in the background. — Fred Stagg’s 34-inch wingspan Salmson 2 A.2 was honored with the Earl Stahl Award for the Best Scale Model at the 2024 FAC Nats in Geneseo NY. Photo by Peter Kaiteris.

Gray biplane model with RAF roundels and spinning propeller. — Mike Stuart, from the U.K., flew his immaculate 27-inch wingspan Blackburn Dart at the 2024 International Indoor Fly-In, held in Nijmegen, Netherlands. Photo by Michal Gasparin.

The beauty of a biplane circling above in flight is hard to beat. Consider one for your fleet. Check my YouTube channel for flights of all four of the biplanes that are featured here.

Dream, ponder, build, and inspire, but most of all, fly!