Scale Matters

Mike McHenry's Gold Medal airplane at the 2026 Control-Line Scale World Championships, a Piper L-4. Orin Humphries photo

World championships, model size choices

By Orin Humphries
September 2026

The world championships

This year I achieved an impossible life’s dream: I competed in the World Scale Championships as a pilot on Team USA. I’m 84, and this honor had zero chance of ever realizing. This contest was conducted under FAI auspices in Buckminster, UK, from July 7-18.

Twenty CL Scale pilots entered this immense contest and 94 RC pilots entered spread in two categories, RC Scale and RC Sport Scale. The pilots came from 24 countries.

The weather was horrid throughout the two weeks of the contest, and it spread us all over the charts. The base wind speed was 12 mph with gusts reaching the lower 20s. Crashes were expectable. Twenty CL Scale models showed up the first day, and 11 models showed up the second. That’s how it was.

I will give a synopsis to the results in this piece, but before I can do a series chronicling this, I must clear my desk of another subject that had to be put off as I prepared for the Championships.

Results

The U.S. team, from left: Orin Humphries, Mike McHenry, F4 Team Manager Jeremy Arvin, Pete Bauer, F4 Team Leader Kathy Bauer. Airplanes: SR-6, B-N Islander, Twin Otter, L-4.

America sent four pilots in CL Scale to the F4B event. “F4B” codes for Control Line Scale. Mike McHenry of Speedway, Ind., won Gold. He is the reigning World Champion for us in CL Scale for 2026-2028. Pete Bauer of Chicago, Ill., is our Bronze medalist. Pete’s wife, Kathy, won Silver Medal Woman Pilot. I came in No. 16 out of the 20 CL Scale models that showed up.

Model Size Choices

The Stearman at left has a span of 44 inches and the Monocoupe's is 35.5 inches. Orin Humphries photo.

Last year at the Nats in Muncie, Ind., we had a base wind to start with at 8 miles per hour with gusts around 12. I pitted for a pilot who brought smaller models having wing spans around 32 inches and less. I pitted him downwind instead of tailwind per my long experience in wind flying. Upon release, the tail still came up and shortened his prop. Later on that day, the wind was higher and rapidly shifting counter-clockwise. I kept shifting his model trying to get him 15 degrees around past downwind, which works if the wind behaves. However, the wind was shifting so rapidly that I could not get him ahead of it and into it at all. We finally just launched and prayed. The model’s tail again came up, but UP elevator kept the prop only kissing the pavement. He struggled for a good 6 to 8 feet, finally getting airspeed enough for effective elevator control and became airborne.

(Two years previously, my Monocoupe had been victimized by the wind similarly and it, too had to scratch its last flight. On the ground this smaller model was uncontrollable.)

Back to the present, Nats 2025, my Stearman with its 44-inch span had made it aloft earlier with just spotting it downwind. Why was my model successful and his was in dire straits? First, you have to understand why some tails want to come up on windy days and others stay down.

For tail sitters the horizontal tail is at a considerable angle of attack to the prop blast. The prop blast is trapped between the ground and the horizontal tail in a narrowing channel, which intensifies the wind speed. This creates a strong lifting force on the tail, which brings about the shortening of the prop.

Why do some tails remain controllable and others raise? It is the weight of the model. That is, it is the weight of the tail of the model. Does your choice of the size of your model subject have enough weight in the tail to fight this phenomenon of prop blast lift?

Rule: Models with wingspans around 36 inches and smaller WILL let the tail rise and shorten the prop. Models with wingspans around 44 inches and up will be controllable.

A Fork in the Road

Many of us are nearing the end of our modeling careers. We will complete a small number of new projects. Ergo, we must husband our building time astutely. Especially those of us who have spent their careers in events other than Scale and who now might want to dabble in Scale with probably finish only one major Scale project. Make it count.

But which way?

You first absolutely must identify your primary goal: is it A) do well on the score board, or B) maximize your pleasure and enjoyment?

Do well on the score board: You MUST chose a project with a large wingspan/low wing loading. This usually means that you will choose a light civilian subject, as Citabria, J-3, Stinson, or BN Islander, etc. Your wingspan will be at or greater than 44 inches and the weight will be in accordance with that. Sixty inches is a magic number, as evinced by the results at World 2026.

Maximize your pleasure: If, however, you have “fallen in love with” a small wing, possibly military subject, then my advice is really unnecessary. Follow your heart! Accept whatever handling problems come along with it and just do it for the fun.

Scale Matters

World championships, model size choices

The world championships

Results

Model Size Choices

A Fork in the Road

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