What Is Trammeling?
What Is Trammeling?
Old-Timers
|As seen in the October 2024 issue of Model Aviation.
OCTOBER IS THE Build Issue month for Model Aviation. Because we Old-Timers (OT) already know (or think we know) all about construction and building, we’re usually light contributors, but getting into the spirit of this issue, I’ll discuss trammeling this month.
What in the world is trammeling? My old Webster’s Dictionary lists six different meanings for the word "trammel." It can be a fish net, a shackle to teach a horse to amble, a pothook, a restraint, an instrument for drawing ellipses, or, finally, any of several devices to adjust or align machine parts. That last definition is the one I’m chasing. Also listed is the word trammeller, which is simply defined as "a person or thing that trammels." (Of course, it’s often done with a trammel.)
The late Bill Evans was one busy guy! He designed dozens of versions of his Scimitar throughout several years, with variations of the name.
Those of us who construct must constantly trammel, or align things, as we build. That can consist of aligning fuselage sides vertically with a jig or a square as we glue everything together while aligning those fuselage sides accurately over the planform view of the plans. Wing ribs need to be aligned vertically with the longerons. Stabilizer/elevator assemblies must be assembled level with the wing and fuselage and with their hinge lines at right angles to the fuselage centerline.
At the flying field, proper wing-to-fuselage alignment is usually more critical on OT aircraft because of more built-in dihedral or polyhedral in their wings. If a wing is casually rubber-banded down with, say, the right tip slightly forward of the left, the dihedral in that right wing half cooperates with the left wing half to act the same as deflected ailerons, causing the airplane to bank and steer left.
Most early OT designs use rubber bands to attach the wing to the fuselage, which requires some form of trammeling every time it’s assembled, unless the wing is "keyed" with small wood blocks to accurately align it at right angles with the fuselage. Nylon wing bolts can do a neat job of alignment, but what self-respecting OT airplane would want to be seen with something that wasn’t used in the era in which it was designed?
We also recognize that wing bolts and even keys can cause damage if, for instance, a wingtip touches the ground during a rough landing, so just as in the good old days, it’s usually necessary to align the wing each time during assembly at the flying field. This can be done by trammeling with a tape measure, yardstick, or even a length of taut string held between the thumbs and forefingers, stretched between the base of the fin and the same point on each wingtip or outer trailing edge. A "close enough" alignment fix would be to accurately place four tiny markers of paint or trim tape on the wing top at the junction of the wing and fuselage so that you can eyeball the alignment from above.
Of course, Free Flight (FF) models are often assembled with small, built-in, asymmetrical alignments to allow for an accurate spiraling climbout, followed by a preset bunt or what might be called an automatic retrammeling when they reach altitude. Oddly enough, there have been cases where an accidental parts misalignment has led to the discovery of new FF trim tricks.
Most ARFs and kit-built models pretty much align themselves, especially when they’ve been laser-cut with the appropriate notches, tabs, etc. built into the kit. As a scratch builder, however, you are always in charge of the alignment details that will determine much of the final flyability of the model.
The popular Lazy Bee novelty is now old enough to be considered an OT model. It’s lightweight, easy to fly, maneuverable, and a heck of a lot of fun.
Novelty Models
This is a term that I just coined, not knowing what else to call them. Consider the general sameness of models, especially those that are used in various competition classes. If you painted them all white, the designs within each competition group, such as Control Line (CL) Aerobatics or RC Aerobatics (Pattern) aircraft, would be a challenge to identify by their design name. CL Speed models, with their distinct asymmetrical wing planforms and helmet cowlings, would also be hard to sort out from one another from a short standoff distance. And so it would be for RC Formula 1 Pylon racers. Even trainer or sport airplanes are commonly quite similar and often recognizable mostly through their unique paint schemes or their displayed names.
This Polaris was newly introduced this year by Old School Model Works. It’s a modern, laser-cut kit derived from the old Scimitar series. See the text for more information.
There’s nothing wrong with those similarities, and, in fact, it’s an expected necessity for most competition airplanes since they evolve over time through trial and error, with occasional design breakthroughs that are quickly picked up and copied by others.
In judged competition, such as Aerobatics, if someone shows up with something radically different, judges can have a bit of a problem scoring it fairly against what they’re accustomed to seeing.
Somewhat often, a distinctly different model comes along that at least catches everyone’s attention, even though few actually get built. Examples would be Snoopy’s Dog House, flying lawn mowers, Skip Ruff’s balloon-like Martian Spaceship, and flying Halloween witches.
Other novelty aircraft develop a cultlike following and flourish—some for just a year or two, while others last longer when offshoot versions also get created. The 1/2A Honker that was pictured in my June 2024 column is an example of a novel design that instantly became popular enough to last for two or three years in club-level racing before fading into the sunset.
A much more lasting novelty airplane that’s had many iterations is Andy Clancy’s Lazy Bee design. They are so easy to fly and so much fun that fliers of every skill level continue to build them.
The October 1993 issue of Model Builder carried two versions of a novelty flying saucer design in a single construction article by Roy Clough Jr. One was for a Cox reed .049 engine, called a Minislot, and the other was for an electric-powered motor called a Zoomslot. Those unusual "slot" names refer to the odd design feature of a large horizontal slot toward the rear third of the airplane. If a 31-year-old design doesn’t seem old enough to mention as an OT, the basic design was originally presented by Roy in the August 1952 issue of Air Trails magazine.
I carefully read Roy’s articles from both magazines and came to the same conclusion, as did many others, when just looking at the drawings: I can see no reason why the little model wouldn’t simply invert itself or go completely out of control during flight. Roy went to great lengths to explain how it did lose control quite often, until he arrived at the final configuration. Somehow, the stability secret didn’t jump off of the page at me because the center of gravity is shown just slightly above the airfoil centerline. Maybe it somehow lies in that wide air slot.
Another unusual design is the tailless Scimitar series designed by Bill Evans. Just as I was completing this column, I spotted a new lookalike kit for the Old School Model Works Polaris on page 13 of the July issue of Model Aviation.
It turns out that the Polaris is actually the latest update to the old Scimitar, but it is redesigned and kitted with laser-cut, interlocking parts for a quicker, more accurate assembly—with no trammeling required.
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