Old-Timers — 2008/08
Soaring with the birds
Bob Angel | [email protected]
OLD-TIME (OT) FF and RC fliers often spend time sharing airspace with various soaring birds. Hawks, vultures, eagles, seagulls, ravens, etc., also enjoy the thermals and often point them out for us. One thing the birds have in common is that their behavior improves as they get to know us and what nice people modelers are.
The vultures (aka turkey buzzards) are the most numerous in my area. As scavengers, they have no talons and are generally shyer than the other birds. They usually steer away from a soaring model. However, after you've flown in an area and gotten acquainted, they'll often let your model join their thermal or even come over and join it. It's a neat experience.
The hawks are often more aggressive and will sometimes make a bluffing pass or even attack a model. But they also seem to learn tolerance after they realize that you're not there to share their food supply. Then they'll either ignore you or occasionally share a thermal.
Awhile back at our local field, Jim Bierbauer was flying a 1/2A model when I heard a "whump" at altitude, followed by an "Oh no!" from him. Looking up, I saw Jim's crippled airplane spiraling down and an eagle leaving the scene of the mugging.
The bird headed west, probably on its way home to Vandenberg Air Force Base (on the central coast of California), where several eagles reside. It was a passing stranger in the neighborhood. We couldn't figure out if it thought the model was prey or was simply practicing when it hit the airplane amidships with both talons, right behind the wing and forward of the stabilizer.
In Praise of Wooden Propellers
Wood propellers are almost a thing of the past, even among OT fliers. The plastic (including fiberglass, etc.) types reign because they can be made faster, cheaper, and with a better finish than wood propellers. And with computer-controlled machinery, they can quickly be custom-made in a variety of sizes and pitches. But it seems odd that many of the purists among us, who refuse to use modern iron-on plastic coverings, don't think twice about attaching a modern plastic propeller in front of that classic silked and doped airframe.
Certainly there was some early use of plastic propellers, but that was mostly in the post–World War II era, which was dominated by CL flying. Many of those old propellers are still around, but, for safety reasons, they should be relegated to display use only. The plastic propellers weren't reinforced, as the modern plastics are, nor were they designed for today's engines' high speeds. Even back then, those blades often separated without being provoked.
Many believe that today's plastic propellers perform better than the wood variety, but most of the difference, if any, is only the result of the smoother finish on the plastics. Many wood propellers seem crude by comparison.
However, with careful propeller selection and some refinishing, I've used wood propellers that offer similar and sometimes better performance than the plastic kind. I have a technique to refinish a wood propeller for smoothness. Scrape away the factory finish using a single-edge razorblade held vertical to the propeller's surface. Observe the safety warnings and don't carve away strength or alter the basic shape. Finish smoothing the wood with progressively finer sanding.
Equip yourself with a plastic baggie or a piece of iron-on film-cover backing. Run a thin line of cyanoacrylate (thin superglue) down one of the four blade surfaces, and then immediately smear and smooth the adhesive with a finger that is protected by the plastic. Let it cure and repeat this for the other three surfaces. Sand with progressively finer grades of paper again, even down to 1,500 grit, and you can end up with a propeller that's as smooth as a baby's cheek. You'll be surprised by how nicely the cyanoacrylate coating sands down, and best of all there's no long waiting period for paint to dry. Just don't breathe that cyanoacrylate sanding dust. Part of the secret is initial selection of a proper low-pitch (4–6 inch) propeller for the job. Any of the currently made wood propellers can be used, but I watch for the old Rev-Up brand at trade shows, swap shops, etc. They are a favorite for high performance, but unfortunately they are no longer produced.
Physics and field observations prove the relative greater safety of wood propellers. They generally weigh roughly half of what similar-size plastic versions weigh. And when the worst happens, the wood propellers usually shear off with minimum damage to flesh and bones, rather than keep coming at you, intact and with lots of momentum.
I'll confess that I do use some plastic propellers, but it's usually when I haven't located a suitable-size wooden blade or have gotten a bit lazy about spending the hour or so needed to produce a finely finished wood propeller.
Book Review
Power: Beyond the Basics: Two-Stroke Glow Engines Vol. 2 — Dave Gierke
Why, you might ask, would OT fliers be interested in a book about modern two-stroke engines?
Because most of us OT aficionados not only build our own airplanes, but we're among those who are most likely to maintain, tune, and repair our own engines. We're also more apt to mix and understand our own fuels: a subject that Dave's book covers thoroughly.
But most of all, the only thing modern about two-stroke engines is the result of progressive little improvements that have been made through the years. And those improvements are much of what the book covers.
Dave Gierke is a youngish old-timer himself. He has a long history of successful competition in several areas of modeling, an excellent grounding in the sciences, and is involved in some modern high-tech projects involving full-scale aircraft, weaponry, etc. Many of us old CL fliers remember him mainly as a champion in that arena.
The book's text and photographs mix modern engines with many of the oldies. An abundance of well-placed photos, charts, and illustrations add greatly to readability. The historical development notes are often keys to understanding modern engines. That history alone makes interesting reading, even if you aren't a nuts-and-bolts type of modeler.
As the title suggests, this book takes us beyond basic two-stroke operation and into combustion processes, carburetion details, fuel-delivery systems, etc. The most interesting areas to me were the several chapters on fuel and lubrication components and how they work together.
I was mostly impressed by the amazing amount of detail that was obviously assembled during a period of several years. Priced at approximately $25, this book is both a good read and an excellent reference manual.
I also have Volume 1 of Dave's book, which is still in print and is a worthwhile primer on two-strokes.
The Tomboy
The Tomboy was a nice little 36-inch model that was first featured in the November 1950 issue of the English Aeromodeller magazine. Each year one model (or more) is selected as a special-event design for the SAM (Society of Antique Modelers) Champs. For some reason, those chosen are often less attractive (some say a tad ugly) airplanes that might not otherwise be seen. But not so for this year's Champs at the AMA flying site in Muncie, Indiana.
The cute Tomboy will be flown in a FF special event. Most of those built in England were powered by small diesels, so this year's event will require a little engine: either a Cox .049 or a 1 cc or smaller diesel.
The special rules are posted on the SAM website. Of course, you will need wheels—not the floats shown on the larger Tomboy in the photograph.
Note About Photos
Both the MA editors and I prefer showing good-quality photos that haven't been published elsewhere. But many of today's nicer pictures are immediately posted on the Internet. Once that happens, they become sort of public domain and instantly become world travelers. So some of you may have seen a couple of this month's photos before, but they fit the text and are of nice quality.
Please consider the following for future submissions to this column:
- Names of the model, photographer, and builder
- Location, event, and any other pertinent information
- Good, clear, uncluttered photos (these are most likely to share the limited space)
- Assurance that the pictures are being sent exclusively for MA
- Mail photos directly to my home address to save steps
Please mail submissions to: Bob Angel 1001 Patterson Rd. Santa Maria, CA 93455
Thanks! — MA
Sources
- Dave Gierke's books, Volumes 1 and 2. (Volume 1 — 2-Stroke Glow Engines for R/C Aircraft — is also available from AMA Supply and Service [item 3071].)
- RCStore.com, (201) 840-4827, https://secure.rcstore.com
- Tomboy rules, plans, kits (Plans are also available from the AMA Plans Service): The Society of Antique Modelers — www.antiquemodeler.org
Transcribed from original scans by AI. Minor OCR errors may remain.
