The whole thing started with gliders. The earliest history of model building is mostly an unknown, but there’s little doubt that gliders were constructed and flown long before propulsion systems were added. Perhaps a caveman stood on a cliff and launched a willow stick with bird feathers glued on to it with dried pine resin. Today, our gliders (or sailplanes, if you prefer) are simply refinements of those obscure beginnings.
There are several competition events for Old-Time (OT) gliders. This year’s Society of Antique Modelers (SAM) Champs will include five glider events. The latest SAM rule book spells out three Free Flight (FF) and one RC event for sailplanes designed prior to 1951. The rules for those events were briefly described in my December 2011 Model Aviation column. I’ll describe the fifth one.
The SAM Champs features five grand champion awards for competition points accumulated in several event categories. There are FF awards for gas-powered and rubber-powered aircraft. RC has awards for spark-ignition power, glow power, and electric power. Hand-Launch Glider is included with FF Rubber as the only glider event accumulating championship points.
This year’s interesting new FF Glider special event is being referred to as “Bungee-Launched 36-Inch Gliders.” The event started in England, and has recently been tried here as an easy-to-fly, fun event. So far, the aircraft have a single construction rule: a 36-inch projected wingspan limit. The projected wingspan is simply measured in a straight line from wingtip to wingtip. If it’s tricky to measure a straight line around a bulky fuselage, you can set the model on the ground with the fuselage aligned toward the sun, and measure the “projected” shadow.
With the rules being so unrestrictive, SAM-era models are usually flown, but so are others—including original designs. However, when competition becomes involved, rules have a way of progressing, such as establishing a maximum flight time (approximately two minutes) and possibly other refinements. Additional limitations should be defined in a SAM Speaks article and posted online well before the October SAM Champs at Boulder City, Nevada.
The launch system is simple. It’s a small hi-start consisting of 25 feet of 1/8-inch flat rubber attached to a sturdy pole at 3 or 4 feet above the ground then 75 feet of string is attached to the rubber. I was skeptical that such a small strip of rubber would do the job, but the SAM Champs manager, Mike Myers (who flies in the event), assured me that with no minimum wing loading, even a length of 1/16-inch rubber could lift the models.
When there’s room around the center pole, it stays put throughout the event. Fliers simply shag their own lines and stretch them in whatever direction the wind is blowing. It’s up to the flier to decide whether to install a dethermalizer. If there’s any psychological investment in the model, a dethermalizer is a good idea. Those lightweight little airplanes can easily be wafted away by a light thermal.
The event seems simple. It may be only a matter of time until it’s tried by RC fliers using some of the lightweight radio gear now available. In the same vein, a few FF pilots are copying RC and flying with electric motors, using lightweight batteries and electronic motor cutoff devices.
SAM OT Updates
This year, the SAM definition of OT aircraft was advanced from those designed through 1942 to those designed through 1950. The 1938 and earlier date for an antique design was unchanged. Maybe a few of you who built and flew one of the later OT designs might be interested in recreating a favorite model from your past.
During the next few months, we can expect to see some new favorites emerge as competition airplanes. Many early FF models aren’t very competitive today because they are low-aspect-ratio designs. A less technical way to think of it is “too much airplane for the amount of wing.” That made sense at the time because stability, trim knowledge, and a decent engine run were more important than soaring ability.
Perusing Frank Zaic’s 1951-52 Model Aeronautic Year Book, I see many higher-aspect ratio and more streamlined designs. The 1952 copyright date means that many—if not most—of the three-view aircraft shown were designed before 1951. Unfortunately, most of the dozens of interesting-looking designs in that source reference don’t show a date or a plans source.
I have several of the Zaic Year Books, but it seems there was a publication gap between the 1938 edition and the 1951-1952 edition. We’ll have to look to other sources for most of the 1940s designs.
The SAM Design Review Committee is cataloging the newer designs, and presumably will be publishing updated versions of the Approved Designs List. Meanwhile, I’ve received a short list of 19 recommended designs from Gene Walloch, who has been a member of that group for years. The committee has already identified more than 400 eligible designs.
Here are few names from that list that I recognize as being popular, although I don’t have a mental picture of most.
• The Senator (Air Trails, March 1949)
• Mousetrap (Air Trails, March 1947)
• Civy Boy (Model Airplane News, November 1949)
• Gool (Flying Aces, February 1950)
• Powerhouse (The Model Craftsman, March 1947)
Most of the newly approved designs will probably be located in the magazines of the era.
Many of those magazines have been digitally recorded and are available from Roland Friestad. See the “Sources” for his contact information.
The plans from Model Builder magazine—also known as Bill Northrop’s Plans Service—are now being distributed through the AMA Plans Service.
Fox engines are out of production, although Fox Manufacturing is still in business and producing other goods. It was no longer possible for the company to compete with good quality, but less-expensive-to-produce, imported engines.
The Fox engine line may have operated with low profits for some time because of Duke Fox’s (1920-1991) personal modeling interests. A brief biographic sketch of “The Duke” (along with his engines) appeared in my December 2012 column and his autobiography is also available on the AMA website.
A special SAM RC event for Fox .35 Stunt engines called Foxacoy was described in my August 2010 MA column. The name is a fusion of Fox and McCoy. Control Line versions of the .35-size Stunt engines of either make are allowed to be used. The demise of Fox engine production should have little effect on the event because so many were made and are still sold by collectors at modest prices.
I’ll close with a simple technical tip for anyone using heat-shrink covering material. Al Lidberg shared it on the SAMTalk Forum message board.
You can easily pull the backing from the covering material by applying a couple of small pieces of tape at a corner. After the backing has been removed, it’s sometimes hard to identify which is the adhesive side. Leave the piece of tape on the material for a while to show you which is the outside.