Up and Around
IF YOU'RE an Old-Timer Free Flight or Control Line buff, this is your column. Whether I'm focusing on models, engines, products, or events, my goal is writing this bimonthly column is to help you have more fun with the facet of modeling you enjoy most. Technical Director Bob Underwood really got my attention with a survey that revealed that less than 10 percent of the membership entered an AMA event last year. If more than 90 percent of our members entered no events at all, why are they in AMA? Is it for the insurance alone? I don't believe that, any more than I believe that the average modeler (who apparently never enters a contest) should dismiss the value of competition.
Engine Technique
FOR OUT FIRST column let's take some of the pain out of the old engine break-in problem with some proven, safe, methods. Break-in or run-in consists of mating the new parts at operating temperature, that combine to make up your new engine, so that it will deliver its maximum intended power. The "operating temperature" is the key to the whole break-in process. As a new engine heats up, parts start to expand and move around. The crankcase expands allowing ball bearing outer races to seek their ideal seating; the top edge of the piston heats up more than the cylinder and thus begins to wear, most times causing it to shine this top edge (lapped pistons). As the piston metal heats up, the highest operating temperature it reaches controls how much it will expand. After the engine is stopped the piston will retain some of this growth as it cools, thus taking a permanent set.
Engine Technique
If two moves equal one fire, the recent move of my company was equal to ten fires and, with the NATS only three weeks away, here are a couple of quick sketches this month on a tank design that may help CL Scale Race engines run a bit faster. The basic shape is borrowed from Bill Wisniewski's suction-feed tank. The main idea is that a model trimmed for speed tracks the circle quite differently than one trimmed for stunt. Many people have asked why their engine won't run out the whole tank; or they must set it off rich at the beginning to keep the engine from going over-lean before the first pit stop. Or it just will not run steady.
