Engine Technique
ENGINE TESTS are just a small part of an overall picture the serious power modeler needs to be concerned about. When I discussed the column format with MA, it was suggested I combine a healthy dose of information useful to the sport modeler with some more sophisticated information useful to the competitive modeler. It's possible to do both. The purpose of this column will be to make your power modeling more enjoyable and proficient. For the purposes of this column, power systems will be defined as being composed of the following sub-systems (elements): 1) Powerplant, 2) Mounting, 3) Fuel Supply, 4) Fuels, 5) Propellers, 6) Operating environment, 7) Measurements, 8) Personal skills.
Engine Technique
PREPARING New Engines For Running: With the exception of Cox engines smaller than .15 displacement, it is standard practice to disassemble, inspect, and prepare each new engine before it is run. If you don't follow this practice, I advise you to begin. The benefits are many and will be described in this and succeeding articles. You will need several tools to do a basic job of preparing your engine. Many engines today are supplied with wrenches that are used for disassembly. I am glad to see this finally happen. The use of properly fitted screwdrivers and wrenches is really important. In the past, modelers bought an assortment of drivers and wrenches that often didn't fit properly. Don't! Do buy proper fitting tools; it's a good idea to take your engine with you and select good quality tools that fit all the screws on the engine. A small crescent wrench will fit a variety of prop nut sizes and a good glow plug wrench will take care of the external screws, nuts and plug. RC carburetors often require additional screwdrivers and wrenches. Miscellaneous tools include tweezers, needle-nose pliers, X-acto knife, and jewelers' files.
Engine Technique
BENCH RUNNING ENGINES: Last month I reviewed the basic procedures to use in preparing new engines to run. Now let's take that engine and run it! I've gone out to the field to run engines and found I've forgotten something I've needed to do the test. Here's my checklist of items: Test stand, large and small tank, tubing, props (test, flight duplicate, flight), fuel(s), fill bulb or pump, plugs, glasses. Also, good battery with leads, tachometer, stopwatch, 3-in-1 oil, tools, rags, notebook and pencil, ear protectors. And engine.
Engine Technique
POWER SYSTEMS: I've remarked that failure to pay attention to, or to understand, details that affect performance is the source of frustration to all types of modelers. There is an obvious principle in power modeling that is often overlooked. Total performance depends on the attention to all details. Problem is, what are all those details? I don't pretend to know them, but there is a way to approach every problem, or goal to ensure a satisfactory result. That is to break the problem into manageable bits, acquire the ability to master each bit, then put all the bits together to achieve optimum performance. Let's discuss some of the problems involved in mounting your engine in any type of model. First: your engine is a machine that performs work. Work performed is the result of combustion in a confined chamber. Heat, pressure, stresses, heat transfer, mechanical conversion of combustion energy into mechanical forces, are all part of understanding the nature of your engine. But, let's make the engine bit easier to work with; your engine vibrates, produces heat and power. It needs to be mounted in such a way that it will do the job you intend for it.
Engine Technique
SEEMS LIKE the 12 days of Christmas, the big day a few days away at this writing, and the first four of a dozen planned articles on power systems are completed. I am receiving letters, will respond to all personally, and print the good information that comes in. Thanks for your interest in the column! Royal Kramer, from Allentown, Pa., writes. Why disassemble engines from .15 to .60 before running? The answers are: (1) you don't have to; but, if you want to be sure of maximum life and performance from your engine, that's how to do it. It's like taking delivery on a new car and then checking it out and taking it back to the dealer to fix minor problems. In this case, you are the buyer and the fixer. (2) To develop (if you wish) personal skills that can add to the enjoyment and results you achieve in power modeling. Over the years I've heard many modelers remark that they get real satisfaction from their ability to "set up" engines. In some, if not all, competitive events, winning just doesn't happen, unless specialized attention is paid to getting specific performance from an engine.
