Control Line: Scale
ACHIEVING smooth, dependable throttle control over two, three, and even four or more engines, is the obvious challenge of multi-engined scale. (It can be mind-bending enough at times to get just one engine to idle and accelerate properly!) But no matter how good you are with a carburetor, long before you can even think about making any adjustments, you must construct a reliable system for opening and closing the engine throttles in unison. The drawings on this page illustrate what I believe are three of the best and most workable multi-throttle linkage systems that you will find in use. All three are designed to operate from a standard 3-line G-S or J-Roberts bellcrank system. They are all flight proven and time tested. Which one is best for any multi-engined projects you may be considering will depend on your own preferences and the dictates of your particular subject aircraft. Let's take a close look at each one!
Control Line: Scale
LAST-minute details are the topic of conversation this month. With me, all of those areas that we work on after a scale model is basically painted, qualify as "last minute details." I'm not talking about rivets, panel lines, and other microscopic details that are only important to the few who build Precision Scale models, but rather to some often large and very commonplace components of full-scale aircraft which are very important to the appearance and realism of any class of CL Scale model. Things like a scale prop, wing walks, prominent external details, dummy exhaust pipes, landing gear struts, antennas, pitot tubes, etc. Details such as these play a big role in capturing the character of the aircraft you are trying to duplicate. They are normally not hard to reproduce but too often tend to be rushed at the last minute because of a fast approaching contest deadline or sunny summer flying weather.
Control Line: Scale
DAVE FALKENHAGEN of Edina, Minnesota sent a sketch of the engine shutoff arrangement that he used in his Sport Scale Clipped Wing Cub (3rd at '78 Nats). Dave uses a G-S Products 3-line bellcrank and handle combination and worked out his shutoff arrangement as follows. First, back off the carburetoridle stop screw so that it does not come into play before the carburetor barrel completely closes. Then construct your three separate control lines (up, down, and throttle) and attach these to the model and handle as you normally would to achieve the full range of throttle movement available at the carburetor. Don't even worry about the shut-off factor at this stage; just be sure that from the control handle you can fully open and close the engine's carb. After this has been satisfactorily achieved, test run the engine with the control system completed and laid out. Have an assistant operate the control handle while you bring the carb's idle stop screw back into play to hold the desired safe low speed setting.
Control Line: Scale
IN case you haven't heard, the 1980 CL Scale World Championships have been cancelled! The deadline that the contest organizers had set for a final entry commitment from the interested countries recently passed without their getting a sufficient number signed up for CL Scale. As I mentioned in my March '80 column, five countries are needed to stage a World Championships. At the time I wrote that column (Dec. '79), only four countries had been firmly committed. I felt fairly confident then that one more nation would sign up in time, but it didn't work out that way. Perhaps the intense political situations that have developed around the world since then, including the talk of an Olympic boycott, may have had something to do with the reluctance of any new countries to sign up? It's hard to say!
Control Line: Scale
POSSIBLY the most out-of-the-ordinary CL Scale models at the Nationals this year were the entries of the sister and brother team of Kathy and Joe Kirn of Anaheim, California. Both of their models were standouts in regards to their style, craftsmanship, and final placement in the competition. Kathy won first place in Senior Sport Scale with a beautiful little Beechcraft V-35 Bonanza, while Joe took first in Senior Precision Scale with a miniaturized version of Tallmantz Aviation's special North American TB-25N camera ship. At my request, Joe and Kathy sent in some photos and interesting data on their winning models. What makes these aircraft especially unique is that both of them are very small .049-powered models and they utilize the "monoline" system of control. This represents a significant break from the norm as far as what you usually see in CL Scale competition. Monoline control is standard practice in all of the CL Speed events, where in-flight drag reduction is of the outmost importance. One line naturally produces less drag than two, and the faster the model flies the more pronounced the drag reduction benefit becomes.
