Low Cost: Torque Meter
A TORQUE meter can be used to compare rubber motors, determine an optimum motor for a model, and help you learn about the characteristics of rubber motors. Commercial torque meters are available but they are quite expensive. One can easily be made from scrap material in just a few minutes, however, and it will serve the purpose quite well as both a teaching device and as a practical tool. The meter shown is suitable for rubber motors used in models up to about 20-in. wing span. For larger motors, some experimenting with wire size and length will be necessary, but the principle remains the same. In operation, the twisting force (torque) of the rubber motor acts on a piece of wire which is anchored at one end. To measure how much torque is developed, a pointer is attached to the wire near the motor hook and a scale is used for comparison purposes. Within some reasonable limits the twisting force does not deform the wire permanently, so that the pointer will return to "0" when the motor is unwound. On our simple meter the scale is not calibrated into measured units (i.e. in./oz. or ft./lbs.) nor is this necessary. What we'll be looking for is comparison torque data between one motor and another, or torque at a few turns compared with many turns, so measured units aren't required. The difference in torque from one number on the scale to the next can be referred to simply as one torque unit.
Little Devil
THE Little Devil was designed for my son Mike's first efforts in the P-30 rubber event. Rules for this event are simple-10 grams of rubber, 9.5" plastic prop, model limited to 30" in any dimension. We wanted to build a simple model, but one that would be easy to maintain. With the sometimes inconsistent rubber available today, we felt the usual stick-and-tissue body construction would be too easy to break. This led to the idea of a rolled balsa tube (or cardboard rocket tube) body, which, if properly strengthened and covered, can be nearly indestructible. A wing mount was necessary, so a pylon, made of polyurethane (green) foam was added. A fixed fin was placed in front of the stabilizer to ensure consistent fin settings. The resulting model has turned out to be a good flier, and even bought home a second-place trophy from its first contest.
Another Approach to Engine Starting
MANY MODELERS now are using handheld engine starters. The resulting reduction in harsh language and cut fingers is most welcome as the days of seemingly endless hand cranking come to an end. Looking back to an older solution to the engine starting problem, about two years ago I assembled a stationary model engine starter from discarded automobile parts. Hand-held starters require one hand to operate the starter, leaving just one hand free for the model. The stationary starter, however, leaves both hands free to securely hold the model. The extra hand also may be used to adjust the needle valve or to operate a bladder-pressure fuel system. Models without a landing gear become easier to start because they are safer to hold with both hands.
Arrow Sport Peanut
THE ARROW Sport V-8 was an unusual airplane when it was new, and is even more unusual now. It is one of very few production planes powered with an automobile engine, a Ford V-8, familiar to generations of hot rodders as the Ford flathead. Buyers were given a choice of models: the Master, with open cockpit; the Master Coupe, with closed cockpit; and the Deluxe Coupe. One real advantage for owner of the Arrow Sport V-8 concerned maintenance. Because of the Ford engine, a complete major engine overhaul cost only $55. There are quite a few model engines that cost more than that today! The plane selected for our model is owned by a man in El Centro, California, who has owned the plane since it was new and has recorded just 800 flight hours in that time. NC 18018 is serial #31, and is a Master Coupe.
Rocketeer 'A'
HERE'S A MODEL that seems, to me, to be the essence of an "old-timer." Cabin models were standard fare during the 30's. Although some parasol or stick models were occasionally seen, more often than not, modelers preferred their efforts to look like real airplanes. The "Rocketeer A" goes beyond just being a cabin model, however, and has its own special characteristics, due to the many curved lines and its distinctive profile. Although popularity of cabin models began to fade with the advent of the pylon model in the mid and late 30's, this model was designed in that time period. Originated by Maurice Schoenbrun, the Rocketeer A had a 40-in. span and was intended for class "A" or "B". It was sold by H&F Model Airplane Co. of Brooklyn, N.Y.
