History Of The Magneto SLICK UNITIZED MAGNETO FEATURES

Fred Slick New Stop plate design allows lag angles to be changed In seconds.

FRONT VIEW

(Courtesy SLICK ELECTRO, INC.) No shielding required on ground wire.

AN'S QUEST FOR things to do his work for him has been, and always will be, the motivating force behind every invention. In the beginning — simple tools and weapons. Then better tools — and better weapons. Then — the wheel, probably the greatest invention anyone ever stumbled upon, leading eventually (after a very long time of successes and failures), to the gasoline engine. The effects of the wheel, and the gas engine, have been felt by every civilized human alive today, even before birth. A baby's life depends on the wheels used in modern medicine. And how many mothers-to-be walk to the hospital? A strange way to begin a history of magnetos? Not

M

Timing pin in rotor simplifies assembly to engine.

Markings on frame and accessory case simplify timing adjustments at periodic checks.

really. Just as most of us depend on the gas engine, the gas engine depends on ignition. The first gas engines used an igniter. This was an assembly of two electrodes mounted inside the combustion chamber. These electrodes would be moved together to allow electric current to flow from one to the other and then, at the proper time, they would be separated, creating an electrical arc between the silver points and igniting the fuel in the cylinder. The power source was a battery. Shorting the contact points through an inductance coil to build up the arc caused the contact points to burn up rapidly and the expensive batteries didn't last long under that kind of strain. And so, man's work became even easier through the development of the permanent magnet generator, later to be called a magneto. Magnetos were first used as a power supply for telephones and were hand driven with a crank, then on gas engines to supply current to the igniter for many hours without replacement. However, this igniter type ignition system was clumsy and would not operate at speeds above 500 rpm. Man's need was greater than 500 rpm. So the search was on once more. A secondary coil was wrapped over the magneto's primary coil and a new breed of magneto was bom, one 24

AUGUST 1971

Spring loaded pawls ease starting, gives strong low-speed spark, and permits running in any position.

Round flange permits mounting In any position onto the engine.

MOUNTING VIEW

ELECTRICAL HARNESS

Slick Electro high temperature aircraft harnesses are designed to improve engine efficiency, coiled conductor improves spark, withstands higher temperatures, scuff resistant coating, no soldered joints in grounding or shielding circuit.

that could produce enough power to jump a stationary gap in the ignitor. And so, the high tension magneto, and the spark plug, added great speed to the gas engine. The high tension magneto had a large stationary horseshoe magnet with a revolving armature between its poles. The armature carried the condenser, coil, and contact points. As the speed of the engine increased, the magneto (which ran IVi times as fast as the engine on six cylinder models) was forced to run faster, creating excessive internal heat. The heat and speed made it increasingly difficult to hold insulation inside the coil when it would spin in the armature. The next logical step was to have the condenser, coil and contact points remain stationary while the magnets revolved. This solution would not have been practical with a magnet that weighed nearly six pounds (as did the early magneto magnet), but improvements in magnet steel soon made this important change possible. Magnet steels have improved so greatly in the last few years in fact that today's steel (Alnico) produces more force with only two-tenths of a pound than six pounds of the early types. Other advances in materials and technology have enabled SLICK ELECTRO to reduce the weight of a magneto from 20 lbs. to 3'/2 lbs., and to reduce the number of parts from about 400 to 190 while improving the reliability of the magneto, both very important in an aircraft magneto. The greatest problem now facing the aircraft magneto is field service. The amount of magneto service normally performed in an average overhaul shop is very small and the repairman loses his technique easily. And, the average mechanic who periodically inspects the engine does not have a synchroscope and the other specialized equipment for proper testing and adjustment of the magneto. SLICK ELECTRO has changed all that. In our newest line of magnetos, we have eliminated the internal adjustments. In making the magneto without adjustments and not serviceable, we have eliminated 40 percent of the weight and 40 percent of the size. We designed the magneto so it would produce a satisfactory spark over a greater range of settings which makes it possible to adjust the timing of the magneto to the engine farther than before. This new breakthrough in magneto design also adds long life to the magneto. The unit is designed so that, properly lubrjqated, the contact points burn at a rate equal to the wearon-.the cam follower. This automatically keeps the magneto reasonably in time with the engine. The minor adjustment that may be required is very simply provided for. The magneto may be easily adjusted to plus or minus four degrees on the engine without affecting the spark, so that the running spark is kept properly timed on the engine. This new exchange magneto should run satisfactorily to a major engine overhaul, then it is simply exchanged for a factory remanufactured unit. No waiting for repairs, no parts to inventory, the used magneto is returned to the factory where all worn parts are discarded and replaced and the castings are replaced. The remanufactured magneto will be as good as new or better (all new engineering improvements will automatically be included) and it will carry a new magneto warranty. Should it be necessary to replace the magneto during the period of time after the warranty and before the major overhaul, it will be replaced on a pro-rata basis exchange with a new warranty. This exchange type of service gives assurance that all magnetos in the field will be up-to-date. There will be no repaired magnetos in the field; all will be completely remanufactured by the experts at SLICK. Time marches on, and man's quest continues. When it comes to aircraft magnetos, we're still working on it!

WARBIRDS OF AMERICA NEWS DIVISION Cf E X P E R I M E N T A L A I R C R A F T ASSOCIATION

Jack Huismann 335 Tower Court Pewaukee, Wisconsin 53072

NEW PIPER P-51 PARTS? - NO CHANCE! The rumor that Piper Aircraft Corp. is planning to produce the P-51 from Cavalier "Mustang II" jigs and fixtures purchased from Cavalier Aircraft Corp. is only partly true. The airplane that Piper plans to produce, however, is not the P-51 but the PE-1 "Enforcer," which they plan to enter in USAF competition for a strike aircraft in the Pave Coin program this summer. The "Enforcer" is a newlydesigned, newly tooled airplane, powered by a Lycoming T-55-L-9 turboprop, and outwardly resembles the North American P-51 design. The craft was specifically designed for counterinsurgency roles by the Sarasota, Florida based Cavalier Aircraft Corp. The entire aircraft package was sold to Piper, but Cavalier still retains the rights to produce piston-engine versions of the "Mustang" for military and civilian customers. None of the existing P-51 parts are interchangeable with the "Enforcer", the latter being a completely new

airplane. Differences between the two are found in the fuselage, cockpit and windshield, wing tip tanks, and internal wing construction. A new canopy which "wraps around" the cockpit has been designed, offering protection against birds and small-arms fire. Armor protection has been added for both the engine and the pilot. Extended loiter capability will be made possible by a Hamilton Standard automatic air-conditioning system. Additional spars have been incorporated in the wing, adding up to ten hard points for hardware attachment. Extensive changes to the engine mount, cowl, and control system were required by the turbo-prop installation. The fuel tanks, which have a capacity of about 400 gals., are an integral part of the wing. As with the P-51, the "Enforcer" mounts six .50 cal. machine guns, but these can be rearmed or recocked in flight which could not be done with the original. In load and range it is expected to outdo the original. The gross weight will be between 13,500 and 14,000 lbs., and take-off distance to clear a 50-ft. obstacle at that weight will be 1600 ft. Its top speed is between 375 and 400 knots/hour, and it will stall at about 90 knots with full fuel and in landing configuration. Its range will be an expected 2600 nautical miles. £)

YOU W O R K ON THE TOP HALF I'LL WORK ON THE BOTTOM A group of dedicated EAA members, including Warbird Don Volkmer, are involved in the restoration of a Convair B-36. That's right — a B-36! And to flying status! The mammoth bomber is presently located at an airport in Texas which is being closed, and the huge monster will have to be moved eventually. © SPORT AVIATION

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