What is the master switch, you ask? The master switch is the first switch on the checklist for starting. It "turns on" the battery and all the power for the electrical systems except ignition, which is powered by the magneto. The master switch actuates a solenoid, which has large contacts capable of handling the current needed by all the electrical systems and the very high current required by the starter. In short, it connects and disconnects the battery to the airplane.

Automobiles don't have such a thing and seldom need to. Aircraft need them because there are times when your safety will depend upon it. I will cite some examples I have been a part of. A Cessna 150 was returning from a cross-country flight when something happened to the power system. It was evening and the pilot (grandson of the plane's owner) turned on the landing lights, which went on momentarily and then went out. A short-circuit condition was suspected. He decided not to turn on the radio but flew the pattern and made sure it was safe for him to land. Fortunately it was an uncontrolled airfield without much traffic at that hour. After landing he found that the landing lights were blackened from being burned out and the fuse was blown.

The next day I was called by the A&P mechanic to find out what happened. I suspected that the voltage regulator had failed, so we started the engine and checked the voltage of the generator at the battery terminals, which showed 16.5 volts. The mechanic opened the battery box and the battery was found to have been boiling so there was a clean-up job to do. Usually the voltage regulator fails by low voltage output, but this was a high-voltage condition.

"Why didn't the fuse protect the landing lights?" the mechanic asked. When the landing lights were switched on a large current flow, resulting from the excessive voltage, surged through the filaments of the bulbs so quickly the fuse blew as the bulbs blew. An interesting aside: The tungsten filament of a bulb, when cold, has a low resistance such that the initial instantaneous current is from 8 to 10 times the steady state current. Bearing that in mind you can understand why everything burned out in a flash.

If the plane had a generator switch and a voltmeter, the pilot could have identified the problem and turned off the generator. Then he could have used the radio and landing lights from battery power. Some larger planes have a generator switch and voltmeter but the little ones don't. Luckily the only other thing that got burned out was the directional gyro.

Some months earlier, on this same plane, smoke was detected in the cabin. Fearing the possibility of fire the master switch was turned off. Later a short circuit was found. Usually this condition causes the circuit breaker or fuse to blow, but sometimes that doesn't happen. At those times it's nice to have another means of cutting off the electrical power.

Here is one that happened to me. In starting my ultralight one day the contacts in the starter solenoid welded closed. With the engine turned off the starter kept on spinning the engine over. I had wired my machine like an automobile so the only thing I could do was to break the battery connection. Knowing that the certified aircraft's master solenoid was rather expensive, I looked in a catalog for boat supplies and there I found a look-alike without a metal case but having all the power-handling capability I needed and more. To give you some idea of what it is capable of, its label says it is rated to handle 65 amps continuous and 750 amps for 10 seconds.

What is the downside, you ask? Its weight is a little less than 1 pound. Sure it requires some current to keep it closed but that is only .66 amps, about the same as a small light bulb. Not bad for what it can do. Also, you have to remember to put it on your checklist to be turned off during shutdown because if you forget, the next time you are going to fly, the battery will be discharged.

If your radio or other electronic equipment is turned on when you are turning off the master switch, the diode is necessary to suppress the high voltage kick that occurs when the actuating coil is turned off. The idea is to protect semiconductors from the resulting voltage transient that can puncture them. If you don't have semiconductor devices in the system, the diode can be left out.

If your local marine equipment supplier doesn't have this item, contact: Cole Hersee Co., 20 Old Colony Ave., South Boston, MA 02127. Phone: (617) 268-2100 (ask for part #24117-01).

Arnold C. Anderson has been flying ultralights since 1982, logging more than 300 hours in his Kasperwing. After 37 years in the engine and aerospace industry as a mechanical engineer, designing electro-mechanical equipment and solving reliability problems in equipment for unmanned deep space missions, Arnold is now retired. He lives in Bellevue, Washington, where he pursues his hobbies, including aerial photography and flying RC airplanes and gliders.

Recalling my first long-distance flight through country that was unfamiliar to me, I prepared early for the flight by using the principles of pilotage that I had learned so many years ago in ground school. Because my Kasperwing ultralight is open to the elements I could not carry a marked chart in my lap; I had to do the next best thing. On a 3- by 5-inch card I noted my compass headings and described each checkpoint with the time I would arrive.

Because of a restricted TCA that extended to ground level, I indicated my turning point and new compass heading, then continued on with more landmarks. I carried the card in a handy pocket that I could reach while scrunched in my seat. Just before taking off, I started my flight timer (the stopwatch feature on my wristwatch). Then, immediately after exiting the pattern took my first compass heading.

All of this preparation paid off because later in the flight, smoke restricted my visibility to about 2 or 3 miles. But I still hit my checkpoints spot on, made my way to my destination and returned without anxiety. By the way, I made a separate card for the return flight.

Pilots who fly certified aircraft that travel at higher speeds and carry an abundance of fuel may be cavalier about pilotage and depend on their GPS. In spite of their ground school training some pilots make no preparation and elect instead to follow highways and go IFR, which is defined as "I follow roads." That is okay but I just feel better knowing where I am all of the time and be prepared to cope with any problem that may be encountered along the way.

Many times I have flown my Kaserpwing 50 miles on 5 gallons, which is not an outstanding achievement, except when there is a headwind. Still, it is a long way from home. A change in the weather always prays in the back of my mind even though I try to limit myself to reasonably stable weather conditions.

So what do you do when the weather throws you a curve such as what happened to a buddy of mine? On his way home he flew through a front that had no visual indication of its existence. My friend suddenly found himself dropping about 1,000 feet followed by severe turbulence. He was about 10 miles from home and pressed on to land at his private strip, which had a cliff on the approach and sloped uphill thereafter. At about 500 feet from touchdown he suddenly dropped and faced immediate disaster with the cliff facing him. With power and hard up elevator, he got down without damage but was shaken by the experience and his near crash. What should he have done? Was there alternative action that he could have taken?

In questioning older, more experienced pilots, their response was the same: Yes there were alternatives. The first was to turn around and go back through the front into stable air and return to his starting point. If that was judged as being too far, he could have flown to an alternate field that had a longer and wider flat runway. Here he would have more forgiving conditions. It is true that unexpected sink can be experienced at any airport but with the aid of a radio, one can get valuable information concerning conditions at a given field.

There seems to be a universal tendency among some pilots and especially relatively inexperienced pilots, to press on in order to get home. Why risk injury or damage to your machine? Either of these takes a long time to fix, not to mention expense. Don't be too proud to turn back. Wait it out and try again later.

Arnold C. Anderson has been flying ultralights since 1982, logging more than 300 hours in his Kasperwing. After 37 years in the engine and aerospace industry as a mechanical engineer, designing electro-mechanical equipment and solving reliability problems in equipment for unmanned deep space missions, Arnold is now retired. He lives in Bellevue, Washington, where he pursues his hobbies, including aerial photography and flying RC airplanes and gliders.

In getting serious about this, let's first look at where one should put strobes. Certified airplanes usually have a rotating beacon on top of the rudder, but that is not visible from below so a strobe is often placed on the belly as well. These are turned on during the day. At dusk the navigation lights are turned on along with the anticollision lights.

We should install our anticollision lights so at least one light can be seen from any direction. If strobes are placed in the outer edge of the wing tips, that goal can be met with only two lights. Of course the other alternative is to place the lights above and below as on certified airplanes, but if that doesn't satisfy your concern you can do both.

Flashing lights of any type have to be a safety benefit. Tests that I have evaluated indicate that a pulsing quartz halogen light is more visible in bright daylight than a strobe. The best pulse appears to be about 1 second on and 1 second off in duration. Strobes appear to work best at night but we don't have to concern ourselves about that because ultralights aren't permitted to fly at night. Ultralight flight is permitted 30 minutes before official sunrise and 30 minutes after official sunset, provided the ultralight has anticollision lights.

One problem with these types of lights is the likelihood of radio frequency interference (RFI) - the result of the pulsed power that surges to the lamp or strobe. The pulse is in the form of a square wave incorporating some very high frequency components that can be picked up by the antenna on your transceiver. You will be subjected to a pop in your headset each time the light flashes on. The interference is easily avoided if some simple precautions are followed.

The circuit to your lights or lamps should not depend upon the airframe for its ground connection. The lights must be wired all the way from the pulse source to the lamp or strobe. There is no need to purchase some super coax cable for this purpose. Regular well-insulated tinned copper wire will do very well.

The trick in eliminating RFI is to twist the wires together. The amount of twisting is important. Ideally the wires should be twisted so there is about one twist per inch. This reduces the power of noise radiated as RFI by 10,000 at 100 Megahertz, and that is a lot of shielding. Higher frequency components of the pulse are attenuated even more. As compared to the noise from your ignition, it is essentially zero interference.

Now we come to our next subject - ignition noise.

This problem is eliminated on certified aircraft by shielding the ignition wires with metal braiding, and then grounding the braid. That may or may not work on your ultralight. I made up a set of shielded wires for my engine and found I couldn't fire the spark plugs. My engine is fired by a capacitance discharge ignition (CDI) system, which produces one pulse with high frequency components in its wave. The shielding, in conjunction with the wire insulation and the wire going to the spark plug, formed a capacitor. The capacitance, though small, shorted out the pulse to ground. This I found out a good deal later from an electrical engineer, who was versed in that sort of thing.

I had to find an alternative means of cutting down the fierce spark noise in my radio. I didn't want to use resistance wire because it has a way of deteriorating with use. Most resistance wire uses a nylon string that has been loaded with graphite as its current conductor. In time the spark current causes the graphite to sublimate (evaporate away), the resistance goes up and the engine will start to miss, especially at high power settings. Not good.

I tried various noise-suppression caps and finally I found one that would do the job satisfactorily. Of course it was the most expensive one so it is no wonder. The best cap I was able to find is a Bosch, part number 356-351-032 marked as having a 1K-ohm impedance. To be sure it doesn't cut out all of the spark noise but by turning up the squelch on my transceiver, it works just fine. The only time I hear any spark noise is when I have an incoming signal, but it is at an acceptable level.

If there is anything better out there I would like to hear about it.

In looking at the shelves of your local auto parts store, you can find a number of oil and gasoline additives. The oil additives with which I am familiar either make the engine oil have a higher viscosity or have some solvent property intended to clean up varnishes in the engine. When I purchased my first new car many years ago, the service manager tried to sell me an additive. He said that after a quart of the additive was added to the oil, they would run the engine for an hour, then drain all of the oil and drive the car 100 miles after which it would run perfectly fine.

I had just graduated from college and had studied engine design in addition to spending considerable time in the engine laboratory. I wanted to ask the critical question: Did they disassemble the engine and inspect it for wear or damage? Also, did they prepare an engineering report describing the test signed by the person in charge of the test?

I let it pass because whenever I've asked one of these suppliers of oil additives for an engineering report on tests run in a laboratory under controlled conditions, the results are disappointing.

The conclusion of all this is, don't deviate from what your engine manufacturer recommends. There is little doubt in my mind that in 4-stroke engines the new synthetic oils are superior to the basic petroleum oils. But my advice still remains, follow your engine manufacturer's recommendations. When it comes to 2-stroke oil, I am convinced synthetic oil is the only way to go. I don't believe any 2-stroke engine manufacturer recommends anything but synthetic 2-stroke oil. It burns cleaner and provides better lubrication at high temperatures and does not require a large quantity per gallon.

Oil in gasoline displaces fuel and burns slowly so it does not provide significant energy to the piston. Before the development of synthetic oils, early 2-stroke motorcycle racers would reduce the amount of oil in the gasoline and the result was more power. One regional champion told me that he ultimately went to 100:1 in his fuel-oil ratio and would win races. In the process, he sacrificed the engine but he would win races. The motorcycle manufacturer sponsored him so the ruined engine was no great loss. He would also do such things as use only one ring on each piston.

What I'm leading up to is this: Whatever you add to your gasoline it is very likely going to reduce the amount of power available to your engine's output. Yes, even alcohol reduces available power. Alcohol has a lower energy content than gasoline.

The question of fuel stabilizers comes up from time to time. For boats or power generators that sit for long periods of time between uses, the manufacturer often recommends a stabilizer. But your ultralight shouldn't have this problem. Every time I fly I usually burn more than half of the fuel in the tank so I am always adding fresh fuel. When winter comes and I quit flying, I drain the remaining fuel and put it in my old truck that doesn't require any special consideration. Of course, I do one more thing. With the fuel line disconnected I run the carburetors dry.

As a final note, if FAA hasn't approved an additive for certified aircraft, then it probably should not be considered acceptable for your ultralight.

Arnold C. Anderson has been flying ultralights since 1982, logging more than 300 hours in his Kasperwing. After 37 years in the engine and aerospace industry as a mechanical engineer, designing electro-mechanical equipment and solving reliability problems in equipment for unmanned deep space missions, Arnold is now retired. He lives in Bellevue, Washington, where he pursues his hobbies, including aerial photography and flying RC airplanes and gliders.

This Bellaire SE was first introduced in April '97 and now reportedly has 220-plus hours of flying time. Co-owned by Arnold Gilmore and Richard Berstling (who assisted Gilmore in building the single-seat aircraft), the Bellaire SE is marketed by Berstling's Bellaire Monoplane Company, which expects to add 2-seat siblings (both side-by-side and tandem seating versions) to its hangar in the near future.

Bellaire designer Richard Berstling recently flew 13 1/2 hours from Florida to Wisconsin in his (and co-owner Arnold Gilmore's) beautifully finished Bellaire SE. Berstling assisted Gilmore in building the original Bellaire SE, a plans-built aircraft first introduced in April '97. The plane Berstling flew currently has a little more than 220 hours on it.

Powered by a 50-hp Rotax 503 dual carb 2-cycle aircraft engine using a 2.58-to-1 reduction drive, the Bellaire cruises at between 85 and 90 mph. When the Rotax B gearbox is changed to a Rotax C drive (with a 3-to-1 ratio), cruise increases to 105 mph.

Climb rate is listed at more than 1,000 feet per minute, with power-on stall speed coming in at 25 mph (power-off stall is 34 indicated), according to Berstling. Standard stick and rudder controls are used with a center stick and left throttle. When built from plans, the plane will take about 2,000 hours to complete, according to the Bellaire Monoplane Company. Component parts are also offered to cut down on building times. The plans consist of 12 pages of 24- x 36-inch CAD drawings.

According to Berstling, the plane will soon be available in a 2-place configuration (both side-by-side and tandem seating versions). Currently three 2-place craft are under construction with completion expected in about 6 months' time. These will be powered by the Rotax 912 series of 4-stroke engines, as well as the 75-hp Walter Micron 4-cycle engine.

- Report filed by Dave Loveman

Single-Cylinder 25-Horse Engine With Powerfin Prop

Above: Earthstar Aircraft has a new engine/propeller combination to offer buyers of their latest Thunder Gull ultralight, the Gull 2000. Right: The 25-hp single-cylinder Hirth F-33 2-cycle engine and Powerfin E Model 3-blade composite prop produces a smoothness "uncharacteristic of a single-cylinder engine," Earthstar claims. The empty weight of the Gull 2000 with this engine/prop combination is only 236 pounds (well under FAR Part 103's 254-pound limit for single-seat U.S. ultralights), according to Earthstar.

Earthstar Aircraft, manufacturer of the Thunder Gull line of single-seat ultralights and 2-seat ultralight trainers and light sport aircraft, is offering a new engine/prop combination on their Thunder Gull 2000* single-seat ultralight. The Gull 2000 features a 4130 chromoly steel fuselage mated to an aluminum wing and tail section.

"Testing has been completed on the Gull 2000 ultralight with the 25-hp Hirth F-33 [single-cylinder 2-cycle] aircraft engine and the Powerfin E Model 3-blade composite propeller," the company reports.

Earlier this year, Earthstar was testing the single-cylinder 26-hp Zanzottera MZ 34 2-cycle engine, which "had a wide power band and good performance, but had a lot of vibration," says Earthstar president and Thunder Gull designer Mark Beierle. Since then, Beierle has installed the Hirth F-33 and the Powerfin prop. "This combination flies the Gull 2000 quite well, with very little vibration," Beierle claims. He has about 35 hours on the engine, belt drive and prop combination and indicates it performs very similarly to a single-cylinder 26-hp Rotax 277 2-cycle engine, "but a lot smoother, and with phenomenal fuel economy." Using the F-33 engine and Powerfin propeller, "the Gull 2000 can fly along at cruise speed with as little as 3,800 rpm," Beierle says.

"The smoothness of [the Hirth F-33 and Powerfin prop] combination is uncharacteristic of a single-cylinder engine," Earthstar notes.

Significantly for ultralighters flying under the provisions of Federal Aviation Regulation Part 103, the new engine and prop reduce the total empty weight of the Gull 2000 to 236 pounds, well under the 254-pound maximum empty weight requirement for Part 103 single-seat ultralights in the United States.

"It gives the kind of performance I am used to, but with very little weight," says Beierle. The Gull 2000's 236-pound empty weight allows pilots to add additional instruments, navigation or communication equipment (like a GPS unit or aircraft transceiver) or other systems, and still stay under the Part 103 weight limit.

Report filed by Dave Loveman with Buzz Chalmers * See "UF! Pilot's Report: Single-Seat Gull 2000 - Excellent as Always," January '01 Ultralight Flying! magazine.