Gas vs Electric
by Mark Gamas
Remember those carefree days as a kid when the wind would pick up and you would race outside trailing your kite behind you; running as fast as you could to see how high you could get it, tugging the string this way and that to make the kite skitter and jump across the sky? As you grew older, your kite grew in complexity. Moving up from the standard one string version with a tail to perhaps the tail-less box kites and maybe even beyond to the high-tech two string sport version that pirouetted on command like a ballerina. So where did you go from there? Was this the peak of your aerobatic toys? Why not make the next jump now to radio controlled (r/c) planes?
So if you have decided you are ready to continue your aerial antics and are prepared to enter the world of Big Boy toys, you have a decision to make, Gas or Electric? This is what I am here to help you with, to start you down the path best suited for you. While I will be talking about the pros and cons of these different power systems in planes, just about everything you find in here is also applicable if you want to try a different branch of the r/c hobby such as cars, trucks, motorcycles or boats. While some specifics and contexts might change, the basic information is the same. So grab your inner child by the hand and lead him over to here to the store window so I can explain your choices. And please, if you can, try not to leave any drool on the window. Between the two, gas has been a viable power source for the r/c field the longest. Back in the day (40 or so years ago anyways), electric motors were just too big and heavy to fly. Since then, the basic gas engine has stayed very much the same. Refinements have been made, but the engines are very similar to the good ole days. Electrics, however, have undergone huge changes and redesigns in he last quarter century and are now a very attractive power source. Within the last fourteen years, the electric motor has undergone a redesign that would be like going from your traditional engine in your car to a rotary one. While both of them take the same input, the way they go about changing it into motion is completely different. So, if you like the tried and true method of doing things and don’t mind being a bit behind the power curve, then gas might be better suited for you. And if you like new technology and keeping up with the latest innovations, then electric should hold a strong appeal for you.
Along with new technology comes a certain cost and complexity. If you want to always have the fastest/strongest stuff in the electric field, you have to have the money and ability to continually update your fleet. Gas, having been refined for so many years, has reached a bit of a plateau and if you buy an engine of a certain size, you know that it will give you pretty much the same power as an engine of the same size that’s ten years old. Whether this is a good or bad thing is all upon how you look at it. As for the complexity, gas by their nature have many tiny, moving parts that must all work in the right harmony to get the most from each explosion inside your engine. If a piece doesn’t want to play nice with the others, you will be going no where real fast. This makes electrics look like an attractive option if you don’t want to be constantly tinkering with your equipment to keep it running. For the most part, this is true. However, electrics also need to have their pieces match up and if they aren’t, you run the possibility of melting or exploding the piece that is not up to snuff with the rest. While electrics have about three pieces that need to work together compared to the possible hundred in a gas engine, if you don’t know a few basics about electricity, you may be in for the “shock” of you life.
This simplicity of the electrics over gas extends, at least partially, to how long it takes you to get into the air after you reach the field. Electrics are powered by batteries that simply need to be plugged before you take to the skies. No fueling up, plugging in your starting system, warming up the engine, making sure everything is in harmony. It’s “plug and fly” at it’s simplest. Once you are in the air, gas and electric tend to be very similar when in similarly sized planes. Flight times are about equal and with a good electric motor, aerobatics are also similar; now this is assuming that you are deaf, of course. Electrics are very quite, sometimes so quite that you can’t hear them once they get a few feet away, but gas is entirely different. Gas engines make a whining sound that is of a highly annoying frequency. Imagine, if you will, a fleet of weed-whacker engines buzzing about the sky, only higher pitched. Not the kind of thing you want zipping around your neighborhood, now is it.
Once you land and prep for the next flight, you find another difference. Your gas plane will come down coated in residue fuel that is a sticky, smelly mess. Have fun cleaning that up when you are ready to go home. If you want to get airborne again, just refuel and you are off again. For electrics, just pop in a new battery and you’re off, assuming you have more than the one battery that is. If not, you are grounded for between a half to a full hour while you recharge your power source.
Now, let’s say that you are in the air when the inevitable happens; you lose power. This can happen in two ways, you run out of fuel/battery power, or you lose signal between the transmitter in your hands and the receiver in the plane. Losing signal is known as a glitch and usually only happens for a split second. Both gas and electric handle this the same way, unless you are too low to the ground to recover or are attempting a maneuver that you can’t get out of. Once you crash, how well your plane fares depends on what it is made of. Gas planes are generally larger/heavier than electric and made of balsa wood so that the vibrations from the engine don’t tear the plane apart. We all can imagine what a wood frame is going to do when it piles into the ground. Electrics are generally smaller/lighter than gas and typically made of foam. Some electrics are balsa, but even these fair better than gas in a crash because they are much lighter. If you crash a foam plane, alls the better because foam tends to just tear in a line where the stress is. A little glue or packing tape across the rip and you are back in the air. Rebuilding a balsa frame, however, is not so simple and I have never seen it done at the field. And God forbid your glitch should cause you to hit someone on the ground. An electric motor will stop spinning in a glitch, but what do you think a heavy gas plane with prop spinning away will do to someone?
Now, if you lose power because you ran out of your power source, you won’t be nearly as bad off. With electric motors, you can generally tell when the battery is going dead on you. You start to lose top-end power and you know it’s time to bring it in. Gas engines will usually just stop on you without giving you the courtesy of a warning, although some will sputter for a few seconds before going out on you completely.
Once in a glide, electrics again have the weight advantage. Gas is hard to glide and you have to be in a fairly steep glide to keep your speed up enough to produce the lift you need to stay airborne. With less weight, electrics don’t need as much lift to stay in the air and will usually glide quite nice. I have been able to keep a plane in the air for a minute or so after my battery got low enough that the motor stopped. Infact, I will just stop my motor and glide from time to time to see how long I can keep it up. Good luck trying to start a gas in mid air if you want to do a glide test because it will never happen. Once that engine stops, you can’t restart it until you bring it back to the pits and get your starting aids on it.
So how much does it cost to get a setup into the air? This depends mostly on the size of the plane and what you want it to do. Let’s start with the smaller planes that you will find in the air at your local park, or what we call parkflyers. For starters, you won’t find gas parkflyers in Boise because the city has banned the use of gas airplanes in the city limits; reasons being because of the noise and risk that they bring into the air with them. For a simple electric starter setup, you can expect to spend between $60 and $160 for a kit that will have everything you need to get flying. Gas doesn’t really have much in the way of starter kits and I have only seen one compared to the two dozen or so decent electric kits and it cost about $400. Now it does have some nicer support components like the transmitter and receiver than the electric starter kits, and if you wanted a similar setup in electric, you would spend about the same, but I think $400 is a little bit much to be spending on a hobby that you might not even like after you try it the first time.
Moving up from the starter kits, electrics still have a bit of an edge over gas in terms of costing less. Both use some of the same support equipment like transmitters, receivers and servos to control the plane so either way you go you will spend about the same on these. Getting a basic motor, battery and speed controller for electric will put you at a much lower price than getting an engine, gas and starter. The draw back is that a basic gas motor will outperform a basic electric in terms of power. Getting an electric setup that will match or exceed a small gas will end up costing you about the same. Once you find yourself moving into the larger planes, gas is the cheaper way to go. Making a larger engine is not much harder than making the small ones and all the same principals still apply. Making a large motor requires slightly different techniques and requires greater power to run and batteries/speed controllers that can deliver that power. Being able to fly an electric plane with a ten foot wingspan will probably cost you several hundred dollars more than if you went with gas.
Support equipment is another thing to consider when totaling the cost. Electrics don’t really have too much that they need to help them get ready for the skies. A good charger is a wise investment as taking care of your batteries properly will extend their life. This can get very expensive, but you can get a decent one fairly cheap. Gas planes need a charger as well, but since the only battery power they need is to run the receiver and servos onboard the plane, a cheap basic charger will suit them fine. Gas do require the use of a glow starter to warm the glow plug (type of spark plug) and something to spin the motor into action, things that are entirely unnecessary for electrics. They also require things like a fuel tank, lines, pump and other fuel handling equipment.
And on that note, let’s take a moment to cover what can happen if you don’t properly handle some of your support items. I will assume that the dangers of gas is well known to you by now so I won’t go into that other than to mention that the fuel used in the r/c hobby has more nitro in it than regular fuel so it is more flammable than the gas you get at the corner station. People don’t normally think about the dangers that a battery posses, though. We have all heard that you shouldn’t throw batteries in a fire and the like, but people don’t realize that you can sometimes put a greater load on a battery in a plane than it can handle and this can cause it to heat up enough to explode. This is a pretty rare case with your basic rechargeable batteries, but has happened on several occasions with the newer chemistry batteries. The new batteries tempt up with lighter weight and more power than traditional rechargeables, but they are not as stable. Mistreat them and you could be in for a very rude awakening as your plane falls from the sky in a cloud of smoke and/or flames.
So now that I have laid out a majority of the strengths and weaknesses that you will find in these two power sources, what are your thoughts? In my opinion, it largely depends on what you intend to fly and where you are going to fly it. It is my view that electrics are the way to go, but if you live out in the country and want to fly large planes, then I can see how gas might be more to your liking. I however prefer not to drive miles away from home just so that I can spend a little time in the air relaxing; I much prefer just being able to grab a plane or even leave one in the car and just stop for a few minutes on the way to or from work at a park or school. This is what I see as being the wave of the future for the r/c hobby and electric power is what is going to take us there, just like our future electric cars.
Copyright 2006 Mark Gamas
