Multi-Engine aircraft - Paul Harrison

There is nothing like the sound of a V6 car engine, or a multi-engine model aircraft. The trouble is keeping them sounding sweet, and running nicely. With a model aircraft powered by a twin, if one runs faster than the other, or one stops mid flight..... you cannot tweak the needle or re-start it.                Bring on the electric multi-engine aircraft.

The problems mentioned above go away with an electric multi. Given the same voltage by the shared battery pack, they just hum together in harmony. I have a few larger, semi-scaled models enjoying more than one power plant.... and couldn't be happier with them.

This is a 72" C130 Hercules.... completely foam built, with four speed 400 can motors to sing in harmony. All four on full tilt using a single 50amp Ripmax speed controller and a 3 cell LiPo pack draw 39 amps. This is only required of course for take off, and tactical climb outs. This Hercules has full navigation lights, controlled from the transmitter. It has no rudder, but steers on the runway with the use of a steerable nose wheel on the rudder channel
	After a conversion to geared 400 cans I thought that an increase in performance and efficiency would be gained. Not so..... 40 amps is still drawn from the same battery / speedo configuration.  It does sound nicer though with the rattling gearbox's as it slumbers past the pits at head height
For scale............   a familiar site at the 08 end of our runway, although I cannot yet fly them both at the same time. The "US Coast Guard" uses one 35 amp controller for the outer motors, and a 40 amp for the inner pair. This aircraft can complete a 14 minute sortie, with many rapid descent and climb outs in that time. It will fly very scale like, and it is a pleasant sight in the sky. This seems to be a more efficient set-up than the geared / 50 amp combo. Rudder on this model gives ground control

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Project design & build - 6mm Depron Shorts Skyvan - Paul Harrison

I have mentioned on numerous occasions on these pages, that I have built a Depron Skyvan.......  this was constructed using a set of 3 photo's traced onto 6mm Depron and cut out using a scalpel. Reinforcement balsa strips and blocks were used at the seams, and very quickly the fuselage rose from the bench. more balsa was used for battery and under carriage mounts, and of course the wing mount points needed a little assistance from balsa and lite-ply. Any long Depron components like the tailplane and fins, were "beefed up" with the assistance of 3mm Carbon fibre. Internally, the fuselage has Depron bulk heads for rigidity.

The wings were a pair of high aspect ratio glider wings that were the last remains of an old bird from 20 years ago. Using the plans, I scaled the span from the chord, and chopped them down to size.  I forgot to mention that this was the method I used to scale up / down the fuselage, as the wings were the only pre-built item I already had. This is what determined the size of the model.

A pair of 21 turn Chinese brushless "Bell motors" were attached to 10mm square hardwood strips, and they were glued into the leading edge of the wings. Polystyrene engine shapes were cut and sanded then glued over the motors for effect, and a pair of 8" x 4" electric props attached via prop adaptors to the 3mm motor shaft.

The wings already had ailerons hinged, so that would be my mode for direction pointing of the Skyvan..... so I glued a pair of Cheap Chinese servos into the wings. This meant that I did not require rudder, and as the Skyvan has two fins and would require two rudders I was pleased not to have to created them. The elevator is just a slab of Depron across the whole tailplane, so this too was an easy build. Old snakes were found in the hanger, so I ran one into the cavernous fuselage from the rear, and just about where it ended, I glued another £5 servo. Without rudder functionality, and with the lack of enthusiasm for chasing down the runway at Hucknall to retrieve an overshot model, I installed a steerable nose wheel. Another servo was glued to the Depron sheet side to move the wheel horn via another nylon snake.

I took the naked plane up to the airfield on a calm day (remember those) and set the throttle for a rapid ground test (after a range and throws check). The Skyvan rose like a Hercules in the Gulf....... Total control, and stable too. after an eight minute flight I was happy enough to attempt a landing, and so slowed it down.  As the wings are supposed to fly slow from their previous incarnation, the Skyvan floated down nicely to a perfect landing. The overshoot was utilised to test the return to the pilots box of the steerable nose wheel.

The plane was painted using poster colours (don't try spraying it with cellulose,  you now know why) to match the blue and white Solarfilm covered wings, and more ground and flight tests were completed. 

I now use cheap imported 5000 MaH 3 cell LiPo packs, which can take this model on a 15 minute excursion around the Hucknall skies. The battery drain is minimal, with the battery pack not even slightly warm after the flight.

Power requirements - What do I need ? - submitted by Webmaster

The best aeromodelling tool that I have bought, is my Astro Watt meter. Now I have one, I could not imagine testing systems before one. Whether you need to know the battery capacity, the speed controller rating or what size prop to use, you need a meter. 

Try to buy a meter from somewhere like Maplins that can handle over 10 amps ! they are very hard to get hold of. A unit from an auto electrical shop may handle about 30 amps, but are of the clamp style and are fairly large. An Astro Watt meter can handle 80 amps.... other makes can handle 100 amps.

When a load for a specific aircraft is needed to be known for whatever reason...... use these methods to obtain it. If you are going to use a three cell LiPo pack of around 1000maH in the model, but are unsure if it is large enough, use a larger one, say 2000maH for this test. Make sure that the Amperage for this test pack is large enough for the drain expected in maH and 'C' value. This way, when you do the test with a large freshly charged pack of the right voltage, its voltage will not drop due to the relatively small load imposed on it. Also make sure that you use a larger amperage speed controller than you expect to need for these tests.

During the test, note the amps drawn and watts read. Change the propeller to see you can get a greater amount of thrust, and once again check the readings. At the end of the tests, choose the prop that you want to use, and note the readings you took for that combination of volts, Amps, Watts and propeller.

With these results, you can purchase the speedo that will handle the power for your motor. You can also estimate the battery pack to buy for your model....  eg.

If the motor / prop combination drew 20 amps on a 11.1volt battery pack, use a speed controller of 25 amps or above rating. The battery you need to use will need to be something like a 2100maH 10C (2.1a x 10 = 21 amps) or a 1200maH 20C (1.2 x 20 = 24 amps). these are the absolute minimum tolerances........ and you should use the largest capacity that the model and your pocket can accept.

Try to standardise on a battery pack that can be used in many models, so that you can use the same pack (or multiples of them) over and over again. Modern cells are capable of delivering 15 to 20C....... so in theory, a 2100maH 20C pack should be able to power a model that requires 42 amps of power. Of course a speed controller rated at greater than 42 amps is required, so the next available size is 45 amps, then 60 amps.

I say in theory, because I have some cheap Japanese packs that are rated at 6000maH - 10C, which should hold up with a drain of 60 amps. These cells get warm on a prolonged flight rated at about 30 amps. I also have packs that are 3300 20C, that are smaller and lighter, but after the same flight in the same aircraft the cells are cold. What I am saying is that some manufacturers may use a different scale to others when it comes to labeling the packs, or at least they may be generous with some of their figures.

First, connect the test battery to the source side of the Wattmeter, then connect the speed controller or other "Load"  to the load side of the meter. as you increase the throttle on your Tx, the meter will show the Amps drawn, the Watts and the Voltage of the cell pack whilst under load

I mentioned combining packs for a greater capacity...... this can be done in two ways, but you must use packs that contain the EXACT same cells, if you are going to combine them. This means manufacturer, cell capacity in maH, 'C' value and cell age.

You can join two identical packs in series....  ie. + on one pack to - on the other pack. This will combine the voltage, giving double that of the individual packs. The amperage however will still be the same as the individual packs. Example one: two 3 cell 11.1 volt 2100maH - 10C - 21 amp packs joined in series will give you a pack of: 22.2 volts 2100 maH x 10C = 21 amp.

If you join them in parallel ie. + on the first pack to + on the other pack and - on the first pack to the - on the other. This will combine the amperage capacity of the two packs, but the voltage will remain the same as individual packs. Example two: two 3 cell 11.1 volt 2100maH - 10C - 21 amp packs joined in parallel will give you a pack of: 11.1 volts 4200 maH x 10C = 42 amp.

Be warned......  a setup with a motor and prop that draws a given amps with a 3 cell pack, will draw a significantly larger current just by adding one cell.

eg.  a 400watt rated brushless motor with................

12" x 6" prop, and a 11.1volt pack draws 22 amps

12" x 6" prop, and a 14,2 volt pack draws 35 amps

This will mean that a 30 amp speed controller that was fine on 3 cells, will not have adequate capacity with a 4 cell pack, and may well smoke heavily when used on full throttle. With the higher amps being drawn, the cells in your pack containing three cells and was adequate for 25amps draw, will not be butch enough if you had four cells in the pack...... This of course is because of the potential drain with the motor running on full power.

With all of that current having to pass between the cells in a pack, the weakest link will be exposed.  Cheaper LiPo packs use a very inferior method of linking cells, and may well be subject to burn out like a fuse within the pack connections. No join, means no circuit, which means no receiver battery which means a rapid decent landing.   See right. If then, you use two packs in series to gain voltage, the link will need to be able to cope with double the amps that they may have been designed for.

Better quality packs will utilise a minimal number of cells. eg an 11.1v pack will contain just 3 cells of high capacity - 3p. A cheaper pack will normally contain larger numbers of lower 'C' rated cells. Ie an 11.1v pack may contain 12 cells...... 4 in series x 3 in parallel - 4s3p. These are the packs that are more likely to fail under heavy loads.

This is the reasoning behind my purchase of the Ammeter. Use a larger capacity cell, and a greater amperage controller,  just so that you know what to use in each model. 

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BEC unit for use on large models with high cell counts - submitted by Webmaster

When using a higher number of cells in electric powered models, generally speed controllers are not happy delivering a sustained power to your radio kit. Manufacturers will normally tell you the maximum number of cells recommended for use with a particular speedo. Over that cell count, you will need to use a separate power supply for your receiver, as the onboard BEC of the speed controller will not have enough power itself. 

If for some reason your motor burns out or jams (as some well known makes have) your speedo will burn out and your radio will have no power for you to control your plane. By using a separate Receiver battery pack you will always have power to your receiver, but  by carrying a 4.8volt pack of AA cells you will obviously be adding extra weight. The alternative is to use a BEC device. Battery Elimination Circuits like this one will supply 4.8volts direct from your LiPo flight pack..... when wired in parallel to your speed controller. 

Rated at 1.5amps with a voltage up to 24v input, these types of units are very versatile in all of your electric models. The one above only weighs 9g including all of the wires, and can be used to drop any battery pack between 24 volts and 6 volts to the voltage that your receiver needs to stay powered at - 4.8v. 

Of course this is not limited to electric flight...... you could use an eight cell pack of Sub 'C's in a large model with the peace of mind that for the duration of the flight, as long as that pack does not fall below 4.8v, your Rx is safely powered.

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LiPo battery safety - submitted by Webmaster

Never fast-charge any battery type unattended.   Never charge LiPo cells/packs at any rate unattended.
Only charge LiPo cells/packs with a charger designed specifically for lithium polymer chemistry. 
LiPo cells can ignite because of unmatched cell capacity or voltage, cell damage, charger failure, 

incorrect charger settings and other factors.
Always use the correct charging voltage. LiPo cells/packs may ignite if connected to a charger supplying more than 6 volts per cell.
Always assure the charger is working properly.
Always charge LiPo cells/packs where no harm can result, no matter what happens.
Never charge a cell/pack in a model. A hot pack may ignite wood, foam or plastic.
Never charge a cell/pack inside a motor vehicle, or in a vehicle’s engine compartment.
Never charge a cell/pack on a wooden workbench, or on any flammable material.

If a cell/pack is involved in a crash:

a. Remove the cell/pack from the model, and place the pack in a fireproof tin.

b. leave the for at least 25 minutes
b. Carefully inspect the cell/pack for shorts in the wiring or connections. If in doubt, cut all wires from the cell/pack.
c. Inspect cells for dents, cracks and splits. Dispose of damaged cells.

Dispose of cells/packs as follows:

Discharge: with the cell/pack in a safe area, connect a moderate resistance across the terminals until the cell/pack is discharged. CAUTION: cell/pack may be hot!
Discard:

- NiMH: place in regular dustbins.
- NiCad: recycle (cadmium is toxic).
- LiPo: puncture plastic envelope, immerse in salt water for several hours, place in regular dustbins.

Handle all cells/packs with care, as they can deliver high currents if shorted. Shorting by a ring, for example, will remove a finger.
Always store cells/packs in a secure location where they cannot be shorted or handled by children.
When constructing a pack, use only cells of the same capacity (maH).

Do not charge battery packs in series. You must select the voltage or cell count printed on the battery label.

Examples:

• If the the battery label says:  "Charge as 2 Cell (7.4V) or may cause fire."  You must select "2 Cells" on your charger for charging.

• If the battery label says:  "Charge as 3 Cell (11.1V) or may cause fire.",  You must select "3 Cells" on your charger for charging.
  
  You must select a charging current not exceeding 1C, higher setting can cause fire. 1C = the amperage rating equal to the capacity of the battery pack. 

Examples: 

• The charge current for an 860mAh battery pack shall not exceed 860mA = 0.86A

• The charge current for an 2100mAh battery pack shall not exceed 2100mA = 2.1A
  

Do not charge a Lithium battery pack unattended !

Store batteries at room temperature.
Do not temporarily store in vehicle, temperature inside of the vehicle may exceed 150 deg. Storing batteries at 170 deg. F for extended period of time may cause battery damage and possible fire.

FAILURE TO FOLLOW THIS INSTRUCTIONS CAN CAUSE FIRE, PERSONAL INJURY AND DAMAGE OF THE PROPERTY.

Taking care of your battery.
Let the battery cool down to ambient temperature before charging. 

Charge battery with high quality LiPo charger.
Set voltage and charging current correctly before the start of charging.
Do not discharge battery below 3V per cell. (2.5V under load).
Do not puncture or mechanically damage the cells.
Check the voltage after the first charge.

            1 cell: 4.2V (4.15 to 4.22)
            2 cell: 8.4V (8.32 to 8.44)
            3 cell: 12.6V (12.48 to 12.66)
            4 cell: 16.8V (16.64 to 16.88)
            5 cell: 18.5V (18.30 to 18.60)

  
Operating temperature. Charge: 32-113 deg F  -   Discharge: 32 to 140 deg F

Battery life cycle:    Battery that loses 20% of the capacity must be removed from service and properly disposed.

First battery use:     Keep the flight time around 6 minutes with 15 minutes break between the flights.

Fly safe.  Charge safe.  Be safe.

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LiPo cell "C" rating - what does that mean ? - submitted by Webmaster

The charge and discharge rates for Lithium batteries are quoted in multiples of "C".   "C" equals the capacity 

of the battery in amps or milliamps. Charging should never be done at more than 1C, however a lower rate than 

1C is perfectly acceptable.

 Examples: for a 360 maH battery.... 1C equals 360 milliamps or 0.36 amps.

                     for a 1250 maH battery.... 1C equals 1250 milliamps or 1.25 amps.

                     for a 2100 maH battery....1C equals 2100 milliamps or 2.1 amps

When applied to maximum discharge ratings, the quoted C is multiplied by the number in front of the C.

Examples: for a 360 maH battery.... 20C equals 7.2amps (20x .036)

                   for a 1250maH battery 15C equals 18.75 amps (15 x 1.25)

                   for a 2100 maH battery....20C equals 42 amps (20 x 21)

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What battery cell type should I use?- submitted by Webmaster

There are currently three main types of batteries in use for electric airplane motors. These are Nickel Cadmium (NiCad), Nickel Metal Hydride (NiMH) and Lithium Polymer (LiPo).

NiCad's are the oldest generation of these batteries. They pack more power but are heavier than the NiMH. The NiMH voltage and subsequently its power tends to fall off fairly fast during the flight. The new generation of batteries,  LiPos have great power for little weight and retain the power throughout the flight. They are however much more expensive than NiCad or NiMH packs. 

Note that more cells in the battery means more voltage, which means more power.

Power (Watts) = Current (Amps) x Voltage (Volts)

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Troubleshooting electric models - submitted by Paul Harrison

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ESC, BEC, and LVC - submitted by Webmaster

ESC - Electronic Speed Control
This device controls the battery voltage that is presented to your motor. Zero voltage (Tx stick at zero) means no power, full voltage (Tx stick all the way forward) means max power. A speed controller will give a full range of speeds in between zero and full.

BEC - Battery Eliminator Circuit
This circuit in your ESC allows the receiver (and servos) and the motor to run from the same battery pack. This saves the weight of second battery. Most modern ESC's have this BEC feature. Be careful to read the manufacturers specs, as BEC's have limitations on number of battery cells and servos that can be safely used. As a rule, after about 14volts, the recommendation is still to use a separate Rx battery pack.

LVC - Low Voltage Cutoff
In a system using BEC speed controller, the power to the motor is cut off when the battery voltage drops below a certain value. Power to the receiver is maintained, enough to allow several minutes of control for a reduced power safe landing with the radio fully functional.

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Introduction to electric flight - submitted by Webmaster

Electric model aircraft are becoming more and more common place, especially in models targeted at the new pilot. The advantages of electric power include reliability, low noise, low vibration, and clean. The disadvantage of earlier systems was low power produced by the early cells and simple motors.

Recent electric airplane motors, combined with advanced batteries, have increased the performance and duration of electric flight dramatically. This type of power system is now a common sight at the flying field. Electric motors work by converting chemical energy stored in the batteries, into motion or mechanical energy. Electrical current from the batteries flows into electromagnet coils. These are repelled by permanent magnets in the motors, causing rotational motion. By repeatedly switching the polarities of the electromagnets, the magnets continually repel, causing smooth rotational motion.

In the more common brushed motors, current switching is accomplished mechanically, by means of sliding contacts known as brushes. The contacts generate heat and can also wear down over time. In brushless motors, the switching happens electronically using a special voltage regulator (speed controller). This second type of motor and its controller are more expensive to make. Its advantage is no friction so no heat, and without brushes to wear out..... the motor power will not fade with age. Brushless motor performance is generally much higher for similar physical size motors, when compared to brushed motor.

As this is the newest form of propulsion we have in aeromodelling, these are the pages that will see the most change in the months to come. Keep checking on these pages if you are at all interested in electric flight, as I wont email everyone every single time I make an addition or update.

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Power prediction - Submitted by Webmaster

With glow engines, the manufacturer’s recommended engine size is generally more than enough power for the airplane. Electric airplanes tend to be a much more critical balance of airplane weight and motor/battery power. Also electric motor and battery systems are much less standardized than their glow counterparts. 

It’s useful to know in advance if an electric airplane, especially one that you are building from a kit or converting from a glow plane will have enough power to fly as you would like it. There are some rules of thumb that can help with this.

Cell types have a different voltage capacity, namely NiCad - about 1.2V, NiMh - about 1.1V, LiPo - about 3.7V 

To find the power produced by your battery system. First, find the number of cells in your flight battery pack.  Multiply number of cells by voltage per cell to get total voltage, eg: 7 NiCad cells = 1.2 V x 7 = 8.4 Volts. Then find or measure the current through the system. Data is available for several motor/propeller/voltage combos on the web: If you can’t find the current “draw” for your system, you may need to measure it on your workbench, using a high capacity watt meter. 

Once you know the current, then use: Power (Watts) = Current (Amps) x Voltage (Volts) Now find the "All up" total weight of your model, including motor, battery and radio components. Divide power by weight (in pounds) to get the “power loading” or “watts per pound”: Power Loading (Watts/Pound) = (Power (Watts) x 16)/ Weight (ounces)

General guidelines for power requirements

For an electric plane to rise off the ground (ROG), you need about 50 watts per pound of model weight.

For an electric plane to do basic aerobatics, you need about 70 watts per pound.

At about 100 watts per pound, you start to not need wings, meaning that the plane can go vertical until out of sight.

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Electric vs Glow Power

Here's 18 reasons why electric-powered planes are better than glow-powered planes:

1. Safer - With glow engines, usually an electric starter is used. If not, then a chicken-stick, or worse, flipping the prop by hand. All these methods have hands and fingers close to the rotating propeller. With an electric, there's no need to have your hand near the prop, it's always remote starting. Also, there's no needle valve adjustments required with electric planes, so there's no reason to have fingers near the prop.

2. Cleaner - Since electric planes don't use glow fuel, the plane isn't slimed with oil after each flight. Therefore, a larger variety of finishes can be used with electrics, including non-fuel-resistant paints.

3. Last Longer - Since electric planes don't use glow fuel, the wood doesn't get soaked with oil over time. Therefore, electric planes can last a lot longer than their glow-powered counterparts.

4. Improved Scale Appearance - Since electrics don't have a cylinder head or muffler sticking out, scale subjects can be modeled more scale. Also, since the spinner of an electric plane never needs to be touched by a starter, scale appearance can be enhanced by painting the spinner (olive drab, for example), if the scale subject requires it. A starter would eventually wear the paint away.

5. More aerodynamic - For the same reasons as improved scale appearance, electrics can be built more aerodynamically efficient, since no cylinder or muffler sticks out into the airflow. Electrics with a spinner allow a smooth transition of airflow from the spinner onto the fuselage at all points.

6. Inexpensive to build - The electric planes I'm involved with are small Speed 400 and 05 can motor powered. They don't take much in materials to construct. And since they're smaller, they take less room to store in the garage, and take less room to transport. I don't have to put the plane in the truck bed, it will fit on the seat in the cab next to me.

7. Inexpensive to fly - Electrics can be viewed as less expensive to operate since fuel at $15 or more per gallon doesn't have to be bought, and glow plugs will never burn out.

8. More reliable - There's no needle valves to tweak on electrics. You never have a poor engine run with electrics. You never have an electric motor go lean or rich. For multi-engine electric planes, you never have one motor quit, and the motors always run at the same RPM. Even counter-rotating props are possible with a simple polarity change.

9. More power - Theoretically, you can pump volts (by increasing the number of cells) into an electric motor until it blows apart. With glow engines, they peak at a certain horsepower, and there isn't much you can do to get more.

10. Limited support equipment - When I fly electric, this is the stuff I can leave at home: Field box, almost all tools, bottle of glow fuel, fuel pump, starter battery, power panel, glow starter, engine starter, cleaning spray, paper towels. When I fly electric, all I need is the plane, the transmitter, and the battery charger (which I attach to my car's battery).

11. Quieter - Electric planes are generally much quieter than internal combustion engines, either glow or gasoline. This is increasingly becoming an issue at flying fields. Many clubs must now follow noise level limitations. When people say "The future is electric", they may be right.

12. No emissions - Since fuel isn't burned in an electric motor, there's no emissions released into the environment.

13. Less charging - When I fly glow powered planes, I have to remember to charge the transmitter, receiver pack, glow starter, and starter battery. With electrics, all I have to do is charge the transmitter, since the motor / receiver battery is charged at the field in just a few minutes.

14. Peace of mind - I never have to check the receiver battery in an electric plane. I never have to wonder if I have enough juice left for that last flight of the day. With BEC in electric planes, when battery power is low, the motor will not run, since it conserves what remains and dedicates it to the receiver. Unless I'm flying a glider stuck in a thermal!

15. Indoor Capability - Because electric-powered planes are quieter and have no emissions, they can be flown indoors, and often are.

16. Gearboxes - Electric motors can be fitted with gearboxes of various ratios to make a wider range of propellers available, and to make thrust more efficient. Overall, providing greater versatility.

17. CG Problems - Sometimes glow planes have issues with fuel draw and center of gravity. For example, with a glow pusher you may have CG changes as fuel is consumed, and fuel draw problems if the fuel lines are too long or if the tank is too low. None of this happens with electrics.

18. Multi-engine planes - Electric motors are ideal for multi-engine planes, whether with two, three, four, or more engines. You never have to worry about one engine quitting in flight, you never have to worry about the motors not being "sync'd" (not running at the same RPM). Plus, can you imagine the oil slime caused by FOUR glow engines? And, electric motors spinning in harmony still has a great sound!

Here's a few things that people typically say about electric planes:

"You have to charge it every time." Well, yeah, you have to fill a fuel tank with fuel every time too, right?

"They take too long to charge." Not really. It's probably about as long as it takes to fuel a glow plane and check to make sure everything is still tight, since the glow plane is shaking itself apart from vibration, helped along by a generous oil slime. Besides, if you have several battery packs you can charge one while you're flying the other.

"They don't fly long enough on a charge." How does near an hour flight time sound? This is what you can get with the newer lithium-polymer batteries. How long does the typical glow plane fly? Maybe 10 minutes? Don't you want to land after all that time?

"I don't know enough about them." That part is up to you. If you want to know about them there are many resources available, especially with the popularity explosion of electrics. But if you think ignorance is bliss, then just keep flying glow planes.

"They're not as powerful as glow planes." What BS! Electric planes with brushless motors can hover and perform "3D" aerobatics just like glow planes.

"They're too expensive." Do you want to spend $10 on a good performing electric motor (ferrite Speed 400) or near $100 for a glow engine? But, like everything, you get what you pay for. You could spend thousands on glow or electric - it's your choice. You can buy a GWS Slow Stick kit for about $35 which includes the motor and prop, throw in a little battery pack and ESC, and have a great flying fun plane that can out-perform some glow planes. What do you think about that?

"They're too small, I can't see them to fly them." More BS. Haven't you seen giant-scale electrics?

"Electric planes are just toys." Wake up! What do you think glow planes are?

"Electric planes don't sound realistic." One of many good things about electric planes is that they're relatively quieter than glow planes. That's a strength, not a weakness. In many parts of the world there are noise restrictions, and noise has even shut down some flying sites. Hey, that glow plane doesn't look realistic, it has a big un-scale muffler sticking out the side and it has oil all over it!

"When are you going to quit the electric crap and fly "real" planes?" I'm going to fly "real" planes someday when I pass the FAA exam and get my private pilot's license. Here's a newsflash for you - a model airplane with an internal combustion engine isn't any more "real" than a model airplane with an electric motor!

When all is said and done you have a choice. It isn't what you fly, but that you fly. I have found that electric is certainly better for me. I trust that you will make the right choice.

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Here is some data gleaned from the Internet regarding material weights. Useful when selecting materials for constructing electric planes especially.