Transitioning from Electric to Glow Powered Planes

Intro

I won a glow-powered RC plane in a raffle this summer.  Before that, all I ever flew was electric RC aircraft.  I thought it might be interesting to talk about the transition, so if you only fly electric, you can understand what’s different with glow-powered engines and figure out if it’s something you’d like to try.

Please watch this video below or follow along with the article here.

First of all, these small combustion engines are called glow engines, because ignition is accomplished by a combination of heating from compression, heating from a glow plug and the catalytic effect of the platinum within the glow plug on the methanol within the fuel.

They are sometimes also called nitro powered because they contain nitro methane.  They typically range in sizes from .1 to 1.6 cubic inches, which is an engine displacement.  Lots of times you drop the decimal point and if you mention a 40-sized engine, you are really talking about .40 cubic inches.   If you need engines with larger displacements, you get into the gasoline engines.  Gas engines have a spark plug like the ones on your lawn mower or car.

Want convert glow engine sizes to brushless motor sizes?  Check out this link.

What else do you need to fly?

So the plane I won was an Alpha 40 RTF (or Ready to Fly), made by Hangar 9.  It’s considered a high-wing trainer, which is perfect for a beginner.

It’s supposed to be ready-to-fly, but what else do you need to get this thing airborne?  You need these 5 things:

1. Glow Fuel.  Fuel with 10% nitro methane is recommended for this particular engine.
2. Fuel pump:  you need a way to pump fuel into the fuel tank.
3. Glow Driver:  you have to heat the glow plug to give your engine ignition.
4. Electric Starter:  to turn the engine to get it running.  You can start them by hand, but an electric started is easier and safer for a beginner.
5. Field Box: They make these field boxes that have everything you need and you carry them to the flight field with you.  I bought a Hobbico UltraTote because it includes 12 volt lead acid battery for DC power, a 12volt electric fuel pump, a 1.2 volt glow driver, a 12 volt electric starter and a place to hold a jug of fuel.  It also has this Deluxe Power Panel that lets you connect all these things to the 12 volt battery via banana plugs.

You don’t need to get a field box like this.  There are alternatives.  They make manual hand crank fuel pumps that work very well, pumping fuel pretty quickly.  Some pilots attach these directly to a red gasoline tank and store their glow fuel in there.  They have portable glow drivers that have a rechargeable battery in them and without cords.  Instead of turning the engine with the electric starter, you can turn them by hand or use a safer option and turn it with a chicken stick.  This is more dangerous and more work, so I would suggest using an electric starter for a beginner.  Now that we got everything we need, let’s go to the flying field and fly this thing.

Getting Ready for Flight

Let’s walk through the engine startup procedure.  I have to admit, I was really intimidated by the engine start procedure initially, but after doing it several times it gets easier and becomes faster to do.

STEP 1.  ADD FUEL.   First, you need to add glow fuel in the tank.  There are 2 hoses coming from the fuel tank.  One is called a fuel line and it goes to the carburetor and the other is called a vent line and it goes to the muffler.   Disconnect the vent line from the muffler so it can act as a vent.  Connect the fuel line to your fuel pump hose.  Since my pump is electric, I just move a switch to start pumping the fuel into the tank.  The switch has 3 positions.  The middle position is off and the other 2 positions either suck the fuel from the fuel tank or suck the fuel from the fuel jug.  If the fuel starts traveling in the wrong direction, you just need to reverse the switch direction.  If you have a manual pump, just turn the crank by hand.  Again, if the fuel travels in the wrong direction, just crank the other way.  So, you fill up the fuel tank.  It usually fills up in less than 30 seconds, but it really depends on the fuel tank size.  You know it’s done when fuel starts coming out of the vent tube.  Shut off the switch immediately and reattach the vent and fuel lines.  Make sure you connect them to the correct places.

STEP 2.  SECURE PLANE.  Place the plane somewhere will it won’t move.   My club has these nice stands that are perfect.  You can also have someone help by holding the wings or standing in front of the tail while the plane is on the ground.

STEP 3.  PRIME ENGINE. When the engine is cold, it’s a good idea to prime the engine.  Note, this part may vary for different engines.  Turn on your transmitter, turn on your receiver and increase the throttle to max.  This will open the carburetor all the way. Put your finger over the carburetor hole and rotate the prop 6 complete revolutions.  This brings fuel from the fuel tank into the carburetor.  Close the throttle, but leave a small opening, maybe 1 or 2 mm gap in the carburetor opening.

STEP 4.  ATTACH GLOW DRIVER.  Attach the glow driver to the glow plug.  This one is pushed on.  If yours has it, you can set the voltage.  We’ll start with the middle setting and increase it later if it doesn’t start.

STEP 5. TURN THE ENGINE OVER.  Put the electric starter firmly on the spinner and squeeze the switch.  You want to make sure the starter is turning in the correct direction, as designated by your engine.  The engine should start within seconds of applying the starter and you can remove the starter.  Let the engine idle for around 30 seconds.  Adjust your throttle trim if necessary to achieve constant low throttle.

STEP 6.  MOVE TO MAX THROTTLE. With the glow driver still attached, smoothly move the throttle to the maximum and the engine should go to max RPMs.  Reduce the throttle to the minimum.

STEP 7.  REMOVE GLOW DRIVER.  Remove the Glow driver.

STEP 8.  POSITION FOR TAKEOFF.  Position the plane for a taxi and take off.

One step I didn’t talk about is engine idle adjustment.  These engines can be adjusted if needed, but this one comes preset so that it doesn’t need any adjustments.

Glow vs. Electric:  What's Different?

Here are some other things that I found are different than electric aircraft:

1. Receiver pack and servo power.  Electric planes have an ESC that typically has a BEC or battery eliminator circuit that powers your servos.  Glow planes usually just have a Nicad or NiMH battery pack to directly power your receiver.  You can also use a BEC with a LIPo battery if you wish.

   

2. Deadstick Landings.  Deadstick Landings are what happens when your engine quits running or runs out of fuel.  Your prop becomes a “dead stick” and you are forced to try to land the plane as soon as possible without any engine power.  While this can happen with electrics, it seems more common with combustion engines.
3. Throttle servo.  You have an additional servo that is used to control the throttle.  The servo horn is connected to a long push rod that is connected to the throttle on the engine.  Moving the servo opens and closes the carburetor.  When the engine first starts, the carburetor is mostly closed, which lets less air and causes the engine to run slowly.  If you open throttle, the carburetor opens, lets more air in and causes the engine to run faster.
4. Throttle cut.  You want a way to quickly close the carburetor fully to stop the engine, in case of an emergency or just to stop the engine after you land the plane.  This is done with a throttle cut, which simply means you lower the throttle low enough that it causes the carburetor to close fully.  Usually you can program you radio to do this for you or you can just lower the throttle trim all the way down.
5. Cleaning off the plane.  The muffler spits out all kinds of oil and exhaust.  You’ll want to clean it off your plane.  Cleaning it off with Windex, Washer fluid or isopropyl alcohol will work.  Use it with a paper towel, or even better microfiber cloth.
6. Engine mounts.  Engines typically have these mounts that stick off the firewall.  Some are adjustable so you can spread them out for wider engines.  They come in different sizes.  Your engine usually has screws or bolts that attach the engine to the mount.  The engine mount is usually bolted to a plywood firewall with blind nuts on the opposite side.
7. Noise.  Hey these things can make some noise, but that’s what I like about them.  Electrics are generally much quieter.  The muffler chosen can make a difference in the sound.  2 and 4 cycle glow engines sound differently, as do gas engines.
8. Weight – These engines tend to be heavier than equivalent electric motors, but it can be argued that the additional mass can do better in wind.  If you starting out with an engine, I would still recommend flying a simulator and/or with an instructor.  These high wing trainers seem to be very popular and relatively easy to fly, but some of the foam electrics are lighter and easier to repair in the event of a crash.

Do you fly both electric and glow planes?  What are some differences that you can share?  Do you have any advice to offer for an electric pilot wanting to try a glow plane?  Also, how do glow and gasoline powered engines compare?  Post your suggestions below.

Mike