CGRetired

My Feedback: (1)

I was just reading my Email this morning and found one from Tower Hobbies that was show-casing the new Hobbico Electri-Star trainer. It is said to be the easiest, cleanest, quiet, economical, and so on. All this is true.

There is always a 'BUT' statement when one of us brings up a subject like this. In my case, there is one, and I hope that you understand where I come from with this.

As with most vetrans to the RC hobby and sport already realize, there is an inherent danger with all types of RC aircraft, with the exception of gliders that don't have power. Electrics and fuel powered airplanes have a rotating propellor that can and will do some damage to our body parts. Some of it can and will be rather severe. With fuel, though, once something gets in the way of the prop, well, it will do it's damage and in most cases, just stop the rotation of the engine and thus the continued damage by that rotating razor blade will cease.

With electrics, however, that's not the case. Most new people must understand, and those that do the training with these new electric trainers that are becoming more and more available, these things will continue to turn until the source of the electricity is removed or the throttle is backed down to idle or stop. Many of our new transmitters, (thinking of the new DX7 for instance) have a built in system to prevent the motor from going to full throttle upon start-up. Many ESC's won't go at all until a certain process is followed, ie move the throttle to full, till it beeps, back to idle till it beeps again.. and so on.. which is good (just an example here.. most do something, if not what I described).

My point here is that instructors MUST take the lead in making sure that their students are aware of the inherent dangers, with both fuel and electrics and how to avoid injury to themselves or others nearby.

My Airtronics RD6000 and RD8000 for instance, (and I am sure most if not all of the other computerized radio's do this) will not allow the TX to transmit until the throttle is pulled to the minimum low setting. My Airtronics has in bold letters TH-HI in the display with a beeping sound if I have the throttle arm anywhere but in the idle position. Students must be made aware of this capability and taught, reminded, whatever, to make sure that their throttle setting is at idle.

Of course, there is always the chance that a new plane could have the throttle reversed, or not have had the ESC set up properly to prevent rotation of the prop upon connecting the battery, and so on. All this is possible and all of you instructor qualified people know this, and of course, Murphy said it best that "anything that can go wrong will go wrong".

Make sure that your students are aware of the possibility of injury with both fuel and electric powered trainers (aircraft of any type for that matter), and especially aware of the potential for electrics to do more damage than fuel powered could. We must remember that with a fuel engine, at least if it is at idle, we can hear it. With electrics, if the battery is connected, and the plane is ready to fly, the prop may or may not be turning. It is easy to forget that a simple push of the throttle will start that motor turning and could injure someone that is in front of that plane.

I recall my instructor telling me to get away from the front of his new Tiger II Electric conversion. No one really knows if it is ready to turn or not. Should he or someone accidentally bump the transmitter and that throttle go to full, and I am in directly in front of it, well, there goes another visit to the Emergency Room and another 5 or 10 stiches.. if not worse. Hey, a lot of us have stiches to prove that these things can.. and will.. bite us if given the opportunity.

Be careful, I guess is what I am trying to say. Make sure that students are aware of the possibility of injury. Most of all, proper training and supervision during those first few flights will insure a lifetime of fun and enjoyment without injury.

Please don't take this as a lecture, just as a reminder that these things are fun, but a note of caution is always prudent.

DS.

perttime

Better safe than sorry.

The risks of electric are different from the risks of glow or gas power plants. I might argue that with electrics there is less need to routinely put your body parts in the vicinity of the propeller.

I would not dismiss the capability of a glider to cause bodily injuries either. A glider fuselage, or a molded wing in the face at anything from 20 to 100 mph would be no fun at all.

Have fun but do not get careless.

CGRetired

My Feedback: (1)

Oh yes, you are right there.. but my point is that with electrics, just because the prop is not turning does not mean that it is not ready to turn. They are easier to reach out and bite you because it is easier to assume that they are not operating. At least with a fuel, if it is at idle, you can both hear it, and see it which is an inherenet warning not to reach across the prop arc. With an electric, if standing in front of it, and the radio is behind, and the prop is not turning, reaching across and bumping the throttle... and this has happened... can ruin your whole day.

I just want to make both instructors and students aware that there are other dangers, new dangers, associated with electrics and not to spoil the sport for either by having a careless accident.

DS

perttime

Absolutely,
I currently only fly small electrics and, as soon as the battery is connected (and while making the connection), I treat the plane as if the propeller were turning.

I suspect that people who are used to IC power might more easily forget to be careful with an electric that does not have the prop turning.

B.L.E.

Excellent point! The one thing that a glow engine will positively not do is start up by surprise because the throttle was accidently bumped or someone was on your channel. How many of us have gone to do another flight on a glow plane only to discover that we forgot to turn the reciever off the last time we flew it. If someone else is using the frequency, the servos start moving. Do that with an electric and the plane may start flying out of control in the pits. So, the first thing you need to do after landing is unplug the power battery....always!! An armed electric plane needs to be treated like a loaded gun. Treat every gun as if it were loaded.....treat every electric plane as if it were armed. Remove the prop berfore doing servo trim adjustments.
With lipo batteries and brushless motors, electrics have gone way past the ready to fly toys that most of us think of when electrics are mentioned. I'm currently flying a 7.2 pound 66 inch wingspan electric that draws over 1000 watts of power from the battery at full power. 1000 watts = 1.3 horsepower. Unlike piston engines, electric motors can make two or three times their rated horsepower for a brief period in an overload situation, like when a body part is trying to stop the prop.

tessmar

Although I'm just a beginner there are two comments I'd like to make:
First...some electric systems (specifically the Hobbico Superstar and Futaba 4YF I started with) have a characteristic that can create a different risk...not enough power to control the aircraft on takeoff to keep it from becoming a hazard to bystanders. If the power to the receiver is turned on with the throttle on the transmitter at any position other than full off, you will only have throttle from that point up (in other words, the starting point will be the new off position. If this is, for example, with the control halfway up, you will only have half throttle to try and fly). Although you still need to arm the ESC by moving the throttle to full and then to off you only will get the amount of throttle from where it was when you turned the receiver on.

Second my instructor warned me of a risk from priming a fuel engine with the glow starter attached. It is entirely possible for the engine to start, and since the approach to priming was to cover the open throttle with a thumb while manually turning the prop to get fuel to the engine, it would be easy for an arm to be in the way if this unexpectedly occurred.

I guess the real message is that model aircraft are not toys, but more like power tools, and should be treated, if anything, with more respect in recognition of the damage they can do to property and life.

Pete1burn

One of the first things my instructor told me is to never put your hands near a stopped engine to do anything with the glow ignitor attached. Even one turn by hand could ignite the fuel.