I am new to RCand just finished installing the servos on my PT40. If I turn my transmitter off before I turn the switch on the plane, the servos go crazy going back anf forth. Did I do something wrong or is this normal?

Thanks,

Harry

Turn the plane off BEFORE the transmitter. The servos act crazy like that because the receiver has no signal to read with the transmitter off. You will fry your servos definitely and probably your receiver as well.

P.S: Turning them on, you turn the transmitter on FIRST, then the airplane.

In short: NEVER leave the plane ON with the transmitter OFF.

Thanks a lot. With all the mistakes I made during the construction, I am glad this one did not fry my new radio.

I hope this thing fly. I am crossing my fingers (not my servos)

As long as the wing and fuselage are built straight and there is a minimal of weight it will fly. But PLEASE join a club so a licensed instructor can teach you and do NOT attempt to learn on your own.

Glad to help, any further questions dont hesitate to ask.

Welcome to the RCU forums, Harry!

It seems that this will be your first experience flying RC.

If so, you need experienced help standing next to you.

I could help finding a club or an experienced instructor in you live in my area.

This site has very good information:

http://www.gettingairborne.com

Yeah, with all systems, 72 MHz or 2.4GHz, receiver off first THEN the transmitter.

CGr.

To the contrary of that when it comes to turning on the TX & RX, so TX is turned on first and then the RX.

Ok, I'm going to step in here for a second and make a clarification on this information, because this is how "old wives's tales" and "false information"gets started. Yes, you should turn you transmitter on before you turn on your receiver, and turn the receiver off first and then the transmitter. This is good practice to get into for several reasons. But are you going to "definitely" fry your servos if you accidentally turn then on/off in the wrong order.More than likely no, and 99 times out of 100 nothing will happen that damages your servo. And you are NOT going to fry your receiver in almost any circumstance. The plain truth is it won't do anything at all do the receiver. It will be fine.

Like Isaid, Iam stepping in here so that false rumors don't get started. It's very easy for rumors to get started here in the Beginner's Forum because of the mix of experience pilots/modelers and beginners. Sometimes something is misstated, or misread, and then false information will start circulating here and in the hobby. Heck, that may be where this information came from. And that is why Iam stepping in here so that we can set the record straight.

Here's where the real danger can come from.As stated by Shd3920 there can be no signal being received by your receiver if you turn it on first, and it can actually be picking up stray signals as well. The biggest danger from this is that it can drive the servo to it's full physical limit which can cause some serious damage to YOURPLANE as there may be more travel in the servo than the control surface can handle. This can cause problems because it is possible that it can damage the control surface and that damage may not be visible and you may not see the damage, then when you fly the plane it can cause a loss of control. Or it could out and out break your control surface. And in some circumstances it is possible to physically damage the servo as well, but as Isaid above it is not likely to happen.

In today's 2.4 Ghz spread spectrum radios another good reason to turn the transmitter on first is that sometimes a receiver can lose it's "bind"to the transmitter if it is turned on before the transmitter. While this can and does happen, it doesn't happen often. And it's definitely not a big deal because all of the Spread Spectrum radios on the market have simple procedures for re-binding the receiver to the transmitter, and it can be done in a few seconds. When the receiver is re-bound to the transmitter everything will be fine and you'll be ready to fly with no problems as all. All the programming for that plane in the radio will still be in place and nothing will be lost.

Rest easy, it's extremely hard to "fry"your radio from something as minor as turning on the receiver first. It's a good habit, by all means, to get into so you don't damage your plane as Iexplained above. But it's very very rare that you can destroy the actual radio equipment. Rest easy.

Welcome to RCU and enjoy the greatest hobby out there.

Ken

Wow.. I totally missed that point in the reply. Fry servos and receiver? Not only is it highly unlikely, but darn near non existent. If that was the case, I'm sure the very first thing in the owners manual (not that anyone reads the darned things) would be DO NOT TURN ON THE RECEIVER BEFORE TURNING ON THE TRANSMITTER OR DAMAGE WILL RESULT.

The lawyers would have a grand time with that.

What IS necessary, for the new technology, the 2.4GHz systems that require a "binding connection" between the transmitter and the receiver, given the fact that the transmitter sends a signal that the receiver accepts and then binds to it, is that the transmitter is turned on first. In some circumstances, turning the receiver on first can cause a loss of bind that may require a re-binding process as you would do when you first set the system up. In that case, remember that the transmitter is the master controller.. has all the necessary information for the receiver.

The receiver remembers only the binding process not the data.. end points, expo, mixing.. all that is in the transmitter and, before it is processed by the receiver, there must be a binding process. If you turn the RX off, that is lost and you have to re-bind or "reset" the connection.

So, if the RX is turned on first, the binding process may not occur. If this is the case, just turn everything off and start over again by turning on the transmitter THEN the receiver. A short time later, the servos will probably go to the point that the transmitter has directed them to go and you're ready to go.

No, the process is more likely to prevent over extending servos to the point where the control surface physical limits will be exceeded thus breaking something like tearing or breaking a hinge, or bending linkage or somethingl like that. The receiver? What frys receivers is overvoltage.. like using an 11.1 LiPo battery pack, without regulation, on a receiver that is designed for 4 to 8 volts DC.. meaning 4 or 5 cell NiMh or NiCd's or 3 cell LiFe packs.. or, as said, LiPo packs with a regulator.

Thanks, Ken, for setting everyone straight.

CGr.

Whatever, it is what I WAS TOLD. Did not intentional give false info. Sorry I replied at all.

shd3920,
To the contrary, we are happy you replied.
That action caused a misconception for you and many others to be cleared up.
This is a good thread because it taught. You helped make it that way.
Thanks,
KW_Counter

Glad I could help . . . by being embarrassed!!!

Well, as they say, "necessity is the mother of invention". No one knows what the answer is until the question is asked.

You know the old addage, "If the tree falls in the woods and there is no-one there to hear it, did it make any noise?"

My oh my.. aren't we just full of proverbs and sayings this morning!!!

CGr

Well, thanks for all the technical information. This forum is sure very good.
I had no idea that a simple question from a dummy could generate so much information.

If the plane flies and land (the most important step), I will send a picture of the proud dummy.

Harry
</p>

Dummy? I think not!!!

CGr.

There is also something here that has not been mentioned and as a 30+ year RC'er I am almost embarrassed to reveal. If your receiver battery pack is low, you would see what you are describing. I was setting up a plane not too long ago and turned on the transmitter and receiver and then set up the servo travel........noting that the throttle servo was adjusted correctly. I turned off the transmitter and the throttle servo went to full open without any input. I turned the transmitter back on and the servo would not center but would jitter and then move back and forth and then make up it's own mind where it wanted to go. Then the rudder started jittering and also the elevator. I thought my whole system had lost it's mind. Then the light came on and I attached a voltage checker to the receiver pack which had been in a drawer for awhile and sure enough my 6V pack had sunk to around 3.4V. I charged it up and everything is fine. If your radio system is new, your batteries could be low so make sure you put a good charge on them and re-check your set-up.

Cheers,
Andy

Yeah, I did that too, on an electric..new build. Only problem with mine was the throttle was reversed.. 5 stiches later.... [:@]

CGr.