Turn on TX or RX first
 

I did some searching and did not find anything that seems to help with my question.
I have had some people tell me that I should always turn on my TX (Spektrum DX6i) before I connect my battery to my receiver (AR600).
My DX6i manual says it does not matter which order I use.
The reason for my question is that I have heard about people who accidently advanced the throttle while getting their plane ready / positioned. If they had delayed turning on the TX they would not have had the resulting damage / injury because of the unexpected prop rotation.????

A receiver not receiving from a TX has far less predictability than one that is... is much riskier with FM than 2.4GHz, but it's a good habit to turn on the TX first.

When using a TX with memory, there would be the risk of turning on the TX while set to the wrong model, with unpredictable results.

Also, if you turn on the TX first, you can focus on it and make sure all the controls are in the right place. If you turn on the model first you may be less inclined to check all the settings.

Me, TX first, every time, always.

It doesn't seem to be a problem with Spektrum gear but with others, especially old FM sets, arming the motor without the Tx on can cause the motor to run. And even though Spectrum gear does not seem to do that there are some who have reported incidents and people from spectrum still advise always turning the Tx on first.

Accepted practice is to ALWAYS turn on the transmitter first and make sure that the
throttle is all the say down. Then plug in the receiver. When you finish the flight, do it
in reverse order---unplug the receiver and then turn off the transmitter.

With the Spektrum line of 2.4 Ghz radios, and Spektrums "Model Match" feature, the receiver won't respond if it doesn't find the transmitter turned on, and on the right model.

But with the wide variety of ESCs out there from both the USA (Castle Creations) and China, one might be able to find a combination that could cause a problem. As for me, running motors of over one KW, it's not wise to take chances.

So, another vote for turning on the transmitter first, then the receiver.

And of course at the other end of the scale if you turn the teeny UM models on with no TX on the RX goes into bind mode and you have rebind to your TX all over again.

So once again TX first is a good habit to get into even if it's not strictly necessary in some cases :).

Steve

Hi, had a few UMs and if you turn on the RX without the TX being powered the plane sits there flashing away waiting to bind, however you shouldnt need to do a rebind, if you turn on the TX the RX will usually find it and will just operate normally.

On the original point of TX RX switching routines - yes the Spektrum system safeguards against the accidental start up issue ( I use Spektrum on all of my planes) but personally I agree with the concensus - Power up the TX before the RX on start up and power down the RX before powering down the TX at the end of the flight.

A slightly different issue but one you need to be VERY careful about:
I was setting up an old plane on a new TX that I had only just acquired, the control surfaces were responding incorrectly so I went into the servo reversing setup on the TX. Purely as a result of being unfamiliar with the TX I scrolled one step too far in the menu and by accident reversed the throttle channel which of course resulted in WOT!:eek: Fortunately it only cost me a new prop and no fingers!:blah:

I have been told (right or wrong) that if you plug in your battery first (activate Rx), the Rx may pick up some random radio signals which could inadvertantly activate the motor and/or the control surfaces.

Been there done that - VERY frightening!!!:eek:

I'm late to the party, but tx 1st and then the rcvr!

I turn my tx on, check for correct plane, check the sticks and lay it down, walk away (couple of feet) then hook up the battery on the plane. I then walk AWAY from the plane, pick up the tx and hook up the lanyard while I am safely away from the plane. Should I bump a stick the plane is a few feet away and can't hit me. I suppose I'd better add this too ... I make sure the plane cannot go in the direction of people or property also. ;)

That was a common problem with the 72 Mhz radios. Much less likely with the quality 2.4 Ghz systems now out there. Even still, with the power levels we are finding on these electric models, not a good idea to take chances.

One of our club members tangled with the prop of a little Ultra Fun Jet last summer. He's OK, but his hand got sliced up a bit. These little Fun Jets have motors that pull some 40 Amps on a 3 cell LiPo. That's in the area of 1/2 horsepower.

Well it certainly looks like the overwhelming position is TX on first and off last.
I will develop an appropriate habit to ensure that I can not inadvertently hit the throttle once the RX battery is hooked up.

Thanks for all of your responses.:)

If you are worried about hitting the throttle inadvertently just keep a rubber band with your tx, run it around the handle on the back, under the bottom on the Tx and around the throttle stick. Then even if you accidentally bump it it will go back down right away. Then, when you are ready to go, just release the band and your off.

Something I would like to second is not getting near the plane while holding the TX or having it dangling from a strap.

Put the TX down, preferably where someone can't muck with it. This will greatly reduce the chances of hitting the throttle.

Correct me if I'm wrong. I always have the throttle on wide open when I attach the battery. The ecs won't arm until I bring it down to low throttle. When I plug them in at low throttle it seams that I don't get full throttle when I push the stick forward. Anyone else have these issues????

Nope Big Johnny - that's the recommended procedure for Castle Creations. Been doing it that way for a long time, never a problem

DX7 gear/throttle interlock
 

Another option, don't know if the DX6i has this ability, but the DX7 has the ability to mix the throttle with the gear switch. With the gear switch "down", the throttle is dead. With the gear switch "up", the throttle is active. This is not original with kyleservicetech, I found it in the internet.

Electric Flight Safety

Ideally every electric aircraft you have should be equipped with an arming device on the craft itself
(either and ESC switch or power interrupter plug) as well as having a throttle cut switch on your
transmitter. Since electric motors can startup unexpectedly and inflict a lot of painful damage the
double precaution can avoid some nasty injuries. Although an arming switch/plug on the aircraft ought
to be sufficient on its own there are times when it is armed with the intention of flying but something
distracts you and the aircraft is now vulnerable to a careless jog of the throttle lever, the transmitter
becomes your last line of defense.
I have implemented a transmitter disable switch for all my aircraft (helis as well as conventional planes)
this way the process is second nature to me. The idea is that whenever the aircraft is not expected to fly
the transmitter switch is in the disable position. The moment before takeoff I switch it to enable, fly as
required then the moment the aircraft touches down and I have completed taxiing it I always click the
switch to disabled.
Some of the more advanced transmitters have the ability to set a throttle cut switch up within their
menus however others need a little work to make it happen. Below I give the process needed to set up a
Spektrum DX7, it is likely this technique can be used on other transmitters, it is well worth doing and if
you are still unsure how try looking online for your particular transmitter.
In my case I use the switch at the top right hand corner of the transmitter as the kill switch, this seems
to be a standard as far as I can tell, the DX7 does have a label saying HOLD for this switch (as well as
Ruder D/R).

Setup Process For the Spektrum DX7 Transmitter:

From your selected plane setup menu (pressing scroll and select simultaneously) move to one of the
mixing channels (kyleservicetech used Mix 3, for mixing with the gear switch).
Select source and destination for the mix to be THRO (short for throttle), the display should show:
THRO -> THRO
Now move to the rate section and set both sections to -100% (you will be able to set one of them with
the throttle stick down and the other with it up).
Move to the SW: section and set it to MIX
Move to the OFFSET section and set it to -100%.
If you toggle the gear switch you should see the text to the right of the THRO -> THRO change from OFF
to ON, when this reads ON the throttle is disabled (this should be with the switch pulled toward you).

[PROG.MIX1]

THRO->THRO ON RATE: -100%-100%

>SW:MIX

OFFSET:-100

Carefully try this out with your model turned on, with the switch toward you it should not be possible to
start the motor at all (even helis should be disabled despite the position of the idle up switch). And, as
always, check all remaining transmitter functions for both direction and unexpected operations. In case
something else got changed by accident.
All that remains now is to cultivate the habit of ensuring the switch is in the disabled position whenever
you pick up the aircraft and whenever it is not on the flying field.

Last but not least, be sure to set the throttle trim to center, or zero off set. If this is not done with the DX7, throwing the gear switch can change the throttle setting at the idle speed of the ESC.

DennyV,

This sounds most interesting. I'll try this on my DX6i. If I can get it to work I'll post a description here.

If you can make it work on your DX6i, the other wattflyer readers might really appreciate a procedure on exactly how you set it up, step by step!

you can't slave the throttle on the dx6i, however if you have some basic soldering skills you can do what i did. change the throttle cut button to a switch, then enable the throttle cut function in the programming. flip the switch and you can't throttle up accidentally. this also means you don't take up a switch and mix.

You know, you have it when you are in Helicopter mode on the DX6i---you would
think it would be available for airplanes, too. Maybe Spektrum will do some kind
of software update or something and make this available.