Throttle hold hazard

[Marco1]

I've observed that if you power up the 400 with throttle hold on and the flight mode switch at the normal position and the throttle stick at low, the rotors will spin once you take it off throttle hold.

Since this is not what you would expect, I think this is a hazard. Anyone else observed the same?

My new mantra - always power up in Normal mode. Everything works as expected.

[BKF]

This seems to be normal. I don't think it should happen, but I've got one of the first run B400s and it does this on mine.

I just make sure I always have TH off when plugging in a battery. Wish I could keep it on, but the ESC/RX won't initialize if the transmitter's throttle is anything other than 0... so I guess it's ok.

[Marco1]

I need ping Horizon on this. As early adopters we need to spread the word about such features.

It would be nice if Horizon included documentation on their ESC with the kit.

So do you like it otherwise?

[Heli Jim]

The thing to do is set your motor trim tab low enough that the rotors DON'T spin with
the stick all the way down. That way, you can turn on the TX, then turn the throttle hold
ON and then power up the heli

when you are ready to fly, then turn off the TH and the heli should still sit there without the
rotors turning.

That is what throttle hold is all about.......it's like the safety switch.

[int2str]

This is completely normal IMHO. You should not initialize the ESC when in throttle hold. Just leave the stick at the bottom.

When you power up the ESC, it takes the current throttle position as baseline "bottom". This is your 0-throttle. So it's important to power up with the stick at the bottom and no throttle hold.

Throttle hold pulls the throttle curve into the negative. As in, it goes lower than the bottom end-point just for safety reasons to make sure the ESC completely understands we want it off. So if you initialize the ESC with hold on, you will see the behavior that you are, since there is a slight difference in throttle positions between the two modes.

Even with my 450, my startup procedure is this:
1) Stick bottom, NO throttle hold
2) Power up heli and wait for ESC initialized beeps (staying clear of rotors as best as possible)
3) Engage throttle hold and walk heli to field

The DX6i even has a throttle hold power-on beep to make sure you're not in throttle hold when you turn on the TX.

I've never had any unwanted spool up at all using the steps above.

[LockMD]

The thing to do is set your motor trim tab low enough that the rotors DON'T spin with
the stick all the way down. That way, you can turn on the TX, then turn the throttle hold
ON and then power up the heli

when you are ready to fly, then turn off the TH and the heli should still sit there without the
rotors turning.

That is what throttle hold is all about.......it's like the safety switch.


Exactly. I turn on tx (throttle stick and trim at 0) turn on throttle hold plug heli in wait for initialization set it down move away flip throttle hold off nothing happens until I raise the trim and I fly away......and reverse after landing I switch throttle hold on before picking it up and leave it on until I turn off the tx.

[randerson07]

Even with my 450, my startup procedure is this:
1) Stick bottom, NO throttle hold
2) Power up heli and wait for ESC initialized beeps (staying clear of rotors as best as possible)
3) Engage throttle hold and walk heli to field

The DX6i even has a throttle hold power-on beep to make sure you're not in throttle hold when you turn on the TX.

I've never had any unwanted spool up at all using the steps above.

I fallow these same steps and I have witnessed what your talking about on my B400. The ESC in my Mini Titan will not initialize when throttle hold is on. It will beep but giving throttle once you turn throttle hold off does nothing.

[sd0]

It even says in the B400 instruction manual not to initialize the ESC while throttle hold is on, and if you do you should disconnect the battery, turn off throttle hold and re-initialize.

[bassplayinDude]

My B400 acts the same way if I initialize the heli with throttle hold on on the Tx. Once I take off throttle hold, the motor spools up. Now I power up Tx, power up heli, then turn on throttle hold. Haven't had any problems since I started doing it this way.

[widower]

In fact, if throttle hold is on when you turn the transmitter on, the transmitter will beep continuously until you turn off throttle hold. This has save me a bunch.

I haven't tried it because what's mentioned here hasn't caught me yet, but I expect that you could fix this problem by setting throt hold to say 2%. This would cause the esc to initialize at 2% throttle, and when hold is turned off, 0 throt stick should still provide a value less than 2%.

[Heli Jim]

Holy cats!!

I have always turned on the TX and then turned on the TH right away.

Then turned on the heli. I did it this way with my CP Pro w/DX7 radio, too.

I never realized that I could have problems from doing that. I'll stop RIGHT NOW!!

thanks for this info.

[LockMD]

Holy cats!!

I have always turned on the TX and then turned on the TH right away.

Then turned on the heli. I did it this way with my CP Pro w/DX7 radio, too.

I never realized that I could have problems from doing that. I'll stop RIGHT NOW!!

thanks for this info.


I've always done it that way and will continue to do so. I think the OP did not have his throttle trim at 0 or low is all....

[The_Russian]

I just ran my throttle trim to idle. That way, I turn off the throttle hold and the rotor does not spin up.

[JimLerch]

Just change your freaking throttle hold "throttle curve" to make it have the same output as non-throttle hold, normal mode, collective all the way down.

Verify you got it right by going to the servo monitor window and switching between throttle hold and normal mode with collective all the way down. If the little indicator on the throttle hold channel doesn't move when you enter throttle hold, there you go!

Now you can initialize the bird with throttle hold engaged and not have to worry about hitting the collective control while reaching for the remote.

If you REALLY want to verify the throttle output, plug a servo into the throttle channel and switch between throttle hold and normal mode, it shouldn't move (there is nothing magic about the throttle channel, it just like any other servo channel)

Of course, I might be a fool and stand to be corrected. But so far so good :smokin: