Why does DX7 not allow starting in throttle-hold?

[kaon]

If throttle-hold is ON while you turn on the DX7 tx, it will beep and flash: "WARNING T.HOLD"
It seems to be cleared only by switching off the t-hold, then you can put it back on.

What's the rationale behind this design?

If it only serves as a reminder, (so that the user doesn't feel puzzled as to why his motor isn't moving), then it is sufficient to just beep and flash for a few seconds, and go into normal functionality.
But it seems to be designed to force the user to transmit a throttle-unheld signal at least for a short period of time. Why?

[Skarn]

I've wondered this myself...as well as why it won't let me start in ST1 or 2 as well....

But it's really not a big deal....simply let it arm, then put TH back on then plug in battery.

Skarn

[saltyzoo]

Originally Posted by Skarn

I've wondered this myself...as well as why it won't let me start in ST1 or 2 as well....

But it's really not a big deal....simply let it arm, then put TH back on then plug in battery.

Skarn

I can understand forcing the mode so you don't screw up, but if it forces throttle hold, it SHOULD force it to be ON not off.

[fogger]

someone should pose this questopn to jr; I'm curious as to the rationalle also. Seems backwards to me.

-Fog

[Stinky Igloo]

Probably because if your t-hold throttle curve is even 1% higher than your F modes curves as soon as you switch it off it will spool up in your face.

[Finless]

I think it was just a "general" idea that they dont want you powering up when the radio is not in the NORMAL condition and thus reminds you to check your switches. Agree is doesnt make sense to do it in hold but they probably just wrote the code to check for any condition switch not in normal and beep. Just my opinion as to why...

Bob

[HeliEdje]

Hi, I read this thread. I have a Futaba T12FG. Had a F6EX to earlier. They both have the same issue.
They can also only been switched on with the TH switch OFF and with the Flightmode Switch on NORMAL

There must be some general filosophy behind it

[Skarn]

Originally Posted by saltyzoo

I can understand forcing the mode so you don't screw up, but if it forces throttle hold, it SHOULD force it to be ON not off.

But if TH is ON, then the mode shouldn't matter either. I always plug in my battery with idle 1 selected and TH ON.

Skarn

[saltyzoo]

Originally Posted by Skarn

But if TH is ON, then the mode shouldn't matter either. I always plug in my battery with idle 1 selected and TH ON.

Skarn

But then you could come out of throttle hold with your throttle off but have the blades spinning 100%. Bad idea. I think it's good that it forces you to normal mode.

[fogger]

Many of us don't even use normal mode. I don't bother with it because the speed controllers I have both have good soft starts. My helis get plugged in with tx in idle up 2 and TH on. The TH switch is the more appropriate safety on the tx, not the throttle stick being down. So again forcing the heli version of this radio to be started with TH ON (and flight mode in whatever) would be more logical for safety IMO.

-Fog

[saltyzoo]

Originally Posted by fogger

Many of us don't even use normal mode. I don't bother with it because the speed controllers I have both have good soft starts. My helis get plugged in with tx in idle up 2 and TH on. The TH switch is the more appropriate safety on the tx, not the throttle stick being down. So again forcing the heli version of this radio to be started with TH ON (and flight mode in whatever) would be more logical for safety IMO.

-Fog

I have to disagree with you. Using normal mode and forcing throttle down, normal mode, throttle hold on provides a double layer of security.

If you bump the throttle hold switch in idle up mode you are in trouble. If you bump it in normal mode you are fine.

Personally, I would never carry my transmitter around unless it was in normal, low throttle, throttle hold.

[fogger]

I wouldn't say you were in trouble if you hit the switch, because as I said I have nice soft starts. It takes 20-30 seconds for my 500's to spool up; it's not instant on-full-speed. I'd have plenty of time to turn the switch back off. But obviously you should set it up the way you are comfortable. I'd at least like the option to change the switch warnings to my own preference for the way I use the radio...

-Fog

[rockjock3]

Originally Posted by Skarn

I've wondered this myself...as well as why it won't let me start in ST1 or 2 as well....

But it's really not a big deal....simply let it arm, then put TH back on then plug in battery.

Skarn

Yea, that doesn't make sense. I don't think it is blanket checking switches and beeping if they aren't in standard because when I first set my radio up and got the T.Hold warning I reversed the operation of the TH switch and still got the T.Hold warning whenever I turned the radio on and had TH armed (as it should be). I think this is somebody programming code that jacked up.

[Skarn]

Originally Posted by saltyzoo

But then you could come out of throttle hold with your throttle off but have the blades spinning 100%. Bad idea. I think it's good that it forces you to normal mode.

Nope, I have soft start enabled on my ESC.....I never use normal mode. A lot of us do this as fogger points out....it's just as safe as being in normal mode, but this way I wont forget to flip to idle 1 prior to taking off and going inverted...

Skarn

[saltyzoo]

Man, I just don't get that. And it most certainly is not as safe. With normal mode you have a double safety. You have only one. Two safeties = safer than one safety.

Let's say I trip, the transmitter slips out of my hand and I bump the throttle hold. By the time I get up and get it under control, the blades are spinning wildly. I'm just not that trusting that nothing will go wrong.

What if I drop the transmitter, hit the switch, and it lands under the heli..... go ahead and reach for it to turn it off, it's only soft start.....

[owde]

Maybe they thought it was safer for people learning, early on the learning curve. Surely someone uses and tests them or glances at the code before they go into full production.

[Skarn]

Originally Posted by saltyzoo

Man, I just don't get that. And it most certainly is not as safe. With normal mode you have a double safety. You have only one. Two safeties = safer than one safety.

Let's say I trip, the transmitter slips out of my hand and I bump the throttle hold. By the time I get up and get it under control, the blades are spinning wildly. I'm just not that trusting that nothing will go wrong.

What if I drop the transmitter, hit the switch, and it lands under the heli..... go ahead and reach for it to turn it off, it's only soft start.....

No, it's a double safety! Soft start and throttle hold!

Ok any scenario is possible.....

Lets say I trip, the transmitter goes flying up in the air, comes down hits me on my head knocks me unconsious....lands in the water and starts sending out all sorts of random signals...meanwhile the heli takes off like a bat out of hell randomly hitting all small children in the area....

Come on man!

You scenario wouldn't happen with the way I do things anyway. I'm not holding my transmitter when I plug in my heli. I have the transmitter on the ground...so the switch will not "accidentally" be hit nor will I drop it! So actuall it's a triple safety since the radio switches cannot be accidentally flipped since I'm not touching it. Like I said, many a heli pilot flies this way.

Skarn

[Finless]

Hehehe... OK I will throw in my argument and how I take off.
I do not put the heli into idle up and flip out of hold. WHY you ask? Safety and checking out the heli first before going to idle up!

I take off in normal and get the heli in a hover... I have a much lower head speed in normal so to me this is safer. Then once in the hover, I check it out (no vibrations, blades tracking, nothing looking like it's going to fall off, etc) and if OK then go into idle up. Once again now with the higher head speed, a quick look to see heli is fine and then I go fly.

Now is this really needed if you have a good soft start and just go into idle up? Well probably not but to me it just seems safer to have control of the throttle as your spooling up and a lower head speed in the first hover.

Bob

[rockjock3]

Originally Posted by Finless

Hehehe... OK I will throw in my argument and how I take off.
I do not put the heli into idle up and flip out of hold. WHY you ask? Safety and checking out the heli first before going to idle up!

I take off in normal and get the heli in a hover... I have a much lower head speed in normal so to me this is safer. Then once in the hover, I check it out (no vibrations, blades tracking, nothing looking like it's going to fall off, etc) and if OK then go into idle up. Once again now with the higher head speed, a quick look to see heli is fine and then I go fly.

Now is this really needed if you have a good soft start and just go into idle up? Well probably not but to me it just seems safer to have control of the throttle as your spooling up and a lower head speed in the first hover.

Bob

Bob,

Thanks for the input. I have learned a lot from your participation in the boards and thanks for that as well.

I see your point with the flight mode switch and can see a need for that alarm. It only alarms if you are not set in normal mode. Cool deal. My big issue and it seems many of the ones in this thread (with Horizon Hobby, not you) is that it doesn't seem to alarm sensibly for the TH switch. It alarms if you have your TH on and forces you to turn it off to arm/activate/boot the radio. So my turn on sequence for my radio is Flight mode normal, TH off, turn the radio on then turn TH on. This doesn't make any sense at all to me as it forces you to turn off one of your safety features to turn the radio on. Now if I was newer than I am it would be very easy to have your TH off when you turn your radio on and then go hook up your battery with your radio transmitting throttle to the heli. Now if the alarm came on when your TH was off to force you to turn it on before the radio would come up that would make sense.

Jay

[rockjock3]

BTW

I sent an email to Horizon telling the Bob is starting all sorts of crap over their radios .

Only kidding. I did email them though about this and referenced the thread so they could respond. I explained how I see the issue and if they had a reasoning behind the TH alarm or not. Hopefully after the long weekend somebody will respond. I have always had quick responses from them and great help, so we will see.