Nano CPx Throttle Hold Problem

[hookedonflying]

I'm wondering if anyone else has had this problem with their Nano. I recently crashed, but noticed that the throttle didn't cut immediately. I ended up breaking one of the blade grips. I thought it was "operator error" at first, but now it has happened 2 times since. Today, as it was flopping around on the ground, I went to pick it up and immediately it stopped when I touched it. Now I am certain that it is not operator error. I checked my throttle hold switch after I picked the heli up and it was fully in the hold position.

One more thought. It is an intermittent problem, but I think it may happen when I hit the kill switch after the heli has already hit the ground. Anyway, this issue could end up costing me a lot of money if it keeps up, especially if it is my transmitter and it happens with my 450. Any thoughts?

Spektrum DX7s Transmitter

-hookedonflying

[GoatRider]

Was it at low-voltage-cutoff? That has a slow ramp-down, that ignores the throttle channel. So what usually happens is it starts reducing power, you crash because of it, but then doesn't let you cut the throttle the rest of the way, it wants to keep doing it on it's own schedule.

You should try not to let the batteries get to LVC. It's reduces their life, and can also sometimes make the 3-in-1 board "forget" it's binding.

The solution is to use the timer feature of your transmitter. Set the timer to "throttle out", at 25%, and a minute or two less than when it would normally hit LVC. That last minute is pretty boring anyways, since it's underpowered.

[hookedonflying]

Originally Posted by GoatRider

Was it at low-voltage-cutoff? That has a slow ramp-down, that ignores the throttle channel. So what usually happens is it starts reducing power, you crash because of it, but then doesn't let you cut the throttle the rest of the way, it wants to keep doing it on it's own schedule.

You should try not to let the batteries get to LVC. It's reduces their life, and can also sometimes make the 3-in-1 board "forget" it's binding.

The solution is to use the timer feature of your transmitter. Set the timer to "throttle out", at 25%, and a minute or two less than when it would normally hit LVC. That last minute is pretty boring anyways, since it's underpowered.

I never run my batteries below about 7.78, so that's not it. Thanks so much for the reply, though. I've broken 2 blade grips in 2 days now. Ugh! Now I'm down, because I will upgrade to aluminum grips for strength.

[Smok1n]

7.78? You probably meant 3.78v. Anyway, strange problem with TH not working as expected. So, at 3.78v you're not hitting LVC. Have you tried rebinding with the TX?

[Wheelhaus]

Can you replicate the condition on a bench? What is your throttle hold %? When you hit TH, does the motor stay at full speed or does it slow at all?

It's possible you may need to lower the TH %, or increase negative throttle travel a click or two. The on-board ESC may not be registering the TH % as being low enough.

[hookedonflying]

Originally Posted by Smok1n

7.78? You probably meant 3.78v. Anyway, strange problem with TH not working as expected. So, at 3.78v you're not hitting LVC. Have you tried rebinding with the TX?

I did try rebinding the TX, after the first time. Yes, I did mean 3.78v. My bad.

Originally Posted by Wheelhaus

Can you replicate the condition on a bench? What is your throttle hold %? When you hit TH, does the motor stay at full speed or does it slow at all?

It's possible you may need to lower the TH %, or increase negative throttle travel a click or two. The on-board ESC may not be registering the TH % as being low enough.

It seems to cut out completely if I do it on the bench. I have it set at 0%. I will try negative. That may work. It seems to only happen if I cut out slightly too late (just after contact). For that reason, I'm not sure how fast the motor is running, as it is only flopping around like a fish.

I think as I grow more confident in my skills to "save it", I am slower to hit the kill switch. I have to get back to killing it when it's 3' off the ground. lol

[Bhujang]

What's the setting in the tx for the TH is it zero? Or 10%? Try using a negative -10 maybe that will work... Maybe try a fresh channel on the tx...

[soulbender]

Someone here gave a good explanation why it's supposed to be at 10% and not 0% but I cant remember and couldn't find the post.

I have experienced the same sort of problem you have. It will happen after the 3 minute mark usually. But more often right before LVC. Never figured out why.

[CAMOMAN]

When mine was new it also wouldn't shut off with TH never figured it out but after putting in new main motor because OEM wore out and upgrading to the 35C cells it hasn't happened yet just saying,,,,,,

[hookedonflying]

I'm really wondering just how many crashes this thing can take. I did put padding under the canopy by the edges of the board to protect it, but I really crash it regularly. Sometimes it's hard to tell it it's momentum or if the TH doesn't cut the motor right away. I know there isn't much momentum on these little light blades, though, so I really think it's more likely a TH problem. I have it at -10% now. Doesn't seem to have made a difference, but still running test "crashes". lol

[GoatRider]

It's not how many crashes it can take. It's how likely that "critical hit" is. I've heard of someone breaking the board on one light tap on the first flight. Damn that must have hurt. But I went over 100 flights, with more than one good crash per flight, before I had a board problem. It probably also depends on how well the board was soldered in the first place.

[hookedonflying]

Well, this bird has plenty of crashes. I've probably got over 100 flights on it easily with at least 5 crashes per flight. Now, not all of them are really bad crashes, mind you, but they are still crashes.

Just took a flight. Here are some troubling observations:
* Crashed very lightly (upright) and cut power before it hit the ground. Motor stopped, but then reved up for about a second and cut out. TH was engaged. Luckily, the blades were not inhibited, so no harm.
* On crashes, power sometimes cuts out momentarily, then engages again. I'm talking power to the board itself. Blue light out, then back on. It's like it's resetting. Once it went out for a good 3 or 4 seconds. I thought at first it was a safety cut to the power on crashes, but now I'm not sure.

Thoughts?

[alcangie]

i have the same problem with my 310 flights/many crashes brushless nano. But I never took the time to figure it out so I can't help you. I just tought that this is maybe normal, since i don't really know what happens in the electronics when the motor stops when you hit the ground.

[wulfrun]

This is intriguing. Up to yet, I've not crashed my Nano in a way that tests the idea but I suspect Blade didn't implement the throttle-hold idea well. On my mSR and mSR X the throttle-hold does not kill the throttle immediately if the motor is still under load, i.e. if you're a split-second late and the model's hit before you flip the switch. Looks like the Nano (and maybe the mCP X) might suffer from the same problem...

[hookedonflying]

Very interesting, wulfrun. That seems to be exactly what my nano is doing. If I am a split second late, thinking I can still save it, then it doesn't seem to cut out right away. I really didn't notice this at first, but I think I was totally paranoid and hit the kill switch way earlier. I guess I will need to learn to "give up" earlier. lol

[GoatRider]

Originally Posted by hookedonflying

Very interesting, wulfrun. That seems to be exactly what my nano is doing. If I am a split second late, thinking I can still save it, then it doesn't seem to cut out right away. I really didn't notice this at first, but I think I was totally paranoid and hit the kill switch way earlier. I guess I will need to learn to "give up" earlier. lol

I've actually been giving up later. I had a few near misses where I hit TH, and it landed on it's feet. I coulda saved it! Now I've found if I land on it's side, I can usually bump the throttle and get it to stand up. For some reason it always ends up nose-in, so I've had to learn to take off that way. It's probably hard on the motor, but it beats the walk-of-shame®

[hookedonflying]

Well, I don't normally have the walk of shame if I'm in my basement. lol If I'm at a gym I may try that to avoid having to make the "walk" soooo many times.

[hookedonflying]

Okay, here's the latest update. Really acting weird and taking long time to "rebind" after crash. Black wire just broke off at the battery connector and it looks like the white wire is not very strong. I'll post an update as soon as I figure out how to rewire this battery connector. Do I have to get a new connector?

[hookedonflying]

Okay, after I rewired the plug the latest problems with the electronics cutting out after crash are totally gone. Funny how these things actually need electric to run. lol

I don't have an update on the TH problem, because that hasn't happened yet after the rewire. I suspect it is just as mentioned earlier... normal if you don't cut the power BEFORE you hit.

[hookedonflying]

Definitely have to cut power before it hits something. I was inverted and ran into a table, hit TH as soon as I could, but the heli hit the floor and continued to spin in an inverted position. It was probably 2 seconds or so. It finally cut out, I presume because it finally sensed no load. Ugh!