Jumping up and down too frequently during hover

[muscleman]

I just got this BL mod up and running. The governor mode of the ESC is TX. I think I probably got too much head speed. The battery is super hot. Hover only needs a tiny bit of positive pitch.

Shall I change the ESC to another mode and then reduce the head speed in some way?

[Russell Harding]

Could be many things...

Is your pitch set properly? Zero at mid-stick and symmetric? It could be over pitched causing the 'little stick to hover'.

What is the head speed? You can always turn the head speed down by lowering the throttle curve (You are using a flat throttle curve, right? You need a flat curve to set the gov to)

You could try a different gov mode, but this is unlikely to fix any of your problems. How fresh are your batteries? Most BL mods are tough on batteries and if they aren't good and new, then you'll likely be stressing them.

What is your motor/esc? What size/type of batteries are recommended for your setup, and do you have them?

Also, double check the mechanics: sloppy servos, jittery servos, loose main shaft / main gear dropped down, etc.

[JonJet]

If you've got gov TX mode, then your throttle curve can set your headspeed...nobody can say you need to run flat out, use whatever works for you

You didn't reveal the setup you are using, so it's hard to diagnose the problem

Motor? Pinion? TC? PC?

Helpful info if you want helpful advice

[muscleman]

http://www.hobbyking.com/hobbyking/s...X_FBL100_.html
http://www.hobbyking.com/hobbyking/s...X_FBL100_.html
http://www.hobbyking.com/hobbyking/s..._100_etc_.html

The above links are my main, tail motors and dual ESC.

The mcpx servos are brand new, bought from Amazon.com yesterday.

The batteries are the following:
http://hobbyking.com/hobbyking/store...ade_mCPx_.html

Regarding the pitch, I inserted the 3 servo arms into the mid hole of the mcpx servo. It is a bit tight, but seems to be ok. I have 65% pitch on my TX. I used a pitch gauge to measure. Positive and negative pitch seems to be around 13 degrees.

Regarding the governor setups, I asked in a separate thread.
https://www.helifreak.com/attachment...0&d=1429028667

I have 65% flat curve for normal mode in TX and 70% for stunt mode as NCCraig suggested. I flipped the switch but it never changes the speed.

NCCraig said:"You don't need to worry about pinion count and motor KV in TX GOV. Those adjustment are only applied in the Setup GOV mode.
Setting the target head speed, pinion tooth count, etc. does nothing unless you set your governor to GOV Setup as I have stated before. There is a Excel spreadsheet in the BLHeli code software that tells you what the head speed is in GOV TX mode associated to different flat throttle inputs. "

But when I change the throttle flat curve, the head speed doesn't change. It seems to be running at the max possible speed and my battery is really hot.

[JonJet]

I recently used very similar BLHeli settings on an mCPX with the exact same components...

I tested every TC setting from 40 to 75 in 5-point increments and heard a definite rpm change at each step

Using 75 pos/neg pitch travel, it was very manageable with lots of punch when called for using Oversky's 300 mAh 45C

Seems the variant is the middle servo hole

[Russell Harding]

If you have a way to program your ESC, it may be useful to confirm the programming.

You could also confirm the head speed with a tach or possibly a sound-based app.

[muscleman]

Originally Posted by JonJet

I recently used very similar BLHeli settings on an mCPX with the exact same components...

I tested every TC setting from 40 to 75 in 5-point increments and heard a definite rpm change at each step

Using 75 pos/neg pitch travel, it was very manageable with lots of punch when called for using Oversky's 300 mAh 45C

Seems the variant is the middle servo hole

The mid hole is very small. I had to drill it bigger, but it was still tight. I can try to drill it even bigger.

I am using the mid hole for my mcpx V1 and there was no stability problems at all.

My other concern is the over heating of the battery. Not sure why it is so hot. Maybe the head speed is way too high?

Are you using TX mode in your ESC in BLHeli software?

[JonJet]

Originally Posted by muscleman

The mid hole is very small. I had to drill it bigger, but it was still tight. I can try to drill it even bigger.

I am using the mid hole for my mcpx V1 and there was no stability problems at all.

My other concern is the over heating of the battery. Not sure why it is so hot. Maybe the head speed is way too high?

Are you using TX mode in your ESC in BLHeli software?

Yes...there are only 4 diffs between the settings I used and yours...

1) P gain is set 1.00
2) I gain is set 1.00
3) Startup power is set 1.00
4) Spoolup time 9 seconds

I believe everything else was identical to yours...but for some reason you are not hearing rpm changes, which is very odd indeed...

You might be running at 100%...which is not a good thing at all

[muscleman]

Originally Posted by JonJet

Yes...there are only 4 diffs between the settings I used and yours...

1) P gain is set 1.00
2) I gain is set 1.00
3) Startup power is set 1.00
4) Spoolup time 9 seconds

I believe everything else was identical to yours...but for some reason you are not hearing rpm changes, which is very odd indeed...

You might be running at 100%...which is not a good thing at all

Thank you! I will give it a try. Do you know what these P gain I gain settings mean?

My theory is that the ESC is trying to run at super high target RPM that my battery could not support, so when I set 60% or 75% throttle curve, there was no difference. At the same time, the battery is suspiciously hot.

[JonJet]

I suppose an explanation is somewhere in the BLHeli threads...I'm not sure what they mean

[Russell Harding]

Look up PID controller on Wikipedia. Pretty good explanation.

[muscleman]

Originally Posted by JonJet

Yes...there are only 4 diffs between the settings I used and yours...

1) P gain is set 1.00
2) I gain is set 1.00
3) Startup power is set 1.00
4) Spoolup time 9 seconds

I believe everything else was identical to yours...but for some reason you are not hearing rpm changes, which is very odd indeed...

You might be running at 100%...which is not a good thing at all

Did you solder the signal wires of the dual ESC to the resistor tap or the two power sockets for brushed main and tail motors?

[JonJet]

I honestly don't recall...it was a friend's heli and all I did was flash BLHeli to the main and tail and do the mechanical setup...then shipped it back to AR

[muscleman]

Originally Posted by JonJet

I honestly don't recall...it was a friend's heli and all I did was flash BLHeli to the main and tail and do the mechanical setup...then shipped it back to AR

Thanks!

I turned gov mode to OFF and finally I can control the head speed.
It was insanely high. I am currently setting the throttle curve as 0-10-20-30-40 in normal mode and now it feels like my mcpx V1, and my battery is no longer hot.
I think I should try to get a tachometer app to figure out the current head speed.
Then I will replace the main blades with the 130x blades and lower the head speed even more.

[muscleman]

Originally Posted by muscleman

Thanks!

I turned gov mode to OFF and finally I can control the head speed.
It was insanely high. I am currently setting the throttle curve as 0-10-20-30-40 in normal mode and now it feels like my mcpx V1, and my battery is no longer hot.
I think I should try to get a tachometer app to figure out the current head speed.
Then I will replace the main blades with the 130x blades and lower the head speed even more.

The BL outrunner has much higher torque than the brushed motor, so it should support the 130x blades better.

[JonJet]

Running such a lowered TC might give you tail troubles...also, the outrunner motors work a lot better at a flat setting

Giving it plenty of headroom will keep the main turning at the same rpm a lot easier, even at hard pitch changes

I would raise it up a bit...say 60 flat in normal mode and control the insane lift with pitch servo travel...start around 20-25-30-35-40 and increase each value 5 points at a time, as needed (since you have insane headspeed I really have no idea where you will end up)

You might also want to set the PWM Freq to light damped for the tail...I assume you have a good-sized tail rotor? RCC 65mm?

[muscleman]

Originally Posted by JonJet

Running such a lowered TC might give you tail troubles...also, the outrunner motors work a lot better at a flat setting

Giving it plenty of headroom will keep the main turning at the same rpm a lot easier, even at hard pitch changes

I would raise it up a bit...say 60 flat in normal mode and control the insane lift with pitch servo travel...start around 20-25-30-35-40 and increase each value 5 points at a time, as needed (since you have insane headspeed I really have no idea where you will end up)

You might also want to set the PWM Freq to light damped for the tail...I assume you have a good-sized tail rotor? RCC 65mm?

I haven't had tail issues yet. I am using the 47 mm rotor. I may use the 65 mm rotor if I see problems.

[JonJet]

I saw huge tail wag with a Lynx 47mm...then Heli+yeah suggested a RCC65mm tail rotor and 4712 (the BLHeli God) suggested PWM light damped...cured it all

Here's the short thread...

https://www.helifreak.com/showthread.php?t=699808

[muscleman]

Originally Posted by JonJet

I saw huge tail wag with a Lynx 47mm...then Heli+yeah suggested a RCC65mm tail rotor and 4712 (the BLHeli God) suggested PWM light damped...cured it all

Here's the short thread...

https://www.helifreak.com/showthread.php?t=699808

Thanks! I will try it if I have tail problems.

I currently have default tail ESC settings in BLHeli. I think it is PWM medium damped. Not sure what the difference is.

[muscleman]

I used a 0.6 mm drill bit to open up the servo holes and now the heli no longer jumps up and down. You are right. It was related to the servo hole issue.

However, I found the flight time to be shorter than my stock mcpx v1. The esc is usually hot after the flight.