XP12a and 3a BL-heli programming?

[Rattler888]

Hi guys,
Expecting an XP-12a and XP-3a in the mail shortly flashed with BLHeli (by Dylan) and I'm just after recommendations on whether I need to do any programming, and what setup I should use. Or are the defaults fine to get started?

Thanks

[SuperBee364]

Defaults are fine to get ya started.

[Rattler888]

Cheers Bee
Out of interest what can I expect from the defaults? If I set, say, a flat 80% throttle curve what will it do? And do ya need to tell it your throttle range first?

Thx

[SuperBee364]

It kinda depends on which version of BLHeli you have flashed. I haven't kept up with the changes, but on my version, the default setting is tx gov mode. That means that when you go through the arming sequence, the throttle setting seen by the esc during arming will be used as the rpm the governor tries to maintain. I'll try to explain that a bit...

Arming sequence:

1. TH on while plugging in heli battery. Reason: ESC needs to see 0 throttle signal to start the arming sequence.

2. TH off. At this point, whatever throttle the ESC sees is used as the target throttle speed for governing.

3. TH on: Finishes the arming sequence. Flipping TH off at this point will cause the motor to spool up.

So to change the target speed, adjust your throttle curve to what you want prior to going through the arming sequence.

The "Sweet Spot" for governing depends on too many variables to just say "Use xx% throttle". Experiment with different values and find what works best for you. On my HP05s, I like between 80-86% for outdoor high power flight. For indoors, I go 50-60%. At around 60%, I would estimate the head speed is just about the same as a stock brushed motor, but the power is substantially better.

[sskaug]

Originally Posted by SuperBee364

It kinda depends on which version of BLHeli you have flashed. I haven't kept up with the changes, but on my version, the default setting is tx gov mode. That means that when you go through the arming sequence, the throttle setting seen by the esc during arming will be used as the rpm the governor tries to maintain. I'll try to explain that a bit...
....

Well.... For all versions of BLHeli gov TX is the default mode. In that mode the throttle during arming sequence do not influence headspeed. It is only the throttle value when running that sets headspeed.

However, in gov arm mode (which is not default), the max throttle during the arming sequence will set headepeed (and throttle is ignored while running).

[SuperBee364]

Thanks for clearing that up, Steffen.

So does the throttle value seen during arming influence anything at all in Gov TX mode?

[sskaug]

Originally Posted by SuperBee364

...
So does the throttle value seen during arming influence anything at all in Gov TX mode?

Nope. Nada!

[Rattler888]

Guys that makes perfect sense, thankyou very much

[Rattler888]

Just got this setup working in my friend's mcpx, thanks to everyone's advice on helifreak we got it installed without a hitch!

There is one thing I'm not clear on about how BLHeli works that I couldn't find in the manual..

When you start it up in the default Gov TX mode, say I set my tx throttle curve to 60%, the BLHeli Gov target becomes 60% of what? Is it 60% of the max headspeed? 60% of the maximum speed of the motor? Just curious how it determines the max, since we didn't have to teach the ESC max throttle or tell it what motor is attached.

Cheers

[Chris Gardill]

Learn something new everyday. Didn't realized that applied to Gov Arm mode only. Thanks.

Originally Posted by sskaug

Nope. Nada!

[Rattler888]

Originally Posted by Rattler888

Just got this setup working in my friend's mcpx, thanks to everyone's advice on helifreak we got it installed without a hitch!

There is one thing I'm not clear on about how BLHeli works that I couldn't find in the manual..

When you start it up in the default Gov TX mode, say I set my tx throttle curve to 60%, the BLHeli Gov target becomes 60% of what? Is it 60% of the max headspeed? 60% of the maximum speed of the motor? Just curious how it determines the max, since we didn't have to teach the ESC max throttle or tell it what motor is attached.

Cheers

okay, finally bit the bullet and read the 74! pages in the BLHeli sticky. All is explained, you just gotta be patient!

Seems the values are hard-coded based on the throttle input. The second post links to an excel spreadsheet that gives some standard values, and there is a good explanation on this page:
https://www.helifreak.com/showthread...390517&page=13