450l spool-up kick.

[Euclid]

Firstly to those here that convinced me the 6S trex 450l was the one to get rather than the 3S version I send a heart felt thanks, you were spot on.

The 450 is now built and I've just finished putting my first 3 batteries through it. As everybody has said it is a lot more stable than any of the micros I've been flying. So my first, 'is this normal' question. I've yet to program idle-up but in normal mode as I advance the throttle up from zero very gently the motor goes from stationary to a 100 or so RPM in one step; there's no gradual increment from 1 RPM, 2 RPM...etc. With the heli on a smooth surface this sudden burst of inertia spins the heli anti clockwise in its vertical axis. So the exam question is, 'is this behaviour normal or should it spool up gradually from zero with no sudden kick?'

Watching the transmitter monitor the throttle output increases linearly with the throttle stick position so I'm assuming it's being caused by the ESC; that has been programmed for Soft Start, I think. I can counter the effect by putting in a little left hand rudder before throttle but at the moment I don't know if this is a fault I need to fix or it's normal. And so the learning curve continues, grateful for your collective (pun not intended) words of wisdom.

John

[Jay23]

I too have just finished building my 6s 450l, but I'm waiting for my spirit pro to arrive so haven't set it up proper yet, I will be watching this thread for tips. I have been flying a mcpx bl (from fp heli), he's a flighty little fella isn't he!

[tomatwalden]

.. With the heli on a smooth surface this sudden burst of inertia spins the heli anti clockwise in its vertical axis. So the exam question is, 'is this behaviour normal or should it spool up gradually from zero with no sudden kick?'

Watching the transmitter monitor the throttle output increases linearly with the throttle stick position so I'm assuming it's being caused by the ESC; that has been programmed for Soft Start, I think.

..

Not normal, no. There should be a gradual spool up of the blades allowing the tail blades to reach enough speed to counter the torque. This "soft start" setting should be configured in the ESC and is not visible in the transmitter.

What ESC do you have?

Here's a (very old!) video of my Trex 500 EFL Pro with stock Align ESC. This is what the soft-start should look like..

https://www.youtube.com/watch?v=g9_l5GBu7lQ

[Euclid]

Thanks Tom, no mine is nothing like your video. It's the stock Align ESC/BEC that comes with the kit, a RCE-BL45X. I guess my next task is to check that I did programme it for soft start. Failing that...

John

[Grumpy]

That was going to be my suggestion i.e. double check that you have soft start programmed. Some ESC soft starts are 'softer' than others, some do have a bit of an initial kick as the motor and ESC synchronise.

[tomatwalden]

Don't forget to remove main blades, and back off the pinion before you muck around with ESC settings! Don't disconnect the motor however as you need that to hear the ESC beeps.

[Euclid]

Thanks guys. ESC check it is then but it'll have to be next weekend unless I get lucky and get home during the week. Domestic duties now have to be attended to (and no, that's not a euphemism for something else). I'll report back my success or otherwise. Thanks again.

[Euclid]

Thanks guys, it was the ESC that hadn't been setup correctly. When I thought I was setting it up a couple of weeks ago I was actually setting everything to position 1; soft start wasn't. Now those beeps as the ESC initialises mean something. Oh, and taking the safety precaution of removing the blades before playing has probably saved me a trip to A&E!

[tomatwalden]

Glad you got it working ... and with all your fingers still attached! Sounds like a good lesson learnt too which will stand you in good stead when you have larger helis!