Originally Posted by kensp

All ESCs are the same in that they all require programing to set up correctly for twins.

To reduce problems I always buy ESCs in pairs for my twins. This increases the chance of getting 2 ESCs from the same manufacturing batch as these will likely be more identical.

Ken

I lucked out on that one in that I DID buy two identical esc's at the same time, so that's one less thing to worry about I guess. I just don't know what this "correct programming" that is required that you speak of is...

The things to check, programming wise, are; soft start set to "off" or "normal", and throttle range setting. I had the same issue with my 262 early on, and found the running a separate BEC, and disabling the BECs on both ESCs( by removing the red wire from the connector that goes to you receiver) solved it.

Also make sure to set the number of cells (3 or 4) unless the ESC is auto detect, and the other critical setting is timing - usually a choice of low or high timing - will depend on your motor but with a twin like this and high kv motor low timing should work well and be efficient.

Your ESCs should have a set of programming instructions - follow them or go online and and look up the ESC manual to program it. You should always double check the programming. You will find the instructions on setting the Throttle High/Low point. Normally to set the throttle high/low position you would plug the battery in on the plane, before turning on the TX place the throttle at the top, turn on the TX and you should hear a tone or series of beeps, at that point bring the throttle down all the way to the bottom and you should hear another tone - setting the throttle high/low point. The next time you throttle up the motor should start. It does vary between ESC brands so check your instructions that came with the ESC.



Chris

That's what's throwing me a bit: Both esc's are sounding off in perfect unity when I hook up the battery. Both give the 3 beeps for 3S also. No issues there.

My guess is that your ESCs are programmed the same in general but you need to set the throttle curve's high and low. (the ESCs both need to know the position of the throttle) Your ESC manual should cover that.

To rule out that it is some motor issue you could try swapping the ESCs between motors and see if the same issue with the "late start" of the motor starts with the other motor too.

This is all good information. Thanks everyone, I appreciate it. I'll keep you posted with what happens.

Wait-- so they run OK and in sync with a fully charged battery and the problem only happens when the batteries are very low?

That's normal (though bad) behavior for twins. The ESCs decide independently when to trigger their LVC, and the *NEVER* do it at exactly the same time. And since the voltage recovers immediately after the first one shuts down, the second one stays on for quite a while. You can cut power to reset the LVC, but the motors won't ever reliably run together when the battery is near the cutoff voltage.

Best solution is to use a separate LVC device between the Rx and the y-cable. The stand-alone LVC will throttle back both motors together. I prefer the Dimension Engineering SmartBEC for this purpose, but there are lots of others that work just as well.

Originally Posted by rdeis

Wait-- so they run OK and in sync with a fully charged battery and the problem only happens when the batteries are very low?

No, that's not the case at all. Did I write that somewhere? The only time they do not start at the same time is when I apply power. One motor starts right away while the other one doesn't kick in until about 50% throttle, then you can hear it jump right to the same speed as the first one (it catches up instantly). So if I run at 70% and above the entire time, I'm good. I just didn't plan on running at 70% and above constantly.

Runnikee- Sounds like a throttle range issue to me. The one that starts above 50% doesn't know where zero throttle is.

Originally Posted by Cougar Zeke

Runnikee- Sounds like a throttle range issue to me. The one that starts above 50% doesn't know where zero throttle is.

The most frustrating part about these things is that there's no reason for it not to work. You plug one into one side of the Y connector, the other into the other side, and they SHOULD both work. But NOOOOOOOOO! Hahaha! The joy of modeling.

More stuff.

Originally Posted by Runnikee

The most frustrating part about these things is that there's no reason for it not to work. You plug one into one side of the Y connector, the other into the other side, and they SHOULD both work. But NOOOOOOOOO! Hahaha! The joy of modeling.

Set the throttle range for each ESC separately (connecting only one ESC at a time) according to the instructions.

Originally Posted by topher39

Set the throttle range for each ESC separately (connecting only one ESC at a time) according to the instructions.

Then when I hook them up to the Y connector they should work normally as if nothing happened? I'm new to the "twins" concept other than a cargo plane I scratch-built back in the day with none of these issues. I appreciate the help from you all.

The only other problem I have with this model is that the screws that hold the wing in place are junk. I'm going to go to Lowes to get some higher quality ones that I can tighten and remove without stripping the heads so easily.

I ordered these from HK to replace the stock 3mm screws: http://www.hobbyking.com/hobbyking/s...40_20pcs_.html

They work great!

Originally Posted by Runnikee

Then when I hook them up to the Y connector they should work normally as if nothing happened? I'm new to the "twins" concept other than a cargo plane I scratch-built back in the day with none of these issues. I appreciate the help from you all.

Yes, once you program each ESC separately, you join them with the way and you should be in sync.