Helijive 120 unexpected power loss

[datatools]

I just experienced an unexpected power loss with my Goblin 700, and want some feedback before tossing it up in the air again. My Goblin manual states that I have a 21T main gear - brand new build here. I'm running the Helijive 120, not sure what version I have but I just purchased it a week ago from RotorQuest, so I assume its the latest version 13 (how do I tell)? I have the ESC connected to a Pyro 750-50 motor, and I have it mounted in the Goblin ESC tray with the heat sink down and double sided tape holding it there along with a velcro strap. While flying today, I was amazing at the power this heli has and pulling some big air moves. Suddenly 2 mins and 30 sec into the flight I realized the heli was losing power and started looking for a landing spot as power spooled WAY down. As I got closer to the ground and prepared for an emergency landing, the motor suddenly started to regain power and it surged up in the air. At this point I hit throttle hold and did an auto landing. I didnt realize the ESC LED will flash to give codes, so I never looked at it. I had the ESC programmed in GAS mode 2 for my maiden voyage testing, and the TX was set on idle 1 at 60% straight curve. My question is, what would cause this? Do I need to program mode 4 or 5, do I need to change my 21T motor pinion to say a 22 or higher (to reduce head speed and put less draw on the motor). Any help will be much appreciated. Thanks. Bryan

[Wh1teAfr1can]

you more than likely ran into an overcurrent or overtemp situation as you were running the pwm too low. I would suggest reprogramming mode 4 and then setting it to 65% as your 3d headspeed. What you observed was normal shut down. are you running the heatsink or just pushing the plate of the esc against the base plate of the goblin? if so do you have any thermal compound in-between?

[swalko]

This is the way how Helijive/Jive handle commutation errors.

[Slyster]

My Goblin 500 does this with the Jive 80LV and Quantum motor.. I turned on KSA mode and never an issue after that.. but it shouldn't do that with a Pyro.

[datatools]

Originally Posted by Wh1teAfr1can

you more than likely ran into an overcurrent or overtemp situation as you were running the pwm too low. I would suggest reprogramming mode 4 and then setting it to 65% as your 3d headspeed. What you observed was normal shut down. are you running the heatsink or just pushing the plate of the esc against the base plate of the goblin? if so do you have any thermal compound in-between?

I have the ESC attached to the Goblin tray with double sided tape. It is not thermal tape or anything special, just what I had on hand. Would it make much difference to put thermal tape between the ESC and aluminum tray, or is the difference minor?

[Wh1teAfr1can]

I would definitely change over to thermal tape. you are insulating it from the tray currently. so make sure the aluminum plate on the helijive is on the bottom against the tray and use thermal pad to connect it then strap it down snugly you need some sort of heat sink because in a goblin where the airflow to the esc area is limited you need a little extra cooling.

[dl7uae]

I suspect another reason:

The JIVE always calculates the ETA of the next zero-crossing (EMF pulse for sensorless commutation). If a pulse arrives far out of the ETA window then the JIVE must assume an upcoming commutation problem which would lead into a bad commutation failure, ESC and motor could be destroyed. So he reduces PWM and attempts to "re-synchronize". No LED flashing afterwards.

[Vinger]

Why GAS MODE?

[datatools]

I reprogrammed to mode 4 and the heli works great now. No more unexpected power loss. However, what I noticed from the single flight I did in gas mode was that it had amazing power. I chose the gas mode for initial flights because I thought it would be more like the nitro helis I'm used to flying, this is my first electric.

Originally Posted by Vinger

Why GAS MODE?