Phoenix 25, rough start question.

[IA-Flyer]

Hi,
I purchased an E-flite Park 370-4100 and a new Phoenix 25 (A on the top) two days ago.
It’s my first brushless so I didn’t know what to expect, but I have read in the past that brushless motors can start rough.
I powered it up with the default settings but changed the cutoff voltage to 9v for my 3-cell pack.

The prop kicks back and forth and sounds like it has a broken tooth if I advance the throttle normally.
If I quickly advance the throttle to about 1/3rd it seems to work fine once the motor is spinning.
I haven’t tried just slowly advancing the throttle to see what happens because for the first few clicks it seems to just get worse and I don’t want to break anything.
I was out flying last evening and slowly brought the throttle up (old habits die hard) and could see the prop was kicking back and forth in the air! :confused:
I did a google search on it and found several reports on this forum about the new software rev causing rough starts.
I haven’t tried “fast start” because of the weak gearbox I’m using, but there was little difference between very soft and soft.

Thanks for any help, I just need to know if this is normal because it’s my first experience with brushless motors and controllers.
I could post a short video showing how it behaves, if it would help.

Regards,
Jim

[Bernie Wolfard]

Jim,

Change the slow start setting to fast start (9.7 option 3). This won’t hurt your gearbox. If no joy, redo your solder connections between the ESC and the motor. If this doesn’t work please post more detail, specifically your battery type, gear ratio and prop size.

Bernie

[IA-Flyer]

Hi Bernie,
I tried it with break disabled and fast start last night and it does seem better. I’ll try it with fast start and the brake set to default later today.
I live in an area where I’ve never seen a brushless run until I bought this one.
I have a feeling it’s acting normally, I just didn’t want to take any chances because it didn’t seem normal compared to my brushed motors.

I notice once the prop is spinning it is very smooth. I can back out of the throttle (break off) and let the prop slow to a fast windmill and it throttles up just fine. It seems very smooth other than the initial start.

The combination I’m using is:
GWS SS, 2-GWS Pico servos
E-flite Park 370-4100
GWS “D” 6.6 gearbox
CC Phoenix 25
GP ElectriFly 1200 3-cell (8c 9.6A max)
GWS 11x4.7 SF (tested 9.2A or close)

Short amp tests, not flown yet:
10x4.7 GWS SF 8.2A
10x7 APC E 8.0A
11x7 APC E 9.2A (fresh pack.)
12x6 APC E 9.2A

I couldn’t heat-gun the controller during the (11x4.7 SF) test flight because of where it is located, but it didn’t feel warm.
The motor checked 133 degrees.
The Battery was 98 degrees.
Outside temp was 83 degrees.

Thanks!

Jim

[Shawn Palmer]

Just FYI - try to keep those cells to 8A or less at wide open throttle, and best to use the SF props other than the APC "E"'s

Shawn

[IA-Flyer]

Thanks Shawn,
Hey, I was talking with Headless a little while ago and found the problem!
Being new to brushless setups I didn’t realize how important motor lead length is. One of the motor connectors stuck out 1mm more than the others because a defect (hole) in the bottom caused a solder puddle on the ESC side. The sides of the connector are clean, and the plug went well into it, so I didn’t think it would be a problem.
I pulled the other connectors out 1mm each to match it and the motor runs like a champ!
It must have caused an impedance change or something.
I’ll look for a replacement connector and change it asap. The combo is working fine now, thanks!


I wasn’t sure about the E props but I want a lower throttle setting and higher pitch for just cruising around so I’ll look for a higher pitched SF prop.
I’ve lurked around the E-Zone quite a bit over the last year but never see much about props. Is the extra weight a problem with the E props or do they just not work as efficiently? I guess if I can’t use the E’s my prop choices are very limited.

Yea, I bought the GP pack because it said 8c, then I read somewhere that it’s a re-labeled Kokam.
Kokam doesn’t even make a 1200 so it must be one of their 4-6c 1150’s?
Not happy, burned again! :confused:

Thanks for a great controller!

Jim

[Shawn Palmer]

On low rpm parkie set-ups, the SF props are far more efficient than the E's. Once you get in the 7-8k rpm range, they're about equal, and over 8k, the E's start to shine.

Shawn