Speed Control Problem
 

I am new to flying helicopters, been flying planes for about 7 years. I have a helimax mx450 xs with the recommended motor and speed control, the problem that I am having is that the motor starts up and then when I get to about quarter throttle it cuts off completely. I am not well versed in electric flight either, so any help is appreciated.

RE: Speed Control Problem
 

what speed control are you using?
did you set a lipo voltage cut off?
what size motor?
what lipo size?

RE: Speed Control Problem
 

Helimax 40A Brushless ESC
Electrifly Ammo 28-45-2700kV
impulse power, 3s1p 11.1V, 2100 mAH, 33.6A 16C

according to the speed control manual if will cut off power when the battery reaches 65% of full charge, it is having a problem even when the battery is fully charged.

RE: Speed Control Problem
 

Try doing a search on transmitter setup, Maybe?? Seems like I remember a similar problem having something to do with setting curves on the xmitr. But, then again, I'm old anf fuzzy brained..........

RE: Speed Control Problem
 

Good idea, splat - if he is using a programmable TX and he has his throttle curve like 0-25-0-0-0, that would do it!!!

RE: Speed Control Problem
 

my throttle curve is set at 0-50-80-90-100

RE: Speed Control Problem
 

Have you gotten the drivetrain nice and loose? If it's too tight (e.g. tail belt) you could be loading the ESC too much on spinup and getting a cutout. It wouldn't surprise me with the HMX ESC-- it slams in way too hard on startup.

RE: Speed Control Problem
 

yea, the belt is set so that I can almost pinch it together.

RE: Speed Control Problem
 

Hmmmm.... you still could be cutting out. I think I'd try lowering the throttle curve (even below the point where it won't fly) and experiment with easing the revs up.

I bought the HMX 40A with the first MX I got, and it worked exactly as it was intended. I replaced it with a Phoenix 35 almost immediately. It may not be the problem, but I might bin it just because I had an excuse. Personal opinion, but I really don't like that ESC.

RE: Speed Control Problem
 

Just a general comment, most of these tests can be made with the
airframe screwed down to a table [picnic table or?] to make the spool up
in a risk free environment. I used a small rectangular piece of 1/8 ply
set through the landing skids. You can test the load on the blades as you increase
pitch. With the use of a temp gun you could probe for heat on the esc, motor
parts and other moving bearing areas. I ended up disabling most of the
limitations on my 35 amp CC after 5 minor crashes due to esc shutdown.
I have 160 contact free flights on my M titan so far. skyhawk

RE: Speed Control Problem
 

skyhawk - why don't you enable soft cut off?

RE: Speed Control Problem
 

You shouldn't use a cutoff or current limiter on a heli. If you're not monitoring your flight times, then do :).