chuckers

Hiyas,

Anybody feel like solving a mystery today?

I just finished building my first 'real' plane; an Estarter configured as follows:

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350 motor
Pixie 20P ESC
GWS NiMh 730mah 8.4v (7 cell) battery
Hitec HS55 servos
GWS 6ch receiver
Futaba 6EXA
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Here's the problem.
As I increase power to the throttle everything is fine until the left stick gets halfway between the full down and full up positions. (By 'halfway" I mean that the stick is at 'click' 12 of 25). On a fully charged battery, at 11 clicks of throttle, the motor will run well for more than 10 minutes, no problem. If I push the stick up 'one more click' (to click 12 of 25) the motor cuts out immediately. The problem is 100% repeatable and very consistent. I see the same behavior with a fully charged battery as I do when I am near the end of my battery life.

I don't have any experience with the 350 motor so I cannot tell if it is running at 'half' power or full power when it cuts off. I suspect that it is NEAR full power ('cause it's pretty loud) but NOT at full power when it cuts of because the LED on the Pixie 20P ESC is still flashing right up until everything cuts off. (I am told that the Pixie 20P LED will remain on constntly while the motor is running at full power.)

I know that my ESC currently has a cutoff voltage of 5.0v, I'm considering changing that to 4.0v, but I don't know if that will help. (This was suggested by the folk at Castle Creations). Do you think that adding power is pulling my fully charged NiMh to less than 5.0v? Will using an excessively low cut off voltage do damage to NiMh batteries? (A cut off voltage of 5.0v equates to 0.71v/cell, and a cut off voltage of 4.0v equates to 0.57v/cell.)

Although the Futaba radio has 'end point adjustments' I don't see anything related to being able to use the full range of the stick. (I tried adjustign the EPA to 120% but didn't see any difference.)

I've cycled the battery 3 times and I'm pleased with the life span. When fully charged it will run the motor for 12-14 minutes on the bench at 'maximum' power (max power being the point just below where it cuts off).

BTW, thanks to all of y'all for lots of good tips about building an Estarter. I've been lurking for a month while I built and today's my first time posting. Here's pic. I finished biulding a week ago but haven't tried to fly yet becasue it's awfully windy lately.

Thanks in advance,
Chuckers