2bluerussian

I've had my Axe CP-L for a while now and have started to get the itch to start replacing some of the stock parts on it. However, since it is an RTF, virtually no information exists on the stock components (or even the setup for that matter). I set out to compile a list specs that I could use to intelligently buy upgrade/conversion/separate components for the axe. I did some minor searching and had a hard time finding these numbers, so hopefully I’m not duplicating with this post. Even if I am, I guess it is always good to have multiple measurements.

My configuration for these measurements: stock motors, stock radio, stock 3-in-1, JCS flat airfoil blades, CNC bell-hiller, CNC swashplate, approx 40 flight on the motors.

I welcome any comments, questions, discussions or other suggested measurements. If you’ve measured things differently or find a different set of parameters that work better than the stock, please share.

You’ll notice a couple of numbers are listed as will be updated in a future edit. These are items that I thought I measured, but can’t quite seem to find the numbers. I will measure them and post the results as an edit for continuity.


Motors and head setup:
-Stock head speed (idle up, zero pitch): 2,340 RPM (Battery 11.5V @ 11.75A). FYI I saw little change in speed at 100% throttle, presumably due to increased drag from pitch increase.
-Tail Rotor RPM: 6,150RPM (11.8V @ 2.25A)
-Stock motor RPM/volt: 3200 (or 3800 depending on measurement method). 3200 was measured with a free-spinning encoder and DC supply. 3800 was using a “generator method” where the motor was spun at a known rate and the voltage was measured coming from the motor. 3200 RPM/Volt seems to fit better with other measurements made.
-Stock motor no load current: 1.23 Amps (at 10V)
-Stock motor resistance: 0.222 ohms
-Stock motor diameter: 27mm
-Stock motor length (mounting flange to back end): 38mm
-Max motor diameter that fits in Axe compartment: 30mm
-Stock motor mounting screw type: 2.5mm diameter x 5.0mm long
-Stock motor mounting screw-to-screw distance (Bolt circle dia): 15.88mm
-Gear ratio for main rotor: 180(drive) / 14(pinion) = 12.86:1 reduction
-Gear ratio for tail rotor: 48(drive) / 8(pinion) = 6:1 reduction
-Maximum current for the main motor ESC: xx.xx Amps (100% throttle, idle up), updated on future edit, but 11.5V @ 11.75A is probably a good start (see first entry)
-Maximum current for the tail motor ESC: x.xxA (at xx.xV, full right stick), updated on future edit, but 11.8V @ 2.25A is probably a good start (see second entry)


Blade and pitch information:
-Pitch range (normal mode): 0deg to 10deg
-Pitch range (idle-up): -10deg to 10deg (from Bell-Hiller instructions)
-Main blade length (one blade, mounting hole to tip): 24cm
-Main blade mounting screw: 2mm (that means you can’t use helimax’s blade balancer!!)
-Blade thickness at grip area: 11/64in
-Balsa blade weight (one blade): 14.26g (average of two measurements)
-JCS blade weight (one blade): Will be updated soon in a future edit
-Current draw of stock electronics at idle (no servo motion, no motors on): 0.06A at 12.64V


Throttle Curves:
This is for the stock radio and 3in1. I measured the voltage for each of the listed throttle positions. Bear in mind that on the stock radio, “25%” or “75%” is pretty subjective and was really hard to judge where that was. This is one of those places that if the people who have upgraded to computer radios have better curves, let us know.

Throttle curve – Normal mode:
Stick position_____Voltage_____________Percentage
0%...........................0.................... ...........0%
~25%.......................4.46V.................. ......36%
50%.........................7.88V................. .......63%
~75%.......................11.60V................. .....93%
100%.......................12.48V................. ......100%

Throttle curve – Idle up mode:
Stick position Voltage Percentage
0..............................12.47V............. ..........100%
~25%.......................10.40V................. ......83%
50%.........................7.80V................. ........63%
~75%.......................11.50V................. ......92%
100%.......................12.48V................. .......100%

By the way, anyone looking for a good place to start on programmable radio settings for the axe I would recommend checking out the link below to some great work done by shadow99

http://www.rcuniverse.com/forum/m_76...tm.htm#7697931