I’ve been quite irritated with my carbon fiber landing legs I came up with for my Alien H4 680mm quadcopter.  The legs are on servo-less electric retracts which I have assigned to a channel on my transmitter.  I can put the gear up or down during flight.  That’s cool, especially with a 3-axis gimbal for the camera.  It keeps the legs out of the photos or video.

The problem I’ve had is with the 6 millimeter carbon fiber tubing I’ve used for the legs.  Those tubes wrap around the 4mm “trunnion” which comes out of the retract.  When taking off, landing, or working on my quad the legs take a beating and over time crack.  Just two days ago two legs snapped in grass as the copter shifted laterally during takeoff.

Lucky for me I have a cousin who has a machine shop.  I had him make me up some aluminum landing legs.  They have a 4mm section which replaces the trunnion, then expand to 6mm.  The “shoulder” between the 6mm and 4mm supports most of the weight, and the aluminum is MUCH stronger.

Yes what about the weight difference?  Each leg of the carbon fiber landing legs with trunnion and rubber cap was 7 grams.  The new aluminum legs with rubber cap are 15 grams.  I’m adding 28 grams to the whole bird with this upgrade.  Not terrible.

Below is a video of the old CF retracts in action.

I’ve now started a new build, the new Arris X-Speed 250 racing quadcopter which was kindly provided for review here by myrcmodel.com.  The basic frame is put together as seen below.

Arris X-Speed 250 Quadcopter Frame

I shot a five minute video of the unboxing and examination of the parts for the basic unassembled kit below.

Reader Pat’s question and answer continues.  The two previous questions were related to drone lighting and the electric retractable landing gear.

How do you calibrate your motors, or did you mean that you’re throttle calibrating your ESCs?

I must have written somewhere that I had “calibrated the motors” on my large 960mm hexacopter.  Pat’s terminology is better.  I mostly likely was referring to throttle calibration of the ESCs.  The process of throttle calibrating my ESCs was a pain.  As it turned out there was a funky issue between my particular ESC model (Hobby-Wing Pro 40A) and my transmitter, a Taranis XD9.

Tarot 5008/340kv Motor

Typically a throttle calibration would be something like this.  Power up the ESC with the throttle at maximum.  After the ESC beeps, reduce throttle to minimum.  It should only take a few seconds.  But the above mentioned issue caused many of my ESCs to randomly not arm.  It would seem that the distance of the throw was not enough, or that the throttle stick wasn’t going all the way down to -100.  I fixed the throttle stick later but that’s not how I resolved the calibration issue.

After much reading I found that if I set my throttle distances from -89 to +100 and then did the calibration it worked. I would then set the throttle back to -100 to +100 after they were all calibrated.  Then all motors would arm.

Regarding the Tarnanis not going all the way down to -100, the throttle stick would go down but would not stay at -100. It would stay somewhere around -95.  That would mean arming problems as well, plus I would get the Taranis “throttle warning” and would have to move the sticks to be able to do anything.  I had to take apart the Taranis and tweak the throttle screws until it went all the way down.  Then of course my center point calibration with my flight controller went wonky.  So I ended up doing all stick related calibrations for the Taranis and Taranis/SuperX controller over again.