Rui Manuel Cravo Marques's Posts (7)

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My First Hexa Flight

Here is the first flight of my first hexa :D used software AC2.5.4 wich gave an excellent flight (I had 2 yaw twiches) Loiter still needing some work in software or PID. I think throttle rate is a bit higher causing those ups and downs. Alt hold seemed to work better with version 2.2. RTL worked pretty well and that option to disengage auto landing it's great. Thanks Marco and dev team. The hexa and the quad behave a little different. The hexa is almost as driving a 4x4 much more stable but still agile, it needs less angle to correct position. I'm not used to it yet. I know now that all my stability problems with my quad using 2.5.4 were due to too large props in a small frame. The hexa is much more forgiving about this. X650 pro Xaircraft frame, sunnysky x2212 980kv motors and 10x4.7sf apc props, 6000mah 3s 25/50c nanotech battery about 2kgs for all, having about 15m flight time with this config.

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The Relevance of Propellers

Hi again. Latelly I've been testing some different propellers on my quad and checking the main differences between them. For my emax gt 2218 930kv , my 3S batt and the 1500 / 1600 weight, I was using those cheap 12x4.5 props. I even bought 12 pairs for $25 or so, and one thing I can tell you about them... FORGET ABOUT IT. After 2 crashes from wich I could not tell if it was a motor or prop problem, I decided to test other props. I started thinking that too much flexibility would have a negative impact, both on material resistance after a couple of flights and prop deformation on higher RPMs giving it less efficiency.

Looking close to one of those cheap props with about 3 flights, I noticed the plastic was becoming fragile near the joint to the hub (becoming white as if it was heavily bended). At APC page you can read about the forces involved and afecting a prop, so I decided to start using higher quality and stiffer props, and I'm not regreted.

There are some models wich mix carbon with nylon giving it a good stiffness. I'm using composite APC E series and APC slowfly and also those carbon nylon ones and all seem to behave very well.

One thing you will be noticing is the much quieter noise and less vibration you get from the motors. Balancing is almost unnecessary, and with 12x6 apc e, I managed to get about 2 min. more flying time. So, forget about cheap propellers. I believe they are like tires in a car. If they're not good, you'll crash for shure if you push them.

If you just hover, and don't make sudden alt changes or high pitched maneuvers, the cheap ones will stand, otherwise, get high quality props.

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My quad + Firmware Arducopter 2.1

Finally I've managed to have some time and do a little flight to test the Arducopter v2.1 firmware.

Here is my quad and some specs I hope you find them usefull somehow :

Weight (with camera on board) : 1700gr

Weight (without camera) : 1500gr

Battery : Turnigy 5000mAh 3S / 30-40C

Motors : 4 x EMAX GT 2812-11 930KV (about $15 each from plus2city - behaving very well so far)

ESCs : 4 x AE 30Amp  (about $12 from hobbywing, behaving surprisinglly well so far)

APM 2560 + oilpan + Ardcuopter 2.1 firmware

12x4.5 propellers (not the best ones, this are a little soft, I'm waiting for some stiffer ones)

I got about 10m flight time with the camera



PID Rate Roll (and Pitch) adjusted to 0.075 (default was 0.145 but I got to much oscillations. The in flight PID adjustment using ch6 it's no doubt a super add on. I had never touched the PIDs before, but now I really needed since the quad was oscillating too much, especially on descents).

PID Stabilize Roll (and Pitch) adjusted to 4.550 (default was 4.5)

This 2 Videos, are from the same flight.

First one, videocamera from the ground (most of the time you don't see the quad, since I had no cameraman :) , but if you look closely towards the end, you will have a great chance to watch my belly eheheh)


Second video from camera on board. I left the time stamp so you can check the battery duration. Conditions were almost perfect. No wind at all, about 13ºC.



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