Hi all,
I just experienced the thrill and exhilaration of my first flight and hard landing! I build my frame from scratch so I was seriously nervous. I did a hover 1m from the ground and then panicked a bit and brought it down for a hard landing. I broke some parts of my landing gear, but I now realize I had a poor design in that area.
I have one question that I want some help on. I experienced that the quad was quite stable but slowly drifted in one direction. It seem to always drift in this particular direction. Should it more or less stay in the same place or can this be due to :
1. Not taking off from a 100% level surface
2. Some balance issue due to my frame, CG maybe not preciously in the right spot
3. Unbalanced props ( I did not balance mine )
Cant wait to fix my landing gear and fly again. First time flying or even seeing a quad fly in real life !!!!
Replies
Andre,
A drift in one direction is likely to be
1) Wind - quads will always drift down wind without manual or automated correction
2) Level - when you first arm the quad after powering it up it will go through an automatic levelling procedure. If you are not perfectly level it will then try to hold that attitude in flight and this will cause a drift. Use a bubble level to set you quad level before you arm it. You can also do an inflight level when you get comfortable with hovering flight - see the wiki
3) Airframe - you may have an asymmetry in your airframe/motors causing off centre thrust. you can usually see this if you have a carefull look at the airframe and motor mounts. Centre of gravity issues are similar.
To find out what your problem is first try disarming, rotating your quad 90 degrees and rearming it. If it used to drift north and continues to drift north then you have an external factor (ie a breeze). If it now it drifts east (for example) you have an internal problem (ie out of level or twisted airframe)
regards
Andrew
From the brief description, I would suspect a CG issue. See the troubleshooting in the manual. Were you in stabilize? Even a highly tuned quad can move about like a hockypuck on ice without a pilot. In 3D if it is not altitude-controlled.
If this were unbalanced props, I would expect vibration. Other issues result in oscillation. Do you know about RC-initiated leveling and auto-trim? It is in that troubleshooting section. I use a cable to find and adjust CG, try to get the arms level from a single hanging point, ideally in line with the XY gyro.
Congratulations on your first flight! I hope you learned a lot to refactor your design, and that your lessons learned come easily and perhaps with fewer broken parts in the future.