Hi all, On Saturday I tried to go flying with my Alta6 again. It had been a while since my last flight and was excited to get it up again. It was pretty windy but thought that I would be fine. But when launching the Alta I think I got a wind gust and my Alta tipped over. I killed the motors as fast as I could but two props where damaged. Any tips on launching the Alta when there is a bit more wind than you would like?
From my experience with other drones if the wind is over 6 or 7 mph use extreme caution. 7mph can easily turn to 15 if it is a gusty day and you cannot recover from that unless you have superpowers. Use the Windy app or bring along an anemometer like the HOLDPEAK 866B Digital Anemometer to you know what the wind speed is. Do not guess. At the very least tie a 36" long 1" wide or an 18" long 1/2" wide ribbon to a stick or light stand and if the ribbon flutters out to 45º it is probably too windy to fly. You can use an anemometer to calibrate your ribbon gage and make it more useful. A lot of RC airplane guys have ribbons tied to their transmitter antennas. Make sure the area is wide open. No trees, walls, parked cars or other obstructions that will cause unseen turbulence. Make sure the drone is facing into the wind and you are not directly behind it. If my calculations are correct the rotor loading (total rotor area/weight) is about just a little bit higher for an Alta6 than the Phantom 4 so the Alta should be able to handle a wind that is just a little bit higher. The max wind published for a Phantom 4 is 10m/sec or about 20 mph. With the increased rotor loading stability may be a little better in a constant 20 mph wind but with a top speed of 40 you would be nuts to fly in that kind of wind. My personal limit for all drones is 10 mph with gusts to 15. That means the leaves and small twigs are in constant motion. Alta 6: 5 pounds per rotor / 1.76 sq ft per rotor = 2.86 pounds per square foot Phantom 4: .75 pounds per rotor / 0.349 sq ft per rotor = 2.15 pounds per square foot In the absence of an anemometer, you may find this Beaufort Scale Chart useful. Beaufort scale 3 - be very careful, 4 - extreme caution, 5 - make sure you are insured and there is enough money in the bank for a new drone, and 6 - tell us where the send flowers.
Hi Robbert: What I do, given the windy conditions you describe, is to avoid hesitating when taking off and landing -- in other words try to transition from "on ground" to "in the air" or "in the air" to "on the ground" as quickly as possible so that you don't catch one of the landing gear legs on the ground and then have the wind rotate the ALTA around that. For take offs, I typically do this maneuver by starting the motors at idle, listening for a second or so to make sure everything's OK, and then moving the throttle up pretty rapidly to get the ALTA off the ground, out of ground effect, and into the air in one smooth movement. That's not necessarily going to stop any downwind drift, but it transitions rapidly through the "danger zone" when two legs have lifted off, and one is still on the ground. Landing is also a bit tricky because you have to completely null out any downwind drift and, at the same time, punch through the ground effect "bubble" of compressed air directly underneath the ALTA and get all three legs on the ground and with weight on them as quickly as possible consistent with not thumping the ALTA on the ground too hard. Hope this helps Andy Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Hey Andy, Thanks for the tips. I indeed was probably too slow on the throttle to get it safe in the air. But probably should have stayed on the ground with the wind gusts that were going on anyway.
Yeah, gusting winds can be tricky to deal with -- especially if they're being caused by curl-over or curl-around buildings/trees etc. because the wind direction is highly inconsistent. On occasions I've resorted to taking off and landing in the lee of a building or a vehicle just to try to shield the ALTA from some of the worst gusts. Andy Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert