Just got a new spark. Love it.

Tested it out just now, and noticed that after I accelerate at full tilt and I let off the stick, the spark will drift backwards a bit and to the left. Slightly Up too.

I tested this in various directions, and there is little to no wind, so I don't think it was the wind. Is this a hardware issue? Need new props already possibly?

not sure the cause, but it is a widely reported phenomenon.

Will you upload  us the file from your flight? There might be a hidden terror that we are currently not able to see

Hey William, could you refer the video and export the flight log for analysis? Thanks in advance!