First test and prop flew off. Need help

[W.W.]

I build my first quad today and went to test fly it. When I took off everything was fine except for some oscillation. I gave it a quick burst of throttle and one of the props flew off. At first I thought it was a loose nut so I put the prop back on and took off again. I wanted to replicate the result so I could figure out the problem so I gave it a quick burst of throttle and both props across from each other came flying off. After some inspection I realized that as it spun it unscrewed the nut on both motors. I'm wondering in I need counter sunk shaft/screw or if a medium strength loctite will hold in flight but still be able to take it off if a prop breaks.
Thanks, Ivan

 

[holtneil]

Hi Ivan , i think we all had props come off when we start on this hobby , it should not need lock tight , you need to do them up very tight then they should not spin off , if you still want to use lock tight then use blue, but like i said they should not come off if tight enough , i lost one prop the first flight and had not lost one yet and must have 80 flights now , are they nuts or spinners, if nuts you can always put 2 nuts on and lock them together so they cant come off , or use nylock nuts
The oscillation may be the p or i gain to high , if its a fast oscillation its the p gain , if its a slow oscillation its the i gain