Here's some tips to keep your drones:
1) reduce power before you make a turn...I usually cut it back about 10% ...this gives them a performance edge
2) Dont turn too tightly.....I will start turning ...then hit the F3 view to make sure they are staying with me...while I contune to turn...I will go back and forth between cockpit and F3 view .....once your turn is finished...level out... ...wait about 30 - 40 seconds to allow your drones to settle into formation....then go back to full power
using these methods i have never lost a drone
Good Luck
Helm