Recommend the following:
Lost Link / Fly Away:
1. Go back to spot you were at when the drone flew away/lost link
2. Identify landmarks at the your location, and where you last saw the drone w/the direction of flight
3. Add ~10 degrees left and right to that direction and consider that search line/area
4. Estimate flight time left on battery at time of fly away into your potential crash/landing location/distance
Next time:
1) Program a cut switch on your racing drone (throttle hold switch) and if you see it flying away, it may not be too late to cut the throttle with the switch on your controller.
2) To help next time (assumes you find your drone or get another); You can buy and install 1 or both of these items fairly easily:
A) "Discovery Buzzer" (vendor Hobby King: ~$3.20 each) -- if you lose your drone, it enables a loud buzzer sound to help find it (Enables you to flip a switch on the Remote Controller at any time to initiate the buzzer to help find the drone); small light weight device that connects to an open channel on the drone receiver and is programmed to activate via one of the Remote Controller switches.
* Ref links:
https://www.youtube.com/watch?v=EcATaRdRbHU (Youtube: "Discovery Buzzer Connected" shows how to connect this small device to drone)
HobbyKing® Discovery Buzzer (Hobby King)
B) "Signal Lost Alarm & Lost Plane Finder" (vendor Hobby King: $4.70 each) -- If you lose signal to your drone, this small device detects the loss of Transmitter signal and emits a loud buzzer alarm. (enables you to recognize when you have lost link, and to use your controller to help find the drone if lost); small light weight device that connects in-series with one of the 3-wire ports on the Drone Receiver. Alarm initiates when link lost or within ~1 min & 20 sec after the Remote Controller is turned off
* Ref Links:
or
Signal loss Alarm & Lost Plane Finder (Ref Hobby King Link)