Editor's note: The CH (initials for 'rainbow' in Chinese) series of drones have gained international fame for their performance in anti-terrorism warfare in the Middle East and Africa, as well as their highly efficient civil missions such as geological exploration and maritime surveillance.

They are developed by the China Academy of Aerospace Aerodynamics (CAAA), affiliated to the NASA-like China Aerospace Science and Technology Corporation (CASC). The drones are, in essence, aerial platforms whose missions – military or civilian – depend on the payload.

The CH-4 is among the most sophisticated and popular drones in the international market. In mid-June, several CH-4 vehicles underwent test flights at an undisclosed airport in northwest China. Before the flights, the crew members posed for photos in front of the drones.

A CH-4 drone takes off during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 drone takes off during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 drone taxis preparatory to a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 drone makes a sharp turn after take-off during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 drone prepares to land during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 drone is removed from the runway after finishing a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

Three CH-4 drones park side-by-side for all-round examination before a scheduled test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 drone parks on the apron of an undisclosed airport in northwest China ready for a scheduled test flight in mid-June. [Photo by Chen Boyuan / China.org.cn]

Three CH-4 drones park side-by-side on the apron of an undisclosed airport in northwest China for a scheduled test flight in mid-June. [Photo by Chen Boyuan / China.org.cn]

Three CH-4 drones park side-by-side on the apron of an undisclosed airport in northwest China for a scheduled test flight in mid-June. [Photo by Chen Boyuan / China.org.cn]

A protective cover with a 'remove before flight' notice is placed on the pitot tube of a CH-4 drone parking on the apron of an undisclosed airport in northwest China for a scheduled test flight in mid-June. [Photo by Chen Boyuan / China.org.cn]

Crew members control a CH-4 drone from a modular extendable rigid wall shelter (MERWS) during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

Crew members control a CH-4 drone from a modular extendable rigid wall shelter (MERWS) during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

Crew members control a CH-4 drone from a modular extendable rigid wall shelter (MERWS) during a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

The photo shows a label attached to the uniform of a CH staff member that reads “China Space Special Aerial Vehicle Test Center.” The crew members of CH-4 drone conduct a test flight for a CH-4 type in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

Crew members of CH-4 drone pose for photos before the drones prior to a scheduled test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

The satellite dish for remote communication and data link is unfolded near the apron of an undisclosed airport in northwest China as several CH-4 drones undergo test flights in mid-June. [Photo by Chen Boyuan / China.org.cn]

Crew members of CH-4 drone pose for photos before the drones prior to a scheduled test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

Crew members of CH-4 drone pose for photos before the drones prior to a scheduled test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

Crew members of CH-4 drone pose for photos before the drones prior to a scheduled test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

A CH-4 crew member examines part of the drone's front undercarriage before a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]

CH-4 crew members examine the drone's engine before a test flight in mid-June at an undisclosed airport in northwest China. [Photo by Chen Boyuan / China.org.cn]