The prop used is a slow fly electric Prop 9047R (R stands for right rotation) and 9047.
diameter: 9 Inches ( 229 mm)
pitch: 4.7 inches (119 mm)
The Thrust is =kp * P * D^3 * RPM^2
where kp is a constant related to the model of the prop.
At 8000 RPM this type of prop can generate a Thrust of around 600g. Here where you can find a calculator . That’s mean that theorically those 4 props can generate a thrust of 2.4 kg