Method and apparatus for artificial distribution of insects or spray

A method of setting up an air velocity gradient, the method comprising:

• flying an aircraft in excess of stall speed and ambient air, the aircraft having a diffuser mounted thereon, the diffuser being for distributing insects from an aircraft, the diffuser being mountable on the aircraft, the diffuser comprising:
• at least one distribution tube for connection to a source at a first end and open to an outside of the distribution tube at a second end for distribution of the insects;
• a nozzle surrounding the second end, the nozzle narrowing towards a throat and widening downstream of said throat and being configured to allow part of a flight airstream to enter the diffuser and decrease in velocity downstream of said throat;
• and a tube cover surrounding the second end within the nozzle, the tube cover having an open aerofoil-shaped cross section, the tube cover and the second end both being located downstream of said throat, the diffuser thereby shielding the insects being distributed, the diffuser thereby forming an air transition volume, the air transition volume comprising a first transition volume part immediately behind an opening of said distribution tube, at a location shielded by said tube cover and surrounded by said nozzle;
• setting up the air transition volume using the diffuser, the air transition volume being between the aircraft flying in excess of an aircraft stall speed and in excess of 110 km/h, and the ambient air, the air transition volume being set up by the diffuser to comprise:
• the first transition volume part immediately behind the opening of said distribution tube of the diffuser, at a location shielded by said tube cover and surrounded by said nozzle, the first transition volume part defined by an airspeed of air exiting the opening at a velocity of at least 1 m/s less than a speed of the aircraft;
• successive further transition volume parts receding from the first transition volume part rearwardly of the diffuser, said further transition volume parts eventually merging into the ambient air, the transition volume being characterized by a maximum wind shear over any cubic centimeter volume within the air transition volume being less than 60 km/h.