Mick remarked that it is on his mind not very realistic the PBY droping red fire retardant. (Borate)
When I did configure the water drop effects I based myself on french documents of the Protection Civile who did use the Catalina as firebomber in their early times.
But as it is quite possible that Mick is right I changed a bit the entry.
In the aircraft.cfg for the waterdrop effects.
Please find the fix for that in this zip.
Yours,
Michael "Papi" Vader