Ground Pattern Performance of the
SEI Industries Bambi 324—Gallon Helibucket

To select the proper helicopter speed, use Table 1 to determine the coverage level required by the NFDRS or Fire Behavior Fuel Model. The coverage levels in Table 1 represent the coverage level required for an average fire intensity for each fuel model. The required coverage level can be adjusted up or down depending on the actual fire intensity. Once the required coverage level is determined, the airspeed can be found. Use the graph for the material dropped (water, foam, or gum-thickened retardant) to find the speed that produces the longest line for the desired coverage level. The same information can be found in the appropriate drop table.

For example if a fire is burning in NFDRS Fuel Model F (Fire Behavior Model 5), represented by intermediate brush (green), Table 1 shows that a coverage level of 3 is required. The graph for water shows that for coverage level 3, a speed of about 64 knots produces the longest line. The ground drop characteristics for the Bambi 324-gallon helibucket were derived through controlled test drop procedures on flat ground (Figure 8). This information is to serve only as a guide in assisting field personnel to determine the proper drop height and airspeed for delivering water, foam, or gum-thickened retardant. Actual coverage may vary depending on terrain, wind, weather, and pilot proficiency.

Figure 8—Drop test of the Bambi 324-gallon helibucket.