TM 1-1520-240-10            7A-8-1 SECTION  VIII.  DRAG 7A-8-1.  Description. The drag chart (fig. 7A-8-1) shows the torque change required for flight due to drag area change as a result of external configuration changes. 7A-8-2.  Use of Chart. The primary use of the chart is illustrated by the example. To  determine  the  change  in  torque,  it  is  necessary  to know the drag area change, TAS, PA, and FAT.  From the table below find the drag area change associated with the configuration, or estimate if necessary.  Enter chart at known drag area change, move right to TAS, move down to PA, move left to FAT, then move down and read change in engine torque. 7A-8-3.  Conditions. The drag chart is based on operating at 100% RRPM. Table 7A–8-1.  Change in Drag Area of Typical External Loads LOAD DRAG AREA CHANGE SQ FT CONTAINERS: (1) 8 FT x 8FT x 20 FT CONEX 150/100(2) ISU-60 62 ISU-90 81 (2) ISU-90 115(2) (2) 500 GAL FUEL CELLS 40 (3) 500 GAL FUEL CELLS 60 (4) 500 GAL FUEL CELLS 80 TRUCKS: (1) HMMWV (ENCLOSED VE- HICLE) 49/28(2) HMMWV (TOW LAUNCHER) 54/31(2) M34 1/2 TON DUMP 100 M35 2 1/2 TON CARGO 80 HOWITZERS: M2A1-105MM 50 M102-105MM 50 M198-105MM 149/50(2) HELICOPTERS: OH-58 HELICOPTER 93(3) UH-60 HELICOPTER 175(3) AH-64 HELICOPTER 170(3) CH-47 HELICOPTER 230(2)(4) (1) RIGGED IN ACCORDANCE WITH FM 10-450 (2) WITH DUAL POINT SUSPEN SION (3) RIGGED IN ACCORDANCE WITH TM-1-1670-260-12&P (UNMARK) (4) RIGGED IN ACCORDANCE WITH TM 1-1520-240-BD DATA BASIS: ESTIMATED/ FLIGHT TEST