The constant, k, was determined by letting γ = 1.25, e = 0.10, and F = 3.14X105 ft lb/lb for M6, H8,
and T8 propellants and 3.56X105 ft lb/lb for M6 and M2 propellants. k also includes a term to convert
the answer to grams. The constants were found to be k = 2.66X10-4 gm sec2/ft2 lb and 3.01X10-4 gm
sec2/ft2 lb for M6 and M2 propellants respectively.
(c) As an example of how this equation may be refined, assume that a thruster must move a hatch
under an aerodynamic load, Fa, which is a linear function of stroke, as shown in figure 47. The hatch
weighs 100 lbs and has a mass moment of inertia, Iy, about its hinge of 90 in.-lb-sec2. In addition,
the maximum allowable angular acceleration, α, is set at 5 rad/sec2.
Figure 47. Load vs stroke relationship for a thruster.
(d) If a thruster is mounted at an angle of 15from the vertical, the equation of motion may be set up as