Table XlV. Coefficients for Form Function (Sewn-Perforated Propellant)

e. Equation (37) governs the production of propellant gas in a multiperforated propellant before the web has burned

through; equation (38) governs the production of the gas after the web has burned through. With propellant grains in

which there is no perforation or only one perforation, equation (38) is not needed because a zero web fraction

corresponds to the complete consumption of the propellant. These equations are close approximations of the true

geometrical form functions, and the coefficients are defined in terms of propellant dimensions.

f. The coefficients for the geometric form functions of single-perforated grains are:

Where:

w = propellant web

D = diameter of grain

d = diameter of perforation

L = propellant grain length

g. Coefficients for form functions of seven-perforated grains are presented in table XIV.

Table XlV. Coefficients for Form Function (Sewn-Perforated Propellant)

D/d

Coef

L/d

1.5

2.0

2.5

3.0

3.5

Ke..................

0.8490

0.8362

0.8335

0.8316

0.8303

8 K1..................

0.9111

0.9300

0.9414

0.9490

0.9544

K2..................

0.0702

0.0938

0.1079

0.1174

0.1241

Ke..................

0.8563

0.8516

0.8487

0.8468

0.8455

10 K1..................

0.9447

0.9673

0.9808

0.9898

0.9963

K2..................

0.0884

0.1157

0.1321

0.1430

0.1508

Ke..................

0.8652

0.8603

0.8574

0.8554

0.8541

12 K1..................

0.9673

0.9923

1.0073

1.0173

1.0245

K2..................

0.1021

0.1320

0.1499

0.1619

0.1785

(1) Equations of definition of volume.

V1=V0 + A1s

(39)

before telescoping tube stop

V2 = V0 + (A1 - A2) S1 + A2S

after telescoping tube stop

(40)

Where:

V1 = volume during telescoping tube stroke

V0 = initial free volume

A1 = piston area during telescoping tube stroke

V2 = volume during inner tube stroke

A2 = piston area during inner tube stroke

S1 = telescoping tube stroke

s = length of stroke at time t