of the preliminary design of propellant actuated devices.

Methods of approximating parameters not generally

given in design requirements are presented. Materials,

safety factors, and methods of calculating wall strengths

and selecting tube sizes to be used in propellant

actuated devices are discussed.

The design of

individual components of the devices is described, and

the use of protective finishes and dissimilar metals is

outlined.

point in the design of propellant actuated devices is the

requirements which list in detail the size, weight,

above).

strength, and performance of the device. A typical list

of design requirements includes the following.

or damper requirements.

catapults, removers, and occasionally thrusters specify

in design requirements. The design requirements may

specify acceleration, rate of change of acceleration, and

velocity, but, not the stroke necessary to satisfy these

maximum rate of change of acceleration, *a* The

.

requirements. Stroke and velocity but not acceleration

stroke, *S*, of such devices can be estimated by using the

may be specified for thrusters.

The envelope

following equation, the derivation of which is contained

specifications may give exterior dimensions but not the

in chapter 5.

internal volume and expansion ratio nor the propellant

charge and cartridge size. The unspecified parameters

must be determined by the designer in conjunction with

the ballistician. Methods of approximating stroke, stroke

performance characteristics when fired at 70 .:

F

time, working pressures, and propellant charges are

presented here. The last parameter is treated in greater

detail in chapter 5.

† The quantities used here are the actual quantities measured during the development of the M5 Catapult. They are used in

these equations to illustrate the usability of the equations. The acceleration and rate of change of acceleration are usually given as

specified maxima. The values of these two quantities to be used in these equations for preliminary design are chosen by the designer

from experience. Chapter 6 gives step-by-step use of the equations for some examples.

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