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2.2 INSTRUMENTATION

The instrumentation for this project falls into two general classes:
rocket-borne and aircraft-borne cloud samplers,

Two types of aircraft,

B-57D's and WB-50's, were used,
2.2.1

Rocket-Borne Cloud Sampler.

The rocket, a 20 foot long unit,

consisted of an air-sampling nose section, a two-stage propulsion unit and

various items of auxiliary equipment {Reference 57).
The air-sampling diffuser of the nose section was. 36 inches long from
the intake orifice to the filter,

An additional 32 inches of length behind the

filter was occupied by exhaust ports and auxiliary equipment.

The extreme

forward part of the rocket was a conical section 5 inches long which sealed
the intake orifice prior to the time when sampling was begun,

The orifice of

the diffuser was 2 inches in diameter and the filter was 8-1/2 inches in diameter.

An expansion from 2 inches to 8-1/2 inches in diameter in a length

of 36 inches gave an expansion angle of 10 degrees, the maximum at- which
the flow would not separate from the diffuser walls,

The filter was an 8 inch

circle of matted cellulose fiber coated with stearic acid to help retain the
particles.

It was supported by a wire retaining screen,

The inside wall of

the diffuser was in the form of a revolved segment of a circle 250 inches in
radius and was parallel to the axis of the rocket at the orifice.

Particles

entering the sampling section were decelerated from about twice the sonic

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