A density independent anemometer for use at altitudes between 20 and 50 km has been developed and successfully operated on an air sampling research balloon flight. Its operation is based on the pulsed generation of ions within the air stream and their subsequent detection at a measured distance. Closed loop retriggering of the electric discharge results in a pulse train whose frequency varies directly with the air velocity. Semiconductor circuitry is used throughout, including an automatic discharge restarting circuit. Designed for monitoring velocities between 5 and 50 m/sec, the instrument range can be conveniently extended in both directions by suitable repositioning of the anemometer probes.

1.
Physical Measurements in Gas Dynamics and Combustion, R. W. Ladenburg, B. Lewis, R. N. Pease, and H. S. Taylor, Ed., (Princeton University Press, Princeton, N.J., 1954), Vol. IX, p. 139 ff.
2.
Velocity Measuring by use of High Energy Electrons, U.S. Patent No. 2 637 208, Glenn L. Mellen, 5 May, 1953.
3.
W. C.
Cooley
and
H. G.
Stever
,
Rev. Sci. Instr.
23
,
151
(
1952
).
4.
J. D. Cobine, Gaseous Conductors (Dover Publications, Inc., New York, 1958), p. 163 ff.
5.
W. T.
Starr
,
Electro‐Technol.
,
69
,
128
(
1962
).
6.
Ref. 4, p. 96 ff.
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