Directory of U.S. Military Rockets and Missiles
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Atlantic Research PWN-7 Rooster

The PWN-7A Rooster was a variant of the PWN-6 Kitty (Arcas) sounding rocket. Instead of a temperature transmitter, it used a ROBIN (Rocket Balloon Instrument) inflatable falling sphere as its payload. At the apogee of the probe's trajectory, a metalized balloon was released and inflated. While it was slowly descending back to earth, the balloon was tracked by a high-precision radar on the ground. Using the balloon's known mass and volume, the radar track could be used to calculate atmospheric data like wind speed/direction and air density. The latter could then be used to calculate air pressure and temperature.

Photo: via ORDATA Website

Other than the PWN-6 radiosonde-equipped Arcas, the PWN-7A Arcas-ROBIN required a high-precision radar to get air temperature data. However, its altitude and temperature measurement ranges were somewhat greater than that of the PWN-6's instrument. The PWN-7A was replaced in the 1970s by the PWN-12A, the ROBIN variant of the Super Loki-Dart sounding rocket family.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for PWN-7A:

Length2.07 m (6 ft 9.5 in)
Diameter11.4 cm (4.5 in)
Finspan33 cm (13 in)
Weight41 kg (90 lb)
Speed> 3950 km/h (2455 mph)
Ceiling65 km (40 miles; 210000 ft)
PropulsionAtlantic Research SR45-AR-1 solid-fuel rocket; 1490 kN (336 lb) for 29 s

Main Sources

[1] Richard B. Morrow, Mitchell S. Pines: "Small Sounding Rockets", Small Rocket Press, 2000
[2] Peter Alway: "Rockets of the World", Saturn Press, 1999
[3] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
[4] "Model Designation of Military Aircraft, Rockets and Guided Missiles", Department of Defense, 1970
[5] ORDATA Online Website

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Last Updated: 22 December 2005