Aerojet Tests High-Speed Engine
Series of Tests Validate Engine for New Strike Missile

SACRAMENTO, Calif., Dec. 2, 2004 -- Aerojet, a GenCorp Inc. (NYSE: GY) company, conducted a series of simulated flight condition tests of its high-speed hypersonic engine for the HyFly program. HyFly (Hypersonic Flight) is a high-speed, long-range strike missile demonstrator program.

Tests of the Aerojet engine were conducted in a wind tunnel at speeds of Mach 4, 5 and 6.5. Flying Mach 6.5 is the equivalent of hitting a target 600 miles away in less than 10 minutes.

Aerojet is designing and building the hypersonic engine for Boeing Phantom Works, who will integrate the engines into the HyFly flight test vehicles.

“Aerojet’s demonstration of its uniquely designed hypersonic engine demonstrates the company’s abilities to meet the new needs of the nation’s military,” said Aerojet President Michael Martin. “Our hypersonic engine technology will enable the U.S. military to reach long-range threats in minutes, versus hours with current missiles.” Flight tests are expected to get underway in 2006.

Aerojet is a world-recognized aerospace and defense leader principally serving the missile and space propulsion, and defense and armaments markets. GenCorp is a leading technology-based manufacturer of aerospace and defense products and systems with a real estate business segment that includes activities related to the development, sale and leasing of the Company’s real estate assets. Additional information about Aerojet and GenCorp can be obtained by visiting the Companies’ web sites at http://www.aerojet.com and http://www.GenCorp.com.

Forward-Looking Statements

This press release contains forward-looking statements based on current management expectations. Numerous factors, including those related to market conditions and those detailed from time to time in GenCorp's filings with the Securities and Exchange Commission, may cause results to differ materially from those anticipated in the forward-looking statements. Many of the factors that will determine GenCorp's future results are beyond the ability of GenCorp to control or predict. These statements are subject to risks and uncertainties and, therefore, actual results may differ materially. Readers should not place undue reliance on forward-looking statements, which reflect management's views only as of the date hereof. GenCorp undertakes no obligation to revise or update any forward-looking statements, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise.

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