The Estes Cold Power model rocket line was an innovative but short-lived series of model rockets produced by Estes Industries, a leading manufacturer of model rocket kits. Unlike traditional model rockets that use solid propellant engines, Cold Power rockets were designed to use pressurized gas (specifically, freon or a similar refrigerant) to provide propulsion. Here are some key details about the Estes Cold Power model rocket line:

The Cold Power rockets used a unique propulsion system that relied on the rapid expansion of pressurized gas to produce thrust. The gas, stored in a liquid state, was released into a nozzle where it rapidly expanded and propelled the rocket.

Freon (a type of refrigerant gas) was commonly used as the propellant. When the liquid freon was released, it would vaporize quickly, creating thrust.

One of the main advantages touted by Estes for the Cold Power rockets was their safety. Because they did not use solid propellants or any form of combustion, they were considered safer to handle and launch, especially for young hobbyists. The propulsion system was reusable, as the pressurized gas containers could be refilled or replaced.

Estes introduced the Cold Power line during the late 1960s and early 1970s. The concept was innovative at the time, offering an alternative to the traditional solid-propellant rockets that dominated the market.

The concept is described in US patent 3,650,214, Toy Rocket and Gas Propellant System, filed by Charles J. Green on January 21, 1969 and granted on March 21, 1972 and assigned to Vashon Industries, Inc, (Charles Green lived on Vashon Island, Washington).

Despite the potential advantages, the Cold Power rockets did not achieve the same level of popularity as traditional Estes rockets. Several factors contributed to this, including the limited performance capabilities of the gas propulsion system compared to solid propellant engines.

Additionally, the use of freon became increasingly scrutinized due to environmental concerns. Freon and other similar refrigerants were found to contribute to ozone depletion, leading to regulatory restrictions and reduced availability.