Developing fuel with higher heat sink is widely carried out to meet the cooling requirement for an air breathing hypersonic vehicle. Especially, a recooling cycle has been newly proposed for an actively cooled scramjet to reduce the fuel flow for cooling. Fuel heat sink (cooling capacity) is repeatedly used to indirectly increase the fuel heat sink in a recooling cycle. The variation of fuel thermal property related with heat transfer and flow as temperature and pressure is added to the one-dimensional analytical fin-type model for rectangular ducts. Heat transfer performance comparison between recooling cycle and regenerative cooling is carried out, and detailed discussion about the variation and influence of heat transfer and flow characteristics caused by the introduction of the recooling process are discussed. Performance comparison between a recooling cycle at supercritical pressure and it at subcritical condition is also investigated. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.