Hybrid Engines

A hybrid jet engine would be nice, as it would allow smaller SSTOs to be possible. Bacically it would be a power cycle for the jet engines, it would be heavier and more expensive then a normal jet engines, and the closed cycle mode would have similar stats to the mage engines. The hybrid engine would be fueled by jet fuel in open cycle mode and jet fuel + oxodizer in closed cycle. The oxodizer could be stored in a separate tank from the jet fuel.